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 "ext4_jbd2.h" 22 #include "ext4.h" 23 #include "group.h" 24 25 /* 26 * with AGGRESSIVE_CHECK allocator runs consistency checks over 27 * structures. these checks slow things down a lot 28 */ 29 #define AGGRESSIVE_CHECK__ 30 31 /* 32 * with DOUBLE_CHECK defined mballoc creates persistent in-core 33 * bitmaps, maintains and uses them to check for double allocations 34 */ 35 #define DOUBLE_CHECK__ 36 37 /* 38 */ 39 #define MB_DEBUG__ 40 #ifdef MB_DEBUG 41 #define mb_debug(fmt, a...) printk(fmt, ##a) 42 #else 43 #define mb_debug(fmt, a...) 44 #endif 45 46 /* 47 * with EXT4_MB_HISTORY mballoc stores last N allocations in memory 48 * and you can monitor it in /proc/fs/ext4/<dev>/mb_history 49 */ 50 #define EXT4_MB_HISTORY 51 #define EXT4_MB_HISTORY_ALLOC 1 /* allocation */ 52 #define EXT4_MB_HISTORY_PREALLOC 2 /* preallocated blocks used */ 53 #define EXT4_MB_HISTORY_DISCARD 4 /* preallocation discarded */ 54 #define EXT4_MB_HISTORY_FREE 8 /* free */ 55 56 #define EXT4_MB_HISTORY_DEFAULT (EXT4_MB_HISTORY_ALLOC | \ 57 EXT4_MB_HISTORY_PREALLOC) 58 59 /* 60 * How long mballoc can look for a best extent (in found extents) 61 */ 62 #define MB_DEFAULT_MAX_TO_SCAN 200 63 64 /* 65 * How long mballoc must look for a best extent 66 */ 67 #define MB_DEFAULT_MIN_TO_SCAN 10 68 69 /* 70 * How many groups mballoc will scan looking for the best chunk 71 */ 72 #define MB_DEFAULT_MAX_GROUPS_TO_SCAN 5 73 74 /* 75 * with 'ext4_mb_stats' allocator will collect stats that will be 76 * shown at umount. The collecting costs though! 77 */ 78 #define MB_DEFAULT_STATS 1 79 80 /* 81 * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served 82 * by the stream allocator, which purpose is to pack requests 83 * as close each to other as possible to produce smooth I/O traffic 84 * We use locality group prealloc space for stream request. 85 * We can tune the same via /proc/fs/ext4/<parition>/stream_req 86 */ 87 #define MB_DEFAULT_STREAM_THRESHOLD 16 /* 64K */ 88 89 /* 90 * for which requests use 2^N search using buddies 91 */ 92 #define MB_DEFAULT_ORDER2_REQS 2 93 94 /* 95 * default group prealloc size 512 blocks 96 */ 97 #define MB_DEFAULT_GROUP_PREALLOC 512 98 99 static struct kmem_cache *ext4_pspace_cachep; 100 static struct kmem_cache *ext4_ac_cachep; 101 102 #ifdef EXT4_BB_MAX_BLOCKS 103 #undef EXT4_BB_MAX_BLOCKS 104 #endif 105 #define EXT4_BB_MAX_BLOCKS 30 106 107 struct ext4_free_metadata { 108 ext4_group_t group; 109 unsigned short num; 110 ext4_grpblk_t blocks[EXT4_BB_MAX_BLOCKS]; 111 struct list_head list; 112 }; 113 114 struct ext4_group_info { 115 unsigned long bb_state; 116 unsigned long bb_tid; 117 struct ext4_free_metadata *bb_md_cur; 118 unsigned short bb_first_free; 119 unsigned short bb_free; 120 unsigned short bb_fragments; 121 struct list_head bb_prealloc_list; 122 #ifdef DOUBLE_CHECK 123 void *bb_bitmap; 124 #endif 125 unsigned short bb_counters[]; 126 }; 127 128 #define EXT4_GROUP_INFO_NEED_INIT_BIT 0 129 #define EXT4_GROUP_INFO_LOCKED_BIT 1 130 131 #define EXT4_MB_GRP_NEED_INIT(grp) \ 132 (test_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &((grp)->bb_state))) 133 134 135 struct ext4_prealloc_space { 136 struct list_head pa_inode_list; 137 struct list_head pa_group_list; 138 union { 139 struct list_head pa_tmp_list; 140 struct rcu_head pa_rcu; 141 } u; 142 spinlock_t pa_lock; 143 atomic_t pa_count; 144 unsigned pa_deleted; 145 ext4_fsblk_t pa_pstart; /* phys. block */ 146 ext4_lblk_t pa_lstart; /* log. block */ 147 unsigned short pa_len; /* len of preallocated chunk */ 148 unsigned short pa_free; /* how many blocks are free */ 149 unsigned short pa_linear; /* consumed in one direction 150 * strictly, for grp prealloc */ 151 spinlock_t *pa_obj_lock; 152 struct inode *pa_inode; /* hack, for history only */ 153 }; 154 155 156 struct ext4_free_extent { 157 ext4_lblk_t fe_logical; 158 ext4_grpblk_t fe_start; 159 ext4_group_t fe_group; 160 int fe_len; 161 }; 162 163 /* 164 * Locality group: 165 * we try to group all related changes together 166 * so that writeback can flush/allocate them together as well 167 * Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC 168 * (512). We store prealloc space into the hash based on the pa_free blocks 169 * order value.ie, fls(pa_free)-1; 170 */ 171 #define PREALLOC_TB_SIZE 10 172 struct ext4_locality_group { 173 /* for allocator */ 174 /* to serialize allocates */ 175 struct mutex lg_mutex; 176 /* list of preallocations */ 177 struct list_head lg_prealloc_list[PREALLOC_TB_SIZE]; 178 spinlock_t lg_prealloc_lock; 179 }; 180 181 struct ext4_allocation_context { 182 struct inode *ac_inode; 183 struct super_block *ac_sb; 184 185 /* original request */ 186 struct ext4_free_extent ac_o_ex; 187 188 /* goal request (after normalization) */ 189 struct ext4_free_extent ac_g_ex; 190 191 /* the best found extent */ 192 struct ext4_free_extent ac_b_ex; 193 194 /* copy of the bext found extent taken before preallocation efforts */ 195 struct ext4_free_extent ac_f_ex; 196 197 /* number of iterations done. we have to track to limit searching */ 198 unsigned long ac_ex_scanned; 199 __u16 ac_groups_scanned; 200 __u16 ac_found; 201 __u16 ac_tail; 202 __u16 ac_buddy; 203 __u16 ac_flags; /* allocation hints */ 204 __u8 ac_status; 205 __u8 ac_criteria; 206 __u8 ac_repeats; 207 __u8 ac_2order; /* if request is to allocate 2^N blocks and 208 * N > 0, the field stores N, otherwise 0 */ 209 __u8 ac_op; /* operation, for history only */ 210 struct page *ac_bitmap_page; 211 struct page *ac_buddy_page; 212 struct ext4_prealloc_space *ac_pa; 213 struct ext4_locality_group *ac_lg; 214 }; 215 216 #define AC_STATUS_CONTINUE 1 217 #define AC_STATUS_FOUND 2 218 #define AC_STATUS_BREAK 3 219 220 struct ext4_mb_history { 221 struct ext4_free_extent orig; /* orig allocation */ 222 struct ext4_free_extent goal; /* goal allocation */ 223 struct ext4_free_extent result; /* result allocation */ 224 unsigned pid; 225 unsigned ino; 226 __u16 found; /* how many extents have been found */ 227 __u16 groups; /* how many groups have been scanned */ 228 __u16 tail; /* what tail broke some buddy */ 229 __u16 buddy; /* buddy the tail ^^^ broke */ 230 __u16 flags; 231 __u8 cr:3; /* which phase the result extent was found at */ 232 __u8 op:4; 233 __u8 merged:1; 234 }; 235 236 struct ext4_buddy { 237 struct page *bd_buddy_page; 238 void *bd_buddy; 239 struct page *bd_bitmap_page; 240 void *bd_bitmap; 241 struct ext4_group_info *bd_info; 242 struct super_block *bd_sb; 243 __u16 bd_blkbits; 244 ext4_group_t bd_group; 245 }; 246 #define EXT4_MB_BITMAP(e4b) ((e4b)->bd_bitmap) 247 #define EXT4_MB_BUDDY(e4b) ((e4b)->bd_buddy) 248 249 #ifndef EXT4_MB_HISTORY 250 static inline void ext4_mb_store_history(struct ext4_allocation_context *ac) 251 { 252 return; 253 } 254 #else 255 static void ext4_mb_store_history(struct ext4_allocation_context *ac); 256 #endif 257 258 #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) 259 260 static struct proc_dir_entry *proc_root_ext4; 261 struct buffer_head *read_block_bitmap(struct super_block *, ext4_group_t); 262 263 static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap, 264 ext4_group_t group); 265 static void ext4_mb_poll_new_transaction(struct super_block *, handle_t *); 266 static void ext4_mb_free_committed_blocks(struct super_block *); 267 static void ext4_mb_return_to_preallocation(struct inode *inode, 268 struct ext4_buddy *e4b, sector_t block, 269 int count); 270 static void ext4_mb_put_pa(struct ext4_allocation_context *, 271 struct super_block *, struct ext4_prealloc_space *pa); 272 static int ext4_mb_init_per_dev_proc(struct super_block *sb); 273 static int ext4_mb_destroy_per_dev_proc(struct super_block *sb); 274 275 276 static inline void ext4_lock_group(struct super_block *sb, ext4_group_t group) 277 { 278 struct ext4_group_info *grinfo = ext4_get_group_info(sb, group); 279 280 bit_spin_lock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state)); 281 } 282 283 static inline void ext4_unlock_group(struct super_block *sb, 284 ext4_group_t group) 285 { 286 struct ext4_group_info *grinfo = ext4_get_group_info(sb, group); 287 288 bit_spin_unlock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state)); 289 } 290 291 static inline int ext4_is_group_locked(struct super_block *sb, 292 ext4_group_t group) 293 { 294 struct ext4_group_info *grinfo = ext4_get_group_info(sb, group); 295 296 return bit_spin_is_locked(EXT4_GROUP_INFO_LOCKED_BIT, 297 &(grinfo->bb_state)); 298 } 299 300 static ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb, 301 struct ext4_free_extent *fex) 302 { 303 ext4_fsblk_t block; 304 305 block = (ext4_fsblk_t) fex->fe_group * EXT4_BLOCKS_PER_GROUP(sb) 306 + fex->fe_start 307 + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block); 308 return block; 309 } 310 #endif 311