xref: /linux/include/linux/threads.h (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732)
1 #ifndef _LINUX_THREADS_H
2 #define _LINUX_THREADS_H
3 
4 
5 /*
6  * The default limit for the nr of threads is now in
7  * /proc/sys/kernel/threads-max.
8  */
9 
10 /*
11  * Maximum supported processors.  Setting this smaller saves quite a
12  * bit of memory.  Use nr_cpu_ids instead of this except for static bitmaps.
13  */
14 #ifndef CONFIG_NR_CPUS
15 /* FIXME: This should be fixed in the arch's Kconfig */
16 #define CONFIG_NR_CPUS	1
17 #endif
18 
19 /* Places which use this should consider cpumask_var_t. */
20 #define NR_CPUS		CONFIG_NR_CPUS
21 
22 #define MIN_THREADS_LEFT_FOR_ROOT 4
23 
24 /*
25  * This controls the default maximum pid allocated to a process
26  */
27 #define PID_MAX_DEFAULT (CONFIG_BASE_SMALL ? 0x1000 : 0x8000)
28 
29 /*
30  * A maximum of 4 million PIDs should be enough for a while.
31  * [NOTE: PID/TIDs are limited to 2^29 ~= 500+ million, see futex.h.]
32  */
33 #define PID_MAX_LIMIT (CONFIG_BASE_SMALL ? PAGE_SIZE * 8 : \
34 	(sizeof(long) > 4 ? 4 * 1024 * 1024 : PID_MAX_DEFAULT))
35 
36 /*
37  * Define a minimum number of pids per cpu.  Heuristically based
38  * on original pid max of 32k for 32 cpus.  Also, increase the
39  * minimum settable value for pid_max on the running system based
40  * on similar defaults.  See kernel/pid.c:pidmap_init() for details.
41  */
42 #define PIDS_PER_CPU_DEFAULT	1024
43 #define PIDS_PER_CPU_MIN	8
44 
45 #endif
46