1c33e97efSMauro Carvalho Chehab.. SPDX-License-Identifier: GPL-2.0 2c33e97efSMauro Carvalho Chehab 3c33e97efSMauro Carvalho Chehab==================== 4c33e97efSMauro Carvalho ChehabThe /proc Filesystem 5c33e97efSMauro Carvalho Chehab==================== 6c33e97efSMauro Carvalho Chehab 7c33e97efSMauro Carvalho Chehab===================== ======================================= ================ 8c33e97efSMauro Carvalho Chehab/proc/sys Terrehon Bowden <terrehon@pacbell.net>, October 7 1999 9c33e97efSMauro Carvalho Chehab Bodo Bauer <bb@ricochet.net> 10c33e97efSMauro Carvalho Chehab2.4.x update Jorge Nerin <comandante@zaralinux.com> November 14 2000 11c33e97efSMauro Carvalho Chehabmove /proc/sys Shen Feng <shen@cn.fujitsu.com> April 1 2009 12c33e97efSMauro Carvalho Chehabfixes/update part 1.1 Stefani Seibold <stefani@seibold.net> June 9 2009 13c33e97efSMauro Carvalho Chehab===================== ======================================= ================ 14c33e97efSMauro Carvalho Chehab 15c33e97efSMauro Carvalho Chehab 16c33e97efSMauro Carvalho Chehab 17c33e97efSMauro Carvalho Chehab.. Table of Contents 18c33e97efSMauro Carvalho Chehab 19c33e97efSMauro Carvalho Chehab 0 Preface 20c33e97efSMauro Carvalho Chehab 0.1 Introduction/Credits 21c33e97efSMauro Carvalho Chehab 0.2 Legal Stuff 22c33e97efSMauro Carvalho Chehab 23c33e97efSMauro Carvalho Chehab 1 Collecting System Information 24c33e97efSMauro Carvalho Chehab 1.1 Process-Specific Subdirectories 25c33e97efSMauro Carvalho Chehab 1.2 Kernel data 26c33e97efSMauro Carvalho Chehab 1.3 IDE devices in /proc/ide 27c33e97efSMauro Carvalho Chehab 1.4 Networking info in /proc/net 28c33e97efSMauro Carvalho Chehab 1.5 SCSI info 29c33e97efSMauro Carvalho Chehab 1.6 Parallel port info in /proc/parport 30c33e97efSMauro Carvalho Chehab 1.7 TTY info in /proc/tty 31c33e97efSMauro Carvalho Chehab 1.8 Miscellaneous kernel statistics in /proc/stat 32c33e97efSMauro Carvalho Chehab 1.9 Ext4 file system parameters 33c33e97efSMauro Carvalho Chehab 34c33e97efSMauro Carvalho Chehab 2 Modifying System Parameters 35c33e97efSMauro Carvalho Chehab 36c33e97efSMauro Carvalho Chehab 3 Per-Process Parameters 37c33e97efSMauro Carvalho Chehab 3.1 /proc/<pid>/oom_adj & /proc/<pid>/oom_score_adj - Adjust the oom-killer 38c33e97efSMauro Carvalho Chehab score 39c33e97efSMauro Carvalho Chehab 3.2 /proc/<pid>/oom_score - Display current oom-killer score 40c33e97efSMauro Carvalho Chehab 3.3 /proc/<pid>/io - Display the IO accounting fields 41c33e97efSMauro Carvalho Chehab 3.4 /proc/<pid>/coredump_filter - Core dump filtering settings 42c33e97efSMauro Carvalho Chehab 3.5 /proc/<pid>/mountinfo - Information about mounts 43c33e97efSMauro Carvalho Chehab 3.6 /proc/<pid>/comm & /proc/<pid>/task/<tid>/comm 44c33e97efSMauro Carvalho Chehab 3.7 /proc/<pid>/task/<tid>/children - Information about task children 45c33e97efSMauro Carvalho Chehab 3.8 /proc/<pid>/fdinfo/<fd> - Information about opened file 46c33e97efSMauro Carvalho Chehab 3.9 /proc/<pid>/map_files - Information about memory mapped files 47c33e97efSMauro Carvalho Chehab 3.10 /proc/<pid>/timerslack_ns - Task timerslack value 48c33e97efSMauro Carvalho Chehab 3.11 /proc/<pid>/patch_state - Livepatch patch operation state 49c33e97efSMauro Carvalho Chehab 3.12 /proc/<pid>/arch_status - Task architecture specific information 50f1f1f256SIvan Babrou 3.13 /proc/<pid>/fd - List of symlinks to open files 51c33e97efSMauro Carvalho Chehab 52c33e97efSMauro Carvalho Chehab 4 Configuring procfs 53c33e97efSMauro Carvalho Chehab 4.1 Mount options 54c33e97efSMauro Carvalho Chehab 5537e7647aSAlexey Gladkov 5 Filesystem behavior 5637e7647aSAlexey Gladkov 57c33e97efSMauro Carvalho ChehabPreface 58c33e97efSMauro Carvalho Chehab======= 59c33e97efSMauro Carvalho Chehab 60c33e97efSMauro Carvalho Chehab0.1 Introduction/Credits 61c33e97efSMauro Carvalho Chehab------------------------ 62c33e97efSMauro Carvalho Chehab 63c33e97efSMauro Carvalho ChehabThis documentation is part of a soon (or so we hope) to be released book on 64c33e97efSMauro Carvalho Chehabthe SuSE Linux distribution. As there is no complete documentation for the 65c33e97efSMauro Carvalho Chehab/proc file system and we've used many freely available sources to write these 66c33e97efSMauro Carvalho Chehabchapters, it seems only fair to give the work back to the Linux community. 67c33e97efSMauro Carvalho ChehabThis work is based on the 2.2.* kernel version and the upcoming 2.4.*. I'm 68c33e97efSMauro Carvalho Chehabafraid it's still far from complete, but we hope it will be useful. As far as 69c33e97efSMauro Carvalho Chehabwe know, it is the first 'all-in-one' document about the /proc file system. It 70c33e97efSMauro Carvalho Chehabis focused on the Intel x86 hardware, so if you are looking for PPC, ARM, 71c33e97efSMauro Carvalho ChehabSPARC, AXP, etc., features, you probably won't find what you are looking for. 72c33e97efSMauro Carvalho ChehabIt also only covers IPv4 networking, not IPv6 nor other protocols - sorry. But 73c33e97efSMauro Carvalho Chehabadditions and patches are welcome and will be added to this document if you 74c33e97efSMauro Carvalho Chehabmail them to Bodo. 75c33e97efSMauro Carvalho Chehab 76c33e97efSMauro Carvalho ChehabWe'd like to thank Alan Cox, Rik van Riel, and Alexey Kuznetsov and a lot of 77c33e97efSMauro Carvalho Chehabother people for help compiling this documentation. We'd also like to extend a 78c33e97efSMauro Carvalho Chehabspecial thank you to Andi Kleen for documentation, which we relied on heavily 79c33e97efSMauro Carvalho Chehabto create this document, as well as the additional information he provided. 80c33e97efSMauro Carvalho ChehabThanks to everybody else who contributed source or docs to the Linux kernel 81c33e97efSMauro Carvalho Chehaband helped create a great piece of software... :) 82c33e97efSMauro Carvalho Chehab 83c33e97efSMauro Carvalho ChehabIf you have any comments, corrections or additions, please don't hesitate to 84c33e97efSMauro Carvalho Chehabcontact Bodo Bauer at bb@ricochet.net. We'll be happy to add them to this 85c33e97efSMauro Carvalho Chehabdocument. 86c33e97efSMauro Carvalho Chehab 87c33e97efSMauro Carvalho ChehabThe latest version of this document is available online at 88d2ea66a6SRandy Dunlaphttps://www.kernel.org/doc/html/latest/filesystems/proc.html 89c33e97efSMauro Carvalho Chehab 90c33e97efSMauro Carvalho ChehabIf the above direction does not works for you, you could try the kernel 91c33e97efSMauro Carvalho Chehabmailing list at linux-kernel@vger.kernel.org and/or try to reach me at 92c33e97efSMauro Carvalho Chehabcomandante@zaralinux.com. 93c33e97efSMauro Carvalho Chehab 94c33e97efSMauro Carvalho Chehab0.2 Legal Stuff 95c33e97efSMauro Carvalho Chehab--------------- 96c33e97efSMauro Carvalho Chehab 97c33e97efSMauro Carvalho ChehabWe don't guarantee the correctness of this document, and if you come to us 98c33e97efSMauro Carvalho Chehabcomplaining about how you screwed up your system because of incorrect 99c33e97efSMauro Carvalho Chehabdocumentation, we won't feel responsible... 100c33e97efSMauro Carvalho Chehab 101c33e97efSMauro Carvalho ChehabChapter 1: Collecting System Information 102c33e97efSMauro Carvalho Chehab======================================== 103c33e97efSMauro Carvalho Chehab 104c33e97efSMauro Carvalho ChehabIn This Chapter 105c33e97efSMauro Carvalho Chehab--------------- 106c33e97efSMauro Carvalho Chehab* Investigating the properties of the pseudo file system /proc and its 107c33e97efSMauro Carvalho Chehab ability to provide information on the running Linux system 108c33e97efSMauro Carvalho Chehab* Examining /proc's structure 109c33e97efSMauro Carvalho Chehab* Uncovering various information about the kernel and the processes running 110c33e97efSMauro Carvalho Chehab on the system 111c33e97efSMauro Carvalho Chehab 112c33e97efSMauro Carvalho Chehab------------------------------------------------------------------------------ 113c33e97efSMauro Carvalho Chehab 114c33e97efSMauro Carvalho ChehabThe proc file system acts as an interface to internal data structures in the 115c33e97efSMauro Carvalho Chehabkernel. It can be used to obtain information about the system and to change 116c33e97efSMauro Carvalho Chehabcertain kernel parameters at runtime (sysctl). 117c33e97efSMauro Carvalho Chehab 118c33e97efSMauro Carvalho ChehabFirst, we'll take a look at the read-only parts of /proc. In Chapter 2, we 119c33e97efSMauro Carvalho Chehabshow you how you can use /proc/sys to change settings. 120c33e97efSMauro Carvalho Chehab 121c33e97efSMauro Carvalho Chehab1.1 Process-Specific Subdirectories 122c33e97efSMauro Carvalho Chehab----------------------------------- 123c33e97efSMauro Carvalho Chehab 124c33e97efSMauro Carvalho ChehabThe directory /proc contains (among other things) one subdirectory for each 125c33e97efSMauro Carvalho Chehabprocess running on the system, which is named after the process ID (PID). 126c33e97efSMauro Carvalho Chehab 127059db434SRandy DunlapThe link 'self' points to the process reading the file system. Each process 128c33e97efSMauro Carvalho Chehabsubdirectory has the entries listed in Table 1-1. 129c33e97efSMauro Carvalho Chehab 130059db434SRandy DunlapNote that an open file descriptor to /proc/<pid> or to any of its 131c33e97efSMauro Carvalho Chehabcontained files or subdirectories does not prevent <pid> being reused 132c33e97efSMauro Carvalho Chehabfor some other process in the event that <pid> exits. Operations on 133c33e97efSMauro Carvalho Chehabopen /proc/<pid> file descriptors corresponding to dead processes 134c33e97efSMauro Carvalho Chehabnever act on any new process that the kernel may, through chance, have 135c33e97efSMauro Carvalho Chehabalso assigned the process ID <pid>. Instead, operations on these FDs 136c33e97efSMauro Carvalho Chehabusually fail with ESRCH. 137c33e97efSMauro Carvalho Chehab 138c33e97efSMauro Carvalho Chehab.. table:: Table 1-1: Process specific entries in /proc 139c33e97efSMauro Carvalho Chehab 140c33e97efSMauro Carvalho Chehab ============= =============================================================== 141c33e97efSMauro Carvalho Chehab File Content 142c33e97efSMauro Carvalho Chehab ============= =============================================================== 143c33e97efSMauro Carvalho Chehab clear_refs Clears page referenced bits shown in smaps output 144c33e97efSMauro Carvalho Chehab cmdline Command line arguments 145c33e97efSMauro Carvalho Chehab cpu Current and last cpu in which it was executed (2.4)(smp) 146c33e97efSMauro Carvalho Chehab cwd Link to the current working directory 147c33e97efSMauro Carvalho Chehab environ Values of environment variables 148c33e97efSMauro Carvalho Chehab exe Link to the executable of this process 149c33e97efSMauro Carvalho Chehab fd Directory, which contains all file descriptors 150c33e97efSMauro Carvalho Chehab maps Memory maps to executables and library files (2.4) 151c33e97efSMauro Carvalho Chehab mem Memory held by this process 152c33e97efSMauro Carvalho Chehab root Link to the root directory of this process 153c33e97efSMauro Carvalho Chehab stat Process status 154c33e97efSMauro Carvalho Chehab statm Process memory status information 155c33e97efSMauro Carvalho Chehab status Process status in human readable form 156c33e97efSMauro Carvalho Chehab wchan Present with CONFIG_KALLSYMS=y: it shows the kernel function 157c33e97efSMauro Carvalho Chehab symbol the task is blocked in - or "0" if not blocked. 158c33e97efSMauro Carvalho Chehab pagemap Page table 159c33e97efSMauro Carvalho Chehab stack Report full stack trace, enable via CONFIG_STACKTRACE 160c33e97efSMauro Carvalho Chehab smaps An extension based on maps, showing the memory consumption of 161c33e97efSMauro Carvalho Chehab each mapping and flags associated with it 162c33e97efSMauro Carvalho Chehab smaps_rollup Accumulated smaps stats for all mappings of the process. This 163c33e97efSMauro Carvalho Chehab can be derived from smaps, but is faster and more convenient 164c33e97efSMauro Carvalho Chehab numa_maps An extension based on maps, showing the memory locality and 165c33e97efSMauro Carvalho Chehab binding policy as well as mem usage (in pages) of each mapping. 166c33e97efSMauro Carvalho Chehab ============= =============================================================== 167c33e97efSMauro Carvalho Chehab 168c33e97efSMauro Carvalho ChehabFor example, to get the status information of a process, all you have to do is 169c33e97efSMauro Carvalho Chehabread the file /proc/PID/status:: 170c33e97efSMauro Carvalho Chehab 171c33e97efSMauro Carvalho Chehab >cat /proc/self/status 172c33e97efSMauro Carvalho Chehab Name: cat 173c33e97efSMauro Carvalho Chehab State: R (running) 174c33e97efSMauro Carvalho Chehab Tgid: 5452 175c33e97efSMauro Carvalho Chehab Pid: 5452 176c33e97efSMauro Carvalho Chehab PPid: 743 177c33e97efSMauro Carvalho Chehab TracerPid: 0 (2.4) 178c33e97efSMauro Carvalho Chehab Uid: 501 501 501 501 179c33e97efSMauro Carvalho Chehab Gid: 100 100 100 100 180c33e97efSMauro Carvalho Chehab FDSize: 256 181c33e97efSMauro Carvalho Chehab Groups: 100 14 16 182522dc4e5SChunguang Wu Kthread: 0 183c33e97efSMauro Carvalho Chehab VmPeak: 5004 kB 184c33e97efSMauro Carvalho Chehab VmSize: 5004 kB 185c33e97efSMauro Carvalho Chehab VmLck: 0 kB 186c33e97efSMauro Carvalho Chehab VmHWM: 476 kB 187c33e97efSMauro Carvalho Chehab VmRSS: 476 kB 188c33e97efSMauro Carvalho Chehab RssAnon: 352 kB 189c33e97efSMauro Carvalho Chehab RssFile: 120 kB 190c33e97efSMauro Carvalho Chehab RssShmem: 4 kB 191c33e97efSMauro Carvalho Chehab VmData: 156 kB 192c33e97efSMauro Carvalho Chehab VmStk: 88 kB 193c33e97efSMauro Carvalho Chehab VmExe: 68 kB 194c33e97efSMauro Carvalho Chehab VmLib: 1412 kB 195c33e97efSMauro Carvalho Chehab VmPTE: 20 kb 196c33e97efSMauro Carvalho Chehab VmSwap: 0 kB 197c33e97efSMauro Carvalho Chehab HugetlbPages: 0 kB 198c33e97efSMauro Carvalho Chehab CoreDumping: 0 199c33e97efSMauro Carvalho Chehab THP_enabled: 1 200c33e97efSMauro Carvalho Chehab Threads: 1 201c33e97efSMauro Carvalho Chehab SigQ: 0/28578 202c33e97efSMauro Carvalho Chehab SigPnd: 0000000000000000 203c33e97efSMauro Carvalho Chehab ShdPnd: 0000000000000000 204c33e97efSMauro Carvalho Chehab SigBlk: 0000000000000000 205c33e97efSMauro Carvalho Chehab SigIgn: 0000000000000000 206c33e97efSMauro Carvalho Chehab SigCgt: 0000000000000000 207c33e97efSMauro Carvalho Chehab CapInh: 00000000fffffeff 208c33e97efSMauro Carvalho Chehab CapPrm: 0000000000000000 209c33e97efSMauro Carvalho Chehab CapEff: 0000000000000000 210c33e97efSMauro Carvalho Chehab CapBnd: ffffffffffffffff 211c33e97efSMauro Carvalho Chehab CapAmb: 0000000000000000 212c33e97efSMauro Carvalho Chehab NoNewPrivs: 0 213c33e97efSMauro Carvalho Chehab Seccomp: 0 214c33e97efSMauro Carvalho Chehab Speculation_Store_Bypass: thread vulnerable 215fe719888SAnand K Mistry SpeculationIndirectBranch: conditional enabled 216c33e97efSMauro Carvalho Chehab voluntary_ctxt_switches: 0 217c33e97efSMauro Carvalho Chehab nonvoluntary_ctxt_switches: 1 218c33e97efSMauro Carvalho Chehab 219c33e97efSMauro Carvalho ChehabThis shows you nearly the same information you would get if you viewed it with 220c33e97efSMauro Carvalho Chehabthe ps command. In fact, ps uses the proc file system to obtain its 221c33e97efSMauro Carvalho Chehabinformation. But you get a more detailed view of the process by reading the 222c33e97efSMauro Carvalho Chehabfile /proc/PID/status. It fields are described in table 1-2. 223c33e97efSMauro Carvalho Chehab 224c33e97efSMauro Carvalho ChehabThe statm file contains more detailed information about the process 225c33e97efSMauro Carvalho Chehabmemory usage. Its seven fields are explained in Table 1-3. The stat file 226059db434SRandy Dunlapcontains detailed information about the process itself. Its fields are 227c33e97efSMauro Carvalho Chehabexplained in Table 1-4. 228c33e97efSMauro Carvalho Chehab 229c33e97efSMauro Carvalho Chehab(for SMP CONFIG users) 230c33e97efSMauro Carvalho Chehab 231c33e97efSMauro Carvalho ChehabFor making accounting scalable, RSS related information are handled in an 232c33e97efSMauro Carvalho Chehabasynchronous manner and the value may not be very precise. To see a precise 233c33e97efSMauro Carvalho Chehabsnapshot of a moment, you can see /proc/<pid>/smaps file and scan page table. 234c33e97efSMauro Carvalho ChehabIt's slow but very precise. 235c33e97efSMauro Carvalho Chehab 236d2ea66a6SRandy Dunlap.. table:: Table 1-2: Contents of the status fields (as of 4.19) 237c33e97efSMauro Carvalho Chehab 238c33e97efSMauro Carvalho Chehab ========================== =================================================== 239c33e97efSMauro Carvalho Chehab Field Content 240c33e97efSMauro Carvalho Chehab ========================== =================================================== 241c33e97efSMauro Carvalho Chehab Name filename of the executable 242c33e97efSMauro Carvalho Chehab Umask file mode creation mask 243c33e97efSMauro Carvalho Chehab State state (R is running, S is sleeping, D is sleeping 244c33e97efSMauro Carvalho Chehab in an uninterruptible wait, Z is zombie, 245c33e97efSMauro Carvalho Chehab T is traced or stopped) 246c33e97efSMauro Carvalho Chehab Tgid thread group ID 247c33e97efSMauro Carvalho Chehab Ngid NUMA group ID (0 if none) 248c33e97efSMauro Carvalho Chehab Pid process id 249c33e97efSMauro Carvalho Chehab PPid process id of the parent process 250df61e945SChen Linxuan TracerPid PID of process tracing this process (0 if not, or 251df61e945SChen Linxuan the tracer is outside of the current pid namespace) 252c33e97efSMauro Carvalho Chehab Uid Real, effective, saved set, and file system UIDs 253c33e97efSMauro Carvalho Chehab Gid Real, effective, saved set, and file system GIDs 254c33e97efSMauro Carvalho Chehab FDSize number of file descriptor slots currently allocated 255c33e97efSMauro Carvalho Chehab Groups supplementary group list 256c33e97efSMauro Carvalho Chehab NStgid descendant namespace thread group ID hierarchy 257c33e97efSMauro Carvalho Chehab NSpid descendant namespace process ID hierarchy 258c33e97efSMauro Carvalho Chehab NSpgid descendant namespace process group ID hierarchy 259c33e97efSMauro Carvalho Chehab NSsid descendant namespace session ID hierarchy 260522dc4e5SChunguang Wu Kthread kernel thread flag, 1 is yes, 0 is no 261c33e97efSMauro Carvalho Chehab VmPeak peak virtual memory size 262c33e97efSMauro Carvalho Chehab VmSize total program size 263c33e97efSMauro Carvalho Chehab VmLck locked memory size 264c33e97efSMauro Carvalho Chehab VmPin pinned memory size 265c33e97efSMauro Carvalho Chehab VmHWM peak resident set size ("high water mark") 266c33e97efSMauro Carvalho Chehab VmRSS size of memory portions. It contains the three 267c33e97efSMauro Carvalho Chehab following parts 268c33e97efSMauro Carvalho Chehab (VmRSS = RssAnon + RssFile + RssShmem) 269c33e97efSMauro Carvalho Chehab RssAnon size of resident anonymous memory 270c33e97efSMauro Carvalho Chehab RssFile size of resident file mappings 271c33e97efSMauro Carvalho Chehab RssShmem size of resident shmem memory (includes SysV shm, 272c33e97efSMauro Carvalho Chehab mapping of tmpfs and shared anonymous mappings) 273c33e97efSMauro Carvalho Chehab VmData size of private data segments 274c33e97efSMauro Carvalho Chehab VmStk size of stack segments 275c33e97efSMauro Carvalho Chehab VmExe size of text segment 276c33e97efSMauro Carvalho Chehab VmLib size of shared library code 277c33e97efSMauro Carvalho Chehab VmPTE size of page table entries 278c33e97efSMauro Carvalho Chehab VmSwap amount of swap used by anonymous private data 279c33e97efSMauro Carvalho Chehab (shmem swap usage is not included) 280c33e97efSMauro Carvalho Chehab HugetlbPages size of hugetlb memory portions 281c33e97efSMauro Carvalho Chehab CoreDumping process's memory is currently being dumped 282c33e97efSMauro Carvalho Chehab (killing the process may lead to a corrupted core) 283c33e97efSMauro Carvalho Chehab THP_enabled process is allowed to use THP (returns 0 when 284c33e97efSMauro Carvalho Chehab PR_SET_THP_DISABLE is set on the process 285c33e97efSMauro Carvalho Chehab Threads number of threads 286c33e97efSMauro Carvalho Chehab SigQ number of signals queued/max. number for queue 287c33e97efSMauro Carvalho Chehab SigPnd bitmap of pending signals for the thread 288c33e97efSMauro Carvalho Chehab ShdPnd bitmap of shared pending signals for the process 289c33e97efSMauro Carvalho Chehab SigBlk bitmap of blocked signals 290c33e97efSMauro Carvalho Chehab SigIgn bitmap of ignored signals 291c33e97efSMauro Carvalho Chehab SigCgt bitmap of caught signals 292c33e97efSMauro Carvalho Chehab CapInh bitmap of inheritable capabilities 293c33e97efSMauro Carvalho Chehab CapPrm bitmap of permitted capabilities 294c33e97efSMauro Carvalho Chehab CapEff bitmap of effective capabilities 295c33e97efSMauro Carvalho Chehab CapBnd bitmap of capabilities bounding set 296c33e97efSMauro Carvalho Chehab CapAmb bitmap of ambient capabilities 297c33e97efSMauro Carvalho Chehab NoNewPrivs no_new_privs, like prctl(PR_GET_NO_NEW_PRIV, ...) 298c33e97efSMauro Carvalho Chehab Seccomp seccomp mode, like prctl(PR_GET_SECCOMP, ...) 299c33e97efSMauro Carvalho Chehab Speculation_Store_Bypass speculative store bypass mitigation status 300fe719888SAnand K Mistry SpeculationIndirectBranch indirect branch speculation mode 301c33e97efSMauro Carvalho Chehab Cpus_allowed mask of CPUs on which this process may run 302c33e97efSMauro Carvalho Chehab Cpus_allowed_list Same as previous, but in "list format" 303c33e97efSMauro Carvalho Chehab Mems_allowed mask of memory nodes allowed to this process 304c33e97efSMauro Carvalho Chehab Mems_allowed_list Same as previous, but in "list format" 305c33e97efSMauro Carvalho Chehab voluntary_ctxt_switches number of voluntary context switches 306c33e97efSMauro Carvalho Chehab nonvoluntary_ctxt_switches number of non voluntary context switches 307c33e97efSMauro Carvalho Chehab ========================== =================================================== 308c33e97efSMauro Carvalho Chehab 309c33e97efSMauro Carvalho Chehab 310d2ea66a6SRandy Dunlap.. table:: Table 1-3: Contents of the statm fields (as of 2.6.8-rc3) 311c33e97efSMauro Carvalho Chehab 312c33e97efSMauro Carvalho Chehab ======== =============================== ============================== 313c33e97efSMauro Carvalho Chehab Field Content 314c33e97efSMauro Carvalho Chehab ======== =============================== ============================== 315c33e97efSMauro Carvalho Chehab size total program size (pages) (same as VmSize in status) 316c33e97efSMauro Carvalho Chehab resident size of memory portions (pages) (same as VmRSS in status) 317c33e97efSMauro Carvalho Chehab shared number of pages that are shared (i.e. backed by a file, same 318c33e97efSMauro Carvalho Chehab as RssFile+RssShmem in status) 319c33e97efSMauro Carvalho Chehab trs number of pages that are 'code' (not including libs; broken, 320c33e97efSMauro Carvalho Chehab includes data segment) 321c33e97efSMauro Carvalho Chehab lrs number of pages of library (always 0 on 2.6) 322c33e97efSMauro Carvalho Chehab drs number of pages of data/stack (including libs; broken, 323c33e97efSMauro Carvalho Chehab includes library text) 324c33e97efSMauro Carvalho Chehab dt number of dirty pages (always 0 on 2.6) 325c33e97efSMauro Carvalho Chehab ======== =============================== ============================== 326c33e97efSMauro Carvalho Chehab 327c33e97efSMauro Carvalho Chehab 328d2ea66a6SRandy Dunlap.. table:: Table 1-4: Contents of the stat fields (as of 2.6.30-rc7) 329c33e97efSMauro Carvalho Chehab 330c33e97efSMauro Carvalho Chehab ============= =============================================================== 331c33e97efSMauro Carvalho Chehab Field Content 332c33e97efSMauro Carvalho Chehab ============= =============================================================== 333c33e97efSMauro Carvalho Chehab pid process id 334c33e97efSMauro Carvalho Chehab tcomm filename of the executable 335c33e97efSMauro Carvalho Chehab state state (R is running, S is sleeping, D is sleeping in an 336c33e97efSMauro Carvalho Chehab uninterruptible wait, Z is zombie, T is traced or stopped) 337c33e97efSMauro Carvalho Chehab ppid process id of the parent process 338c33e97efSMauro Carvalho Chehab pgrp pgrp of the process 339c33e97efSMauro Carvalho Chehab sid session id 340c33e97efSMauro Carvalho Chehab tty_nr tty the process uses 341c33e97efSMauro Carvalho Chehab tty_pgrp pgrp of the tty 342c33e97efSMauro Carvalho Chehab flags task flags 343c33e97efSMauro Carvalho Chehab min_flt number of minor faults 344c33e97efSMauro Carvalho Chehab cmin_flt number of minor faults with child's 345c33e97efSMauro Carvalho Chehab maj_flt number of major faults 346c33e97efSMauro Carvalho Chehab cmaj_flt number of major faults with child's 347c33e97efSMauro Carvalho Chehab utime user mode jiffies 348c33e97efSMauro Carvalho Chehab stime kernel mode jiffies 349c33e97efSMauro Carvalho Chehab cutime user mode jiffies with child's 350c33e97efSMauro Carvalho Chehab cstime kernel mode jiffies with child's 351c33e97efSMauro Carvalho Chehab priority priority level 352c33e97efSMauro Carvalho Chehab nice nice level 353c33e97efSMauro Carvalho Chehab num_threads number of threads 354c33e97efSMauro Carvalho Chehab it_real_value (obsolete, always 0) 355c33e97efSMauro Carvalho Chehab start_time time the process started after system boot 356c33e97efSMauro Carvalho Chehab vsize virtual memory size 357c33e97efSMauro Carvalho Chehab rss resident set memory size 358c33e97efSMauro Carvalho Chehab rsslim current limit in bytes on the rss 359c33e97efSMauro Carvalho Chehab start_code address above which program text can run 360c33e97efSMauro Carvalho Chehab end_code address below which program text can run 361c33e97efSMauro Carvalho Chehab start_stack address of the start of the main process stack 362c33e97efSMauro Carvalho Chehab esp current value of ESP 363c33e97efSMauro Carvalho Chehab eip current value of EIP 364c33e97efSMauro Carvalho Chehab pending bitmap of pending signals 365c33e97efSMauro Carvalho Chehab blocked bitmap of blocked signals 366c33e97efSMauro Carvalho Chehab sigign bitmap of ignored signals 367c33e97efSMauro Carvalho Chehab sigcatch bitmap of caught signals 368c33e97efSMauro Carvalho Chehab 0 (place holder, used to be the wchan address, 369c33e97efSMauro Carvalho Chehab use /proc/PID/wchan instead) 370c33e97efSMauro Carvalho Chehab 0 (place holder) 371c33e97efSMauro Carvalho Chehab 0 (place holder) 372c33e97efSMauro Carvalho Chehab exit_signal signal to send to parent thread on exit 373c33e97efSMauro Carvalho Chehab task_cpu which CPU the task is scheduled on 374c33e97efSMauro Carvalho Chehab rt_priority realtime priority 375c33e97efSMauro Carvalho Chehab policy scheduling policy (man sched_setscheduler) 376c33e97efSMauro Carvalho Chehab blkio_ticks time spent waiting for block IO 377c33e97efSMauro Carvalho Chehab gtime guest time of the task in jiffies 378c33e97efSMauro Carvalho Chehab cgtime guest time of the task children in jiffies 379c33e97efSMauro Carvalho Chehab start_data address above which program data+bss is placed 380c33e97efSMauro Carvalho Chehab end_data address below which program data+bss is placed 381c33e97efSMauro Carvalho Chehab start_brk address above which program heap can be expanded with brk() 382c33e97efSMauro Carvalho Chehab arg_start address above which program command line is placed 383c33e97efSMauro Carvalho Chehab arg_end address below which program command line is placed 384c33e97efSMauro Carvalho Chehab env_start address above which program environment is placed 385c33e97efSMauro Carvalho Chehab env_end address below which program environment is placed 386c33e97efSMauro Carvalho Chehab exit_code the thread's exit_code in the form reported by the waitpid 387c33e97efSMauro Carvalho Chehab system call 388c33e97efSMauro Carvalho Chehab ============= =============================================================== 389c33e97efSMauro Carvalho Chehab 390c33e97efSMauro Carvalho ChehabThe /proc/PID/maps file contains the currently mapped memory regions and 391c33e97efSMauro Carvalho Chehabtheir access permissions. 392c33e97efSMauro Carvalho Chehab 393c33e97efSMauro Carvalho ChehabThe format is:: 394c33e97efSMauro Carvalho Chehab 395c33e97efSMauro Carvalho Chehab address perms offset dev inode pathname 396c33e97efSMauro Carvalho Chehab 397c33e97efSMauro Carvalho Chehab 08048000-08049000 r-xp 00000000 03:00 8312 /opt/test 398c33e97efSMauro Carvalho Chehab 08049000-0804a000 rw-p 00001000 03:00 8312 /opt/test 399c33e97efSMauro Carvalho Chehab 0804a000-0806b000 rw-p 00000000 00:00 0 [heap] 400c33e97efSMauro Carvalho Chehab a7cb1000-a7cb2000 ---p 00000000 00:00 0 401c33e97efSMauro Carvalho Chehab a7cb2000-a7eb2000 rw-p 00000000 00:00 0 402c33e97efSMauro Carvalho Chehab a7eb2000-a7eb3000 ---p 00000000 00:00 0 403c33e97efSMauro Carvalho Chehab a7eb3000-a7ed5000 rw-p 00000000 00:00 0 404c33e97efSMauro Carvalho Chehab a7ed5000-a8008000 r-xp 00000000 03:00 4222 /lib/libc.so.6 405c33e97efSMauro Carvalho Chehab a8008000-a800a000 r--p 00133000 03:00 4222 /lib/libc.so.6 406c33e97efSMauro Carvalho Chehab a800a000-a800b000 rw-p 00135000 03:00 4222 /lib/libc.so.6 407c33e97efSMauro Carvalho Chehab a800b000-a800e000 rw-p 00000000 00:00 0 408c33e97efSMauro Carvalho Chehab a800e000-a8022000 r-xp 00000000 03:00 14462 /lib/libpthread.so.0 409c33e97efSMauro Carvalho Chehab a8022000-a8023000 r--p 00013000 03:00 14462 /lib/libpthread.so.0 410c33e97efSMauro Carvalho Chehab a8023000-a8024000 rw-p 00014000 03:00 14462 /lib/libpthread.so.0 411c33e97efSMauro Carvalho Chehab a8024000-a8027000 rw-p 00000000 00:00 0 412c33e97efSMauro Carvalho Chehab a8027000-a8043000 r-xp 00000000 03:00 8317 /lib/ld-linux.so.2 413c33e97efSMauro Carvalho Chehab a8043000-a8044000 r--p 0001b000 03:00 8317 /lib/ld-linux.so.2 414c33e97efSMauro Carvalho Chehab a8044000-a8045000 rw-p 0001c000 03:00 8317 /lib/ld-linux.so.2 415c33e97efSMauro Carvalho Chehab aff35000-aff4a000 rw-p 00000000 00:00 0 [stack] 416c33e97efSMauro Carvalho Chehab ffffe000-fffff000 r-xp 00000000 00:00 0 [vdso] 417c33e97efSMauro Carvalho Chehab 418c33e97efSMauro Carvalho Chehabwhere "address" is the address space in the process that it occupies, "perms" 419c33e97efSMauro Carvalho Chehabis a set of permissions:: 420c33e97efSMauro Carvalho Chehab 421c33e97efSMauro Carvalho Chehab r = read 422c33e97efSMauro Carvalho Chehab w = write 423c33e97efSMauro Carvalho Chehab x = execute 424c33e97efSMauro Carvalho Chehab s = shared 425c33e97efSMauro Carvalho Chehab p = private (copy on write) 426c33e97efSMauro Carvalho Chehab 427c33e97efSMauro Carvalho Chehab"offset" is the offset into the mapping, "dev" is the device (major:minor), and 428c33e97efSMauro Carvalho Chehab"inode" is the inode on that device. 0 indicates that no inode is associated 429c33e97efSMauro Carvalho Chehabwith the memory region, as the case would be with BSS (uninitialized data). 430c33e97efSMauro Carvalho ChehabThe "pathname" shows the name associated file for this mapping. If the mapping 431c33e97efSMauro Carvalho Chehabis not associated with a file: 432c33e97efSMauro Carvalho Chehab 433d09e8ca6SPasha Tatashin =================== =========================================== 434c33e97efSMauro Carvalho Chehab [heap] the heap of the program 435c33e97efSMauro Carvalho Chehab [stack] the stack of the main process 436c33e97efSMauro Carvalho Chehab [vdso] the "virtual dynamic shared object", 437c33e97efSMauro Carvalho Chehab the kernel system call handler 438d09e8ca6SPasha Tatashin [anon:<name>] a private anonymous mapping that has been 4399a10064fSColin Cross named by userspace 440d09e8ca6SPasha Tatashin [anon_shmem:<name>] an anonymous shared memory mapping that has 441d09e8ca6SPasha Tatashin been named by userspace 442d09e8ca6SPasha Tatashin =================== =========================================== 443c33e97efSMauro Carvalho Chehab 444c33e97efSMauro Carvalho Chehab or if empty, the mapping is anonymous. 445c33e97efSMauro Carvalho Chehab 446c33e97efSMauro Carvalho ChehabThe /proc/PID/smaps is an extension based on maps, showing the memory 447c33e97efSMauro Carvalho Chehabconsumption for each of the process's mappings. For each mapping (aka Virtual 448c33e97efSMauro Carvalho ChehabMemory Area, or VMA) there is a series of lines such as the following:: 449c33e97efSMauro Carvalho Chehab 450c33e97efSMauro Carvalho Chehab 08048000-080bc000 r-xp 00000000 03:02 13130 /bin/bash 451c33e97efSMauro Carvalho Chehab 452c33e97efSMauro Carvalho Chehab Size: 1084 kB 453c33e97efSMauro Carvalho Chehab KernelPageSize: 4 kB 454c33e97efSMauro Carvalho Chehab MMUPageSize: 4 kB 455c33e97efSMauro Carvalho Chehab Rss: 892 kB 456c33e97efSMauro Carvalho Chehab Pss: 374 kB 45730934843SVincent Whitchurch Pss_Dirty: 0 kB 458c33e97efSMauro Carvalho Chehab Shared_Clean: 892 kB 459c33e97efSMauro Carvalho Chehab Shared_Dirty: 0 kB 460c33e97efSMauro Carvalho Chehab Private_Clean: 0 kB 461c33e97efSMauro Carvalho Chehab Private_Dirty: 0 kB 462c33e97efSMauro Carvalho Chehab Referenced: 892 kB 463c33e97efSMauro Carvalho Chehab Anonymous: 0 kB 464c33e97efSMauro Carvalho Chehab LazyFree: 0 kB 465c33e97efSMauro Carvalho Chehab AnonHugePages: 0 kB 466c33e97efSMauro Carvalho Chehab ShmemPmdMapped: 0 kB 467c33e97efSMauro Carvalho Chehab Shared_Hugetlb: 0 kB 468c33e97efSMauro Carvalho Chehab Private_Hugetlb: 0 kB 469c33e97efSMauro Carvalho Chehab Swap: 0 kB 470c33e97efSMauro Carvalho Chehab SwapPss: 0 kB 471c33e97efSMauro Carvalho Chehab KernelPageSize: 4 kB 472c33e97efSMauro Carvalho Chehab MMUPageSize: 4 kB 473c33e97efSMauro Carvalho Chehab Locked: 0 kB 474c33e97efSMauro Carvalho Chehab THPeligible: 0 475c33e97efSMauro Carvalho Chehab VmFlags: rd ex mr mw me dw 476c33e97efSMauro Carvalho Chehab 477c33e97efSMauro Carvalho ChehabThe first of these lines shows the same information as is displayed for the 478c33e97efSMauro Carvalho Chehabmapping in /proc/PID/maps. Following lines show the size of the mapping 479c33e97efSMauro Carvalho Chehab(size); the size of each page allocated when backing a VMA (KernelPageSize), 480c33e97efSMauro Carvalho Chehabwhich is usually the same as the size in the page table entries; the page size 481c33e97efSMauro Carvalho Chehabused by the MMU when backing a VMA (in most cases, the same as KernelPageSize); 482c33e97efSMauro Carvalho Chehabthe amount of the mapping that is currently resident in RAM (RSS); the 483c33e97efSMauro Carvalho Chehabprocess' proportional share of this mapping (PSS); and the number of clean and 484c33e97efSMauro Carvalho Chehabdirty shared and private pages in the mapping. 485c33e97efSMauro Carvalho Chehab 486c33e97efSMauro Carvalho ChehabThe "proportional set size" (PSS) of a process is the count of pages it has 487c33e97efSMauro Carvalho Chehabin memory, where each page is divided by the number of processes sharing it. 488c33e97efSMauro Carvalho ChehabSo if a process has 1000 pages all to itself, and 1000 shared with one other 48930934843SVincent Whitchurchprocess, its PSS will be 1500. "Pss_Dirty" is the portion of PSS which 49030934843SVincent Whitchurchconsists of dirty pages. ("Pss_Clean" is not included, but it can be 49130934843SVincent Whitchurchcalculated by subtracting "Pss_Dirty" from "Pss".) 492c33e97efSMauro Carvalho Chehab 493c33e97efSMauro Carvalho ChehabNote that even a page which is part of a MAP_SHARED mapping, but has only 494c33e97efSMauro Carvalho Chehaba single pte mapped, i.e. is currently used by only one process, is accounted 495c33e97efSMauro Carvalho Chehabas private and not as shared. 496c33e97efSMauro Carvalho Chehab 497c33e97efSMauro Carvalho Chehab"Referenced" indicates the amount of memory currently marked as referenced or 498c33e97efSMauro Carvalho Chehabaccessed. 499c33e97efSMauro Carvalho Chehab 500c33e97efSMauro Carvalho Chehab"Anonymous" shows the amount of memory that does not belong to any file. Even 501c33e97efSMauro Carvalho Chehaba mapping associated with a file may contain anonymous pages: when MAP_PRIVATE 502c33e97efSMauro Carvalho Chehaband a page is modified, the file page is replaced by a private anonymous copy. 503c33e97efSMauro Carvalho Chehab 504c33e97efSMauro Carvalho Chehab"LazyFree" shows the amount of memory which is marked by madvise(MADV_FREE). 505c33e97efSMauro Carvalho ChehabThe memory isn't freed immediately with madvise(). It's freed in memory 506c33e97efSMauro Carvalho Chehabpressure if the memory is clean. Please note that the printed value might 507c33e97efSMauro Carvalho Chehabbe lower than the real value due to optimizations used in the current 508c33e97efSMauro Carvalho Chehabimplementation. If this is not desirable please file a bug report. 509c33e97efSMauro Carvalho Chehab 510c33e97efSMauro Carvalho Chehab"AnonHugePages" shows the ammount of memory backed by transparent hugepage. 511c33e97efSMauro Carvalho Chehab 512c33e97efSMauro Carvalho Chehab"ShmemPmdMapped" shows the ammount of shared (shmem/tmpfs) memory backed by 513c33e97efSMauro Carvalho Chehabhuge pages. 514c33e97efSMauro Carvalho Chehab 515c33e97efSMauro Carvalho Chehab"Shared_Hugetlb" and "Private_Hugetlb" show the ammounts of memory backed by 516c33e97efSMauro Carvalho Chehabhugetlbfs page which is *not* counted in "RSS" or "PSS" field for historical 517c33e97efSMauro Carvalho Chehabreasons. And these are not included in {Shared,Private}_{Clean,Dirty} field. 518c33e97efSMauro Carvalho Chehab 519c33e97efSMauro Carvalho Chehab"Swap" shows how much would-be-anonymous memory is also used, but out on swap. 520c33e97efSMauro Carvalho Chehab 521c33e97efSMauro Carvalho ChehabFor shmem mappings, "Swap" includes also the size of the mapped (and not 522c33e97efSMauro Carvalho Chehabreplaced by copy-on-write) part of the underlying shmem object out on swap. 523c33e97efSMauro Carvalho Chehab"SwapPss" shows proportional swap share of this mapping. Unlike "Swap", this 524c33e97efSMauro Carvalho Chehabdoes not take into account swapped out page of underlying shmem objects. 525c33e97efSMauro Carvalho Chehab"Locked" indicates whether the mapping is locked in memory or not. 526cb55b838SYang Shi 527c33e97efSMauro Carvalho Chehab"THPeligible" indicates whether the mapping is eligible for allocating THP 528cb55b838SYang Shipages as well as the THP is PMD mappable or not - 1 if true, 0 otherwise. 529cb55b838SYang ShiIt just shows the current status. 530c33e97efSMauro Carvalho Chehab 531c33e97efSMauro Carvalho Chehab"VmFlags" field deserves a separate description. This member represents the 532c33e97efSMauro Carvalho Chehabkernel flags associated with the particular virtual memory area in two letter 533c33e97efSMauro Carvalho Chehabencoded manner. The codes are the following: 534c33e97efSMauro Carvalho Chehab 535c33e97efSMauro Carvalho Chehab == ======================================= 536c33e97efSMauro Carvalho Chehab rd readable 537c33e97efSMauro Carvalho Chehab wr writeable 538c33e97efSMauro Carvalho Chehab ex executable 539c33e97efSMauro Carvalho Chehab sh shared 540c33e97efSMauro Carvalho Chehab mr may read 541c33e97efSMauro Carvalho Chehab mw may write 542c33e97efSMauro Carvalho Chehab me may execute 543c33e97efSMauro Carvalho Chehab ms may share 544c33e97efSMauro Carvalho Chehab gd stack segment growns down 545c33e97efSMauro Carvalho Chehab pf pure PFN range 546c33e97efSMauro Carvalho Chehab dw disabled write to the mapped file 547c33e97efSMauro Carvalho Chehab lo pages are locked in memory 548c33e97efSMauro Carvalho Chehab io memory mapped I/O area 549c33e97efSMauro Carvalho Chehab sr sequential read advise provided 550c33e97efSMauro Carvalho Chehab rr random read advise provided 551c33e97efSMauro Carvalho Chehab dc do not copy area on fork 552c33e97efSMauro Carvalho Chehab de do not expand area on remapping 553c33e97efSMauro Carvalho Chehab ac area is accountable 554c33e97efSMauro Carvalho Chehab nr swap space is not reserved for the area 555c33e97efSMauro Carvalho Chehab ht area uses huge tlb pages 5561f7faca2SPeter Xu sf synchronous page fault 557c33e97efSMauro Carvalho Chehab ar architecture specific flag 5581f7faca2SPeter Xu wf wipe on fork 559c33e97efSMauro Carvalho Chehab dd do not include area into core dump 560c33e97efSMauro Carvalho Chehab sd soft dirty flag 561c33e97efSMauro Carvalho Chehab mm mixed map area 562c33e97efSMauro Carvalho Chehab hg huge page advise flag 563c33e97efSMauro Carvalho Chehab nh no huge page advise flag 564c33e97efSMauro Carvalho Chehab mg mergable advise flag 565d5ddc6d9SMauro Carvalho Chehab bt arm64 BTI guarded page 566868770c9SSzabolcs Nagy mt arm64 MTE allocation tags are enabled 5671f7faca2SPeter Xu um userfaultfd missing tracking 5681f7faca2SPeter Xu uw userfaultfd wr-protect tracking 569*54007f81SYu-cheng Yu ss shadow stack page 570c33e97efSMauro Carvalho Chehab == ======================================= 571c33e97efSMauro Carvalho Chehab 572c33e97efSMauro Carvalho ChehabNote that there is no guarantee that every flag and associated mnemonic will 573c33e97efSMauro Carvalho Chehabbe present in all further kernel releases. Things get changed, the flags may 574c33e97efSMauro Carvalho Chehabbe vanished or the reverse -- new added. Interpretation of their meaning 575c33e97efSMauro Carvalho Chehabmight change in future as well. So each consumer of these flags has to 576c33e97efSMauro Carvalho Chehabfollow each specific kernel version for the exact semantic. 577c33e97efSMauro Carvalho Chehab 578c33e97efSMauro Carvalho ChehabThis file is only present if the CONFIG_MMU kernel configuration option is 579c33e97efSMauro Carvalho Chehabenabled. 580c33e97efSMauro Carvalho Chehab 581c33e97efSMauro Carvalho ChehabNote: reading /proc/PID/maps or /proc/PID/smaps is inherently racy (consistent 582c33e97efSMauro Carvalho Chehaboutput can be achieved only in the single read call). 583c33e97efSMauro Carvalho Chehab 584c33e97efSMauro Carvalho ChehabThis typically manifests when doing partial reads of these files while the 585c33e97efSMauro Carvalho Chehabmemory map is being modified. Despite the races, we do provide the following 586c33e97efSMauro Carvalho Chehabguarantees: 587c33e97efSMauro Carvalho Chehab 588c33e97efSMauro Carvalho Chehab1) The mapped addresses never go backwards, which implies no two 589c33e97efSMauro Carvalho Chehab regions will ever overlap. 590c33e97efSMauro Carvalho Chehab2) If there is something at a given vaddr during the entirety of the 591c33e97efSMauro Carvalho Chehab life of the smaps/maps walk, there will be some output for it. 592c33e97efSMauro Carvalho Chehab 593c33e97efSMauro Carvalho ChehabThe /proc/PID/smaps_rollup file includes the same fields as /proc/PID/smaps, 594c33e97efSMauro Carvalho Chehabbut their values are the sums of the corresponding values for all mappings of 595c33e97efSMauro Carvalho Chehabthe process. Additionally, it contains these fields: 596c33e97efSMauro Carvalho Chehab 597c33e97efSMauro Carvalho Chehab- Pss_Anon 598c33e97efSMauro Carvalho Chehab- Pss_File 599c33e97efSMauro Carvalho Chehab- Pss_Shmem 600c33e97efSMauro Carvalho Chehab 601c33e97efSMauro Carvalho ChehabThey represent the proportional shares of anonymous, file, and shmem pages, as 602c33e97efSMauro Carvalho Chehabdescribed for smaps above. These fields are omitted in smaps since each 603c33e97efSMauro Carvalho Chehabmapping identifies the type (anon, file, or shmem) of all pages it contains. 604c33e97efSMauro Carvalho ChehabThus all information in smaps_rollup can be derived from smaps, but at a 605c33e97efSMauro Carvalho Chehabsignificantly higher cost. 606c33e97efSMauro Carvalho Chehab 607c33e97efSMauro Carvalho ChehabThe /proc/PID/clear_refs is used to reset the PG_Referenced and ACCESSED/YOUNG 608c33e97efSMauro Carvalho Chehabbits on both physical and virtual pages associated with a process, and the 609c33e97efSMauro Carvalho Chehabsoft-dirty bit on pte (see Documentation/admin-guide/mm/soft-dirty.rst 610c33e97efSMauro Carvalho Chehabfor details). 611c33e97efSMauro Carvalho ChehabTo clear the bits for all the pages associated with the process:: 612c33e97efSMauro Carvalho Chehab 613c33e97efSMauro Carvalho Chehab > echo 1 > /proc/PID/clear_refs 614c33e97efSMauro Carvalho Chehab 615c33e97efSMauro Carvalho ChehabTo clear the bits for the anonymous pages associated with the process:: 616c33e97efSMauro Carvalho Chehab 617c33e97efSMauro Carvalho Chehab > echo 2 > /proc/PID/clear_refs 618c33e97efSMauro Carvalho Chehab 619c33e97efSMauro Carvalho ChehabTo clear the bits for the file mapped pages associated with the process:: 620c33e97efSMauro Carvalho Chehab 621c33e97efSMauro Carvalho Chehab > echo 3 > /proc/PID/clear_refs 622c33e97efSMauro Carvalho Chehab 623c33e97efSMauro Carvalho ChehabTo clear the soft-dirty bit:: 624c33e97efSMauro Carvalho Chehab 625c33e97efSMauro Carvalho Chehab > echo 4 > /proc/PID/clear_refs 626c33e97efSMauro Carvalho Chehab 627c33e97efSMauro Carvalho ChehabTo reset the peak resident set size ("high water mark") to the process's 628c33e97efSMauro Carvalho Chehabcurrent value:: 629c33e97efSMauro Carvalho Chehab 630c33e97efSMauro Carvalho Chehab > echo 5 > /proc/PID/clear_refs 631c33e97efSMauro Carvalho Chehab 632c33e97efSMauro Carvalho ChehabAny other value written to /proc/PID/clear_refs will have no effect. 633c33e97efSMauro Carvalho Chehab 634c33e97efSMauro Carvalho ChehabThe /proc/pid/pagemap gives the PFN, which can be used to find the pageflags 635c33e97efSMauro Carvalho Chehabusing /proc/kpageflags and number of times a page is mapped using 636c33e97efSMauro Carvalho Chehab/proc/kpagecount. For detailed explanation, see 637c33e97efSMauro Carvalho ChehabDocumentation/admin-guide/mm/pagemap.rst. 638c33e97efSMauro Carvalho Chehab 639c33e97efSMauro Carvalho ChehabThe /proc/pid/numa_maps is an extension based on maps, showing the memory 640c33e97efSMauro Carvalho Chehablocality and binding policy, as well as the memory usage (in pages) of 641c33e97efSMauro Carvalho Chehabeach mapping. The output follows a general format where mapping details get 642c33e97efSMauro Carvalho Chehabsummarized separated by blank spaces, one mapping per each file line:: 643c33e97efSMauro Carvalho Chehab 644c33e97efSMauro Carvalho Chehab address policy mapping details 645c33e97efSMauro Carvalho Chehab 646c33e97efSMauro Carvalho Chehab 00400000 default file=/usr/local/bin/app mapped=1 active=0 N3=1 kernelpagesize_kB=4 647c33e97efSMauro Carvalho Chehab 00600000 default file=/usr/local/bin/app anon=1 dirty=1 N3=1 kernelpagesize_kB=4 648c33e97efSMauro Carvalho Chehab 3206000000 default file=/lib64/ld-2.12.so mapped=26 mapmax=6 N0=24 N3=2 kernelpagesize_kB=4 649c33e97efSMauro Carvalho Chehab 320621f000 default file=/lib64/ld-2.12.so anon=1 dirty=1 N3=1 kernelpagesize_kB=4 650c33e97efSMauro Carvalho Chehab 3206220000 default file=/lib64/ld-2.12.so anon=1 dirty=1 N3=1 kernelpagesize_kB=4 651c33e97efSMauro Carvalho Chehab 3206221000 default anon=1 dirty=1 N3=1 kernelpagesize_kB=4 652c33e97efSMauro Carvalho Chehab 3206800000 default file=/lib64/libc-2.12.so mapped=59 mapmax=21 active=55 N0=41 N3=18 kernelpagesize_kB=4 653c33e97efSMauro Carvalho Chehab 320698b000 default file=/lib64/libc-2.12.so 654c33e97efSMauro Carvalho Chehab 3206b8a000 default file=/lib64/libc-2.12.so anon=2 dirty=2 N3=2 kernelpagesize_kB=4 655c33e97efSMauro Carvalho Chehab 3206b8e000 default file=/lib64/libc-2.12.so anon=1 dirty=1 N3=1 kernelpagesize_kB=4 656c33e97efSMauro Carvalho Chehab 3206b8f000 default anon=3 dirty=3 active=1 N3=3 kernelpagesize_kB=4 657c33e97efSMauro Carvalho Chehab 7f4dc10a2000 default anon=3 dirty=3 N3=3 kernelpagesize_kB=4 658c33e97efSMauro Carvalho Chehab 7f4dc10b4000 default anon=2 dirty=2 active=1 N3=2 kernelpagesize_kB=4 659c33e97efSMauro Carvalho Chehab 7f4dc1200000 default file=/anon_hugepage\040(deleted) huge anon=1 dirty=1 N3=1 kernelpagesize_kB=2048 660c33e97efSMauro Carvalho Chehab 7fff335f0000 default stack anon=3 dirty=3 N3=3 kernelpagesize_kB=4 661c33e97efSMauro Carvalho Chehab 7fff3369d000 default mapped=1 mapmax=35 active=0 N3=1 kernelpagesize_kB=4 662c33e97efSMauro Carvalho Chehab 663c33e97efSMauro Carvalho ChehabWhere: 664c33e97efSMauro Carvalho Chehab 665c33e97efSMauro Carvalho Chehab"address" is the starting address for the mapping; 666c33e97efSMauro Carvalho Chehab 667c33e97efSMauro Carvalho Chehab"policy" reports the NUMA memory policy set for the mapping (see Documentation/admin-guide/mm/numa_memory_policy.rst); 668c33e97efSMauro Carvalho Chehab 669c33e97efSMauro Carvalho Chehab"mapping details" summarizes mapping data such as mapping type, page usage counters, 670c33e97efSMauro Carvalho Chehabnode locality page counters (N0 == node0, N1 == node1, ...) and the kernel page 671c33e97efSMauro Carvalho Chehabsize, in KB, that is backing the mapping up. 672c33e97efSMauro Carvalho Chehab 673c33e97efSMauro Carvalho Chehab1.2 Kernel data 674c33e97efSMauro Carvalho Chehab--------------- 675c33e97efSMauro Carvalho Chehab 676c33e97efSMauro Carvalho ChehabSimilar to the process entries, the kernel data files give information about 677c33e97efSMauro Carvalho Chehabthe running kernel. The files used to obtain this information are contained in 678c33e97efSMauro Carvalho Chehab/proc and are listed in Table 1-5. Not all of these will be present in your 679c33e97efSMauro Carvalho Chehabsystem. It depends on the kernel configuration and the loaded modules, which 680c33e97efSMauro Carvalho Chehabfiles are there, and which are missing. 681c33e97efSMauro Carvalho Chehab 682c33e97efSMauro Carvalho Chehab.. table:: Table 1-5: Kernel info in /proc 683c33e97efSMauro Carvalho Chehab 684c33e97efSMauro Carvalho Chehab ============ =============================================================== 685c33e97efSMauro Carvalho Chehab File Content 686c33e97efSMauro Carvalho Chehab ============ =============================================================== 687c33e97efSMauro Carvalho Chehab apm Advanced power management info 688c33e97efSMauro Carvalho Chehab buddyinfo Kernel memory allocator information (see text) (2.5) 689c33e97efSMauro Carvalho Chehab bus Directory containing bus specific information 690c33e97efSMauro Carvalho Chehab cmdline Kernel command line 691c33e97efSMauro Carvalho Chehab cpuinfo Info about the CPU 692c33e97efSMauro Carvalho Chehab devices Available devices (block and character) 693c33e97efSMauro Carvalho Chehab dma Used DMS channels 694c33e97efSMauro Carvalho Chehab filesystems Supported filesystems 695c33e97efSMauro Carvalho Chehab driver Various drivers grouped here, currently rtc (2.4) 696c33e97efSMauro Carvalho Chehab execdomains Execdomains, related to security (2.4) 697c33e97efSMauro Carvalho Chehab fb Frame Buffer devices (2.4) 698c33e97efSMauro Carvalho Chehab fs File system parameters, currently nfs/exports (2.4) 699c33e97efSMauro Carvalho Chehab ide Directory containing info about the IDE subsystem 700c33e97efSMauro Carvalho Chehab interrupts Interrupt usage 701c33e97efSMauro Carvalho Chehab iomem Memory map (2.4) 702c33e97efSMauro Carvalho Chehab ioports I/O port usage 703c33e97efSMauro Carvalho Chehab irq Masks for irq to cpu affinity (2.4)(smp?) 704c33e97efSMauro Carvalho Chehab isapnp ISA PnP (Plug&Play) Info (2.4) 705c33e97efSMauro Carvalho Chehab kcore Kernel core image (can be ELF or A.OUT(deprecated in 2.4)) 706c33e97efSMauro Carvalho Chehab kmsg Kernel messages 707c33e97efSMauro Carvalho Chehab ksyms Kernel symbol table 7084ba1d726SRandy Dunlap loadavg Load average of last 1, 5 & 15 minutes; 7094ba1d726SRandy Dunlap number of processes currently runnable (running or on ready queue); 7104ba1d726SRandy Dunlap total number of processes in system; 7114ba1d726SRandy Dunlap last pid created. 71293ea4a0bSRandy Dunlap All fields are separated by one space except "number of 71393ea4a0bSRandy Dunlap processes currently runnable" and "total number of processes 71493ea4a0bSRandy Dunlap in system", which are separated by a slash ('/'). Example: 71593ea4a0bSRandy Dunlap 0.61 0.61 0.55 3/828 22084 716c33e97efSMauro Carvalho Chehab locks Kernel locks 717c33e97efSMauro Carvalho Chehab meminfo Memory info 718c33e97efSMauro Carvalho Chehab misc Miscellaneous 719c33e97efSMauro Carvalho Chehab modules List of loaded modules 720c33e97efSMauro Carvalho Chehab mounts Mounted filesystems 721c33e97efSMauro Carvalho Chehab net Networking info (see text) 722c33e97efSMauro Carvalho Chehab pagetypeinfo Additional page allocator information (see text) (2.5) 723c33e97efSMauro Carvalho Chehab partitions Table of partitions known to the system 724c33e97efSMauro Carvalho Chehab pci Deprecated info of PCI bus (new way -> /proc/bus/pci/, 725c33e97efSMauro Carvalho Chehab decoupled by lspci (2.4) 726c33e97efSMauro Carvalho Chehab rtc Real time clock 727c33e97efSMauro Carvalho Chehab scsi SCSI info (see text) 728c33e97efSMauro Carvalho Chehab slabinfo Slab pool info 729c33e97efSMauro Carvalho Chehab softirqs softirq usage 730c33e97efSMauro Carvalho Chehab stat Overall statistics 731c33e97efSMauro Carvalho Chehab swaps Swap space utilization 732c33e97efSMauro Carvalho Chehab sys See chapter 2 733c33e97efSMauro Carvalho Chehab sysvipc Info of SysVIPC Resources (msg, sem, shm) (2.4) 734c33e97efSMauro Carvalho Chehab tty Info of tty drivers 735c33e97efSMauro Carvalho Chehab uptime Wall clock since boot, combined idle time of all cpus 736c33e97efSMauro Carvalho Chehab version Kernel version 737c33e97efSMauro Carvalho Chehab video bttv info of video resources (2.4) 738c33e97efSMauro Carvalho Chehab vmallocinfo Show vmalloced areas 739c33e97efSMauro Carvalho Chehab ============ =============================================================== 740c33e97efSMauro Carvalho Chehab 741c33e97efSMauro Carvalho ChehabYou can, for example, check which interrupts are currently in use and what 742c33e97efSMauro Carvalho Chehabthey are used for by looking in the file /proc/interrupts:: 743c33e97efSMauro Carvalho Chehab 744c33e97efSMauro Carvalho Chehab > cat /proc/interrupts 745c33e97efSMauro Carvalho Chehab CPU0 746c33e97efSMauro Carvalho Chehab 0: 8728810 XT-PIC timer 747c33e97efSMauro Carvalho Chehab 1: 895 XT-PIC keyboard 748c33e97efSMauro Carvalho Chehab 2: 0 XT-PIC cascade 749c33e97efSMauro Carvalho Chehab 3: 531695 XT-PIC aha152x 750c33e97efSMauro Carvalho Chehab 4: 2014133 XT-PIC serial 751c33e97efSMauro Carvalho Chehab 5: 44401 XT-PIC pcnet_cs 752c33e97efSMauro Carvalho Chehab 8: 2 XT-PIC rtc 753c33e97efSMauro Carvalho Chehab 11: 8 XT-PIC i82365 754c33e97efSMauro Carvalho Chehab 12: 182918 XT-PIC PS/2 Mouse 755c33e97efSMauro Carvalho Chehab 13: 1 XT-PIC fpu 756c33e97efSMauro Carvalho Chehab 14: 1232265 XT-PIC ide0 757c33e97efSMauro Carvalho Chehab 15: 7 XT-PIC ide1 758c33e97efSMauro Carvalho Chehab NMI: 0 759c33e97efSMauro Carvalho Chehab 760c33e97efSMauro Carvalho ChehabIn 2.4.* a couple of lines where added to this file LOC & ERR (this time is the 761c33e97efSMauro Carvalho Chehaboutput of a SMP machine):: 762c33e97efSMauro Carvalho Chehab 763c33e97efSMauro Carvalho Chehab > cat /proc/interrupts 764c33e97efSMauro Carvalho Chehab 765c33e97efSMauro Carvalho Chehab CPU0 CPU1 766c33e97efSMauro Carvalho Chehab 0: 1243498 1214548 IO-APIC-edge timer 767c33e97efSMauro Carvalho Chehab 1: 8949 8958 IO-APIC-edge keyboard 768c33e97efSMauro Carvalho Chehab 2: 0 0 XT-PIC cascade 769c33e97efSMauro Carvalho Chehab 5: 11286 10161 IO-APIC-edge soundblaster 770c33e97efSMauro Carvalho Chehab 8: 1 0 IO-APIC-edge rtc 771c33e97efSMauro Carvalho Chehab 9: 27422 27407 IO-APIC-edge 3c503 772c33e97efSMauro Carvalho Chehab 12: 113645 113873 IO-APIC-edge PS/2 Mouse 773c33e97efSMauro Carvalho Chehab 13: 0 0 XT-PIC fpu 774c33e97efSMauro Carvalho Chehab 14: 22491 24012 IO-APIC-edge ide0 775c33e97efSMauro Carvalho Chehab 15: 2183 2415 IO-APIC-edge ide1 776c33e97efSMauro Carvalho Chehab 17: 30564 30414 IO-APIC-level eth0 777c33e97efSMauro Carvalho Chehab 18: 177 164 IO-APIC-level bttv 778c33e97efSMauro Carvalho Chehab NMI: 2457961 2457959 779c33e97efSMauro Carvalho Chehab LOC: 2457882 2457881 780c33e97efSMauro Carvalho Chehab ERR: 2155 781c33e97efSMauro Carvalho Chehab 782c33e97efSMauro Carvalho ChehabNMI is incremented in this case because every timer interrupt generates a NMI 783c33e97efSMauro Carvalho Chehab(Non Maskable Interrupt) which is used by the NMI Watchdog to detect lockups. 784c33e97efSMauro Carvalho Chehab 785c33e97efSMauro Carvalho ChehabLOC is the local interrupt counter of the internal APIC of every CPU. 786c33e97efSMauro Carvalho Chehab 787c33e97efSMauro Carvalho ChehabERR is incremented in the case of errors in the IO-APIC bus (the bus that 788c33e97efSMauro Carvalho Chehabconnects the CPUs in a SMP system. This means that an error has been detected, 789c33e97efSMauro Carvalho Chehabthe IO-APIC automatically retry the transmission, so it should not be a big 790c33e97efSMauro Carvalho Chehabproblem, but you should read the SMP-FAQ. 791c33e97efSMauro Carvalho Chehab 792c33e97efSMauro Carvalho ChehabIn 2.6.2* /proc/interrupts was expanded again. This time the goal was for 793c33e97efSMauro Carvalho Chehab/proc/interrupts to display every IRQ vector in use by the system, not 794c33e97efSMauro Carvalho Chehabjust those considered 'most important'. The new vectors are: 795c33e97efSMauro Carvalho Chehab 796c33e97efSMauro Carvalho ChehabTHR 797c33e97efSMauro Carvalho Chehab interrupt raised when a machine check threshold counter 798c33e97efSMauro Carvalho Chehab (typically counting ECC corrected errors of memory or cache) exceeds 799c33e97efSMauro Carvalho Chehab a configurable threshold. Only available on some systems. 800c33e97efSMauro Carvalho Chehab 801c33e97efSMauro Carvalho ChehabTRM 802c33e97efSMauro Carvalho Chehab a thermal event interrupt occurs when a temperature threshold 803c33e97efSMauro Carvalho Chehab has been exceeded for the CPU. This interrupt may also be generated 804c33e97efSMauro Carvalho Chehab when the temperature drops back to normal. 805c33e97efSMauro Carvalho Chehab 806c33e97efSMauro Carvalho ChehabSPU 807c33e97efSMauro Carvalho Chehab a spurious interrupt is some interrupt that was raised then lowered 808c33e97efSMauro Carvalho Chehab by some IO device before it could be fully processed by the APIC. Hence 809c33e97efSMauro Carvalho Chehab the APIC sees the interrupt but does not know what device it came from. 810c33e97efSMauro Carvalho Chehab For this case the APIC will generate the interrupt with a IRQ vector 811c33e97efSMauro Carvalho Chehab of 0xff. This might also be generated by chipset bugs. 812c33e97efSMauro Carvalho Chehab 813059db434SRandy DunlapRES, CAL, TLB 814c33e97efSMauro Carvalho Chehab rescheduling, call and TLB flush interrupts are 815c33e97efSMauro Carvalho Chehab sent from one CPU to another per the needs of the OS. Typically, 816c33e97efSMauro Carvalho Chehab their statistics are used by kernel developers and interested users to 817c33e97efSMauro Carvalho Chehab determine the occurrence of interrupts of the given type. 818c33e97efSMauro Carvalho Chehab 819c33e97efSMauro Carvalho ChehabThe above IRQ vectors are displayed only when relevant. For example, 820c33e97efSMauro Carvalho Chehabthe threshold vector does not exist on x86_64 platforms. Others are 821c33e97efSMauro Carvalho Chehabsuppressed when the system is a uniprocessor. As of this writing, only 822c33e97efSMauro Carvalho Chehabi386 and x86_64 platforms support the new IRQ vector displays. 823c33e97efSMauro Carvalho Chehab 824c33e97efSMauro Carvalho ChehabOf some interest is the introduction of the /proc/irq directory to 2.4. 825059db434SRandy DunlapIt could be used to set IRQ to CPU affinity. This means that you can "hook" an 826c33e97efSMauro Carvalho ChehabIRQ to only one CPU, or to exclude a CPU of handling IRQs. The contents of the 827c33e97efSMauro Carvalho Chehabirq subdir is one subdir for each IRQ, and two files; default_smp_affinity and 828c33e97efSMauro Carvalho Chehabprof_cpu_mask. 829c33e97efSMauro Carvalho Chehab 830c33e97efSMauro Carvalho ChehabFor example:: 831c33e97efSMauro Carvalho Chehab 832c33e97efSMauro Carvalho Chehab > ls /proc/irq/ 833c33e97efSMauro Carvalho Chehab 0 10 12 14 16 18 2 4 6 8 prof_cpu_mask 834c33e97efSMauro Carvalho Chehab 1 11 13 15 17 19 3 5 7 9 default_smp_affinity 835c33e97efSMauro Carvalho Chehab > ls /proc/irq/0/ 836c33e97efSMauro Carvalho Chehab smp_affinity 837c33e97efSMauro Carvalho Chehab 838c33e97efSMauro Carvalho Chehabsmp_affinity is a bitmask, in which you can specify which CPUs can handle the 839059db434SRandy DunlapIRQ. You can set it by doing:: 840c33e97efSMauro Carvalho Chehab 841c33e97efSMauro Carvalho Chehab > echo 1 > /proc/irq/10/smp_affinity 842c33e97efSMauro Carvalho Chehab 843c33e97efSMauro Carvalho ChehabThis means that only the first CPU will handle the IRQ, but you can also echo 844c33e97efSMauro Carvalho Chehab5 which means that only the first and third CPU can handle the IRQ. 845c33e97efSMauro Carvalho Chehab 846c33e97efSMauro Carvalho ChehabThe contents of each smp_affinity file is the same by default:: 847c33e97efSMauro Carvalho Chehab 848c33e97efSMauro Carvalho Chehab > cat /proc/irq/0/smp_affinity 849c33e97efSMauro Carvalho Chehab ffffffff 850c33e97efSMauro Carvalho Chehab 851c33e97efSMauro Carvalho ChehabThere is an alternate interface, smp_affinity_list which allows specifying 852059db434SRandy Dunlapa CPU range instead of a bitmask:: 853c33e97efSMauro Carvalho Chehab 854c33e97efSMauro Carvalho Chehab > cat /proc/irq/0/smp_affinity_list 855c33e97efSMauro Carvalho Chehab 1024-1031 856c33e97efSMauro Carvalho Chehab 857c33e97efSMauro Carvalho ChehabThe default_smp_affinity mask applies to all non-active IRQs, which are the 858c33e97efSMauro Carvalho ChehabIRQs which have not yet been allocated/activated, and hence which lack a 859c33e97efSMauro Carvalho Chehab/proc/irq/[0-9]* directory. 860c33e97efSMauro Carvalho Chehab 861c33e97efSMauro Carvalho ChehabThe node file on an SMP system shows the node to which the device using the IRQ 862c33e97efSMauro Carvalho Chehabreports itself as being attached. This hardware locality information does not 863c33e97efSMauro Carvalho Chehabinclude information about any possible driver locality preference. 864c33e97efSMauro Carvalho Chehab 865c33e97efSMauro Carvalho Chehabprof_cpu_mask specifies which CPUs are to be profiled by the system wide 866059db434SRandy Dunlapprofiler. Default value is ffffffff (all CPUs if there are only 32 of them). 867c33e97efSMauro Carvalho Chehab 868c33e97efSMauro Carvalho ChehabThe way IRQs are routed is handled by the IO-APIC, and it's Round Robin 869c33e97efSMauro Carvalho Chehabbetween all the CPUs which are allowed to handle it. As usual the kernel has 870c33e97efSMauro Carvalho Chehabmore info than you and does a better job than you, so the defaults are the 871c33e97efSMauro Carvalho Chehabbest choice for almost everyone. [Note this applies only to those IO-APIC's 872c33e97efSMauro Carvalho Chehabthat support "Round Robin" interrupt distribution.] 873c33e97efSMauro Carvalho Chehab 874c33e97efSMauro Carvalho ChehabThere are three more important subdirectories in /proc: net, scsi, and sys. 875c33e97efSMauro Carvalho ChehabThe general rule is that the contents, or even the existence of these 876c33e97efSMauro Carvalho Chehabdirectories, depend on your kernel configuration. If SCSI is not enabled, the 877c33e97efSMauro Carvalho Chehabdirectory scsi may not exist. The same is true with the net, which is there 878c33e97efSMauro Carvalho Chehabonly when networking support is present in the running kernel. 879c33e97efSMauro Carvalho Chehab 880c33e97efSMauro Carvalho ChehabThe slabinfo file gives information about memory usage at the slab level. 881c33e97efSMauro Carvalho ChehabLinux uses slab pools for memory management above page level in version 2.2. 882c33e97efSMauro Carvalho ChehabCommonly used objects have their own slab pool (such as network buffers, 883c33e97efSMauro Carvalho Chehabdirectory cache, and so on). 884c33e97efSMauro Carvalho Chehab 885c33e97efSMauro Carvalho Chehab:: 886c33e97efSMauro Carvalho Chehab 887c33e97efSMauro Carvalho Chehab > cat /proc/buddyinfo 888c33e97efSMauro Carvalho Chehab 889c33e97efSMauro Carvalho Chehab Node 0, zone DMA 0 4 5 4 4 3 ... 890c33e97efSMauro Carvalho Chehab Node 0, zone Normal 1 0 0 1 101 8 ... 891c33e97efSMauro Carvalho Chehab Node 0, zone HighMem 2 0 0 1 1 0 ... 892c33e97efSMauro Carvalho Chehab 893c33e97efSMauro Carvalho ChehabExternal fragmentation is a problem under some workloads, and buddyinfo is a 894c33e97efSMauro Carvalho Chehabuseful tool for helping diagnose these problems. Buddyinfo will give you a 895c33e97efSMauro Carvalho Chehabclue as to how big an area you can safely allocate, or why a previous 896c33e97efSMauro Carvalho Chehaballocation failed. 897c33e97efSMauro Carvalho Chehab 898c33e97efSMauro Carvalho ChehabEach column represents the number of pages of a certain order which are 899c33e97efSMauro Carvalho Chehabavailable. In this case, there are 0 chunks of 2^0*PAGE_SIZE available in 900c33e97efSMauro Carvalho ChehabZONE_DMA, 4 chunks of 2^1*PAGE_SIZE in ZONE_DMA, 101 chunks of 2^4*PAGE_SIZE 901c33e97efSMauro Carvalho Chehabavailable in ZONE_NORMAL, etc... 902c33e97efSMauro Carvalho Chehab 903c33e97efSMauro Carvalho ChehabMore information relevant to external fragmentation can be found in 904c33e97efSMauro Carvalho Chehabpagetypeinfo:: 905c33e97efSMauro Carvalho Chehab 906c33e97efSMauro Carvalho Chehab > cat /proc/pagetypeinfo 907c33e97efSMauro Carvalho Chehab Page block order: 9 908c33e97efSMauro Carvalho Chehab Pages per block: 512 909c33e97efSMauro Carvalho Chehab 910c33e97efSMauro Carvalho Chehab Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10 911c33e97efSMauro Carvalho Chehab Node 0, zone DMA, type Unmovable 0 0 0 1 1 1 1 1 1 1 0 912c33e97efSMauro Carvalho Chehab Node 0, zone DMA, type Reclaimable 0 0 0 0 0 0 0 0 0 0 0 913c33e97efSMauro Carvalho Chehab Node 0, zone DMA, type Movable 1 1 2 1 2 1 1 0 1 0 2 914c33e97efSMauro Carvalho Chehab Node 0, zone DMA, type Reserve 0 0 0 0 0 0 0 0 0 1 0 915c33e97efSMauro Carvalho Chehab Node 0, zone DMA, type Isolate 0 0 0 0 0 0 0 0 0 0 0 916c33e97efSMauro Carvalho Chehab Node 0, zone DMA32, type Unmovable 103 54 77 1 1 1 11 8 7 1 9 917c33e97efSMauro Carvalho Chehab Node 0, zone DMA32, type Reclaimable 0 0 2 1 0 0 0 0 1 0 0 918c33e97efSMauro Carvalho Chehab Node 0, zone DMA32, type Movable 169 152 113 91 77 54 39 13 6 1 452 919c33e97efSMauro Carvalho Chehab Node 0, zone DMA32, type Reserve 1 2 2 2 2 0 1 1 1 1 0 920c33e97efSMauro Carvalho Chehab Node 0, zone DMA32, type Isolate 0 0 0 0 0 0 0 0 0 0 0 921c33e97efSMauro Carvalho Chehab 922c33e97efSMauro Carvalho Chehab Number of blocks type Unmovable Reclaimable Movable Reserve Isolate 923c33e97efSMauro Carvalho Chehab Node 0, zone DMA 2 0 5 1 0 924c33e97efSMauro Carvalho Chehab Node 0, zone DMA32 41 6 967 2 0 925c33e97efSMauro Carvalho Chehab 926c33e97efSMauro Carvalho ChehabFragmentation avoidance in the kernel works by grouping pages of different 927c33e97efSMauro Carvalho Chehabmigrate types into the same contiguous regions of memory called page blocks. 928059db434SRandy DunlapA page block is typically the size of the default hugepage size, e.g. 2MB on 929c33e97efSMauro Carvalho ChehabX86-64. By keeping pages grouped based on their ability to move, the kernel 930c33e97efSMauro Carvalho Chehabcan reclaim pages within a page block to satisfy a high-order allocation. 931c33e97efSMauro Carvalho Chehab 932c33e97efSMauro Carvalho ChehabThe pagetypinfo begins with information on the size of a page block. It 933c33e97efSMauro Carvalho Chehabthen gives the same type of information as buddyinfo except broken down 934c33e97efSMauro Carvalho Chehabby migrate-type and finishes with details on how many page blocks of each 935c33e97efSMauro Carvalho Chehabtype exist. 936c33e97efSMauro Carvalho Chehab 937c33e97efSMauro Carvalho ChehabIf min_free_kbytes has been tuned correctly (recommendations made by hugeadm 938c33e97efSMauro Carvalho Chehabfrom libhugetlbfs https://github.com/libhugetlbfs/libhugetlbfs/), one can 939c33e97efSMauro Carvalho Chehabmake an estimate of the likely number of huge pages that can be allocated 940c33e97efSMauro Carvalho Chehabat a given point in time. All the "Movable" blocks should be allocatable 941c33e97efSMauro Carvalho Chehabunless memory has been mlock()'d. Some of the Reclaimable blocks should 942c33e97efSMauro Carvalho Chehabalso be allocatable although a lot of filesystem metadata may have to be 943c33e97efSMauro Carvalho Chehabreclaimed to achieve this. 944c33e97efSMauro Carvalho Chehab 945c33e97efSMauro Carvalho Chehab 946c33e97efSMauro Carvalho Chehabmeminfo 947c33e97efSMauro Carvalho Chehab~~~~~~~ 948c33e97efSMauro Carvalho Chehab 949c33e97efSMauro Carvalho ChehabProvides information about distribution and utilization of memory. This 9508d719afcSMike Rapoportvaries by architecture and compile options. Some of the counters reported 9518d719afcSMike Rapoporthere overlap. The memory reported by the non overlapping counters may not 9528d719afcSMike Rapoportadd up to the overall memory usage and the difference for some workloads 9538d719afcSMike Rapoportcan be substantial. In many cases there are other means to find out 9548d719afcSMike Rapoportadditional memory using subsystem specific interfaces, for instance 9558d719afcSMike Rapoport/proc/net/sockstat for TCP memory allocations. 9568d719afcSMike Rapoport 95739799b64SJohannes WeinerExample output. You may not have all of these fields. 958c33e97efSMauro Carvalho Chehab 959c33e97efSMauro Carvalho Chehab:: 960c33e97efSMauro Carvalho Chehab 961c33e97efSMauro Carvalho Chehab > cat /proc/meminfo 962c33e97efSMauro Carvalho Chehab 96339799b64SJohannes Weiner MemTotal: 32858820 kB 96439799b64SJohannes Weiner MemFree: 21001236 kB 96539799b64SJohannes Weiner MemAvailable: 27214312 kB 96639799b64SJohannes Weiner Buffers: 581092 kB 96739799b64SJohannes Weiner Cached: 5587612 kB 968c33e97efSMauro Carvalho Chehab SwapCached: 0 kB 96939799b64SJohannes Weiner Active: 3237152 kB 97039799b64SJohannes Weiner Inactive: 7586256 kB 97139799b64SJohannes Weiner Active(anon): 94064 kB 97239799b64SJohannes Weiner Inactive(anon): 4570616 kB 97339799b64SJohannes Weiner Active(file): 3143088 kB 97439799b64SJohannes Weiner Inactive(file): 3015640 kB 97539799b64SJohannes Weiner Unevictable: 0 kB 97639799b64SJohannes Weiner Mlocked: 0 kB 977c33e97efSMauro Carvalho Chehab SwapTotal: 0 kB 978c33e97efSMauro Carvalho Chehab SwapFree: 0 kB 979f6498b77SJohannes Weiner Zswap: 1904 kB 980f6498b77SJohannes Weiner Zswapped: 7792 kB 98139799b64SJohannes Weiner Dirty: 12 kB 982c33e97efSMauro Carvalho Chehab Writeback: 0 kB 98339799b64SJohannes Weiner AnonPages: 4654780 kB 98439799b64SJohannes Weiner Mapped: 266244 kB 98539799b64SJohannes Weiner Shmem: 9976 kB 98639799b64SJohannes Weiner KReclaimable: 517708 kB 98739799b64SJohannes Weiner Slab: 660044 kB 98839799b64SJohannes Weiner SReclaimable: 517708 kB 98939799b64SJohannes Weiner SUnreclaim: 142336 kB 99039799b64SJohannes Weiner KernelStack: 11168 kB 99139799b64SJohannes Weiner PageTables: 20540 kB 992ebc97a52SYosry Ahmed SecPageTables: 0 kB 993c33e97efSMauro Carvalho Chehab NFS_Unstable: 0 kB 994c33e97efSMauro Carvalho Chehab Bounce: 0 kB 995c33e97efSMauro Carvalho Chehab WritebackTmp: 0 kB 99639799b64SJohannes Weiner CommitLimit: 16429408 kB 99739799b64SJohannes Weiner Committed_AS: 7715148 kB 99839799b64SJohannes Weiner VmallocTotal: 34359738367 kB 99939799b64SJohannes Weiner VmallocUsed: 40444 kB 100039799b64SJohannes Weiner VmallocChunk: 0 kB 100139799b64SJohannes Weiner Percpu: 29312 kB 1002bd23024bSTomas Mudrunka EarlyMemtestBad: 0 kB 1003c33e97efSMauro Carvalho Chehab HardwareCorrupted: 0 kB 100439799b64SJohannes Weiner AnonHugePages: 4149248 kB 1005c33e97efSMauro Carvalho Chehab ShmemHugePages: 0 kB 1006c33e97efSMauro Carvalho Chehab ShmemPmdMapped: 0 kB 100739799b64SJohannes Weiner FileHugePages: 0 kB 100839799b64SJohannes Weiner FilePmdMapped: 0 kB 100939799b64SJohannes Weiner CmaTotal: 0 kB 101039799b64SJohannes Weiner CmaFree: 0 kB 101139799b64SJohannes Weiner HugePages_Total: 0 101239799b64SJohannes Weiner HugePages_Free: 0 101339799b64SJohannes Weiner HugePages_Rsvd: 0 101439799b64SJohannes Weiner HugePages_Surp: 0 101539799b64SJohannes Weiner Hugepagesize: 2048 kB 101639799b64SJohannes Weiner Hugetlb: 0 kB 101739799b64SJohannes Weiner DirectMap4k: 401152 kB 101839799b64SJohannes Weiner DirectMap2M: 10008576 kB 101939799b64SJohannes Weiner DirectMap1G: 24117248 kB 1020c33e97efSMauro Carvalho Chehab 1021c33e97efSMauro Carvalho ChehabMemTotal 1022059db434SRandy Dunlap Total usable RAM (i.e. physical RAM minus a few reserved 1023c33e97efSMauro Carvalho Chehab bits and the kernel binary code) 1024c33e97efSMauro Carvalho ChehabMemFree 102539799b64SJohannes Weiner Total free RAM. On highmem systems, the sum of LowFree+HighFree 1026c33e97efSMauro Carvalho ChehabMemAvailable 1027c33e97efSMauro Carvalho Chehab An estimate of how much memory is available for starting new 1028c33e97efSMauro Carvalho Chehab applications, without swapping. Calculated from MemFree, 1029c33e97efSMauro Carvalho Chehab SReclaimable, the size of the file LRU lists, and the low 1030c33e97efSMauro Carvalho Chehab watermarks in each zone. 1031c33e97efSMauro Carvalho Chehab The estimate takes into account that the system needs some 1032c33e97efSMauro Carvalho Chehab page cache to function well, and that not all reclaimable 1033c33e97efSMauro Carvalho Chehab slab will be reclaimable, due to items being in use. The 1034c33e97efSMauro Carvalho Chehab impact of those factors will vary from system to system. 1035c33e97efSMauro Carvalho ChehabBuffers 1036c33e97efSMauro Carvalho Chehab Relatively temporary storage for raw disk blocks 1037c33e97efSMauro Carvalho Chehab shouldn't get tremendously large (20MB or so) 1038c33e97efSMauro Carvalho ChehabCached 103939799b64SJohannes Weiner In-memory cache for files read from the disk (the 104039799b64SJohannes Weiner pagecache) as well as tmpfs & shmem. 104139799b64SJohannes Weiner Doesn't include SwapCached. 1042c33e97efSMauro Carvalho ChehabSwapCached 1043c33e97efSMauro Carvalho Chehab Memory that once was swapped out, is swapped back in but 1044c33e97efSMauro Carvalho Chehab still also is in the swapfile (if memory is needed it 1045c33e97efSMauro Carvalho Chehab doesn't need to be swapped out AGAIN because it is already 1046c33e97efSMauro Carvalho Chehab in the swapfile. This saves I/O) 1047c33e97efSMauro Carvalho ChehabActive 1048c33e97efSMauro Carvalho Chehab Memory that has been used more recently and usually not 1049c33e97efSMauro Carvalho Chehab reclaimed unless absolutely necessary. 1050c33e97efSMauro Carvalho ChehabInactive 1051c33e97efSMauro Carvalho Chehab Memory which has been less recently used. It is more 1052c33e97efSMauro Carvalho Chehab eligible to be reclaimed for other purposes 105339799b64SJohannes WeinerUnevictable 105439799b64SJohannes Weiner Memory allocated for userspace which cannot be reclaimed, such 105539799b64SJohannes Weiner as mlocked pages, ramfs backing pages, secret memfd pages etc. 105639799b64SJohannes WeinerMlocked 105739799b64SJohannes Weiner Memory locked with mlock(). 1058c33e97efSMauro Carvalho ChehabHighTotal, HighFree 1059059db434SRandy Dunlap Highmem is all memory above ~860MB of physical memory. 1060c33e97efSMauro Carvalho Chehab Highmem areas are for use by userspace programs, or 1061c33e97efSMauro Carvalho Chehab for the pagecache. The kernel must use tricks to access 1062c33e97efSMauro Carvalho Chehab this memory, making it slower to access than lowmem. 1063c33e97efSMauro Carvalho ChehabLowTotal, LowFree 1064c33e97efSMauro Carvalho Chehab Lowmem is memory which can be used for everything that 1065c33e97efSMauro Carvalho Chehab highmem can be used for, but it is also available for the 1066c33e97efSMauro Carvalho Chehab kernel's use for its own data structures. Among many 1067c33e97efSMauro Carvalho Chehab other things, it is where everything from the Slab is 1068c33e97efSMauro Carvalho Chehab allocated. Bad things happen when you're out of lowmem. 1069c33e97efSMauro Carvalho ChehabSwapTotal 1070c33e97efSMauro Carvalho Chehab total amount of swap space available 1071c33e97efSMauro Carvalho ChehabSwapFree 1072c33e97efSMauro Carvalho Chehab Memory which has been evicted from RAM, and is temporarily 1073c33e97efSMauro Carvalho Chehab on the disk 1074f6498b77SJohannes WeinerZswap 1075f6498b77SJohannes Weiner Memory consumed by the zswap backend (compressed size) 1076f6498b77SJohannes WeinerZswapped 1077f6498b77SJohannes Weiner Amount of anonymous memory stored in zswap (original size) 1078c33e97efSMauro Carvalho ChehabDirty 1079c33e97efSMauro Carvalho Chehab Memory which is waiting to get written back to the disk 1080c33e97efSMauro Carvalho ChehabWriteback 1081c33e97efSMauro Carvalho Chehab Memory which is actively being written back to the disk 1082c33e97efSMauro Carvalho ChehabAnonPages 1083c33e97efSMauro Carvalho Chehab Non-file backed pages mapped into userspace page tables 1084c33e97efSMauro Carvalho ChehabMapped 1085c33e97efSMauro Carvalho Chehab files which have been mmaped, such as libraries 1086c33e97efSMauro Carvalho ChehabShmem 1087c33e97efSMauro Carvalho Chehab Total memory used by shared memory (shmem) and tmpfs 1088c33e97efSMauro Carvalho ChehabKReclaimable 1089c33e97efSMauro Carvalho Chehab Kernel allocations that the kernel will attempt to reclaim 1090c33e97efSMauro Carvalho Chehab under memory pressure. Includes SReclaimable (below), and other 1091c33e97efSMauro Carvalho Chehab direct allocations with a shrinker. 1092c33e97efSMauro Carvalho ChehabSlab 1093c33e97efSMauro Carvalho Chehab in-kernel data structures cache 1094c33e97efSMauro Carvalho ChehabSReclaimable 1095c33e97efSMauro Carvalho Chehab Part of Slab, that might be reclaimed, such as caches 1096c33e97efSMauro Carvalho ChehabSUnreclaim 1097c33e97efSMauro Carvalho Chehab Part of Slab, that cannot be reclaimed on memory pressure 109839799b64SJohannes WeinerKernelStack 109939799b64SJohannes Weiner Memory consumed by the kernel stacks of all tasks 1100c33e97efSMauro Carvalho ChehabPageTables 110139799b64SJohannes Weiner Memory consumed by userspace page tables 1102ebc97a52SYosry AhmedSecPageTables 1103ebc97a52SYosry Ahmed Memory consumed by secondary page tables, this currently 1104ebc97a52SYosry Ahmed currently includes KVM mmu allocations on x86 and arm64. 1105c33e97efSMauro Carvalho ChehabNFS_Unstable 11068d92890bSNeilBrown Always zero. Previous counted pages which had been written to 11078d92890bSNeilBrown the server, but has not been committed to stable storage. 1108c33e97efSMauro Carvalho ChehabBounce 1109c33e97efSMauro Carvalho Chehab Memory used for block device "bounce buffers" 1110c33e97efSMauro Carvalho ChehabWritebackTmp 1111c33e97efSMauro Carvalho Chehab Memory used by FUSE for temporary writeback buffers 1112c33e97efSMauro Carvalho ChehabCommitLimit 1113c33e97efSMauro Carvalho Chehab Based on the overcommit ratio ('vm.overcommit_ratio'), 1114c33e97efSMauro Carvalho Chehab this is the total amount of memory currently available to 1115c33e97efSMauro Carvalho Chehab be allocated on the system. This limit is only adhered to 1116c33e97efSMauro Carvalho Chehab if strict overcommit accounting is enabled (mode 2 in 1117c33e97efSMauro Carvalho Chehab 'vm.overcommit_memory'). 1118c33e97efSMauro Carvalho Chehab 1119c33e97efSMauro Carvalho Chehab The CommitLimit is calculated with the following formula:: 1120c33e97efSMauro Carvalho Chehab 1121c33e97efSMauro Carvalho Chehab CommitLimit = ([total RAM pages] - [total huge TLB pages]) * 1122c33e97efSMauro Carvalho Chehab overcommit_ratio / 100 + [total swap pages] 1123c33e97efSMauro Carvalho Chehab 1124c33e97efSMauro Carvalho Chehab For example, on a system with 1G of physical RAM and 7G 1125c33e97efSMauro Carvalho Chehab of swap with a `vm.overcommit_ratio` of 30 it would 1126c33e97efSMauro Carvalho Chehab yield a CommitLimit of 7.3G. 1127c33e97efSMauro Carvalho Chehab 1128c33e97efSMauro Carvalho Chehab For more details, see the memory overcommit documentation 1129ee65728eSMike Rapoport in mm/overcommit-accounting. 1130c33e97efSMauro Carvalho ChehabCommitted_AS 1131c33e97efSMauro Carvalho Chehab The amount of memory presently allocated on the system. 1132c33e97efSMauro Carvalho Chehab The committed memory is a sum of all of the memory which 1133c33e97efSMauro Carvalho Chehab has been allocated by processes, even if it has not been 1134c33e97efSMauro Carvalho Chehab "used" by them as of yet. A process which malloc()'s 1G 1135c33e97efSMauro Carvalho Chehab of memory, but only touches 300M of it will show up as 1136c33e97efSMauro Carvalho Chehab using 1G. This 1G is memory which has been "committed" to 1137c33e97efSMauro Carvalho Chehab by the VM and can be used at any time by the allocating 1138c33e97efSMauro Carvalho Chehab application. With strict overcommit enabled on the system 1139c33e97efSMauro Carvalho Chehab (mode 2 in 'vm.overcommit_memory'), allocations which would 1140c33e97efSMauro Carvalho Chehab exceed the CommitLimit (detailed above) will not be permitted. 1141c33e97efSMauro Carvalho Chehab This is useful if one needs to guarantee that processes will 1142c33e97efSMauro Carvalho Chehab not fail due to lack of memory once that memory has been 1143c33e97efSMauro Carvalho Chehab successfully allocated. 1144c33e97efSMauro Carvalho ChehabVmallocTotal 114539799b64SJohannes Weiner total size of vmalloc virtual address space 1146c33e97efSMauro Carvalho ChehabVmallocUsed 1147c33e97efSMauro Carvalho Chehab amount of vmalloc area which is used 1148c33e97efSMauro Carvalho ChehabVmallocChunk 1149c33e97efSMauro Carvalho Chehab largest contiguous block of vmalloc area which is free 1150c33e97efSMauro Carvalho ChehabPercpu 1151c33e97efSMauro Carvalho Chehab Memory allocated to the percpu allocator used to back percpu 1152c33e97efSMauro Carvalho Chehab allocations. This stat excludes the cost of metadata. 1153bd23024bSTomas MudrunkaEarlyMemtestBad 1154bd23024bSTomas Mudrunka The amount of RAM/memory in kB, that was identified as corrupted 1155bd23024bSTomas Mudrunka by early memtest. If memtest was not run, this field will not 1156bd23024bSTomas Mudrunka be displayed at all. Size is never rounded down to 0 kB. 1157bd23024bSTomas Mudrunka That means if 0 kB is reported, you can safely assume 1158bd23024bSTomas Mudrunka there was at least one pass of memtest and none of the passes 1159bd23024bSTomas Mudrunka found a single faulty byte of RAM. 116039799b64SJohannes WeinerHardwareCorrupted 116139799b64SJohannes Weiner The amount of RAM/memory in KB, the kernel identifies as 116239799b64SJohannes Weiner corrupted. 116339799b64SJohannes WeinerAnonHugePages 116439799b64SJohannes Weiner Non-file backed huge pages mapped into userspace page tables 116539799b64SJohannes WeinerShmemHugePages 116639799b64SJohannes Weiner Memory used by shared memory (shmem) and tmpfs allocated 116739799b64SJohannes Weiner with huge pages 116839799b64SJohannes WeinerShmemPmdMapped 116939799b64SJohannes Weiner Shared memory mapped into userspace with huge pages 117039799b64SJohannes WeinerFileHugePages 117139799b64SJohannes Weiner Memory used for filesystem data (page cache) allocated 117239799b64SJohannes Weiner with huge pages 117339799b64SJohannes WeinerFilePmdMapped 117439799b64SJohannes Weiner Page cache mapped into userspace with huge pages 117539799b64SJohannes WeinerCmaTotal 117639799b64SJohannes Weiner Memory reserved for the Contiguous Memory Allocator (CMA) 117739799b64SJohannes WeinerCmaFree 117839799b64SJohannes Weiner Free remaining memory in the CMA reserves 117939799b64SJohannes WeinerHugePages_Total, HugePages_Free, HugePages_Rsvd, HugePages_Surp, Hugepagesize, Hugetlb 118039799b64SJohannes Weiner See Documentation/admin-guide/mm/hugetlbpage.rst. 118139799b64SJohannes WeinerDirectMap4k, DirectMap2M, DirectMap1G 118239799b64SJohannes Weiner Breakdown of page table sizes used in the kernel's 118339799b64SJohannes Weiner identity mapping of RAM 1184c33e97efSMauro Carvalho Chehab 1185c33e97efSMauro Carvalho Chehabvmallocinfo 1186c33e97efSMauro Carvalho Chehab~~~~~~~~~~~ 1187c33e97efSMauro Carvalho Chehab 1188c33e97efSMauro Carvalho ChehabProvides information about vmalloced/vmaped areas. One line per area, 1189c33e97efSMauro Carvalho Chehabcontaining the virtual address range of the area, size in bytes, 1190c33e97efSMauro Carvalho Chehabcaller information of the creator, and optional information depending 1191c33e97efSMauro Carvalho Chehabon the kind of area: 1192c33e97efSMauro Carvalho Chehab 1193c33e97efSMauro Carvalho Chehab ========== =================================================== 1194c33e97efSMauro Carvalho Chehab pages=nr number of pages 1195c33e97efSMauro Carvalho Chehab phys=addr if a physical address was specified 1196c33e97efSMauro Carvalho Chehab ioremap I/O mapping (ioremap() and friends) 1197c33e97efSMauro Carvalho Chehab vmalloc vmalloc() area 1198c33e97efSMauro Carvalho Chehab vmap vmap()ed pages 1199c33e97efSMauro Carvalho Chehab user VM_USERMAP area 1200c33e97efSMauro Carvalho Chehab vpages buffer for pages pointers was vmalloced (huge area) 1201c33e97efSMauro Carvalho Chehab N<node>=nr (Only on NUMA kernels) 1202c33e97efSMauro Carvalho Chehab Number of pages allocated on memory node <node> 1203c33e97efSMauro Carvalho Chehab ========== =================================================== 1204c33e97efSMauro Carvalho Chehab 1205c33e97efSMauro Carvalho Chehab:: 1206c33e97efSMauro Carvalho Chehab 1207c33e97efSMauro Carvalho Chehab > cat /proc/vmallocinfo 1208c33e97efSMauro Carvalho Chehab 0xffffc20000000000-0xffffc20000201000 2101248 alloc_large_system_hash+0x204 ... 1209c33e97efSMauro Carvalho Chehab /0x2c0 pages=512 vmalloc N0=128 N1=128 N2=128 N3=128 1210c33e97efSMauro Carvalho Chehab 0xffffc20000201000-0xffffc20000302000 1052672 alloc_large_system_hash+0x204 ... 1211c33e97efSMauro Carvalho Chehab /0x2c0 pages=256 vmalloc N0=64 N1=64 N2=64 N3=64 1212c33e97efSMauro Carvalho Chehab 0xffffc20000302000-0xffffc20000304000 8192 acpi_tb_verify_table+0x21/0x4f... 1213c33e97efSMauro Carvalho Chehab phys=7fee8000 ioremap 1214c33e97efSMauro Carvalho Chehab 0xffffc20000304000-0xffffc20000307000 12288 acpi_tb_verify_table+0x21/0x4f... 1215c33e97efSMauro Carvalho Chehab phys=7fee7000 ioremap 1216c33e97efSMauro Carvalho Chehab 0xffffc2000031d000-0xffffc2000031f000 8192 init_vdso_vars+0x112/0x210 1217c33e97efSMauro Carvalho Chehab 0xffffc2000031f000-0xffffc2000032b000 49152 cramfs_uncompress_init+0x2e ... 1218c33e97efSMauro Carvalho Chehab /0x80 pages=11 vmalloc N0=3 N1=3 N2=2 N3=3 1219c33e97efSMauro Carvalho Chehab 0xffffc2000033a000-0xffffc2000033d000 12288 sys_swapon+0x640/0xac0 ... 1220c33e97efSMauro Carvalho Chehab pages=2 vmalloc N1=2 1221c33e97efSMauro Carvalho Chehab 0xffffc20000347000-0xffffc2000034c000 20480 xt_alloc_table_info+0xfe ... 1222c33e97efSMauro Carvalho Chehab /0x130 [x_tables] pages=4 vmalloc N0=4 1223c33e97efSMauro Carvalho Chehab 0xffffffffa0000000-0xffffffffa000f000 61440 sys_init_module+0xc27/0x1d00 ... 1224c33e97efSMauro Carvalho Chehab pages=14 vmalloc N2=14 1225c33e97efSMauro Carvalho Chehab 0xffffffffa000f000-0xffffffffa0014000 20480 sys_init_module+0xc27/0x1d00 ... 1226c33e97efSMauro Carvalho Chehab pages=4 vmalloc N1=4 1227c33e97efSMauro Carvalho Chehab 0xffffffffa0014000-0xffffffffa0017000 12288 sys_init_module+0xc27/0x1d00 ... 1228c33e97efSMauro Carvalho Chehab pages=2 vmalloc N1=2 1229c33e97efSMauro Carvalho Chehab 0xffffffffa0017000-0xffffffffa0022000 45056 sys_init_module+0xc27/0x1d00 ... 1230c33e97efSMauro Carvalho Chehab pages=10 vmalloc N0=10 1231c33e97efSMauro Carvalho Chehab 1232c33e97efSMauro Carvalho Chehab 1233c33e97efSMauro Carvalho Chehabsoftirqs 1234c33e97efSMauro Carvalho Chehab~~~~~~~~ 1235c33e97efSMauro Carvalho Chehab 1236059db434SRandy DunlapProvides counts of softirq handlers serviced since boot time, for each CPU. 1237c33e97efSMauro Carvalho Chehab 1238c33e97efSMauro Carvalho Chehab:: 1239c33e97efSMauro Carvalho Chehab 1240c33e97efSMauro Carvalho Chehab > cat /proc/softirqs 1241c33e97efSMauro Carvalho Chehab CPU0 CPU1 CPU2 CPU3 1242c33e97efSMauro Carvalho Chehab HI: 0 0 0 0 1243c33e97efSMauro Carvalho Chehab TIMER: 27166 27120 27097 27034 1244c33e97efSMauro Carvalho Chehab NET_TX: 0 0 0 17 1245c33e97efSMauro Carvalho Chehab NET_RX: 42 0 0 39 1246c33e97efSMauro Carvalho Chehab BLOCK: 0 0 107 1121 1247c33e97efSMauro Carvalho Chehab TASKLET: 0 0 0 290 1248c33e97efSMauro Carvalho Chehab SCHED: 27035 26983 26971 26746 1249c33e97efSMauro Carvalho Chehab HRTIMER: 0 0 0 0 1250c33e97efSMauro Carvalho Chehab RCU: 1678 1769 2178 2250 1251c33e97efSMauro Carvalho Chehab 1252e24ccaafSPaul Gortmaker1.3 Networking info in /proc/net 1253c33e97efSMauro Carvalho Chehab-------------------------------- 1254c33e97efSMauro Carvalho Chehab 1255c33e97efSMauro Carvalho ChehabThe subdirectory /proc/net follows the usual pattern. Table 1-8 shows the 1256c33e97efSMauro Carvalho Chehabadditional values you get for IP version 6 if you configure the kernel to 1257c33e97efSMauro Carvalho Chehabsupport this. Table 1-9 lists the files and their meaning. 1258c33e97efSMauro Carvalho Chehab 1259c33e97efSMauro Carvalho Chehab 1260c33e97efSMauro Carvalho Chehab.. table:: Table 1-8: IPv6 info in /proc/net 1261c33e97efSMauro Carvalho Chehab 1262c33e97efSMauro Carvalho Chehab ========== ===================================================== 1263c33e97efSMauro Carvalho Chehab File Content 1264c33e97efSMauro Carvalho Chehab ========== ===================================================== 1265c33e97efSMauro Carvalho Chehab udp6 UDP sockets (IPv6) 1266c33e97efSMauro Carvalho Chehab tcp6 TCP sockets (IPv6) 1267c33e97efSMauro Carvalho Chehab raw6 Raw device statistics (IPv6) 1268c33e97efSMauro Carvalho Chehab igmp6 IP multicast addresses, which this host joined (IPv6) 1269c33e97efSMauro Carvalho Chehab if_inet6 List of IPv6 interface addresses 1270c33e97efSMauro Carvalho Chehab ipv6_route Kernel routing table for IPv6 1271c33e97efSMauro Carvalho Chehab rt6_stats Global IPv6 routing tables statistics 1272c33e97efSMauro Carvalho Chehab sockstat6 Socket statistics (IPv6) 1273c33e97efSMauro Carvalho Chehab snmp6 Snmp data (IPv6) 1274c33e97efSMauro Carvalho Chehab ========== ===================================================== 1275c33e97efSMauro Carvalho Chehab 1276c33e97efSMauro Carvalho Chehab.. table:: Table 1-9: Network info in /proc/net 1277c33e97efSMauro Carvalho Chehab 1278c33e97efSMauro Carvalho Chehab ============= ================================================================ 1279c33e97efSMauro Carvalho Chehab File Content 1280c33e97efSMauro Carvalho Chehab ============= ================================================================ 1281c33e97efSMauro Carvalho Chehab arp Kernel ARP table 1282c33e97efSMauro Carvalho Chehab dev network devices with statistics 1283c33e97efSMauro Carvalho Chehab dev_mcast the Layer2 multicast groups a device is listening too 1284c33e97efSMauro Carvalho Chehab (interface index, label, number of references, number of bound 1285c33e97efSMauro Carvalho Chehab addresses). 1286c33e97efSMauro Carvalho Chehab dev_stat network device status 1287c33e97efSMauro Carvalho Chehab ip_fwchains Firewall chain linkage 1288c33e97efSMauro Carvalho Chehab ip_fwnames Firewall chain names 1289c33e97efSMauro Carvalho Chehab ip_masq Directory containing the masquerading tables 1290c33e97efSMauro Carvalho Chehab ip_masquerade Major masquerading table 1291c33e97efSMauro Carvalho Chehab netstat Network statistics 1292c33e97efSMauro Carvalho Chehab raw raw device statistics 1293c33e97efSMauro Carvalho Chehab route Kernel routing table 1294c33e97efSMauro Carvalho Chehab rpc Directory containing rpc info 1295c33e97efSMauro Carvalho Chehab rt_cache Routing cache 1296c33e97efSMauro Carvalho Chehab snmp SNMP data 1297c33e97efSMauro Carvalho Chehab sockstat Socket statistics 12988b0a211dSYang Yang softnet_stat Per-CPU incoming packets queues statistics of online CPUs 1299c33e97efSMauro Carvalho Chehab tcp TCP sockets 1300c33e97efSMauro Carvalho Chehab udp UDP sockets 1301c33e97efSMauro Carvalho Chehab unix UNIX domain sockets 1302c33e97efSMauro Carvalho Chehab wireless Wireless interface data (Wavelan etc) 1303c33e97efSMauro Carvalho Chehab igmp IP multicast addresses, which this host joined 1304c33e97efSMauro Carvalho Chehab psched Global packet scheduler parameters. 1305c33e97efSMauro Carvalho Chehab netlink List of PF_NETLINK sockets 1306c33e97efSMauro Carvalho Chehab ip_mr_vifs List of multicast virtual interfaces 1307c33e97efSMauro Carvalho Chehab ip_mr_cache List of multicast routing cache 1308c33e97efSMauro Carvalho Chehab ============= ================================================================ 1309c33e97efSMauro Carvalho Chehab 1310c33e97efSMauro Carvalho ChehabYou can use this information to see which network devices are available in 1311c33e97efSMauro Carvalho Chehabyour system and how much traffic was routed over those devices:: 1312c33e97efSMauro Carvalho Chehab 1313c33e97efSMauro Carvalho Chehab > cat /proc/net/dev 1314c33e97efSMauro Carvalho Chehab Inter-|Receive |[... 1315c33e97efSMauro Carvalho Chehab face |bytes packets errs drop fifo frame compressed multicast|[... 1316c33e97efSMauro Carvalho Chehab lo: 908188 5596 0 0 0 0 0 0 [... 1317c33e97efSMauro Carvalho Chehab ppp0:15475140 20721 410 0 0 410 0 0 [... 1318c33e97efSMauro Carvalho Chehab eth0: 614530 7085 0 0 0 0 0 1 [... 1319c33e97efSMauro Carvalho Chehab 1320c33e97efSMauro Carvalho Chehab ...] Transmit 1321c33e97efSMauro Carvalho Chehab ...] bytes packets errs drop fifo colls carrier compressed 1322c33e97efSMauro Carvalho Chehab ...] 908188 5596 0 0 0 0 0 0 1323c33e97efSMauro Carvalho Chehab ...] 1375103 17405 0 0 0 0 0 0 1324c33e97efSMauro Carvalho Chehab ...] 1703981 5535 0 0 0 3 0 0 1325c33e97efSMauro Carvalho Chehab 1326c33e97efSMauro Carvalho ChehabIn addition, each Channel Bond interface has its own directory. For 1327c33e97efSMauro Carvalho Chehabexample, the bond0 device will have a directory called /proc/net/bond0/. 1328c33e97efSMauro Carvalho ChehabIt will contain information that is specific to that bond, such as the 1329c33e97efSMauro Carvalho Chehabcurrent slaves of the bond, the link status of the slaves, and how 1330c33e97efSMauro Carvalho Chehabmany times the slaves link has failed. 1331c33e97efSMauro Carvalho Chehab 1332e24ccaafSPaul Gortmaker1.4 SCSI info 1333c33e97efSMauro Carvalho Chehab------------- 1334c33e97efSMauro Carvalho Chehab 1335d2ea66a6SRandy DunlapIf you have a SCSI or ATA host adapter in your system, you'll find a 1336d2ea66a6SRandy Dunlapsubdirectory named after the driver for this adapter in /proc/scsi. 1337d2ea66a6SRandy DunlapYou'll also see a list of all recognized SCSI devices in /proc/scsi:: 1338c33e97efSMauro Carvalho Chehab 1339c33e97efSMauro Carvalho Chehab >cat /proc/scsi/scsi 1340c33e97efSMauro Carvalho Chehab Attached devices: 1341c33e97efSMauro Carvalho Chehab Host: scsi0 Channel: 00 Id: 00 Lun: 00 1342c33e97efSMauro Carvalho Chehab Vendor: IBM Model: DGHS09U Rev: 03E0 1343c33e97efSMauro Carvalho Chehab Type: Direct-Access ANSI SCSI revision: 03 1344c33e97efSMauro Carvalho Chehab Host: scsi0 Channel: 00 Id: 06 Lun: 00 1345c33e97efSMauro Carvalho Chehab Vendor: PIONEER Model: CD-ROM DR-U06S Rev: 1.04 1346c33e97efSMauro Carvalho Chehab Type: CD-ROM ANSI SCSI revision: 02 1347c33e97efSMauro Carvalho Chehab 1348c33e97efSMauro Carvalho Chehab 1349c33e97efSMauro Carvalho ChehabThe directory named after the driver has one file for each adapter found in 1350c33e97efSMauro Carvalho Chehabthe system. These files contain information about the controller, including 1351c33e97efSMauro Carvalho Chehabthe used IRQ and the IO address range. The amount of information shown is 1352c33e97efSMauro Carvalho Chehabdependent on the adapter you use. The example shows the output for an Adaptec 1353c33e97efSMauro Carvalho ChehabAHA-2940 SCSI adapter:: 1354c33e97efSMauro Carvalho Chehab 1355c33e97efSMauro Carvalho Chehab > cat /proc/scsi/aic7xxx/0 1356c33e97efSMauro Carvalho Chehab 1357c33e97efSMauro Carvalho Chehab Adaptec AIC7xxx driver version: 5.1.19/3.2.4 1358c33e97efSMauro Carvalho Chehab Compile Options: 1359c33e97efSMauro Carvalho Chehab TCQ Enabled By Default : Disabled 1360c33e97efSMauro Carvalho Chehab AIC7XXX_PROC_STATS : Disabled 1361c33e97efSMauro Carvalho Chehab AIC7XXX_RESET_DELAY : 5 1362c33e97efSMauro Carvalho Chehab Adapter Configuration: 1363c33e97efSMauro Carvalho Chehab SCSI Adapter: Adaptec AHA-294X Ultra SCSI host adapter 1364c33e97efSMauro Carvalho Chehab Ultra Wide Controller 1365c33e97efSMauro Carvalho Chehab PCI MMAPed I/O Base: 0xeb001000 1366c33e97efSMauro Carvalho Chehab Adapter SEEPROM Config: SEEPROM found and used. 1367c33e97efSMauro Carvalho Chehab Adaptec SCSI BIOS: Enabled 1368c33e97efSMauro Carvalho Chehab IRQ: 10 1369c33e97efSMauro Carvalho Chehab SCBs: Active 0, Max Active 2, 1370c33e97efSMauro Carvalho Chehab Allocated 15, HW 16, Page 255 1371c33e97efSMauro Carvalho Chehab Interrupts: 160328 1372c33e97efSMauro Carvalho Chehab BIOS Control Word: 0x18b6 1373c33e97efSMauro Carvalho Chehab Adapter Control Word: 0x005b 1374c33e97efSMauro Carvalho Chehab Extended Translation: Enabled 1375c33e97efSMauro Carvalho Chehab Disconnect Enable Flags: 0xffff 1376c33e97efSMauro Carvalho Chehab Ultra Enable Flags: 0x0001 1377c33e97efSMauro Carvalho Chehab Tag Queue Enable Flags: 0x0000 1378c33e97efSMauro Carvalho Chehab Ordered Queue Tag Flags: 0x0000 1379c33e97efSMauro Carvalho Chehab Default Tag Queue Depth: 8 1380c33e97efSMauro Carvalho Chehab Tagged Queue By Device array for aic7xxx host instance 0: 1381c33e97efSMauro Carvalho Chehab {255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255} 1382c33e97efSMauro Carvalho Chehab Actual queue depth per device for aic7xxx host instance 0: 1383c33e97efSMauro Carvalho Chehab {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1} 1384c33e97efSMauro Carvalho Chehab Statistics: 1385c33e97efSMauro Carvalho Chehab (scsi0:0:0:0) 1386c33e97efSMauro Carvalho Chehab Device using Wide/Sync transfers at 40.0 MByte/sec, offset 8 1387c33e97efSMauro Carvalho Chehab Transinfo settings: current(12/8/1/0), goal(12/8/1/0), user(12/15/1/0) 1388c33e97efSMauro Carvalho Chehab Total transfers 160151 (74577 reads and 85574 writes) 1389c33e97efSMauro Carvalho Chehab (scsi0:0:6:0) 1390c33e97efSMauro Carvalho Chehab Device using Narrow/Sync transfers at 5.0 MByte/sec, offset 15 1391c33e97efSMauro Carvalho Chehab Transinfo settings: current(50/15/0/0), goal(50/15/0/0), user(50/15/0/0) 1392c33e97efSMauro Carvalho Chehab Total transfers 0 (0 reads and 0 writes) 1393c33e97efSMauro Carvalho Chehab 1394c33e97efSMauro Carvalho Chehab 1395e24ccaafSPaul Gortmaker1.5 Parallel port info in /proc/parport 1396c33e97efSMauro Carvalho Chehab--------------------------------------- 1397c33e97efSMauro Carvalho Chehab 1398c33e97efSMauro Carvalho ChehabThe directory /proc/parport contains information about the parallel ports of 1399c33e97efSMauro Carvalho Chehabyour system. It has one subdirectory for each port, named after the port 1400c33e97efSMauro Carvalho Chehabnumber (0,1,2,...). 1401c33e97efSMauro Carvalho Chehab 1402c33e97efSMauro Carvalho ChehabThese directories contain the four files shown in Table 1-10. 1403c33e97efSMauro Carvalho Chehab 1404c33e97efSMauro Carvalho Chehab 1405c33e97efSMauro Carvalho Chehab.. table:: Table 1-10: Files in /proc/parport 1406c33e97efSMauro Carvalho Chehab 1407c33e97efSMauro Carvalho Chehab ========= ==================================================================== 1408c33e97efSMauro Carvalho Chehab File Content 1409c33e97efSMauro Carvalho Chehab ========= ==================================================================== 1410c33e97efSMauro Carvalho Chehab autoprobe Any IEEE-1284 device ID information that has been acquired. 1411c33e97efSMauro Carvalho Chehab devices list of the device drivers using that port. A + will appear by the 1412c33e97efSMauro Carvalho Chehab name of the device currently using the port (it might not appear 1413c33e97efSMauro Carvalho Chehab against any). 1414c33e97efSMauro Carvalho Chehab hardware Parallel port's base address, IRQ line and DMA channel. 1415c33e97efSMauro Carvalho Chehab irq IRQ that parport is using for that port. This is in a separate 1416c33e97efSMauro Carvalho Chehab file to allow you to alter it by writing a new value in (IRQ 1417c33e97efSMauro Carvalho Chehab number or none). 1418c33e97efSMauro Carvalho Chehab ========= ==================================================================== 1419c33e97efSMauro Carvalho Chehab 1420e24ccaafSPaul Gortmaker1.6 TTY info in /proc/tty 1421c33e97efSMauro Carvalho Chehab------------------------- 1422c33e97efSMauro Carvalho Chehab 1423c33e97efSMauro Carvalho ChehabInformation about the available and actually used tty's can be found in the 1424c33e97efSMauro Carvalho Chehabdirectory /proc/tty. You'll find entries for drivers and line disciplines in 1425c33e97efSMauro Carvalho Chehabthis directory, as shown in Table 1-11. 1426c33e97efSMauro Carvalho Chehab 1427c33e97efSMauro Carvalho Chehab 1428c33e97efSMauro Carvalho Chehab.. table:: Table 1-11: Files in /proc/tty 1429c33e97efSMauro Carvalho Chehab 1430c33e97efSMauro Carvalho Chehab ============= ============================================== 1431c33e97efSMauro Carvalho Chehab File Content 1432c33e97efSMauro Carvalho Chehab ============= ============================================== 1433c33e97efSMauro Carvalho Chehab drivers list of drivers and their usage 1434c33e97efSMauro Carvalho Chehab ldiscs registered line disciplines 1435c33e97efSMauro Carvalho Chehab driver/serial usage statistic and status of single tty lines 1436c33e97efSMauro Carvalho Chehab ============= ============================================== 1437c33e97efSMauro Carvalho Chehab 1438c33e97efSMauro Carvalho ChehabTo see which tty's are currently in use, you can simply look into the file 1439c33e97efSMauro Carvalho Chehab/proc/tty/drivers:: 1440c33e97efSMauro Carvalho Chehab 1441c33e97efSMauro Carvalho Chehab > cat /proc/tty/drivers 1442c33e97efSMauro Carvalho Chehab pty_slave /dev/pts 136 0-255 pty:slave 1443c33e97efSMauro Carvalho Chehab pty_master /dev/ptm 128 0-255 pty:master 1444c33e97efSMauro Carvalho Chehab pty_slave /dev/ttyp 3 0-255 pty:slave 1445c33e97efSMauro Carvalho Chehab pty_master /dev/pty 2 0-255 pty:master 1446c33e97efSMauro Carvalho Chehab serial /dev/cua 5 64-67 serial:callout 1447c33e97efSMauro Carvalho Chehab serial /dev/ttyS 4 64-67 serial 1448c33e97efSMauro Carvalho Chehab /dev/tty0 /dev/tty0 4 0 system:vtmaster 1449c33e97efSMauro Carvalho Chehab /dev/ptmx /dev/ptmx 5 2 system 1450c33e97efSMauro Carvalho Chehab /dev/console /dev/console 5 1 system:console 1451c33e97efSMauro Carvalho Chehab /dev/tty /dev/tty 5 0 system:/dev/tty 1452c33e97efSMauro Carvalho Chehab unknown /dev/tty 4 1-63 console 1453c33e97efSMauro Carvalho Chehab 1454c33e97efSMauro Carvalho Chehab 1455e24ccaafSPaul Gortmaker1.7 Miscellaneous kernel statistics in /proc/stat 1456c33e97efSMauro Carvalho Chehab------------------------------------------------- 1457c33e97efSMauro Carvalho Chehab 1458c33e97efSMauro Carvalho ChehabVarious pieces of information about kernel activity are available in the 1459c33e97efSMauro Carvalho Chehab/proc/stat file. All of the numbers reported in this file are aggregates 1460c33e97efSMauro Carvalho Chehabsince the system first booted. For a quick look, simply cat the file:: 1461c33e97efSMauro Carvalho Chehab 1462c33e97efSMauro Carvalho Chehab > cat /proc/stat 1463d2ea66a6SRandy Dunlap cpu 237902850 368826709 106375398 1873517540 1135548 0 14507935 0 0 0 1464d2ea66a6SRandy Dunlap cpu0 60045249 91891769 26331539 468411416 495718 0 5739640 0 0 0 1465d2ea66a6SRandy Dunlap cpu1 59746288 91759249 26609887 468860630 312281 0 4384817 0 0 0 1466d2ea66a6SRandy Dunlap cpu2 59489247 92985423 26904446 467808813 171668 0 2268998 0 0 0 1467d2ea66a6SRandy Dunlap cpu3 58622065 92190267 26529524 468436680 155879 0 2114478 0 0 0 1468d2ea66a6SRandy Dunlap intr 8688370575 8 3373 0 0 0 0 0 0 1 40791 0 0 353317 0 0 0 0 224789828 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 190974333 41958554 123983334 43 0 224593 0 0 0 <more 0's deleted> 1469d2ea66a6SRandy Dunlap ctxt 22848221062 1470d2ea66a6SRandy Dunlap btime 1605316999 1471d2ea66a6SRandy Dunlap processes 746787147 1472d2ea66a6SRandy Dunlap procs_running 2 1473c33e97efSMauro Carvalho Chehab procs_blocked 0 1474d2ea66a6SRandy Dunlap softirq 12121874454 100099120 3938138295 127375644 2795979 187870761 0 173808342 3072582055 52608 224184354 1475c33e97efSMauro Carvalho Chehab 1476c33e97efSMauro Carvalho ChehabThe very first "cpu" line aggregates the numbers in all of the other "cpuN" 1477c33e97efSMauro Carvalho Chehablines. These numbers identify the amount of time the CPU has spent performing 1478c33e97efSMauro Carvalho Chehabdifferent kinds of work. Time units are in USER_HZ (typically hundredths of a 1479c33e97efSMauro Carvalho Chehabsecond). The meanings of the columns are as follows, from left to right: 1480c33e97efSMauro Carvalho Chehab 1481c33e97efSMauro Carvalho Chehab- user: normal processes executing in user mode 1482c33e97efSMauro Carvalho Chehab- nice: niced processes executing in user mode 1483c33e97efSMauro Carvalho Chehab- system: processes executing in kernel mode 1484c33e97efSMauro Carvalho Chehab- idle: twiddling thumbs 1485c33e97efSMauro Carvalho Chehab- iowait: In a word, iowait stands for waiting for I/O to complete. But there 1486c33e97efSMauro Carvalho Chehab are several problems: 1487c33e97efSMauro Carvalho Chehab 1488059db434SRandy Dunlap 1. CPU will not wait for I/O to complete, iowait is the time that a task is 1489059db434SRandy Dunlap waiting for I/O to complete. When CPU goes into idle state for 1490059db434SRandy Dunlap outstanding task I/O, another task will be scheduled on this CPU. 1491c33e97efSMauro Carvalho Chehab 2. In a multi-core CPU, the task waiting for I/O to complete is not running 1492c33e97efSMauro Carvalho Chehab on any CPU, so the iowait of each CPU is difficult to calculate. 1493c33e97efSMauro Carvalho Chehab 3. The value of iowait field in /proc/stat will decrease in certain 1494c33e97efSMauro Carvalho Chehab conditions. 1495c33e97efSMauro Carvalho Chehab 1496c33e97efSMauro Carvalho Chehab So, the iowait is not reliable by reading from /proc/stat. 1497c33e97efSMauro Carvalho Chehab- irq: servicing interrupts 1498c33e97efSMauro Carvalho Chehab- softirq: servicing softirqs 1499c33e97efSMauro Carvalho Chehab- steal: involuntary wait 1500c33e97efSMauro Carvalho Chehab- guest: running a normal guest 1501c33e97efSMauro Carvalho Chehab- guest_nice: running a niced guest 1502c33e97efSMauro Carvalho Chehab 1503c33e97efSMauro Carvalho ChehabThe "intr" line gives counts of interrupts serviced since boot time, for each 1504c33e97efSMauro Carvalho Chehabof the possible system interrupts. The first column is the total of all 1505c33e97efSMauro Carvalho Chehabinterrupts serviced including unnumbered architecture specific interrupts; 1506c33e97efSMauro Carvalho Chehabeach subsequent column is the total for that particular numbered interrupt. 1507c33e97efSMauro Carvalho ChehabUnnumbered interrupts are not shown, only summed into the total. 1508c33e97efSMauro Carvalho Chehab 1509c33e97efSMauro Carvalho ChehabThe "ctxt" line gives the total number of context switches across all CPUs. 1510c33e97efSMauro Carvalho Chehab 1511c33e97efSMauro Carvalho ChehabThe "btime" line gives the time at which the system booted, in seconds since 1512c33e97efSMauro Carvalho Chehabthe Unix epoch. 1513c33e97efSMauro Carvalho Chehab 1514c33e97efSMauro Carvalho ChehabThe "processes" line gives the number of processes and threads created, which 1515c33e97efSMauro Carvalho Chehabincludes (but is not limited to) those created by calls to the fork() and 1516c33e97efSMauro Carvalho Chehabclone() system calls. 1517c33e97efSMauro Carvalho Chehab 1518c33e97efSMauro Carvalho ChehabThe "procs_running" line gives the total number of threads that are 1519c33e97efSMauro Carvalho Chehabrunning or ready to run (i.e., the total number of runnable threads). 1520c33e97efSMauro Carvalho Chehab 1521c33e97efSMauro Carvalho ChehabThe "procs_blocked" line gives the number of processes currently blocked, 1522c33e97efSMauro Carvalho Chehabwaiting for I/O to complete. 1523c33e97efSMauro Carvalho Chehab 1524c33e97efSMauro Carvalho ChehabThe "softirq" line gives counts of softirqs serviced since boot time, for each 1525c33e97efSMauro Carvalho Chehabof the possible system softirqs. The first column is the total of all 1526c33e97efSMauro Carvalho Chehabsoftirqs serviced; each subsequent column is the total for that particular 1527c33e97efSMauro Carvalho Chehabsoftirq. 1528c33e97efSMauro Carvalho Chehab 1529c33e97efSMauro Carvalho Chehab 1530e24ccaafSPaul Gortmaker1.8 Ext4 file system parameters 1531c33e97efSMauro Carvalho Chehab------------------------------- 1532c33e97efSMauro Carvalho Chehab 1533c33e97efSMauro Carvalho ChehabInformation about mounted ext4 file systems can be found in 1534c33e97efSMauro Carvalho Chehab/proc/fs/ext4. Each mounted filesystem will have a directory in 1535c33e97efSMauro Carvalho Chehab/proc/fs/ext4 based on its device name (i.e., /proc/fs/ext4/hdc or 1536d2ea66a6SRandy Dunlap/proc/fs/ext4/sda9 or /proc/fs/ext4/dm-0). The files in each per-device 1537d2ea66a6SRandy Dunlapdirectory are shown in Table 1-12, below. 1538c33e97efSMauro Carvalho Chehab 1539c33e97efSMauro Carvalho Chehab.. table:: Table 1-12: Files in /proc/fs/ext4/<devname> 1540c33e97efSMauro Carvalho Chehab 1541c33e97efSMauro Carvalho Chehab ============== ========================================================== 1542c33e97efSMauro Carvalho Chehab File Content 1543c33e97efSMauro Carvalho Chehab mb_groups details of multiblock allocator buddy cache of free blocks 1544c33e97efSMauro Carvalho Chehab ============== ========================================================== 1545c33e97efSMauro Carvalho Chehab 1546e24ccaafSPaul Gortmaker1.9 /proc/consoles 1547059db434SRandy Dunlap------------------- 1548c33e97efSMauro Carvalho ChehabShows registered system console lines. 1549c33e97efSMauro Carvalho Chehab 1550c33e97efSMauro Carvalho ChehabTo see which character device lines are currently used for the system console 1551c33e97efSMauro Carvalho Chehab/dev/console, you may simply look into the file /proc/consoles:: 1552c33e97efSMauro Carvalho Chehab 1553c33e97efSMauro Carvalho Chehab > cat /proc/consoles 1554c33e97efSMauro Carvalho Chehab tty0 -WU (ECp) 4:7 1555c33e97efSMauro Carvalho Chehab ttyS0 -W- (Ep) 4:64 1556c33e97efSMauro Carvalho Chehab 1557c33e97efSMauro Carvalho ChehabThe columns are: 1558c33e97efSMauro Carvalho Chehab 1559c33e97efSMauro Carvalho Chehab+--------------------+-------------------------------------------------------+ 1560c33e97efSMauro Carvalho Chehab| device | name of the device | 1561c33e97efSMauro Carvalho Chehab+====================+=======================================================+ 1562c33e97efSMauro Carvalho Chehab| operations | * R = can do read operations | 1563c33e97efSMauro Carvalho Chehab| | * W = can do write operations | 1564c33e97efSMauro Carvalho Chehab| | * U = can do unblank | 1565c33e97efSMauro Carvalho Chehab+--------------------+-------------------------------------------------------+ 1566c33e97efSMauro Carvalho Chehab| flags | * E = it is enabled | 1567c33e97efSMauro Carvalho Chehab| | * C = it is preferred console | 1568c33e97efSMauro Carvalho Chehab| | * B = it is primary boot console | 1569c33e97efSMauro Carvalho Chehab| | * p = it is used for printk buffer | 1570c33e97efSMauro Carvalho Chehab| | * b = it is not a TTY but a Braille device | 1571c33e97efSMauro Carvalho Chehab| | * a = it is safe to use when cpu is offline | 1572c33e97efSMauro Carvalho Chehab+--------------------+-------------------------------------------------------+ 1573c33e97efSMauro Carvalho Chehab| major:minor | major and minor number of the device separated by a | 1574c33e97efSMauro Carvalho Chehab| | colon | 1575c33e97efSMauro Carvalho Chehab+--------------------+-------------------------------------------------------+ 1576c33e97efSMauro Carvalho Chehab 1577c33e97efSMauro Carvalho ChehabSummary 1578c33e97efSMauro Carvalho Chehab------- 1579c33e97efSMauro Carvalho Chehab 1580c33e97efSMauro Carvalho ChehabThe /proc file system serves information about the running system. It not only 1581c33e97efSMauro Carvalho Chehaballows access to process data but also allows you to request the kernel status 1582c33e97efSMauro Carvalho Chehabby reading files in the hierarchy. 1583c33e97efSMauro Carvalho Chehab 1584c33e97efSMauro Carvalho ChehabThe directory structure of /proc reflects the types of information and makes 1585c33e97efSMauro Carvalho Chehabit easy, if not obvious, where to look for specific data. 1586c33e97efSMauro Carvalho Chehab 1587c33e97efSMauro Carvalho ChehabChapter 2: Modifying System Parameters 1588c33e97efSMauro Carvalho Chehab====================================== 1589c33e97efSMauro Carvalho Chehab 1590c33e97efSMauro Carvalho ChehabIn This Chapter 1591c33e97efSMauro Carvalho Chehab--------------- 1592c33e97efSMauro Carvalho Chehab 1593c33e97efSMauro Carvalho Chehab* Modifying kernel parameters by writing into files found in /proc/sys 1594c33e97efSMauro Carvalho Chehab* Exploring the files which modify certain parameters 1595c33e97efSMauro Carvalho Chehab* Review of the /proc/sys file tree 1596c33e97efSMauro Carvalho Chehab 1597c33e97efSMauro Carvalho Chehab------------------------------------------------------------------------------ 1598c33e97efSMauro Carvalho Chehab 1599c33e97efSMauro Carvalho ChehabA very interesting part of /proc is the directory /proc/sys. This is not only 1600c33e97efSMauro Carvalho Chehaba source of information, it also allows you to change parameters within the 1601c33e97efSMauro Carvalho Chehabkernel. Be very careful when attempting this. You can optimize your system, 1602c33e97efSMauro Carvalho Chehabbut you can also cause it to crash. Never alter kernel parameters on a 1603c33e97efSMauro Carvalho Chehabproduction system. Set up a development machine and test to make sure that 1604c33e97efSMauro Carvalho Chehabeverything works the way you want it to. You may have no alternative but to 1605c33e97efSMauro Carvalho Chehabreboot the machine once an error has been made. 1606c33e97efSMauro Carvalho Chehab 1607059db434SRandy DunlapTo change a value, simply echo the new value into the file. 1608059db434SRandy DunlapYou need to be root to do this. You can create your own boot script 1609059db434SRandy Dunlapto perform this every time your system boots. 1610c33e97efSMauro Carvalho Chehab 1611c33e97efSMauro Carvalho ChehabThe files in /proc/sys can be used to fine tune and monitor miscellaneous and 1612c33e97efSMauro Carvalho Chehabgeneral things in the operation of the Linux kernel. Since some of the files 1613c33e97efSMauro Carvalho Chehabcan inadvertently disrupt your system, it is advisable to read both 1614c33e97efSMauro Carvalho Chehabdocumentation and source before actually making adjustments. In any case, be 1615c33e97efSMauro Carvalho Chehabvery careful when writing to any of these files. The entries in /proc may 1616c33e97efSMauro Carvalho Chehabchange slightly between the 2.1.* and the 2.2 kernel, so if there is any doubt 1617d2ea66a6SRandy Dunlapreview the kernel documentation in the directory linux/Documentation. 1618c33e97efSMauro Carvalho ChehabThis chapter is heavily based on the documentation included in the pre 2.2 1619c33e97efSMauro Carvalho Chehabkernels, and became part of it in version 2.2.1 of the Linux kernel. 1620c33e97efSMauro Carvalho Chehab 1621d2ea66a6SRandy DunlapPlease see: Documentation/admin-guide/sysctl/ directory for descriptions of 1622d2ea66a6SRandy Dunlapthese entries. 1623c33e97efSMauro Carvalho Chehab 1624c33e97efSMauro Carvalho ChehabSummary 1625c33e97efSMauro Carvalho Chehab------- 1626c33e97efSMauro Carvalho Chehab 1627c33e97efSMauro Carvalho ChehabCertain aspects of kernel behavior can be modified at runtime, without the 1628c33e97efSMauro Carvalho Chehabneed to recompile the kernel, or even to reboot the system. The files in the 1629c33e97efSMauro Carvalho Chehab/proc/sys tree can not only be read, but also modified. You can use the echo 1630c33e97efSMauro Carvalho Chehabcommand to write value into these files, thereby changing the default settings 1631c33e97efSMauro Carvalho Chehabof the kernel. 1632c33e97efSMauro Carvalho Chehab 1633c33e97efSMauro Carvalho Chehab 1634c33e97efSMauro Carvalho ChehabChapter 3: Per-process Parameters 1635c33e97efSMauro Carvalho Chehab================================= 1636c33e97efSMauro Carvalho Chehab 1637c33e97efSMauro Carvalho Chehab3.1 /proc/<pid>/oom_adj & /proc/<pid>/oom_score_adj- Adjust the oom-killer score 1638c33e97efSMauro Carvalho Chehab-------------------------------------------------------------------------------- 1639c33e97efSMauro Carvalho Chehab 1640059db434SRandy DunlapThese files can be used to adjust the badness heuristic used to select which 1641059db434SRandy Dunlapprocess gets killed in out of memory (oom) conditions. 1642c33e97efSMauro Carvalho Chehab 1643c33e97efSMauro Carvalho ChehabThe badness heuristic assigns a value to each candidate task ranging from 0 1644c33e97efSMauro Carvalho Chehab(never kill) to 1000 (always kill) to determine which process is targeted. The 1645c33e97efSMauro Carvalho Chehabunits are roughly a proportion along that range of allowed memory the process 1646c33e97efSMauro Carvalho Chehabmay allocate from based on an estimation of its current memory and swap use. 1647c33e97efSMauro Carvalho ChehabFor example, if a task is using all allowed memory, its badness score will be 1648c33e97efSMauro Carvalho Chehab1000. If it is using half of its allowed memory, its score will be 500. 1649c33e97efSMauro Carvalho Chehab 1650c33e97efSMauro Carvalho ChehabThe amount of "allowed" memory depends on the context in which the oom killer 1651c33e97efSMauro Carvalho Chehabwas called. If it is due to the memory assigned to the allocating task's cpuset 1652c33e97efSMauro Carvalho Chehabbeing exhausted, the allowed memory represents the set of mems assigned to that 1653c33e97efSMauro Carvalho Chehabcpuset. If it is due to a mempolicy's node(s) being exhausted, the allowed 1654c33e97efSMauro Carvalho Chehabmemory represents the set of mempolicy nodes. If it is due to a memory 1655c33e97efSMauro Carvalho Chehablimit (or swap limit) being reached, the allowed memory is that configured 1656c33e97efSMauro Carvalho Chehablimit. Finally, if it is due to the entire system being out of memory, the 1657c33e97efSMauro Carvalho Chehaballowed memory represents all allocatable resources. 1658c33e97efSMauro Carvalho Chehab 1659c33e97efSMauro Carvalho ChehabThe value of /proc/<pid>/oom_score_adj is added to the badness score before it 1660c33e97efSMauro Carvalho Chehabis used to determine which task to kill. Acceptable values range from -1000 1661c33e97efSMauro Carvalho Chehab(OOM_SCORE_ADJ_MIN) to +1000 (OOM_SCORE_ADJ_MAX). This allows userspace to 1662c33e97efSMauro Carvalho Chehabpolarize the preference for oom killing either by always preferring a certain 1663c33e97efSMauro Carvalho Chehabtask or completely disabling it. The lowest possible value, -1000, is 1664c33e97efSMauro Carvalho Chehabequivalent to disabling oom killing entirely for that task since it will always 1665c33e97efSMauro Carvalho Chehabreport a badness score of 0. 1666c33e97efSMauro Carvalho Chehab 1667c33e97efSMauro Carvalho ChehabConsequently, it is very simple for userspace to define the amount of memory to 1668c33e97efSMauro Carvalho Chehabconsider for each task. Setting a /proc/<pid>/oom_score_adj value of +500, for 1669c33e97efSMauro Carvalho Chehabexample, is roughly equivalent to allowing the remainder of tasks sharing the 1670c33e97efSMauro Carvalho Chehabsame system, cpuset, mempolicy, or memory controller resources to use at least 1671c33e97efSMauro Carvalho Chehab50% more memory. A value of -500, on the other hand, would be roughly 1672c33e97efSMauro Carvalho Chehabequivalent to discounting 50% of the task's allowed memory from being considered 1673c33e97efSMauro Carvalho Chehabas scoring against the task. 1674c33e97efSMauro Carvalho Chehab 1675c33e97efSMauro Carvalho ChehabFor backwards compatibility with previous kernels, /proc/<pid>/oom_adj may also 1676c33e97efSMauro Carvalho Chehabbe used to tune the badness score. Its acceptable values range from -16 1677c33e97efSMauro Carvalho Chehab(OOM_ADJUST_MIN) to +15 (OOM_ADJUST_MAX) and a special value of -17 1678c33e97efSMauro Carvalho Chehab(OOM_DISABLE) to disable oom killing entirely for that task. Its value is 1679c33e97efSMauro Carvalho Chehabscaled linearly with /proc/<pid>/oom_score_adj. 1680c33e97efSMauro Carvalho Chehab 1681c33e97efSMauro Carvalho ChehabThe value of /proc/<pid>/oom_score_adj may be reduced no lower than the last 1682c33e97efSMauro Carvalho Chehabvalue set by a CAP_SYS_RESOURCE process. To reduce the value any lower 1683c33e97efSMauro Carvalho Chehabrequires CAP_SYS_RESOURCE. 1684c33e97efSMauro Carvalho Chehab 1685c33e97efSMauro Carvalho Chehab 1686c33e97efSMauro Carvalho Chehab3.2 /proc/<pid>/oom_score - Display current oom-killer score 1687c33e97efSMauro Carvalho Chehab------------------------------------------------------------- 1688c33e97efSMauro Carvalho Chehab 1689059db434SRandy DunlapThis file can be used to check the current score used by the oom-killer for 1690c33e97efSMauro Carvalho Chehabany given <pid>. Use it together with /proc/<pid>/oom_score_adj to tune which 1691c33e97efSMauro Carvalho Chehabprocess should be killed in an out-of-memory situation. 1692c33e97efSMauro Carvalho Chehab 1693b1aa7c93SMichal HockoPlease note that the exported value includes oom_score_adj so it is 1694b1aa7c93SMichal Hockoeffectively in range [0,2000]. 1695b1aa7c93SMichal Hocko 1696c33e97efSMauro Carvalho Chehab 1697c33e97efSMauro Carvalho Chehab3.3 /proc/<pid>/io - Display the IO accounting fields 1698c33e97efSMauro Carvalho Chehab------------------------------------------------------- 1699c33e97efSMauro Carvalho Chehab 1700059db434SRandy DunlapThis file contains IO statistics for each running process. 1701c33e97efSMauro Carvalho Chehab 1702c33e97efSMauro Carvalho ChehabExample 1703c33e97efSMauro Carvalho Chehab~~~~~~~ 1704c33e97efSMauro Carvalho Chehab 1705c33e97efSMauro Carvalho Chehab:: 1706c33e97efSMauro Carvalho Chehab 1707c33e97efSMauro Carvalho Chehab test:/tmp # dd if=/dev/zero of=/tmp/test.dat & 1708c33e97efSMauro Carvalho Chehab [1] 3828 1709c33e97efSMauro Carvalho Chehab 1710c33e97efSMauro Carvalho Chehab test:/tmp # cat /proc/3828/io 1711c33e97efSMauro Carvalho Chehab rchar: 323934931 1712c33e97efSMauro Carvalho Chehab wchar: 323929600 1713c33e97efSMauro Carvalho Chehab syscr: 632687 1714c33e97efSMauro Carvalho Chehab syscw: 632675 1715c33e97efSMauro Carvalho Chehab read_bytes: 0 1716c33e97efSMauro Carvalho Chehab write_bytes: 323932160 1717c33e97efSMauro Carvalho Chehab cancelled_write_bytes: 0 1718c33e97efSMauro Carvalho Chehab 1719c33e97efSMauro Carvalho Chehab 1720c33e97efSMauro Carvalho ChehabDescription 1721c33e97efSMauro Carvalho Chehab~~~~~~~~~~~ 1722c33e97efSMauro Carvalho Chehab 1723c33e97efSMauro Carvalho Chehabrchar 1724c33e97efSMauro Carvalho Chehab^^^^^ 1725c33e97efSMauro Carvalho Chehab 1726c33e97efSMauro Carvalho ChehabI/O counter: chars read 1727c33e97efSMauro Carvalho ChehabThe number of bytes which this task has caused to be read from storage. This 1728c33e97efSMauro Carvalho Chehabis simply the sum of bytes which this process passed to read() and pread(). 1729c33e97efSMauro Carvalho ChehabIt includes things like tty IO and it is unaffected by whether or not actual 1730c33e97efSMauro Carvalho Chehabphysical disk IO was required (the read might have been satisfied from 1731059db434SRandy Dunlappagecache). 1732c33e97efSMauro Carvalho Chehab 1733c33e97efSMauro Carvalho Chehab 1734c33e97efSMauro Carvalho Chehabwchar 1735c33e97efSMauro Carvalho Chehab^^^^^ 1736c33e97efSMauro Carvalho Chehab 1737c33e97efSMauro Carvalho ChehabI/O counter: chars written 1738c33e97efSMauro Carvalho ChehabThe number of bytes which this task has caused, or shall cause to be written 1739c33e97efSMauro Carvalho Chehabto disk. Similar caveats apply here as with rchar. 1740c33e97efSMauro Carvalho Chehab 1741c33e97efSMauro Carvalho Chehab 1742c33e97efSMauro Carvalho Chehabsyscr 1743c33e97efSMauro Carvalho Chehab^^^^^ 1744c33e97efSMauro Carvalho Chehab 1745c33e97efSMauro Carvalho ChehabI/O counter: read syscalls 1746c33e97efSMauro Carvalho ChehabAttempt to count the number of read I/O operations, i.e. syscalls like read() 1747c33e97efSMauro Carvalho Chehaband pread(). 1748c33e97efSMauro Carvalho Chehab 1749c33e97efSMauro Carvalho Chehab 1750c33e97efSMauro Carvalho Chehabsyscw 1751c33e97efSMauro Carvalho Chehab^^^^^ 1752c33e97efSMauro Carvalho Chehab 1753c33e97efSMauro Carvalho ChehabI/O counter: write syscalls 1754c33e97efSMauro Carvalho ChehabAttempt to count the number of write I/O operations, i.e. syscalls like 1755c33e97efSMauro Carvalho Chehabwrite() and pwrite(). 1756c33e97efSMauro Carvalho Chehab 1757c33e97efSMauro Carvalho Chehab 1758c33e97efSMauro Carvalho Chehabread_bytes 1759c33e97efSMauro Carvalho Chehab^^^^^^^^^^ 1760c33e97efSMauro Carvalho Chehab 1761c33e97efSMauro Carvalho ChehabI/O counter: bytes read 1762c33e97efSMauro Carvalho ChehabAttempt to count the number of bytes which this process really did cause to 1763c33e97efSMauro Carvalho Chehabbe fetched from the storage layer. Done at the submit_bio() level, so it is 1764c33e97efSMauro Carvalho Chehabaccurate for block-backed filesystems. <please add status regarding NFS and 1765c33e97efSMauro Carvalho ChehabCIFS at a later time> 1766c33e97efSMauro Carvalho Chehab 1767c33e97efSMauro Carvalho Chehab 1768c33e97efSMauro Carvalho Chehabwrite_bytes 1769c33e97efSMauro Carvalho Chehab^^^^^^^^^^^ 1770c33e97efSMauro Carvalho Chehab 1771c33e97efSMauro Carvalho ChehabI/O counter: bytes written 1772c33e97efSMauro Carvalho ChehabAttempt to count the number of bytes which this process caused to be sent to 1773c33e97efSMauro Carvalho Chehabthe storage layer. This is done at page-dirtying time. 1774c33e97efSMauro Carvalho Chehab 1775c33e97efSMauro Carvalho Chehab 1776c33e97efSMauro Carvalho Chehabcancelled_write_bytes 1777c33e97efSMauro Carvalho Chehab^^^^^^^^^^^^^^^^^^^^^ 1778c33e97efSMauro Carvalho Chehab 1779c33e97efSMauro Carvalho ChehabThe big inaccuracy here is truncate. If a process writes 1MB to a file and 1780c33e97efSMauro Carvalho Chehabthen deletes the file, it will in fact perform no writeout. But it will have 1781c33e97efSMauro Carvalho Chehabbeen accounted as having caused 1MB of write. 1782c33e97efSMauro Carvalho ChehabIn other words: The number of bytes which this process caused to not happen, 1783c33e97efSMauro Carvalho Chehabby truncating pagecache. A task can cause "negative" IO too. If this task 1784c33e97efSMauro Carvalho Chehabtruncates some dirty pagecache, some IO which another task has been accounted 1785c33e97efSMauro Carvalho Chehabfor (in its write_bytes) will not be happening. We _could_ just subtract that 1786c33e97efSMauro Carvalho Chehabfrom the truncating task's write_bytes, but there is information loss in doing 1787c33e97efSMauro Carvalho Chehabthat. 1788c33e97efSMauro Carvalho Chehab 1789c33e97efSMauro Carvalho Chehab 1790c33e97efSMauro Carvalho Chehab.. Note:: 1791c33e97efSMauro Carvalho Chehab 1792c33e97efSMauro Carvalho Chehab At its current implementation state, this is a bit racy on 32-bit machines: 1793c33e97efSMauro Carvalho Chehab if process A reads process B's /proc/pid/io while process B is updating one 1794c33e97efSMauro Carvalho Chehab of those 64-bit counters, process A could see an intermediate result. 1795c33e97efSMauro Carvalho Chehab 1796c33e97efSMauro Carvalho Chehab 1797c33e97efSMauro Carvalho ChehabMore information about this can be found within the taskstats documentation in 1798c33e97efSMauro Carvalho ChehabDocumentation/accounting. 1799c33e97efSMauro Carvalho Chehab 1800c33e97efSMauro Carvalho Chehab3.4 /proc/<pid>/coredump_filter - Core dump filtering settings 1801c33e97efSMauro Carvalho Chehab--------------------------------------------------------------- 1802c33e97efSMauro Carvalho ChehabWhen a process is dumped, all anonymous memory is written to a core file as 1803c33e97efSMauro Carvalho Chehablong as the size of the core file isn't limited. But sometimes we don't want 1804c33e97efSMauro Carvalho Chehabto dump some memory segments, for example, huge shared memory or DAX. 1805c33e97efSMauro Carvalho ChehabConversely, sometimes we want to save file-backed memory segments into a core 1806c33e97efSMauro Carvalho Chehabfile, not only the individual files. 1807c33e97efSMauro Carvalho Chehab 1808c33e97efSMauro Carvalho Chehab/proc/<pid>/coredump_filter allows you to customize which memory segments 1809c33e97efSMauro Carvalho Chehabwill be dumped when the <pid> process is dumped. coredump_filter is a bitmask 1810c33e97efSMauro Carvalho Chehabof memory types. If a bit of the bitmask is set, memory segments of the 1811c33e97efSMauro Carvalho Chehabcorresponding memory type are dumped, otherwise they are not dumped. 1812c33e97efSMauro Carvalho Chehab 1813c33e97efSMauro Carvalho ChehabThe following 9 memory types are supported: 1814c33e97efSMauro Carvalho Chehab 1815c33e97efSMauro Carvalho Chehab - (bit 0) anonymous private memory 1816c33e97efSMauro Carvalho Chehab - (bit 1) anonymous shared memory 1817c33e97efSMauro Carvalho Chehab - (bit 2) file-backed private memory 1818c33e97efSMauro Carvalho Chehab - (bit 3) file-backed shared memory 1819c33e97efSMauro Carvalho Chehab - (bit 4) ELF header pages in file-backed private memory areas (it is 1820c33e97efSMauro Carvalho Chehab effective only if the bit 2 is cleared) 1821c33e97efSMauro Carvalho Chehab - (bit 5) hugetlb private memory 1822c33e97efSMauro Carvalho Chehab - (bit 6) hugetlb shared memory 1823c33e97efSMauro Carvalho Chehab - (bit 7) DAX private memory 1824c33e97efSMauro Carvalho Chehab - (bit 8) DAX shared memory 1825c33e97efSMauro Carvalho Chehab 1826c33e97efSMauro Carvalho Chehab Note that MMIO pages such as frame buffer are never dumped and vDSO pages 1827c33e97efSMauro Carvalho Chehab are always dumped regardless of the bitmask status. 1828c33e97efSMauro Carvalho Chehab 1829c33e97efSMauro Carvalho Chehab Note that bits 0-4 don't affect hugetlb or DAX memory. hugetlb memory is 1830c33e97efSMauro Carvalho Chehab only affected by bit 5-6, and DAX is only affected by bits 7-8. 1831c33e97efSMauro Carvalho Chehab 1832c33e97efSMauro Carvalho ChehabThe default value of coredump_filter is 0x33; this means all anonymous memory 1833c33e97efSMauro Carvalho Chehabsegments, ELF header pages and hugetlb private memory are dumped. 1834c33e97efSMauro Carvalho Chehab 1835c33e97efSMauro Carvalho ChehabIf you don't want to dump all shared memory segments attached to pid 1234, 1836c33e97efSMauro Carvalho Chehabwrite 0x31 to the process's proc file:: 1837c33e97efSMauro Carvalho Chehab 1838c33e97efSMauro Carvalho Chehab $ echo 0x31 > /proc/1234/coredump_filter 1839c33e97efSMauro Carvalho Chehab 1840c33e97efSMauro Carvalho ChehabWhen a new process is created, the process inherits the bitmask status from its 1841c33e97efSMauro Carvalho Chehabparent. It is useful to set up coredump_filter before the program runs. 1842c33e97efSMauro Carvalho ChehabFor example:: 1843c33e97efSMauro Carvalho Chehab 1844c33e97efSMauro Carvalho Chehab $ echo 0x7 > /proc/self/coredump_filter 1845c33e97efSMauro Carvalho Chehab $ ./some_program 1846c33e97efSMauro Carvalho Chehab 1847c33e97efSMauro Carvalho Chehab3.5 /proc/<pid>/mountinfo - Information about mounts 1848c33e97efSMauro Carvalho Chehab-------------------------------------------------------- 1849c33e97efSMauro Carvalho Chehab 1850c33e97efSMauro Carvalho ChehabThis file contains lines of the form:: 1851c33e97efSMauro Carvalho Chehab 1852c33e97efSMauro Carvalho Chehab 36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 - ext3 /dev/root rw,errors=continue 1853ff9c3d43SChristoph Anton Mitterer (1)(2)(3) (4) (5) (6) (n…m) (m+1)(m+2) (m+3) (m+4) 1854c33e97efSMauro Carvalho Chehab 1855c33e97efSMauro Carvalho Chehab (1) mount ID: unique identifier of the mount (may be reused after umount) 1856c33e97efSMauro Carvalho Chehab (2) parent ID: ID of parent (or of self for the top of the mount tree) 1857c33e97efSMauro Carvalho Chehab (3) major:minor: value of st_dev for files on filesystem 1858c33e97efSMauro Carvalho Chehab (4) root: root of the mount within the filesystem 1859c33e97efSMauro Carvalho Chehab (5) mount point: mount point relative to the process's root 1860c33e97efSMauro Carvalho Chehab (6) mount options: per mount options 1861ff9c3d43SChristoph Anton Mitterer (n…m) optional fields: zero or more fields of the form "tag[:value]" 1862ff9c3d43SChristoph Anton Mitterer (m+1) separator: marks the end of the optional fields 1863ff9c3d43SChristoph Anton Mitterer (m+2) filesystem type: name of filesystem of the form "type[.subtype]" 1864ff9c3d43SChristoph Anton Mitterer (m+3) mount source: filesystem specific information or "none" 1865ff9c3d43SChristoph Anton Mitterer (m+4) super options: per super block options 1866c33e97efSMauro Carvalho Chehab 1867c33e97efSMauro Carvalho ChehabParsers should ignore all unrecognised optional fields. Currently the 1868c33e97efSMauro Carvalho Chehabpossible optional fields are: 1869c33e97efSMauro Carvalho Chehab 1870c33e97efSMauro Carvalho Chehab================ ============================================================== 1871c33e97efSMauro Carvalho Chehabshared:X mount is shared in peer group X 1872c33e97efSMauro Carvalho Chehabmaster:X mount is slave to peer group X 1873c33e97efSMauro Carvalho Chehabpropagate_from:X mount is slave and receives propagation from peer group X [#]_ 1874c33e97efSMauro Carvalho Chehabunbindable mount is unbindable 1875c33e97efSMauro Carvalho Chehab================ ============================================================== 1876c33e97efSMauro Carvalho Chehab 1877c33e97efSMauro Carvalho Chehab.. [#] X is the closest dominant peer group under the process's root. If 1878c33e97efSMauro Carvalho Chehab X is the immediate master of the mount, or if there's no dominant peer 1879c33e97efSMauro Carvalho Chehab group under the same root, then only the "master:X" field is present 1880c33e97efSMauro Carvalho Chehab and not the "propagate_from:X" field. 1881c33e97efSMauro Carvalho Chehab 1882c33e97efSMauro Carvalho ChehabFor more information on mount propagation see: 1883c33e97efSMauro Carvalho Chehab 1884cf06612cSMauro Carvalho Chehab Documentation/filesystems/sharedsubtree.rst 1885c33e97efSMauro Carvalho Chehab 1886c33e97efSMauro Carvalho Chehab 1887c33e97efSMauro Carvalho Chehab3.6 /proc/<pid>/comm & /proc/<pid>/task/<tid>/comm 1888c33e97efSMauro Carvalho Chehab-------------------------------------------------------- 1889059db434SRandy DunlapThese files provide a method to access a task's comm value. It also allows for 1890c33e97efSMauro Carvalho Chehaba task to set its own or one of its thread siblings comm value. The comm value 1891c33e97efSMauro Carvalho Chehabis limited in size compared to the cmdline value, so writing anything longer 1892c33e97efSMauro Carvalho Chehabthen the kernel's TASK_COMM_LEN (currently 16 chars) will result in a truncated 1893c33e97efSMauro Carvalho Chehabcomm value. 1894c33e97efSMauro Carvalho Chehab 1895c33e97efSMauro Carvalho Chehab 1896c33e97efSMauro Carvalho Chehab3.7 /proc/<pid>/task/<tid>/children - Information about task children 1897c33e97efSMauro Carvalho Chehab------------------------------------------------------------------------- 1898c33e97efSMauro Carvalho ChehabThis file provides a fast way to retrieve first level children pids 1899c33e97efSMauro Carvalho Chehabof a task pointed by <pid>/<tid> pair. The format is a space separated 1900c33e97efSMauro Carvalho Chehabstream of pids. 1901c33e97efSMauro Carvalho Chehab 1902059db434SRandy DunlapNote the "first level" here -- if a child has its own children they will 1903059db434SRandy Dunlapnot be listed here; one needs to read /proc/<children-pid>/task/<tid>/children 1904c33e97efSMauro Carvalho Chehabto obtain the descendants. 1905c33e97efSMauro Carvalho Chehab 1906c33e97efSMauro Carvalho ChehabSince this interface is intended to be fast and cheap it doesn't 1907c33e97efSMauro Carvalho Chehabguarantee to provide precise results and some children might be 1908c33e97efSMauro Carvalho Chehabskipped, especially if they've exited right after we printed their 1909059db434SRandy Dunlappids, so one needs to either stop or freeze processes being inspected 1910c33e97efSMauro Carvalho Chehabif precise results are needed. 1911c33e97efSMauro Carvalho Chehab 1912c33e97efSMauro Carvalho Chehab 1913c33e97efSMauro Carvalho Chehab3.8 /proc/<pid>/fdinfo/<fd> - Information about opened file 1914c33e97efSMauro Carvalho Chehab--------------------------------------------------------------- 1915c33e97efSMauro Carvalho ChehabThis file provides information associated with an opened file. The regular 19163845f256SKalesh Singhfiles have at least four fields -- 'pos', 'flags', 'mnt_id' and 'ino'. 19173845f256SKalesh SinghThe 'pos' represents the current offset of the opened file in decimal 19183845f256SKalesh Singhform [see lseek(2) for details], 'flags' denotes the octal O_xxx mask the 19193845f256SKalesh Singhfile has been created with [see open(2) for details] and 'mnt_id' represents 19203845f256SKalesh Singhmount ID of the file system containing the opened file [see 3.5 19213845f256SKalesh Singh/proc/<pid>/mountinfo for details]. 'ino' represents the inode number of 19223845f256SKalesh Singhthe file. 1923c33e97efSMauro Carvalho Chehab 1924c33e97efSMauro Carvalho ChehabA typical output is:: 1925c33e97efSMauro Carvalho Chehab 1926c33e97efSMauro Carvalho Chehab pos: 0 1927c33e97efSMauro Carvalho Chehab flags: 0100002 1928c33e97efSMauro Carvalho Chehab mnt_id: 19 19293845f256SKalesh Singh ino: 63107 1930c33e97efSMauro Carvalho Chehab 1931c33e97efSMauro Carvalho ChehabAll locks associated with a file descriptor are shown in its fdinfo too:: 1932c33e97efSMauro Carvalho Chehab 1933c33e97efSMauro Carvalho Chehab lock: 1: FLOCK ADVISORY WRITE 359 00:13:11691 0 EOF 1934c33e97efSMauro Carvalho Chehab 1935c33e97efSMauro Carvalho ChehabThe files such as eventfd, fsnotify, signalfd, epoll among the regular pos/flags 1936c33e97efSMauro Carvalho Chehabpair provide additional information particular to the objects they represent. 1937c33e97efSMauro Carvalho Chehab 1938c33e97efSMauro Carvalho ChehabEventfd files 1939c33e97efSMauro Carvalho Chehab~~~~~~~~~~~~~ 1940c33e97efSMauro Carvalho Chehab 1941c33e97efSMauro Carvalho Chehab:: 1942c33e97efSMauro Carvalho Chehab 1943c33e97efSMauro Carvalho Chehab pos: 0 1944c33e97efSMauro Carvalho Chehab flags: 04002 1945c33e97efSMauro Carvalho Chehab mnt_id: 9 19463845f256SKalesh Singh ino: 63107 1947c33e97efSMauro Carvalho Chehab eventfd-count: 5a 1948c33e97efSMauro Carvalho Chehab 1949c33e97efSMauro Carvalho Chehabwhere 'eventfd-count' is hex value of a counter. 1950c33e97efSMauro Carvalho Chehab 1951c33e97efSMauro Carvalho ChehabSignalfd files 1952c33e97efSMauro Carvalho Chehab~~~~~~~~~~~~~~ 1953c33e97efSMauro Carvalho Chehab 1954c33e97efSMauro Carvalho Chehab:: 1955c33e97efSMauro Carvalho Chehab 1956c33e97efSMauro Carvalho Chehab pos: 0 1957c33e97efSMauro Carvalho Chehab flags: 04002 1958c33e97efSMauro Carvalho Chehab mnt_id: 9 19593845f256SKalesh Singh ino: 63107 1960c33e97efSMauro Carvalho Chehab sigmask: 0000000000000200 1961c33e97efSMauro Carvalho Chehab 1962c33e97efSMauro Carvalho Chehabwhere 'sigmask' is hex value of the signal mask associated 1963c33e97efSMauro Carvalho Chehabwith a file. 1964c33e97efSMauro Carvalho Chehab 1965c33e97efSMauro Carvalho ChehabEpoll files 1966c33e97efSMauro Carvalho Chehab~~~~~~~~~~~ 1967c33e97efSMauro Carvalho Chehab 1968c33e97efSMauro Carvalho Chehab:: 1969c33e97efSMauro Carvalho Chehab 1970c33e97efSMauro Carvalho Chehab pos: 0 1971c33e97efSMauro Carvalho Chehab flags: 02 1972c33e97efSMauro Carvalho Chehab mnt_id: 9 19733845f256SKalesh Singh ino: 63107 1974c33e97efSMauro Carvalho Chehab tfd: 5 events: 1d data: ffffffffffffffff pos:0 ino:61af sdev:7 1975c33e97efSMauro Carvalho Chehab 1976c33e97efSMauro Carvalho Chehabwhere 'tfd' is a target file descriptor number in decimal form, 1977c33e97efSMauro Carvalho Chehab'events' is events mask being watched and the 'data' is data 1978c33e97efSMauro Carvalho Chehabassociated with a target [see epoll(7) for more details]. 1979c33e97efSMauro Carvalho Chehab 1980c33e97efSMauro Carvalho ChehabThe 'pos' is current offset of the target file in decimal form 1981c33e97efSMauro Carvalho Chehab[see lseek(2)], 'ino' and 'sdev' are inode and device numbers 1982c33e97efSMauro Carvalho Chehabwhere target file resides, all in hex format. 1983c33e97efSMauro Carvalho Chehab 1984c33e97efSMauro Carvalho ChehabFsnotify files 1985c33e97efSMauro Carvalho Chehab~~~~~~~~~~~~~~ 1986c33e97efSMauro Carvalho ChehabFor inotify files the format is the following:: 1987c33e97efSMauro Carvalho Chehab 1988c33e97efSMauro Carvalho Chehab pos: 0 1989c33e97efSMauro Carvalho Chehab flags: 02000000 19903845f256SKalesh Singh mnt_id: 9 19913845f256SKalesh Singh ino: 63107 1992c33e97efSMauro Carvalho Chehab inotify wd:3 ino:9e7e sdev:800013 mask:800afce ignored_mask:0 fhandle-bytes:8 fhandle-type:1 f_handle:7e9e0000640d1b6d 1993c33e97efSMauro Carvalho Chehab 1994059db434SRandy Dunlapwhere 'wd' is a watch descriptor in decimal form, i.e. a target file 1995c33e97efSMauro Carvalho Chehabdescriptor number, 'ino' and 'sdev' are inode and device where the 1996c33e97efSMauro Carvalho Chehabtarget file resides and the 'mask' is the mask of events, all in hex 1997c33e97efSMauro Carvalho Chehabform [see inotify(7) for more details]. 1998c33e97efSMauro Carvalho Chehab 1999c33e97efSMauro Carvalho ChehabIf the kernel was built with exportfs support, the path to the target 2000c33e97efSMauro Carvalho Chehabfile is encoded as a file handle. The file handle is provided by three 2001c33e97efSMauro Carvalho Chehabfields 'fhandle-bytes', 'fhandle-type' and 'f_handle', all in hex 2002c33e97efSMauro Carvalho Chehabformat. 2003c33e97efSMauro Carvalho Chehab 2004c33e97efSMauro Carvalho ChehabIf the kernel is built without exportfs support the file handle won't be 2005c33e97efSMauro Carvalho Chehabprinted out. 2006c33e97efSMauro Carvalho Chehab 2007c33e97efSMauro Carvalho ChehabIf there is no inotify mark attached yet the 'inotify' line will be omitted. 2008c33e97efSMauro Carvalho Chehab 2009c33e97efSMauro Carvalho ChehabFor fanotify files the format is:: 2010c33e97efSMauro Carvalho Chehab 2011c33e97efSMauro Carvalho Chehab pos: 0 2012c33e97efSMauro Carvalho Chehab flags: 02 2013c33e97efSMauro Carvalho Chehab mnt_id: 9 20143845f256SKalesh Singh ino: 63107 2015c33e97efSMauro Carvalho Chehab fanotify flags:10 event-flags:0 2016c33e97efSMauro Carvalho Chehab fanotify mnt_id:12 mflags:40 mask:38 ignored_mask:40000003 2017c33e97efSMauro Carvalho Chehab fanotify ino:4f969 sdev:800013 mflags:0 mask:3b ignored_mask:40000000 fhandle-bytes:8 fhandle-type:1 f_handle:69f90400c275b5b4 2018c33e97efSMauro Carvalho Chehab 2019c33e97efSMauro Carvalho Chehabwhere fanotify 'flags' and 'event-flags' are values used in fanotify_init 2020c33e97efSMauro Carvalho Chehabcall, 'mnt_id' is the mount point identifier, 'mflags' is the value of 2021c33e97efSMauro Carvalho Chehabflags associated with mark which are tracked separately from events 2022059db434SRandy Dunlapmask. 'ino' and 'sdev' are target inode and device, 'mask' is the events 2023c33e97efSMauro Carvalho Chehabmask and 'ignored_mask' is the mask of events which are to be ignored. 2024059db434SRandy DunlapAll are in hex format. Incorporation of 'mflags', 'mask' and 'ignored_mask' 2025059db434SRandy Dunlapprovide information about flags and mask used in fanotify_mark 2026c33e97efSMauro Carvalho Chehabcall [see fsnotify manpage for details]. 2027c33e97efSMauro Carvalho Chehab 2028c33e97efSMauro Carvalho ChehabWhile the first three lines are mandatory and always printed, the rest is 2029c33e97efSMauro Carvalho Chehaboptional and may be omitted if no marks created yet. 2030c33e97efSMauro Carvalho Chehab 2031c33e97efSMauro Carvalho ChehabTimerfd files 2032c33e97efSMauro Carvalho Chehab~~~~~~~~~~~~~ 2033c33e97efSMauro Carvalho Chehab 2034c33e97efSMauro Carvalho Chehab:: 2035c33e97efSMauro Carvalho Chehab 2036c33e97efSMauro Carvalho Chehab pos: 0 2037c33e97efSMauro Carvalho Chehab flags: 02 2038c33e97efSMauro Carvalho Chehab mnt_id: 9 20393845f256SKalesh Singh ino: 63107 2040c33e97efSMauro Carvalho Chehab clockid: 0 2041c33e97efSMauro Carvalho Chehab ticks: 0 2042c33e97efSMauro Carvalho Chehab settime flags: 01 2043c33e97efSMauro Carvalho Chehab it_value: (0, 49406829) 2044c33e97efSMauro Carvalho Chehab it_interval: (1, 0) 2045c33e97efSMauro Carvalho Chehab 2046c33e97efSMauro Carvalho Chehabwhere 'clockid' is the clock type and 'ticks' is the number of the timer expirations 2047c33e97efSMauro Carvalho Chehabthat have occurred [see timerfd_create(2) for details]. 'settime flags' are 2048c33e97efSMauro Carvalho Chehabflags in octal form been used to setup the timer [see timerfd_settime(2) for 2049059db434SRandy Dunlapdetails]. 'it_value' is remaining time until the timer expiration. 2050c33e97efSMauro Carvalho Chehab'it_interval' is the interval for the timer. Note the timer might be set up 2051c33e97efSMauro Carvalho Chehabwith TIMER_ABSTIME option which will be shown in 'settime flags', but 'it_value' 2052c33e97efSMauro Carvalho Chehabstill exhibits timer's remaining time. 2053c33e97efSMauro Carvalho Chehab 20543845f256SKalesh SinghDMA Buffer files 20553845f256SKalesh Singh~~~~~~~~~~~~~~~~ 20563845f256SKalesh Singh 20573845f256SKalesh Singh:: 20583845f256SKalesh Singh 20593845f256SKalesh Singh pos: 0 20603845f256SKalesh Singh flags: 04002 20613845f256SKalesh Singh mnt_id: 9 20623845f256SKalesh Singh ino: 63107 20633845f256SKalesh Singh size: 32768 20643845f256SKalesh Singh count: 2 20653845f256SKalesh Singh exp_name: system-heap 20663845f256SKalesh Singh 20673845f256SKalesh Singhwhere 'size' is the size of the DMA buffer in bytes. 'count' is the file count of 20683845f256SKalesh Singhthe DMA buffer file. 'exp_name' is the name of the DMA buffer exporter. 20693845f256SKalesh Singh 2070c33e97efSMauro Carvalho Chehab3.9 /proc/<pid>/map_files - Information about memory mapped files 2071c33e97efSMauro Carvalho Chehab--------------------------------------------------------------------- 2072c33e97efSMauro Carvalho ChehabThis directory contains symbolic links which represent memory mapped files 2073c33e97efSMauro Carvalho Chehabthe process is maintaining. Example output:: 2074c33e97efSMauro Carvalho Chehab 2075c33e97efSMauro Carvalho Chehab | lr-------- 1 root root 64 Jan 27 11:24 333c600000-333c620000 -> /usr/lib64/ld-2.18.so 2076c33e97efSMauro Carvalho Chehab | lr-------- 1 root root 64 Jan 27 11:24 333c81f000-333c820000 -> /usr/lib64/ld-2.18.so 2077c33e97efSMauro Carvalho Chehab | lr-------- 1 root root 64 Jan 27 11:24 333c820000-333c821000 -> /usr/lib64/ld-2.18.so 2078c33e97efSMauro Carvalho Chehab | ... 2079c33e97efSMauro Carvalho Chehab | lr-------- 1 root root 64 Jan 27 11:24 35d0421000-35d0422000 -> /usr/lib64/libselinux.so.1 2080c33e97efSMauro Carvalho Chehab | lr-------- 1 root root 64 Jan 27 11:24 400000-41a000 -> /usr/bin/ls 2081c33e97efSMauro Carvalho Chehab 2082c33e97efSMauro Carvalho ChehabThe name of a link represents the virtual memory bounds of a mapping, i.e. 2083c33e97efSMauro Carvalho Chehabvm_area_struct::vm_start-vm_area_struct::vm_end. 2084c33e97efSMauro Carvalho Chehab 2085c33e97efSMauro Carvalho ChehabThe main purpose of the map_files is to retrieve a set of memory mapped 2086c33e97efSMauro Carvalho Chehabfiles in a fast way instead of parsing /proc/<pid>/maps or 2087c33e97efSMauro Carvalho Chehab/proc/<pid>/smaps, both of which contain many more records. At the same 2088c33e97efSMauro Carvalho Chehabtime one can open(2) mappings from the listings of two processes and 2089c33e97efSMauro Carvalho Chehabcomparing their inode numbers to figure out which anonymous memory areas 2090c33e97efSMauro Carvalho Chehabare actually shared. 2091c33e97efSMauro Carvalho Chehab 2092c33e97efSMauro Carvalho Chehab3.10 /proc/<pid>/timerslack_ns - Task timerslack value 2093c33e97efSMauro Carvalho Chehab--------------------------------------------------------- 2094c33e97efSMauro Carvalho ChehabThis file provides the value of the task's timerslack value in nanoseconds. 2095059db434SRandy DunlapThis value specifies an amount of time that normal timers may be deferred 2096c33e97efSMauro Carvalho Chehabin order to coalesce timers and avoid unnecessary wakeups. 2097c33e97efSMauro Carvalho Chehab 2098c33e97efSMauro Carvalho ChehabThis allows a task's interactivity vs power consumption tradeoff to be 2099c33e97efSMauro Carvalho Chehabadjusted. 2100c33e97efSMauro Carvalho Chehab 2101059db434SRandy DunlapWriting 0 to the file will set the task's timerslack to the default value. 2102c33e97efSMauro Carvalho Chehab 2103c33e97efSMauro Carvalho ChehabValid values are from 0 - ULLONG_MAX 2104c33e97efSMauro Carvalho Chehab 2105c33e97efSMauro Carvalho ChehabAn application setting the value must have PTRACE_MODE_ATTACH_FSCREDS level 2106c33e97efSMauro Carvalho Chehabpermissions on the task specified to change its timerslack_ns value. 2107c33e97efSMauro Carvalho Chehab 2108c33e97efSMauro Carvalho Chehab3.11 /proc/<pid>/patch_state - Livepatch patch operation state 2109c33e97efSMauro Carvalho Chehab----------------------------------------------------------------- 2110c33e97efSMauro Carvalho ChehabWhen CONFIG_LIVEPATCH is enabled, this file displays the value of the 2111c33e97efSMauro Carvalho Chehabpatch state for the task. 2112c33e97efSMauro Carvalho Chehab 2113c33e97efSMauro Carvalho ChehabA value of '-1' indicates that no patch is in transition. 2114c33e97efSMauro Carvalho Chehab 2115c33e97efSMauro Carvalho ChehabA value of '0' indicates that a patch is in transition and the task is 2116c33e97efSMauro Carvalho Chehabunpatched. If the patch is being enabled, then the task hasn't been 2117c33e97efSMauro Carvalho Chehabpatched yet. If the patch is being disabled, then the task has already 2118c33e97efSMauro Carvalho Chehabbeen unpatched. 2119c33e97efSMauro Carvalho Chehab 2120c33e97efSMauro Carvalho ChehabA value of '1' indicates that a patch is in transition and the task is 2121c33e97efSMauro Carvalho Chehabpatched. If the patch is being enabled, then the task has already been 2122c33e97efSMauro Carvalho Chehabpatched. If the patch is being disabled, then the task hasn't been 2123c33e97efSMauro Carvalho Chehabunpatched yet. 2124c33e97efSMauro Carvalho Chehab 2125c33e97efSMauro Carvalho Chehab3.12 /proc/<pid>/arch_status - task architecture specific status 2126c33e97efSMauro Carvalho Chehab------------------------------------------------------------------- 2127c33e97efSMauro Carvalho ChehabWhen CONFIG_PROC_PID_ARCH_STATUS is enabled, this file displays the 2128c33e97efSMauro Carvalho Chehabarchitecture specific status of the task. 2129c33e97efSMauro Carvalho Chehab 2130c33e97efSMauro Carvalho ChehabExample 2131c33e97efSMauro Carvalho Chehab~~~~~~~ 2132c33e97efSMauro Carvalho Chehab 2133c33e97efSMauro Carvalho Chehab:: 2134c33e97efSMauro Carvalho Chehab 2135c33e97efSMauro Carvalho Chehab $ cat /proc/6753/arch_status 2136c33e97efSMauro Carvalho Chehab AVX512_elapsed_ms: 8 2137c33e97efSMauro Carvalho Chehab 2138c33e97efSMauro Carvalho ChehabDescription 2139c33e97efSMauro Carvalho Chehab~~~~~~~~~~~ 2140c33e97efSMauro Carvalho Chehab 2141059db434SRandy Dunlapx86 specific entries 2142c33e97efSMauro Carvalho Chehab~~~~~~~~~~~~~~~~~~~~~ 2143c33e97efSMauro Carvalho Chehab 2144059db434SRandy DunlapAVX512_elapsed_ms 2145c33e97efSMauro Carvalho Chehab^^^^^^^^^^^^^^^^^^ 2146c33e97efSMauro Carvalho Chehab 2147c33e97efSMauro Carvalho Chehab If AVX512 is supported on the machine, this entry shows the milliseconds 2148c33e97efSMauro Carvalho Chehab elapsed since the last time AVX512 usage was recorded. The recording 2149c33e97efSMauro Carvalho Chehab happens on a best effort basis when a task is scheduled out. This means 2150c33e97efSMauro Carvalho Chehab that the value depends on two factors: 2151c33e97efSMauro Carvalho Chehab 2152c33e97efSMauro Carvalho Chehab 1) The time which the task spent on the CPU without being scheduled 2153c33e97efSMauro Carvalho Chehab out. With CPU isolation and a single runnable task this can take 2154c33e97efSMauro Carvalho Chehab several seconds. 2155c33e97efSMauro Carvalho Chehab 2156c33e97efSMauro Carvalho Chehab 2) The time since the task was scheduled out last. Depending on the 2157c33e97efSMauro Carvalho Chehab reason for being scheduled out (time slice exhausted, syscall ...) 2158c33e97efSMauro Carvalho Chehab this can be arbitrary long time. 2159c33e97efSMauro Carvalho Chehab 2160c33e97efSMauro Carvalho Chehab As a consequence the value cannot be considered precise and authoritative 2161c33e97efSMauro Carvalho Chehab information. The application which uses this information has to be aware 2162c33e97efSMauro Carvalho Chehab of the overall scenario on the system in order to determine whether a 2163c33e97efSMauro Carvalho Chehab task is a real AVX512 user or not. Precise information can be obtained 2164c33e97efSMauro Carvalho Chehab with performance counters. 2165c33e97efSMauro Carvalho Chehab 2166c33e97efSMauro Carvalho Chehab A special value of '-1' indicates that no AVX512 usage was recorded, thus 2167c33e97efSMauro Carvalho Chehab the task is unlikely an AVX512 user, but depends on the workload and the 2168c33e97efSMauro Carvalho Chehab scheduling scenario, it also could be a false negative mentioned above. 2169c33e97efSMauro Carvalho Chehab 2170f1f1f256SIvan Babrou3.13 /proc/<pid>/fd - List of symlinks to open files 2171f1f1f256SIvan Babrou------------------------------------------------------- 2172f1f1f256SIvan BabrouThis directory contains symbolic links which represent open files 2173f1f1f256SIvan Babrouthe process is maintaining. Example output:: 2174f1f1f256SIvan Babrou 2175f1f1f256SIvan Babrou lr-x------ 1 root root 64 Sep 20 17:53 0 -> /dev/null 2176f1f1f256SIvan Babrou l-wx------ 1 root root 64 Sep 20 17:53 1 -> /dev/null 2177f1f1f256SIvan Babrou lrwx------ 1 root root 64 Sep 20 17:53 10 -> 'socket:[12539]' 2178f1f1f256SIvan Babrou lrwx------ 1 root root 64 Sep 20 17:53 11 -> 'socket:[12540]' 2179f1f1f256SIvan Babrou lrwx------ 1 root root 64 Sep 20 17:53 12 -> 'socket:[12542]' 2180f1f1f256SIvan Babrou 2181f1f1f256SIvan BabrouThe number of open files for the process is stored in 'size' member 2182f1f1f256SIvan Babrouof stat() output for /proc/<pid>/fd for fast access. 2183f1f1f256SIvan Babrou------------------------------------------------------- 2184f1f1f256SIvan Babrou 2185f1f1f256SIvan Babrou 2186059db434SRandy DunlapChapter 4: Configuring procfs 2187059db434SRandy Dunlap============================= 2188c33e97efSMauro Carvalho Chehab 2189c33e97efSMauro Carvalho Chehab4.1 Mount options 2190c33e97efSMauro Carvalho Chehab--------------------- 2191c33e97efSMauro Carvalho Chehab 2192c33e97efSMauro Carvalho ChehabThe following mount options are supported: 2193c33e97efSMauro Carvalho Chehab 2194c33e97efSMauro Carvalho Chehab ========= ======================================================== 2195c33e97efSMauro Carvalho Chehab hidepid= Set /proc/<pid>/ access mode. 2196c33e97efSMauro Carvalho Chehab gid= Set the group authorized to learn processes information. 219737e7647aSAlexey Gladkov subset= Show only the specified subset of procfs. 2198c33e97efSMauro Carvalho Chehab ========= ======================================================== 2199c33e97efSMauro Carvalho Chehab 22001c6c4d11SAlexey Gladkovhidepid=off or hidepid=0 means classic mode - everybody may access all 22011c6c4d11SAlexey Gladkov/proc/<pid>/ directories (default). 2202c33e97efSMauro Carvalho Chehab 22031c6c4d11SAlexey Gladkovhidepid=noaccess or hidepid=1 means users may not access any /proc/<pid>/ 22041c6c4d11SAlexey Gladkovdirectories but their own. Sensitive files like cmdline, sched*, status are now 22051c6c4d11SAlexey Gladkovprotected against other users. This makes it impossible to learn whether any 22061c6c4d11SAlexey Gladkovuser runs specific program (given the program doesn't reveal itself by its 22071c6c4d11SAlexey Gladkovbehaviour). As an additional bonus, as /proc/<pid>/cmdline is unaccessible for 22081c6c4d11SAlexey Gladkovother users, poorly written programs passing sensitive information via program 22091c6c4d11SAlexey Gladkovarguments are now protected against local eavesdroppers. 2210c33e97efSMauro Carvalho Chehab 22111c6c4d11SAlexey Gladkovhidepid=invisible or hidepid=2 means hidepid=1 plus all /proc/<pid>/ will be 22121c6c4d11SAlexey Gladkovfully invisible to other users. It doesn't mean that it hides a fact whether a 22131c6c4d11SAlexey Gladkovprocess with a specific pid value exists (it can be learned by other means, e.g. 22141c6c4d11SAlexey Gladkovby "kill -0 $PID"), but it hides process' uid and gid, which may be learned by 22151c6c4d11SAlexey Gladkovstat()'ing /proc/<pid>/ otherwise. It greatly complicates an intruder's task of 22161c6c4d11SAlexey Gladkovgathering information about running processes, whether some daemon runs with 22171c6c4d11SAlexey Gladkovelevated privileges, whether other user runs some sensitive program, whether 22181c6c4d11SAlexey Gladkovother users run any program at all, etc. 2219c33e97efSMauro Carvalho Chehab 22201c6c4d11SAlexey Gladkovhidepid=ptraceable or hidepid=4 means that procfs should only contain 22211c6c4d11SAlexey Gladkov/proc/<pid>/ directories that the caller can ptrace. 2222c33e97efSMauro Carvalho Chehab 2223c33e97efSMauro Carvalho Chehabgid= defines a group authorized to learn processes information otherwise 2224c33e97efSMauro Carvalho Chehabprohibited by hidepid=. If you use some daemon like identd which needs to learn 2225c33e97efSMauro Carvalho Chehabinformation about processes information, just add identd to this group. 222637e7647aSAlexey Gladkov 222737e7647aSAlexey Gladkovsubset=pid hides all top level files and directories in the procfs that 222837e7647aSAlexey Gladkovare not related to tasks. 222937e7647aSAlexey Gladkov 2230059db434SRandy DunlapChapter 5: Filesystem behavior 2231059db434SRandy Dunlap============================== 223237e7647aSAlexey Gladkov 223337e7647aSAlexey GladkovOriginally, before the advent of pid namepsace, procfs was a global file 223437e7647aSAlexey Gladkovsystem. It means that there was only one procfs instance in the system. 223537e7647aSAlexey Gladkov 223637e7647aSAlexey GladkovWhen pid namespace was added, a separate procfs instance was mounted in 223737e7647aSAlexey Gladkoveach pid namespace. So, procfs mount options are global among all 2238565dbe72SMauro Carvalho Chehabmountpoints within the same namespace:: 223937e7647aSAlexey Gladkov 224037e7647aSAlexey Gladkov # grep ^proc /proc/mounts 224137e7647aSAlexey Gladkov proc /proc proc rw,relatime,hidepid=2 0 0 224237e7647aSAlexey Gladkov 224337e7647aSAlexey Gladkov # strace -e mount mount -o hidepid=1 -t proc proc /tmp/proc 224437e7647aSAlexey Gladkov mount("proc", "/tmp/proc", "proc", 0, "hidepid=1") = 0 224537e7647aSAlexey Gladkov +++ exited with 0 +++ 224637e7647aSAlexey Gladkov 224737e7647aSAlexey Gladkov # grep ^proc /proc/mounts 224837e7647aSAlexey Gladkov proc /proc proc rw,relatime,hidepid=2 0 0 224937e7647aSAlexey Gladkov proc /tmp/proc proc rw,relatime,hidepid=2 0 0 225037e7647aSAlexey Gladkov 225137e7647aSAlexey Gladkovand only after remounting procfs mount options will change at all 2252565dbe72SMauro Carvalho Chehabmountpoints:: 225337e7647aSAlexey Gladkov 225437e7647aSAlexey Gladkov # mount -o remount,hidepid=1 -t proc proc /tmp/proc 225537e7647aSAlexey Gladkov 225637e7647aSAlexey Gladkov # grep ^proc /proc/mounts 225737e7647aSAlexey Gladkov proc /proc proc rw,relatime,hidepid=1 0 0 225837e7647aSAlexey Gladkov proc /tmp/proc proc rw,relatime,hidepid=1 0 0 225937e7647aSAlexey Gladkov 226037e7647aSAlexey GladkovThis behavior is different from the behavior of other filesystems. 226137e7647aSAlexey Gladkov 226237e7647aSAlexey GladkovThe new procfs behavior is more like other filesystems. Each procfs mount 226337e7647aSAlexey Gladkovcreates a new procfs instance. Mount options affect own procfs instance. 226437e7647aSAlexey GladkovIt means that it became possible to have several procfs instances 2265565dbe72SMauro Carvalho Chehabdisplaying tasks with different filtering options in one pid namespace:: 226637e7647aSAlexey Gladkov 22671c6c4d11SAlexey Gladkov # mount -o hidepid=invisible -t proc proc /proc 22681c6c4d11SAlexey Gladkov # mount -o hidepid=noaccess -t proc proc /tmp/proc 226937e7647aSAlexey Gladkov # grep ^proc /proc/mounts 22701c6c4d11SAlexey Gladkov proc /proc proc rw,relatime,hidepid=invisible 0 0 22711c6c4d11SAlexey Gladkov proc /tmp/proc proc rw,relatime,hidepid=noaccess 0 0 2272