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/marker.h> 23 #include "ext4_jbd2.h" 24 #include "ext4.h" 25 #include "group.h" 26 27 /* 28 * with AGGRESSIVE_CHECK allocator runs consistency checks over 29 * structures. these checks slow things down a lot 30 */ 31 #define AGGRESSIVE_CHECK__ 32 33 /* 34 * with DOUBLE_CHECK defined mballoc creates persistent in-core 35 * bitmaps, maintains and uses them to check for double allocations 36 */ 37 #define DOUBLE_CHECK__ 38 39 /* 40 */ 41 #define MB_DEBUG__ 42 #ifdef MB_DEBUG 43 #define mb_debug(fmt, a...) printk(fmt, ##a) 44 #else 45 #define mb_debug(fmt, a...) 46 #endif 47 48 /* 49 * with EXT4_MB_HISTORY mballoc stores last N allocations in memory 50 * and you can monitor it in /proc/fs/ext4/<dev>/mb_history 51 */ 52 #define EXT4_MB_HISTORY 53 #define EXT4_MB_HISTORY_ALLOC 1 /* allocation */ 54 #define EXT4_MB_HISTORY_PREALLOC 2 /* preallocated blocks used */ 55 #define EXT4_MB_HISTORY_DISCARD 4 /* preallocation discarded */ 56 #define EXT4_MB_HISTORY_FREE 8 /* free */ 57 58 #define EXT4_MB_HISTORY_DEFAULT (EXT4_MB_HISTORY_ALLOC | \ 59 EXT4_MB_HISTORY_PREALLOC) 60 61 /* 62 * How long mballoc can look for a best extent (in found extents) 63 */ 64 #define MB_DEFAULT_MAX_TO_SCAN 200 65 66 /* 67 * How long mballoc must look for a best extent 68 */ 69 #define MB_DEFAULT_MIN_TO_SCAN 10 70 71 /* 72 * How many groups mballoc will scan looking for the best chunk 73 */ 74 #define MB_DEFAULT_MAX_GROUPS_TO_SCAN 5 75 76 /* 77 * with 'ext4_mb_stats' allocator will collect stats that will be 78 * shown at umount. The collecting costs though! 79 */ 80 #define MB_DEFAULT_STATS 1 81 82 /* 83 * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served 84 * by the stream allocator, which purpose is to pack requests 85 * as close each to other as possible to produce smooth I/O traffic 86 * We use locality group prealloc space for stream request. 87 * We can tune the same via /proc/fs/ext4/<parition>/stream_req 88 */ 89 #define MB_DEFAULT_STREAM_THRESHOLD 16 /* 64K */ 90 91 /* 92 * for which requests use 2^N search using buddies 93 */ 94 #define MB_DEFAULT_ORDER2_REQS 2 95 96 /* 97 * default group prealloc size 512 blocks 98 */ 99 #define MB_DEFAULT_GROUP_PREALLOC 512 100 101 static struct kmem_cache *ext4_pspace_cachep; 102 static struct kmem_cache *ext4_ac_cachep; 103 static struct kmem_cache *ext4_free_ext_cachep; 104 105 struct ext4_free_data { 106 /* this links the free block information from group_info */ 107 struct rb_node node; 108 109 /* this links the free block information from ext4_sb_info */ 110 struct list_head list; 111 112 /* group which free block extent belongs */ 113 ext4_group_t group; 114 115 /* free block extent */ 116 ext4_grpblk_t start_blk; 117 ext4_grpblk_t count; 118 119 /* transaction which freed this extent */ 120 tid_t t_tid; 121 }; 122 123 struct ext4_group_info { 124 unsigned long bb_state; 125 struct rb_root bb_free_root; 126 unsigned short bb_first_free; 127 unsigned short bb_free; 128 unsigned short bb_fragments; 129 struct list_head bb_prealloc_list; 130 #ifdef DOUBLE_CHECK 131 void *bb_bitmap; 132 #endif 133 unsigned short bb_counters[]; 134 }; 135 136 #define EXT4_GROUP_INFO_NEED_INIT_BIT 0 137 #define EXT4_GROUP_INFO_LOCKED_BIT 1 138 139 #define EXT4_MB_GRP_NEED_INIT(grp) \ 140 (test_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &((grp)->bb_state))) 141 142 143 struct ext4_prealloc_space { 144 struct list_head pa_inode_list; 145 struct list_head pa_group_list; 146 union { 147 struct list_head pa_tmp_list; 148 struct rcu_head pa_rcu; 149 } u; 150 spinlock_t pa_lock; 151 atomic_t pa_count; 152 unsigned pa_deleted; 153 ext4_fsblk_t pa_pstart; /* phys. block */ 154 ext4_lblk_t pa_lstart; /* log. block */ 155 unsigned short pa_len; /* len of preallocated chunk */ 156 unsigned short pa_free; /* how many blocks are free */ 157 unsigned short pa_linear; /* consumed in one direction 158 * strictly, for grp prealloc */ 159 spinlock_t *pa_obj_lock; 160 struct inode *pa_inode; /* hack, for history only */ 161 }; 162 163 164 struct ext4_free_extent { 165 ext4_lblk_t fe_logical; 166 ext4_grpblk_t fe_start; 167 ext4_group_t fe_group; 168 int fe_len; 169 }; 170 171 /* 172 * Locality group: 173 * we try to group all related changes together 174 * so that writeback can flush/allocate them together as well 175 * Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC 176 * (512). We store prealloc space into the hash based on the pa_free blocks 177 * order value.ie, fls(pa_free)-1; 178 */ 179 #define PREALLOC_TB_SIZE 10 180 struct ext4_locality_group { 181 /* for allocator */ 182 /* to serialize allocates */ 183 struct mutex lg_mutex; 184 /* list of preallocations */ 185 struct list_head lg_prealloc_list[PREALLOC_TB_SIZE]; 186 spinlock_t lg_prealloc_lock; 187 }; 188 189 struct ext4_allocation_context { 190 struct inode *ac_inode; 191 struct super_block *ac_sb; 192 193 /* original request */ 194 struct ext4_free_extent ac_o_ex; 195 196 /* goal request (after normalization) */ 197 struct ext4_free_extent ac_g_ex; 198 199 /* the best found extent */ 200 struct ext4_free_extent ac_b_ex; 201 202 /* copy of the bext found extent taken before preallocation efforts */ 203 struct ext4_free_extent ac_f_ex; 204 205 /* number of iterations done. we have to track to limit searching */ 206 unsigned long ac_ex_scanned; 207 __u16 ac_groups_scanned; 208 __u16 ac_found; 209 __u16 ac_tail; 210 __u16 ac_buddy; 211 __u16 ac_flags; /* allocation hints */ 212 __u8 ac_status; 213 __u8 ac_criteria; 214 __u8 ac_repeats; 215 __u8 ac_2order; /* if request is to allocate 2^N blocks and 216 * N > 0, the field stores N, otherwise 0 */ 217 __u8 ac_op; /* operation, for history only */ 218 struct page *ac_bitmap_page; 219 struct page *ac_buddy_page; 220 struct ext4_prealloc_space *ac_pa; 221 struct ext4_locality_group *ac_lg; 222 }; 223 224 #define AC_STATUS_CONTINUE 1 225 #define AC_STATUS_FOUND 2 226 #define AC_STATUS_BREAK 3 227 228 struct ext4_mb_history { 229 struct ext4_free_extent orig; /* orig allocation */ 230 struct ext4_free_extent goal; /* goal allocation */ 231 struct ext4_free_extent result; /* result allocation */ 232 unsigned pid; 233 unsigned ino; 234 __u16 found; /* how many extents have been found */ 235 __u16 groups; /* how many groups have been scanned */ 236 __u16 tail; /* what tail broke some buddy */ 237 __u16 buddy; /* buddy the tail ^^^ broke */ 238 __u16 flags; 239 __u8 cr:3; /* which phase the result extent was found at */ 240 __u8 op:4; 241 __u8 merged:1; 242 }; 243 244 struct ext4_buddy { 245 struct page *bd_buddy_page; 246 void *bd_buddy; 247 struct page *bd_bitmap_page; 248 void *bd_bitmap; 249 struct ext4_group_info *bd_info; 250 struct super_block *bd_sb; 251 __u16 bd_blkbits; 252 ext4_group_t bd_group; 253 }; 254 #define EXT4_MB_BITMAP(e4b) ((e4b)->bd_bitmap) 255 #define EXT4_MB_BUDDY(e4b) ((e4b)->bd_buddy) 256 257 #ifndef EXT4_MB_HISTORY 258 static inline void ext4_mb_store_history(struct ext4_allocation_context *ac) 259 { 260 return; 261 } 262 #else 263 static void ext4_mb_store_history(struct ext4_allocation_context *ac); 264 #endif 265 266 #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) 267 268 struct buffer_head *read_block_bitmap(struct super_block *, ext4_group_t); 269 270 static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap, 271 ext4_group_t group); 272 static void ext4_mb_return_to_preallocation(struct inode *inode, 273 struct ext4_buddy *e4b, sector_t block, 274 int count); 275 static void ext4_mb_put_pa(struct ext4_allocation_context *, 276 struct super_block *, struct ext4_prealloc_space *pa); 277 static int ext4_mb_init_per_dev_proc(struct super_block *sb); 278 static int ext4_mb_destroy_per_dev_proc(struct super_block *sb); 279 static void release_blocks_on_commit(journal_t *journal, transaction_t *txn); 280 281 282 static inline void ext4_lock_group(struct super_block *sb, ext4_group_t group) 283 { 284 struct ext4_group_info *grinfo = ext4_get_group_info(sb, group); 285 286 bit_spin_lock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state)); 287 } 288 289 static inline void ext4_unlock_group(struct super_block *sb, 290 ext4_group_t group) 291 { 292 struct ext4_group_info *grinfo = ext4_get_group_info(sb, group); 293 294 bit_spin_unlock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state)); 295 } 296 297 static inline int ext4_is_group_locked(struct super_block *sb, 298 ext4_group_t group) 299 { 300 struct ext4_group_info *grinfo = ext4_get_group_info(sb, group); 301 302 return bit_spin_is_locked(EXT4_GROUP_INFO_LOCKED_BIT, 303 &(grinfo->bb_state)); 304 } 305 306 static ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb, 307 struct ext4_free_extent *fex) 308 { 309 ext4_fsblk_t block; 310 311 block = (ext4_fsblk_t) fex->fe_group * EXT4_BLOCKS_PER_GROUP(sb) 312 + fex->fe_start 313 + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block); 314 return block; 315 } 316 #endif 317