fs/ext4/mballoc.h

   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  */
  27 #ifdef CONFIG_EXT4_DEBUG
  28 extern ushort ext4_mballoc_debug;
  29
  30 #define mb_debug(n, fmt, ...)                                           \
  31 do {                                                                    \
  32         if ((n) <= ext4_mballoc_debug) {                                \
  33                 printk(KERN_DEBUG "(%s, %d): %s: " fmt,                 \
  34                        __FILE__, __LINE__, __func__, ##__VA_ARGS__);    \
  35         }                                                               \
  36 } while (0)
  37 #else
  38 #define mb_debug(n, fmt, ...)   no_printk(fmt, ##__VA_ARGS__)
  39 #endif
  40
  41 #define EXT4_MB_HISTORY_ALLOC           1       /* allocation */
  42 #define EXT4_MB_HISTORY_PREALLOC        2       /* preallocated blocks used */
  43
  44 /*
  45  * How long mballoc can look for a best extent (in found extents)
  46  */
  47 #define MB_DEFAULT_MAX_TO_SCAN          200
  48
  49 /*
  50  * How long mballoc must look for a best extent
  51  */
  52 #define MB_DEFAULT_MIN_TO_SCAN          10
  53
  54 /*
  55  * with 'ext4_mb_stats' allocator will collect stats that will be
  56  * shown at umount. The collecting costs though!
  57  */
  58 #define MB_DEFAULT_STATS                0
  59
  60 /*
  61  * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served
  62  * by the stream allocator, which purpose is to pack requests
  63  * as close each to other as possible to produce smooth I/O traffic
  64  * We use locality group prealloc space for stream request.
  65  * We can tune the same via /proc/fs/ext4/<parition>/stream_req
  66  */
  67 #define MB_DEFAULT_STREAM_THRESHOLD     16      /* 64K */
  68
  69 /*
  70  * for which requests use 2^N search using buddies
  71  */
  72 #define MB_DEFAULT_ORDER2_REQS          2
  73
  74 /*
  75  * default group prealloc size 512 blocks
  76  */
  77 #define MB_DEFAULT_GROUP_PREALLOC       512
  78
  79
  80 struct ext4_free_data {
  81         /* this links the free block information from sb_info */
  82         struct list_head                efd_list;
  83
  84         /* this links the free block information from group_info */
  85         struct rb_node                  efd_node;
  86
  87         /* group which free block extent belongs */
  88         ext4_group_t                    efd_group;
  89
  90         /* free block extent */
  91         ext4_grpblk_t                   efd_start_cluster;
  92         ext4_grpblk_t                   efd_count;
  93
  94         /* transaction which freed this extent */
  95         tid_t                           efd_tid;
  96 };
  97
  98 struct ext4_prealloc_space {
  99         struct list_head        pa_inode_list;
 100         struct list_head        pa_group_list;
 101         union {
 102                 struct list_head pa_tmp_list;
 103                 struct rcu_head pa_rcu;
 104         } u;
 105         spinlock_t              pa_lock;
 106         atomic_t                pa_count;
 107         unsigned                pa_deleted;
 108         ext4_fsblk_t            pa_pstart;      /* phys. block */
 109         ext4_lblk_t             pa_lstart;      /* log. block */
 110         ext4_grpblk_t           pa_len;         /* len of preallocated chunk */
 111         ext4_grpblk_t           pa_free;        /* how many blocks are free */
 112         unsigned short          pa_type;        /* pa type. inode or group */
 113         spinlock_t              *pa_obj_lock;
 114         struct inode            *pa_inode;      /* hack, for history only */
 115 };
 116
 117 enum {
 118         MB_INODE_PA = 0,
 119         MB_GROUP_PA = 1
 120 };
 121
 122 struct ext4_free_extent {
 123         ext4_lblk_t fe_logical;
 124         ext4_grpblk_t fe_start; /* In cluster units */
 125         ext4_group_t fe_group;
 126         ext4_grpblk_t fe_len;   /* In cluster units */
 127 };
 128
 129 /*
 130  * Locality group:
 131  *   we try to group all related changes together
 132  *   so that writeback can flush/allocate them together as well
 133  *   Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC
 134  *   (512). We store prealloc space into the hash based on the pa_free blocks
 135  *   order value.ie, fls(pa_free)-1;
 136  */
 137 #define PREALLOC_TB_SIZE 10
 138 struct ext4_locality_group {
 139         /* for allocator */
 140         /* to serialize allocates */
 141         struct mutex            lg_mutex;
 142         /* list of preallocations */
 143         struct list_head        lg_prealloc_list[PREALLOC_TB_SIZE];
 144         spinlock_t              lg_prealloc_lock;
 145 };
 146
 147 struct ext4_allocation_context {
 148         struct inode *ac_inode;
 149         struct super_block *ac_sb;
 150
 151         /* original request */
 152         struct ext4_free_extent ac_o_ex;
 153
 154         /* goal request (normalized ac_o_ex) */
 155         struct ext4_free_extent ac_g_ex;
 156
 157         /* the best found extent */
 158         struct ext4_free_extent ac_b_ex;
 159
 160         /* copy of the best found extent taken before preallocation efforts */
 161         struct ext4_free_extent ac_f_ex;
 162
 163         __u16 ac_groups_scanned;
 164         __u16 ac_found;
 165         __u16 ac_tail;
 166         __u16 ac_buddy;
 167         __u16 ac_flags;         /* allocation hints */
 168         __u8 ac_status;
 169         __u8 ac_criteria;
 170         __u8 ac_2order;         /* if request is to allocate 2^N blocks and
 171                                  * N > 0, the field stores N, otherwise 0 */
 172         __u8 ac_op;             /* operation, for history only */
 173         struct page *ac_bitmap_page;
 174         struct page *ac_buddy_page;
 175         struct ext4_prealloc_space *ac_pa;
 176         struct ext4_locality_group *ac_lg;
 177 };
 178
 179 #define AC_STATUS_CONTINUE      1
 180 #define AC_STATUS_FOUND         2
 181 #define AC_STATUS_BREAK         3
 182
 183 struct ext4_buddy {
 184         struct page *bd_buddy_page;
 185         void *bd_buddy;
 186         struct page *bd_bitmap_page;
 187         void *bd_bitmap;
 188         struct ext4_group_info *bd_info;
 189         struct super_block *bd_sb;
 190         __u16 bd_blkbits;
 191         ext4_group_t bd_group;
 192 };
 193
 194 static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
 195                                         struct ext4_free_extent *fex)
 196 {
 197         return ext4_group_first_block_no(sb, fex->fe_group) +
 198                 (fex->fe_start << EXT4_SB(sb)->s_cluster_bits);
 199 }
 200
 201 typedef int (*ext4_mballoc_query_range_fn)(
 202         struct super_block              *sb,
 203         ext4_group_t                    agno,
 204         ext4_grpblk_t                   start,
 205         ext4_grpblk_t                   len,
 206         void                            *priv);
 207
 208 int
 209 ext4_mballoc_query_range(
 210         struct super_block              *sb,
 211         ext4_group_t                    agno,
 212         ext4_grpblk_t                   start,
 213         ext4_grpblk_t                   end,
 214         ext4_mballoc_query_range_fn     formatter,
 215         void                            *priv);
 216
 217 #endif