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 #ifdef CONFIG_EXT4_DEBUG 41 extern u8 mb_enable_debug; 42 43 #define mb_debug(n, fmt, a...) \ 44 do { \ 45 if ((n) <= mb_enable_debug) { \ 46 printk(KERN_DEBUG "(%s, %d): %s: ", \ 47 __FILE__, __LINE__, __func__); \ 48 printk(fmt, ## a); \ 49 } \ 50 } while (0) 51 #else 52 #define mb_debug(n, fmt, a...) 53 #endif 54 55 /* 56 * with EXT4_MB_HISTORY mballoc stores last N allocations in memory 57 * and you can monitor it in /proc/fs/ext4/<dev>/mb_history 58 */ 59 #define EXT4_MB_HISTORY 60 #define EXT4_MB_HISTORY_ALLOC 1 /* allocation */ 61 #define EXT4_MB_HISTORY_PREALLOC 2 /* preallocated blocks used */ 62 #define EXT4_MB_HISTORY_DISCARD 4 /* preallocation discarded */ 63 #define EXT4_MB_HISTORY_FREE 8 /* free */ 64 65 #define EXT4_MB_HISTORY_DEFAULT (EXT4_MB_HISTORY_ALLOC | \ 66 EXT4_MB_HISTORY_PREALLOC) 67 68 /* 69 * How long mballoc can look for a best extent (in found extents) 70 */ 71 #define MB_DEFAULT_MAX_TO_SCAN 200 72 73 /* 74 * How long mballoc must look for a best extent 75 */ 76 #define MB_DEFAULT_MIN_TO_SCAN 10 77 78 /* 79 * How many groups mballoc will scan looking for the best chunk 80 */ 81 #define MB_DEFAULT_MAX_GROUPS_TO_SCAN 5 82 83 /* 84 * with 'ext4_mb_stats' allocator will collect stats that will be 85 * shown at umount. The collecting costs though! 86 */ 87 #define MB_DEFAULT_STATS 1 88 89 /* 90 * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served 91 * by the stream allocator, which purpose is to pack requests 92 * as close each to other as possible to produce smooth I/O traffic 93 * We use locality group prealloc space for stream request. 94 * We can tune the same via /proc/fs/ext4/<parition>/stream_req 95 */ 96 #define MB_DEFAULT_STREAM_THRESHOLD 16 /* 64K */ 97 98 /* 99 * for which requests use 2^N search using buddies 100 */ 101 #define MB_DEFAULT_ORDER2_REQS 2 102 103 /* 104 * default group prealloc size 512 blocks 105 */ 106 #define MB_DEFAULT_GROUP_PREALLOC 512 107 108 109 struct ext4_free_data { 110 /* this links the free block information from group_info */ 111 struct rb_node node; 112 113 /* this links the free block information from ext4_sb_info */ 114 struct list_head list; 115 116 /* group which free block extent belongs */ 117 ext4_group_t group; 118 119 /* free block extent */ 120 ext4_grpblk_t start_blk; 121 ext4_grpblk_t count; 122 123 /* transaction which freed this extent */ 124 tid_t t_tid; 125 }; 126 127 struct ext4_prealloc_space { 128 struct list_head pa_inode_list; 129 struct list_head pa_group_list; 130 union { 131 struct list_head pa_tmp_list; 132 struct rcu_head pa_rcu; 133 } u; 134 spinlock_t pa_lock; 135 atomic_t pa_count; 136 unsigned pa_deleted; 137 ext4_fsblk_t pa_pstart; /* phys. block */ 138 ext4_lblk_t pa_lstart; /* log. block */ 139 ext4_grpblk_t pa_len; /* len of preallocated chunk */ 140 ext4_grpblk_t pa_free; /* how many blocks are free */ 141 unsigned short pa_type; /* pa type. inode or group */ 142 spinlock_t *pa_obj_lock; 143 struct inode *pa_inode; /* hack, for history only */ 144 }; 145 146 enum { 147 MB_INODE_PA = 0, 148 MB_GROUP_PA = 1 149 }; 150 151 struct ext4_free_extent { 152 ext4_lblk_t fe_logical; 153 ext4_grpblk_t fe_start; 154 ext4_group_t fe_group; 155 ext4_grpblk_t fe_len; 156 }; 157 158 /* 159 * Locality group: 160 * we try to group all related changes together 161 * so that writeback can flush/allocate them together as well 162 * Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC 163 * (512). We store prealloc space into the hash based on the pa_free blocks 164 * order value.ie, fls(pa_free)-1; 165 */ 166 #define PREALLOC_TB_SIZE 10 167 struct ext4_locality_group { 168 /* for allocator */ 169 /* to serialize allocates */ 170 struct mutex lg_mutex; 171 /* list of preallocations */ 172 struct list_head lg_prealloc_list[PREALLOC_TB_SIZE]; 173 spinlock_t lg_prealloc_lock; 174 }; 175 176 struct ext4_allocation_context { 177 struct inode *ac_inode; 178 struct super_block *ac_sb; 179 180 /* original request */ 181 struct ext4_free_extent ac_o_ex; 182 183 /* goal request (after normalization) */ 184 struct ext4_free_extent ac_g_ex; 185 186 /* the best found extent */ 187 struct ext4_free_extent ac_b_ex; 188 189 /* copy of the bext found extent taken before preallocation efforts */ 190 struct ext4_free_extent ac_f_ex; 191 192 /* number of iterations done. we have to track to limit searching */ 193 unsigned long ac_ex_scanned; 194 __u16 ac_groups_scanned; 195 __u16 ac_found; 196 __u16 ac_tail; 197 __u16 ac_buddy; 198 __u16 ac_flags; /* allocation hints */ 199 __u8 ac_status; 200 __u8 ac_criteria; 201 __u8 ac_repeats; 202 __u8 ac_2order; /* if request is to allocate 2^N blocks and 203 * N > 0, the field stores N, otherwise 0 */ 204 __u8 ac_op; /* operation, for history only */ 205 struct page *ac_bitmap_page; 206 struct page *ac_buddy_page; 207 /* 208 * pointer to the held semaphore upon successful 209 * block allocation 210 */ 211 struct rw_semaphore *alloc_semp; 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 struct rw_semaphore *alloc_semp; 246 }; 247 #define EXT4_MB_BITMAP(e4b) ((e4b)->bd_bitmap) 248 #define EXT4_MB_BUDDY(e4b) ((e4b)->bd_buddy) 249 250 #ifndef EXT4_MB_HISTORY 251 static inline void ext4_mb_store_history(struct ext4_allocation_context *ac) 252 { 253 return; 254 } 255 #endif 256 257 #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) 258 259 static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb, 260 struct ext4_free_extent *fex) 261 { 262 ext4_fsblk_t block; 263 264 block = (ext4_fsblk_t) fex->fe_group * EXT4_BLOCKS_PER_GROUP(sb) 265 + fex->fe_start 266 + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block); 267 return block; 268 } 269 #endif 270