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/blkdev.h> 21 #include <linux/mutex.h> 22 #include "ext4_jbd2.h" 23 #include "ext4.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 #ifdef CONFIG_EXT4_DEBUG 40 extern u8 mb_enable_debug; 41 42 #define mb_debug(n, fmt, a...) \ 43 do { \ 44 if ((n) <= mb_enable_debug) { \ 45 printk(KERN_DEBUG "(%s, %d): %s: ", \ 46 __FILE__, __LINE__, __func__); \ 47 printk(fmt, ## a); \ 48 } \ 49 } while (0) 50 #else 51 #define mb_debug(n, fmt, a...) 52 #endif 53 54 #define EXT4_MB_HISTORY_ALLOC 1 /* allocation */ 55 #define EXT4_MB_HISTORY_PREALLOC 2 /* preallocated blocks used */ 56 57 /* 58 * How long mballoc can look for a best extent (in found extents) 59 */ 60 #define MB_DEFAULT_MAX_TO_SCAN 200 61 62 /* 63 * How long mballoc must look for a best extent 64 */ 65 #define MB_DEFAULT_MIN_TO_SCAN 10 66 67 /* 68 * How many groups mballoc will scan looking for the best chunk 69 */ 70 #define MB_DEFAULT_MAX_GROUPS_TO_SCAN 5 71 72 /* 73 * with 'ext4_mb_stats' allocator will collect stats that will be 74 * shown at umount. The collecting costs though! 75 */ 76 #define MB_DEFAULT_STATS 0 77 78 /* 79 * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served 80 * by the stream allocator, which purpose is to pack requests 81 * as close each to other as possible to produce smooth I/O traffic 82 * We use locality group prealloc space for stream request. 83 * We can tune the same via /proc/fs/ext4/<parition>/stream_req 84 */ 85 #define MB_DEFAULT_STREAM_THRESHOLD 16 /* 64K */ 86 87 /* 88 * for which requests use 2^N search using buddies 89 */ 90 #define MB_DEFAULT_ORDER2_REQS 2 91 92 /* 93 * default group prealloc size 512 blocks 94 */ 95 #define MB_DEFAULT_GROUP_PREALLOC 512 96 97 98 struct ext4_free_data { 99 /* this links the free block information from group_info */ 100 struct rb_node node; 101 102 /* this links the free block information from ext4_sb_info */ 103 struct list_head list; 104 105 /* group which free block extent belongs */ 106 ext4_group_t group; 107 108 /* free block extent */ 109 ext4_grpblk_t start_cluster; 110 ext4_grpblk_t count; 111 112 /* transaction which freed this extent */ 113 tid_t t_tid; 114 }; 115 116 struct ext4_prealloc_space { 117 struct list_head pa_inode_list; 118 struct list_head pa_group_list; 119 union { 120 struct list_head pa_tmp_list; 121 struct rcu_head pa_rcu; 122 } u; 123 spinlock_t pa_lock; 124 atomic_t pa_count; 125 unsigned pa_deleted; 126 ext4_fsblk_t pa_pstart; /* phys. block */ 127 ext4_lblk_t pa_lstart; /* log. block */ 128 ext4_grpblk_t pa_len; /* len of preallocated chunk */ 129 ext4_grpblk_t pa_free; /* how many blocks are free */ 130 unsigned short pa_type; /* pa type. inode or group */ 131 spinlock_t *pa_obj_lock; 132 struct inode *pa_inode; /* hack, for history only */ 133 }; 134 135 enum { 136 MB_INODE_PA = 0, 137 MB_GROUP_PA = 1 138 }; 139 140 struct ext4_free_extent { 141 ext4_lblk_t fe_logical; 142 ext4_grpblk_t fe_start; /* In cluster units */ 143 ext4_group_t fe_group; 144 ext4_grpblk_t fe_len; /* In cluster units */ 145 }; 146 147 /* 148 * Locality group: 149 * we try to group all related changes together 150 * so that writeback can flush/allocate them together as well 151 * Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC 152 * (512). We store prealloc space into the hash based on the pa_free blocks 153 * order value.ie, fls(pa_free)-1; 154 */ 155 #define PREALLOC_TB_SIZE 10 156 struct ext4_locality_group { 157 /* for allocator */ 158 /* to serialize allocates */ 159 struct mutex lg_mutex; 160 /* list of preallocations */ 161 struct list_head lg_prealloc_list[PREALLOC_TB_SIZE]; 162 spinlock_t lg_prealloc_lock; 163 }; 164 165 struct ext4_allocation_context { 166 struct inode *ac_inode; 167 struct super_block *ac_sb; 168 169 /* original request */ 170 struct ext4_free_extent ac_o_ex; 171 172 /* goal request (normalized ac_o_ex) */ 173 struct ext4_free_extent ac_g_ex; 174 175 /* the best found extent */ 176 struct ext4_free_extent ac_b_ex; 177 178 /* copy of the best found extent taken before preallocation efforts */ 179 struct ext4_free_extent ac_f_ex; 180 181 /* number of iterations done. we have to track to limit searching */ 182 unsigned long ac_ex_scanned; 183 __u16 ac_groups_scanned; 184 __u16 ac_found; 185 __u16 ac_tail; 186 __u16 ac_buddy; 187 __u16 ac_flags; /* allocation hints */ 188 __u8 ac_status; 189 __u8 ac_criteria; 190 __u8 ac_2order; /* if request is to allocate 2^N blocks and 191 * N > 0, the field stores N, otherwise 0 */ 192 __u8 ac_op; /* operation, for history only */ 193 struct page *ac_bitmap_page; 194 struct page *ac_buddy_page; 195 struct ext4_prealloc_space *ac_pa; 196 struct ext4_locality_group *ac_lg; 197 }; 198 199 #define AC_STATUS_CONTINUE 1 200 #define AC_STATUS_FOUND 2 201 #define AC_STATUS_BREAK 3 202 203 struct ext4_buddy { 204 struct page *bd_buddy_page; 205 void *bd_buddy; 206 struct page *bd_bitmap_page; 207 void *bd_bitmap; 208 struct ext4_group_info *bd_info; 209 struct super_block *bd_sb; 210 __u16 bd_blkbits; 211 ext4_group_t bd_group; 212 }; 213 #define EXT4_MB_BITMAP(e4b) ((e4b)->bd_bitmap) 214 #define EXT4_MB_BUDDY(e4b) ((e4b)->bd_buddy) 215 216 static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb, 217 struct ext4_free_extent *fex) 218 { 219 return ext4_group_first_block_no(sb, fex->fe_group) + 220 (fex->fe_start << EXT4_SB(sb)->s_cluster_bits); 221 } 222 #endif 223