fs/ext4/mballoc.h

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  fs/ext4/mballoc.h
   4  *
   5  *  Written by: Alex Tomas <alex@clusterfs.com>
   6  *
   7  */
   8 #ifndef _EXT4_MBALLOC_H
   9 #define _EXT4_MBALLOC_H
  10
  11 #include <linux/time.h>
  12 #include <linux/fs.h>
  13 #include <linux/namei.h>
  14 #include <linux/quotaops.h>
  15 #include <linux/buffer_head.h>
  16 #include <linux/module.h>
  17 #include <linux/swap.h>
  18 #include <linux/proc_fs.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/seq_file.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/mutex.h>
  23 #include "ext4_jbd2.h"
  24 #include "ext4.h"
  25
  26 /*
  27  * mb_debug() dynamic printk msgs could be used to debug mballoc code.
  28  */
  29 #ifdef CONFIG_EXT4_DEBUG
  30 #define mb_debug(sb, fmt, ...)                                          \
  31         pr_debug("[%s/%d] EXT4-fs (%s): (%s, %d): %s: " fmt,            \
  32                 current->comm, task_pid_nr(current), sb->s_id,          \
  33                __FILE__, __LINE__, __func__, ##__VA_ARGS__)
  34 #else
  35 #define mb_debug(sb, fmt, ...)  no_printk(fmt, ##__VA_ARGS__)
  36 #endif
  37
  38 #define EXT4_MB_HISTORY_ALLOC           1       /* allocation */
  39 #define EXT4_MB_HISTORY_PREALLOC        2       /* preallocated blocks used */
  40
  41 /*
  42  * How long mballoc can look for a best extent (in found extents)
  43  */
  44 #define MB_DEFAULT_MAX_TO_SCAN          200
  45
  46 /*
  47  * How long mballoc must look for a best extent
  48  */
  49 #define MB_DEFAULT_MIN_TO_SCAN          10
  50
  51 /*
  52  * with 's_mb_stats' allocator will collect stats that will be
  53  * shown at umount. The collecting costs though!
  54  */
  55 #define MB_DEFAULT_STATS                0
  56
  57 /*
  58  * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served
  59  * by the stream allocator, which purpose is to pack requests
  60  * as close each to other as possible to produce smooth I/O traffic
  61  * We use locality group prealloc space for stream request.
  62  * We can tune the same via /proc/fs/ext4/<partition>/stream_req
  63  */
  64 #define MB_DEFAULT_STREAM_THRESHOLD     16      /* 64K */
  65
  66 /*
  67  * for which requests use 2^N search using buddies
  68  */
  69 #define MB_DEFAULT_ORDER2_REQS          2
  70
  71 /*
  72  * default group prealloc size 512 blocks
  73  */
  74 #define MB_DEFAULT_GROUP_PREALLOC       512
  75
  76 /*
  77  * Number of groups to search linearly before performing group scanning
  78  * optimization.
  79  */
  80 #define MB_DEFAULT_LINEAR_LIMIT         4
  81
  82 /*
  83  * Minimum number of groups that should be present in the file system to perform
  84  * group scanning optimizations.
  85  */
  86 #define MB_DEFAULT_LINEAR_SCAN_THRESHOLD        16
  87
  88 /*
  89  * The maximum order upto which CR_BEST_AVAIL_LEN can trim a particular
  90  * allocation request. Example, if we have an order 7 request and max trim order
  91  * of 3, we can trim this request upto order 4.
  92  */
  93 #define MB_DEFAULT_BEST_AVAIL_TRIM_ORDER        3
  94
  95 /*
  96  * Number of valid buddy orders
  97  */
  98 #define MB_NUM_ORDERS(sb)               ((sb)->s_blocksize_bits + 2)
  99
 100 struct ext4_free_data {
 101         /* this links the free block information from sb_info */
 102         struct list_head                efd_list;
 103
 104         /* this links the free block information from group_info */
 105         struct rb_node                  efd_node;
 106
 107         /* group which free block extent belongs */
 108         ext4_group_t                    efd_group;
 109
 110         /* free block extent */
 111         ext4_grpblk_t                   efd_start_cluster;
 112         ext4_grpblk_t                   efd_count;
 113
 114         /* transaction which freed this extent */
 115         tid_t                           efd_tid;
 116 };
 117
 118 struct ext4_prealloc_space {
 119         union {
 120                 struct rb_node  inode_node;             /* for inode PA rbtree */
 121                 struct list_head        lg_list;        /* for lg PAs */
 122         } pa_node;
 123         struct list_head        pa_group_list;
 124         union {
 125                 struct list_head pa_tmp_list;
 126                 struct rcu_head pa_rcu;
 127         } u;
 128         spinlock_t              pa_lock;
 129         atomic_t                pa_count;
 130         unsigned                pa_deleted;
 131         ext4_fsblk_t            pa_pstart;      /* phys. block */
 132         ext4_lblk_t             pa_lstart;      /* log. block */
 133         ext4_grpblk_t           pa_len;         /* len of preallocated chunk */
 134         ext4_grpblk_t           pa_free;        /* how many blocks are free */
 135         unsigned short          pa_type;        /* pa type. inode or group */
 136         union {
 137                 rwlock_t                *inode_lock;    /* locks the rbtree holding this PA */
 138                 spinlock_t              *lg_lock;       /* locks the lg list holding this PA */
 139         } pa_node_lock;
 140         struct inode            *pa_inode;      /* used to get the inode during group discard */
 141 };
 142
 143 enum {
 144         MB_INODE_PA = 0,
 145         MB_GROUP_PA = 1
 146 };
 147
 148 struct ext4_free_extent {
 149         ext4_lblk_t fe_logical;
 150         ext4_grpblk_t fe_start; /* In cluster units */
 151         ext4_group_t fe_group;
 152         ext4_grpblk_t fe_len;   /* In cluster units */
 153 };
 154
 155 /*
 156  * Locality group:
 157  *   we try to group all related changes together
 158  *   so that writeback can flush/allocate them together as well
 159  *   Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC
 160  *   (512). We store prealloc space into the hash based on the pa_free blocks
 161  *   order value.ie, fls(pa_free)-1;
 162  */
 163 #define PREALLOC_TB_SIZE 10
 164 struct ext4_locality_group {
 165         /* for allocator */
 166         /* to serialize allocates */
 167         struct mutex            lg_mutex;
 168         /* list of preallocations */
 169         struct list_head        lg_prealloc_list[PREALLOC_TB_SIZE];
 170         spinlock_t              lg_prealloc_lock;
 171 };
 172
 173 struct ext4_allocation_context {
 174         struct inode *ac_inode;
 175         struct super_block *ac_sb;
 176
 177         /* original request */
 178         struct ext4_free_extent ac_o_ex;
 179
 180         /* goal request (normalized ac_o_ex) */
 181         struct ext4_free_extent ac_g_ex;
 182
 183         /* the best found extent */
 184         struct ext4_free_extent ac_b_ex;
 185
 186         /* copy of the best found extent taken before preallocation efforts */
 187         struct ext4_free_extent ac_f_ex;
 188
 189         /*
 190          * goal len can change in CR_BEST_AVAIL_LEN, so save the original len.
 191          * This is used while adjusting the PA window and for accounting.
 192          */
 193         ext4_grpblk_t   ac_orig_goal_len;
 194
 195         __u32 ac_flags;         /* allocation hints */
 196         __u32 ac_groups_linear_remaining;
 197         __u16 ac_groups_scanned;
 198         __u16 ac_found;
 199         __u16 ac_cX_found[EXT4_MB_NUM_CRS];
 200         __u16 ac_tail;
 201         __u16 ac_buddy;
 202         __u8 ac_status;
 203         __u8 ac_criteria;
 204         __u8 ac_2order;         /* if request is to allocate 2^N blocks and
 205                                  * N > 0, the field stores N, otherwise 0 */
 206         __u8 ac_op;             /* operation, for history only */
 207         struct folio *ac_bitmap_folio;
 208         struct folio *ac_buddy_folio;
 209         struct ext4_prealloc_space *ac_pa;
 210         struct ext4_locality_group *ac_lg;
 211 };
 212
 213 #define AC_STATUS_CONTINUE      1
 214 #define AC_STATUS_FOUND         2
 215 #define AC_STATUS_BREAK         3
 216
 217 struct ext4_buddy {
 218         struct folio *bd_buddy_folio;
 219         void *bd_buddy;
 220         struct folio *bd_bitmap_folio;
 221         void *bd_bitmap;
 222         struct ext4_group_info *bd_info;
 223         struct super_block *bd_sb;
 224         __u16 bd_blkbits;
 225         ext4_group_t bd_group;
 226 };
 227
 228 static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
 229                                         struct ext4_free_extent *fex)
 230 {
 231         return ext4_group_first_block_no(sb, fex->fe_group) +
 232                 (fex->fe_start << EXT4_SB(sb)->s_cluster_bits);
 233 }
 234
 235 static inline loff_t extent_logical_end(struct ext4_sb_info *sbi,
 236                                         struct ext4_free_extent *fex)
 237 {
 238         /* Use loff_t to avoid end exceeding ext4_lblk_t max. */
 239         return (loff_t)fex->fe_logical + EXT4_C2B(sbi, fex->fe_len);
 240 }
 241
 242 static inline loff_t pa_logical_end(struct ext4_sb_info *sbi,
 243                                     struct ext4_prealloc_space *pa)
 244 {
 245         /* Use loff_t to avoid end exceeding ext4_lblk_t max. */
 246         return (loff_t)pa->pa_lstart + EXT4_C2B(sbi, pa->pa_len);
 247 }
 248
 249 typedef int (*ext4_mballoc_query_range_fn)(
 250         struct super_block              *sb,
 251         ext4_group_t                    agno,
 252         ext4_grpblk_t                   start,
 253         ext4_grpblk_t                   len,
 254         void                            *priv);
 255
 256 int
 257 ext4_mballoc_query_range(
 258         struct super_block              *sb,
 259         ext4_group_t                    agno,
 260         ext4_grpblk_t                   start,
 261         ext4_grpblk_t                   end,
 262         ext4_mballoc_query_range_fn     formatter,
 263         void                            *priv);
 264
 265 #endif