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 <linux/mutex.h> 24 #include "ext4_jbd2.h" 25 #include "ext4.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 512 100 101 102 struct ext4_free_data { 103 /* this links the free block information from group_info */ 104 struct rb_node node; 105 106 /* this links the free block information from ext4_sb_info */ 107 struct list_head list; 108 109 /* group which free block extent belongs */ 110 ext4_group_t group; 111 112 /* free block extent */ 113 ext4_grpblk_t start_blk; 114 ext4_grpblk_t count; 115 116 /* transaction which freed this extent */ 117 tid_t t_tid; 118 }; 119 120 struct ext4_prealloc_space { 121 struct list_head pa_inode_list; 122 struct list_head pa_group_list; 123 union { 124 struct list_head pa_tmp_list; 125 struct rcu_head pa_rcu; 126 } u; 127 spinlock_t pa_lock; 128 atomic_t pa_count; 129 unsigned pa_deleted; 130 ext4_fsblk_t pa_pstart; /* phys. block */ 131 ext4_lblk_t pa_lstart; /* log. block */ 132 unsigned short pa_len; /* len of preallocated chunk */ 133 unsigned short pa_free; /* how many blocks are free */ 134 unsigned short pa_type; /* pa type. inode or group */ 135 spinlock_t *pa_obj_lock; 136 struct inode *pa_inode; /* hack, for history only */ 137 }; 138 139 enum { 140 MB_INODE_PA = 0, 141 MB_GROUP_PA = 1 142 }; 143 144 struct ext4_free_extent { 145 ext4_lblk_t fe_logical; 146 ext4_grpblk_t fe_start; 147 ext4_group_t fe_group; 148 int fe_len; 149 }; 150 151 /* 152 * Locality group: 153 * we try to group all related changes together 154 * so that writeback can flush/allocate them together as well 155 * Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC 156 * (512). We store prealloc space into the hash based on the pa_free blocks 157 * order value.ie, fls(pa_free)-1; 158 */ 159 #define PREALLOC_TB_SIZE 10 160 struct ext4_locality_group { 161 /* for allocator */ 162 /* to serialize allocates */ 163 struct mutex lg_mutex; 164 /* list of preallocations */ 165 struct list_head lg_prealloc_list[PREALLOC_TB_SIZE]; 166 spinlock_t lg_prealloc_lock; 167 }; 168 169 struct ext4_allocation_context { 170 struct inode *ac_inode; 171 struct super_block *ac_sb; 172 173 /* original request */ 174 struct ext4_free_extent ac_o_ex; 175 176 /* goal request (after normalization) */ 177 struct ext4_free_extent ac_g_ex; 178 179 /* the best found extent */ 180 struct ext4_free_extent ac_b_ex; 181 182 /* copy of the bext found extent taken before preallocation efforts */ 183 struct ext4_free_extent ac_f_ex; 184 185 /* number of iterations done. we have to track to limit searching */ 186 unsigned long ac_ex_scanned; 187 __u16 ac_groups_scanned; 188 __u16 ac_found; 189 __u16 ac_tail; 190 __u16 ac_buddy; 191 __u16 ac_flags; /* allocation hints */ 192 __u8 ac_status; 193 __u8 ac_criteria; 194 __u8 ac_repeats; 195 __u8 ac_2order; /* if request is to allocate 2^N blocks and 196 * N > 0, the field stores N, otherwise 0 */ 197 __u8 ac_op; /* operation, for history only */ 198 struct page *ac_bitmap_page; 199 struct page *ac_buddy_page; 200 /* 201 * pointer to the held semaphore upon successful 202 * block allocation 203 */ 204 struct rw_semaphore *alloc_semp; 205 struct ext4_prealloc_space *ac_pa; 206 struct ext4_locality_group *ac_lg; 207 }; 208 209 #define AC_STATUS_CONTINUE 1 210 #define AC_STATUS_FOUND 2 211 #define AC_STATUS_BREAK 3 212 213 struct ext4_mb_history { 214 struct ext4_free_extent orig; /* orig allocation */ 215 struct ext4_free_extent goal; /* goal allocation */ 216 struct ext4_free_extent result; /* result allocation */ 217 unsigned pid; 218 unsigned ino; 219 __u16 found; /* how many extents have been found */ 220 __u16 groups; /* how many groups have been scanned */ 221 __u16 tail; /* what tail broke some buddy */ 222 __u16 buddy; /* buddy the tail ^^^ broke */ 223 __u16 flags; 224 __u8 cr:3; /* which phase the result extent was found at */ 225 __u8 op:4; 226 __u8 merged:1; 227 }; 228 229 struct ext4_buddy { 230 struct page *bd_buddy_page; 231 void *bd_buddy; 232 struct page *bd_bitmap_page; 233 void *bd_bitmap; 234 struct ext4_group_info *bd_info; 235 struct super_block *bd_sb; 236 __u16 bd_blkbits; 237 ext4_group_t bd_group; 238 struct rw_semaphore *alloc_semp; 239 }; 240 #define EXT4_MB_BITMAP(e4b) ((e4b)->bd_bitmap) 241 #define EXT4_MB_BUDDY(e4b) ((e4b)->bd_buddy) 242 243 #ifndef EXT4_MB_HISTORY 244 static inline void ext4_mb_store_history(struct ext4_allocation_context *ac) 245 { 246 return; 247 } 248 #endif 249 250 #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) 251 252 static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb, 253 struct ext4_free_extent *fex) 254 { 255 ext4_fsblk_t block; 256 257 block = (ext4_fsblk_t) fex->fe_group * EXT4_BLOCKS_PER_GROUP(sb) 258 + fex->fe_start 259 + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block); 260 return block; 261 } 262 #endif 263