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 #define EXT4_MB_HISTORY_ALLOC 1 /* allocation */ 56 #define EXT4_MB_HISTORY_PREALLOC 2 /* preallocated blocks used */ 57 58 /* 59 * How long mballoc can look for a best extent (in found extents) 60 */ 61 #define MB_DEFAULT_MAX_TO_SCAN 200 62 63 /* 64 * How long mballoc must look for a best extent 65 */ 66 #define MB_DEFAULT_MIN_TO_SCAN 10 67 68 /* 69 * How many groups mballoc will scan looking for the best chunk 70 */ 71 #define MB_DEFAULT_MAX_GROUPS_TO_SCAN 5 72 73 /* 74 * with 'ext4_mb_stats' allocator will collect stats that will be 75 * shown at umount. The collecting costs though! 76 */ 77 #define MB_DEFAULT_STATS 0 78 79 /* 80 * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served 81 * by the stream allocator, which purpose is to pack requests 82 * as close each to other as possible to produce smooth I/O traffic 83 * We use locality group prealloc space for stream request. 84 * We can tune the same via /proc/fs/ext4/<parition>/stream_req 85 */ 86 #define MB_DEFAULT_STREAM_THRESHOLD 16 /* 64K */ 87 88 /* 89 * for which requests use 2^N search using buddies 90 */ 91 #define MB_DEFAULT_ORDER2_REQS 2 92 93 /* 94 * default group prealloc size 512 blocks 95 */ 96 #define MB_DEFAULT_GROUP_PREALLOC 512 97 98 99 struct ext4_free_data { 100 /* this links the free block information from group_info */ 101 struct rb_node node; 102 103 /* this links the free block information from ext4_sb_info */ 104 struct list_head list; 105 106 /* group which free block extent belongs */ 107 ext4_group_t group; 108 109 /* free block extent */ 110 ext4_grpblk_t start_blk; 111 ext4_grpblk_t count; 112 113 /* transaction which freed this extent */ 114 tid_t t_tid; 115 }; 116 117 struct ext4_prealloc_space { 118 struct list_head pa_inode_list; 119 struct list_head pa_group_list; 120 union { 121 struct list_head pa_tmp_list; 122 struct rcu_head pa_rcu; 123 } u; 124 spinlock_t pa_lock; 125 atomic_t pa_count; 126 unsigned pa_deleted; 127 ext4_fsblk_t pa_pstart; /* phys. block */ 128 ext4_lblk_t pa_lstart; /* log. block */ 129 ext4_grpblk_t pa_len; /* len of preallocated chunk */ 130 ext4_grpblk_t pa_free; /* how many blocks are free */ 131 unsigned short pa_type; /* pa type. inode or group */ 132 spinlock_t *pa_obj_lock; 133 struct inode *pa_inode; /* hack, for history only */ 134 }; 135 136 enum { 137 MB_INODE_PA = 0, 138 MB_GROUP_PA = 1 139 }; 140 141 struct ext4_free_extent { 142 ext4_lblk_t fe_logical; 143 ext4_grpblk_t fe_start; 144 ext4_group_t fe_group; 145 ext4_grpblk_t fe_len; 146 }; 147 148 /* 149 * Locality group: 150 * we try to group all related changes together 151 * so that writeback can flush/allocate them together as well 152 * Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC 153 * (512). We store prealloc space into the hash based on the pa_free blocks 154 * order value.ie, fls(pa_free)-1; 155 */ 156 #define PREALLOC_TB_SIZE 10 157 struct ext4_locality_group { 158 /* for allocator */ 159 /* to serialize allocates */ 160 struct mutex lg_mutex; 161 /* list of preallocations */ 162 struct list_head lg_prealloc_list[PREALLOC_TB_SIZE]; 163 spinlock_t lg_prealloc_lock; 164 }; 165 166 struct ext4_allocation_context { 167 struct inode *ac_inode; 168 struct super_block *ac_sb; 169 170 /* original request */ 171 struct ext4_free_extent ac_o_ex; 172 173 /* goal request (after normalization) */ 174 struct ext4_free_extent ac_g_ex; 175 176 /* the best found extent */ 177 struct ext4_free_extent ac_b_ex; 178 179 /* copy of the bext found extent taken before preallocation efforts */ 180 struct ext4_free_extent ac_f_ex; 181 182 /* number of iterations done. we have to track to limit searching */ 183 unsigned long ac_ex_scanned; 184 __u16 ac_groups_scanned; 185 __u16 ac_found; 186 __u16 ac_tail; 187 __u16 ac_buddy; 188 __u16 ac_flags; /* allocation hints */ 189 __u8 ac_status; 190 __u8 ac_criteria; 191 __u8 ac_repeats; 192 __u8 ac_2order; /* if request is to allocate 2^N blocks and 193 * N > 0, the field stores N, otherwise 0 */ 194 __u8 ac_op; /* operation, for history only */ 195 struct page *ac_bitmap_page; 196 struct page *ac_buddy_page; 197 /* 198 * pointer to the held semaphore upon successful 199 * block allocation 200 */ 201 struct rw_semaphore *alloc_semp; 202 struct ext4_prealloc_space *ac_pa; 203 struct ext4_locality_group *ac_lg; 204 }; 205 206 #define AC_STATUS_CONTINUE 1 207 #define AC_STATUS_FOUND 2 208 #define AC_STATUS_BREAK 3 209 210 struct ext4_buddy { 211 struct page *bd_buddy_page; 212 void *bd_buddy; 213 struct page *bd_bitmap_page; 214 void *bd_bitmap; 215 struct ext4_group_info *bd_info; 216 struct super_block *bd_sb; 217 __u16 bd_blkbits; 218 ext4_group_t bd_group; 219 struct rw_semaphore *alloc_semp; 220 }; 221 #define EXT4_MB_BITMAP(e4b) ((e4b)->bd_bitmap) 222 #define EXT4_MB_BUDDY(e4b) ((e4b)->bd_buddy) 223 224 #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) 225 226 static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb, 227 struct ext4_free_extent *fex) 228 { 229 ext4_fsblk_t block; 230 231 block = (ext4_fsblk_t) fex->fe_group * EXT4_BLOCKS_PER_GROUP(sb) 232 + fex->fe_start 233 + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block); 234 return block; 235 } 236 #endif 237