1 /* 2 * fs/ext4/mballoc.h 3 * 4 * Written by: Alex Tomas <alex@clusterfs.com> 5 * 6 */ 7 #ifndef _EXT4_MBALLOC_H 8 #define _EXT4_MBALLOC_H 9 10 #include <linux/time.h> 11 #include <linux/fs.h> 12 #include <linux/namei.h> 13 #include <linux/quotaops.h> 14 #include <linux/buffer_head.h> 15 #include <linux/module.h> 16 #include <linux/swap.h> 17 #include <linux/proc_fs.h> 18 #include <linux/pagemap.h> 19 #include <linux/seq_file.h> 20 #include <linux/version.h> 21 #include <linux/blkdev.h> 22 #include <linux/mutex.h> 23 #include "ext4_jbd2.h" 24 #include "ext4.h" 25 26 /* 27 * with AGGRESSIVE_CHECK allocator runs consistency checks over 28 * structures. these checks slow things down a lot 29 */ 30 #define AGGRESSIVE_CHECK__ 31 32 /* 33 * with DOUBLE_CHECK defined mballoc creates persistent in-core 34 * bitmaps, maintains and uses them to check for double allocations 35 */ 36 #define DOUBLE_CHECK__ 37 38 /* 39 */ 40 #define MB_DEBUG__ 41 #ifdef MB_DEBUG 42 #define mb_debug(fmt, a...) printk(fmt, ##a) 43 #else 44 #define mb_debug(fmt, a...) 45 #endif 46 47 /* 48 * with EXT4_MB_HISTORY mballoc stores last N allocations in memory 49 * and you can monitor it in /proc/fs/ext4/<dev>/mb_history 50 */ 51 #define EXT4_MB_HISTORY 52 #define EXT4_MB_HISTORY_ALLOC 1 /* allocation */ 53 #define EXT4_MB_HISTORY_PREALLOC 2 /* preallocated blocks used */ 54 #define EXT4_MB_HISTORY_DISCARD 4 /* preallocation discarded */ 55 #define EXT4_MB_HISTORY_FREE 8 /* free */ 56 57 #define EXT4_MB_HISTORY_DEFAULT (EXT4_MB_HISTORY_ALLOC | \ 58 EXT4_MB_HISTORY_PREALLOC) 59 60 /* 61 * How long mballoc can look for a best extent (in found extents) 62 */ 63 #define MB_DEFAULT_MAX_TO_SCAN 200 64 65 /* 66 * How long mballoc must look for a best extent 67 */ 68 #define MB_DEFAULT_MIN_TO_SCAN 10 69 70 /* 71 * How many groups mballoc will scan looking for the best chunk 72 */ 73 #define MB_DEFAULT_MAX_GROUPS_TO_SCAN 5 74 75 /* 76 * with 'ext4_mb_stats' allocator will collect stats that will be 77 * shown at umount. The collecting costs though! 78 */ 79 #define MB_DEFAULT_STATS 1 80 81 /* 82 * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served 83 * by the stream allocator, which purpose is to pack requests 84 * as close each to other as possible to produce smooth I/O traffic 85 * We use locality group prealloc space for stream request. 86 * We can tune the same via /proc/fs/ext4/<parition>/stream_req 87 */ 88 #define MB_DEFAULT_STREAM_THRESHOLD 16 /* 64K */ 89 90 /* 91 * for which requests use 2^N search using buddies 92 */ 93 #define MB_DEFAULT_ORDER2_REQS 2 94 95 /* 96 * default group prealloc size 512 blocks 97 */ 98 #define MB_DEFAULT_GROUP_PREALLOC 512 99 100 101 struct ext4_free_data { 102 /* this links the free block information from group_info */ 103 struct rb_node node; 104 105 /* this links the free block information from ext4_sb_info */ 106 struct list_head list; 107 108 /* group which free block extent belongs */ 109 ext4_group_t group; 110 111 /* free block extent */ 112 ext4_grpblk_t start_blk; 113 ext4_grpblk_t count; 114 115 /* transaction which freed this extent */ 116 tid_t t_tid; 117 }; 118 119 struct ext4_prealloc_space { 120 struct list_head pa_inode_list; 121 struct list_head pa_group_list; 122 union { 123 struct list_head pa_tmp_list; 124 struct rcu_head pa_rcu; 125 } u; 126 spinlock_t pa_lock; 127 atomic_t pa_count; 128 unsigned pa_deleted; 129 ext4_fsblk_t pa_pstart; /* phys. block */ 130 ext4_lblk_t pa_lstart; /* log. block */ 131 unsigned short pa_len; /* len of preallocated chunk */ 132 unsigned short pa_free; /* how many blocks are free */ 133 unsigned short pa_type; /* pa type. inode or group */ 134 spinlock_t *pa_obj_lock; 135 struct inode *pa_inode; /* hack, for history only */ 136 }; 137 138 enum { 139 MB_INODE_PA = 0, 140 MB_GROUP_PA = 1 141 }; 142 143 struct ext4_free_extent { 144 ext4_lblk_t fe_logical; 145 ext4_grpblk_t fe_start; 146 ext4_group_t fe_group; 147 int fe_len; 148 }; 149 150 /* 151 * Locality group: 152 * we try to group all related changes together 153 * so that writeback can flush/allocate them together as well 154 * Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC 155 * (512). We store prealloc space into the hash based on the pa_free blocks 156 * order value.ie, fls(pa_free)-1; 157 */ 158 #define PREALLOC_TB_SIZE 10 159 struct ext4_locality_group { 160 /* for allocator */ 161 /* to serialize allocates */ 162 struct mutex lg_mutex; 163 /* list of preallocations */ 164 struct list_head lg_prealloc_list[PREALLOC_TB_SIZE]; 165 spinlock_t lg_prealloc_lock; 166 }; 167 168 struct ext4_allocation_context { 169 struct inode *ac_inode; 170 struct super_block *ac_sb; 171 172 /* original request */ 173 struct ext4_free_extent ac_o_ex; 174 175 /* goal request (after normalization) */ 176 struct ext4_free_extent ac_g_ex; 177 178 /* the best found extent */ 179 struct ext4_free_extent ac_b_ex; 180 181 /* copy of the bext found extent taken before preallocation efforts */ 182 struct ext4_free_extent ac_f_ex; 183 184 /* number of iterations done. we have to track to limit searching */ 185 unsigned long ac_ex_scanned; 186 __u16 ac_groups_scanned; 187 __u16 ac_found; 188 __u16 ac_tail; 189 __u16 ac_buddy; 190 __u16 ac_flags; /* allocation hints */ 191 __u8 ac_status; 192 __u8 ac_criteria; 193 __u8 ac_repeats; 194 __u8 ac_2order; /* if request is to allocate 2^N blocks and 195 * N > 0, the field stores N, otherwise 0 */ 196 __u8 ac_op; /* operation, for history only */ 197 struct page *ac_bitmap_page; 198 struct page *ac_buddy_page; 199 /* 200 * pointer to the held semaphore upon successful 201 * block allocation 202 */ 203 struct rw_semaphore *alloc_semp; 204 struct ext4_prealloc_space *ac_pa; 205 struct ext4_locality_group *ac_lg; 206 }; 207 208 #define AC_STATUS_CONTINUE 1 209 #define AC_STATUS_FOUND 2 210 #define AC_STATUS_BREAK 3 211 212 struct ext4_mb_history { 213 struct ext4_free_extent orig; /* orig allocation */ 214 struct ext4_free_extent goal; /* goal allocation */ 215 struct ext4_free_extent result; /* result allocation */ 216 unsigned pid; 217 unsigned ino; 218 __u16 found; /* how many extents have been found */ 219 __u16 groups; /* how many groups have been scanned */ 220 __u16 tail; /* what tail broke some buddy */ 221 __u16 buddy; /* buddy the tail ^^^ broke */ 222 __u16 flags; 223 __u8 cr:3; /* which phase the result extent was found at */ 224 __u8 op:4; 225 __u8 merged:1; 226 }; 227 228 struct ext4_buddy { 229 struct page *bd_buddy_page; 230 void *bd_buddy; 231 struct page *bd_bitmap_page; 232 void *bd_bitmap; 233 struct ext4_group_info *bd_info; 234 struct super_block *bd_sb; 235 __u16 bd_blkbits; 236 ext4_group_t bd_group; 237 struct rw_semaphore *alloc_semp; 238 }; 239 #define EXT4_MB_BITMAP(e4b) ((e4b)->bd_bitmap) 240 #define EXT4_MB_BUDDY(e4b) ((e4b)->bd_buddy) 241 242 #ifndef EXT4_MB_HISTORY 243 static inline void ext4_mb_store_history(struct ext4_allocation_context *ac) 244 { 245 return; 246 } 247 #endif 248 249 #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) 250 251 static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb, 252 struct ext4_free_extent *fex) 253 { 254 ext4_fsblk_t block; 255 256 block = (ext4_fsblk_t) fex->fe_group * EXT4_BLOCKS_PER_GROUP(sb) 257 + fex->fe_start 258 + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block); 259 return block; 260 } 261 #endif 262