4 * Written by: Alex Tomas <alex@clusterfs.com>
7 #ifndef _EXT4_MBALLOC_H
8 #define _EXT4_MBALLOC_H
10 #include <linux/time.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"
29 * with AGGRESSIVE_CHECK allocator runs consistency checks over
30 * structures. these checks slow things down a lot
32 #define AGGRESSIVE_CHECK__
35 * with DOUBLE_CHECK defined mballoc creates persistent in-core
36 * bitmaps, maintains and uses them to check for double allocations
38 #define DOUBLE_CHECK__
44 #define mb_debug(fmt, a...) printk(fmt, ##a)
46 #define mb_debug(fmt, a...)
50 * with EXT4_MB_HISTORY mballoc stores last N allocations in memory
51 * and you can monitor it in /proc/fs/ext4/<dev>/mb_history
53 #define EXT4_MB_HISTORY
54 #define EXT4_MB_HISTORY_ALLOC 1 /* allocation */
55 #define EXT4_MB_HISTORY_PREALLOC 2 /* preallocated blocks used */
56 #define EXT4_MB_HISTORY_DISCARD 4 /* preallocation discarded */
57 #define EXT4_MB_HISTORY_FREE 8 /* free */
59 #define EXT4_MB_HISTORY_DEFAULT (EXT4_MB_HISTORY_ALLOC | \
60 EXT4_MB_HISTORY_PREALLOC)
63 * How long mballoc can look for a best extent (in found extents)
65 #define MB_DEFAULT_MAX_TO_SCAN 200
68 * How long mballoc must look for a best extent
70 #define MB_DEFAULT_MIN_TO_SCAN 10
73 * How many groups mballoc will scan looking for the best chunk
75 #define MB_DEFAULT_MAX_GROUPS_TO_SCAN 5
78 * with 'ext4_mb_stats' allocator will collect stats that will be
79 * shown at umount. The collecting costs though!
81 #define MB_DEFAULT_STATS 1
84 * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served
85 * by the stream allocator, which purpose is to pack requests
86 * as close each to other as possible to produce smooth I/O traffic
87 * We use locality group prealloc space for stream request.
88 * We can tune the same via /proc/fs/ext4/<parition>/stream_req
90 #define MB_DEFAULT_STREAM_THRESHOLD 16 /* 64K */
93 * for which requests use 2^N search using buddies
95 #define MB_DEFAULT_ORDER2_REQS 2
98 * default group prealloc size 512 blocks
100 #define MB_DEFAULT_GROUP_PREALLOC 512
102 static struct kmem_cache *ext4_pspace_cachep;
103 static struct kmem_cache *ext4_ac_cachep;
104 static struct kmem_cache *ext4_free_ext_cachep;
106 struct ext4_free_data {
107 /* this links the free block information from group_info */
110 /* this links the free block information from ext4_sb_info */
111 struct list_head list;
113 /* group which free block extent belongs */
116 /* free block extent */
117 ext4_grpblk_t start_blk;
120 /* transaction which freed this extent */
124 struct ext4_group_info {
125 unsigned long bb_state;
126 struct rb_root bb_free_root;
127 unsigned short bb_first_free;
128 unsigned short bb_free;
129 unsigned short bb_fragments;
130 struct list_head bb_prealloc_list;
134 struct rw_semaphore alloc_sem;
135 unsigned short bb_counters[];
138 #define EXT4_GROUP_INFO_NEED_INIT_BIT 0
139 #define EXT4_GROUP_INFO_LOCKED_BIT 1
141 #define EXT4_MB_GRP_NEED_INIT(grp) \
142 (test_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &((grp)->bb_state)))
145 struct ext4_prealloc_space {
146 struct list_head pa_inode_list;
147 struct list_head pa_group_list;
149 struct list_head pa_tmp_list;
150 struct rcu_head pa_rcu;
155 ext4_fsblk_t pa_pstart; /* phys. block */
156 ext4_lblk_t pa_lstart; /* log. block */
157 unsigned short pa_len; /* len of preallocated chunk */
158 unsigned short pa_free; /* how many blocks are free */
159 unsigned short pa_linear; /* consumed in one direction
160 * strictly, for grp prealloc */
161 spinlock_t *pa_obj_lock;
162 struct inode *pa_inode; /* hack, for history only */
166 struct ext4_free_extent {
167 ext4_lblk_t fe_logical;
168 ext4_grpblk_t fe_start;
169 ext4_group_t fe_group;
175 * we try to group all related changes together
176 * so that writeback can flush/allocate them together as well
177 * Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC
178 * (512). We store prealloc space into the hash based on the pa_free blocks
179 * order value.ie, fls(pa_free)-1;
181 #define PREALLOC_TB_SIZE 10
182 struct ext4_locality_group {
184 /* to serialize allocates */
185 struct mutex lg_mutex;
186 /* list of preallocations */
187 struct list_head lg_prealloc_list[PREALLOC_TB_SIZE];
188 spinlock_t lg_prealloc_lock;
191 struct ext4_allocation_context {
192 struct inode *ac_inode;
193 struct super_block *ac_sb;
195 /* original request */
196 struct ext4_free_extent ac_o_ex;
198 /* goal request (after normalization) */
199 struct ext4_free_extent ac_g_ex;
201 /* the best found extent */
202 struct ext4_free_extent ac_b_ex;
204 /* copy of the bext found extent taken before preallocation efforts */
205 struct ext4_free_extent ac_f_ex;
207 /* number of iterations done. we have to track to limit searching */
208 unsigned long ac_ex_scanned;
209 __u16 ac_groups_scanned;
213 __u16 ac_flags; /* allocation hints */
217 __u8 ac_2order; /* if request is to allocate 2^N blocks and
218 * N > 0, the field stores N, otherwise 0 */
219 __u8 ac_op; /* operation, for history only */
220 struct page *ac_bitmap_page;
221 struct page *ac_buddy_page;
222 struct ext4_prealloc_space *ac_pa;
223 struct ext4_locality_group *ac_lg;
226 #define AC_STATUS_CONTINUE 1
227 #define AC_STATUS_FOUND 2
228 #define AC_STATUS_BREAK 3
230 struct ext4_mb_history {
231 struct ext4_free_extent orig; /* orig allocation */
232 struct ext4_free_extent goal; /* goal allocation */
233 struct ext4_free_extent result; /* result allocation */
236 __u16 found; /* how many extents have been found */
237 __u16 groups; /* how many groups have been scanned */
238 __u16 tail; /* what tail broke some buddy */
239 __u16 buddy; /* buddy the tail ^^^ broke */
241 __u8 cr:3; /* which phase the result extent was found at */
247 struct page *bd_buddy_page;
249 struct page *bd_bitmap_page;
251 struct ext4_group_info *bd_info;
252 struct super_block *bd_sb;
254 ext4_group_t bd_group;
255 struct rw_semaphore *alloc_semp;
257 #define EXT4_MB_BITMAP(e4b) ((e4b)->bd_bitmap)
258 #define EXT4_MB_BUDDY(e4b) ((e4b)->bd_buddy)
260 #ifndef EXT4_MB_HISTORY
261 static inline void ext4_mb_store_history(struct ext4_allocation_context *ac)
266 static void ext4_mb_store_history(struct ext4_allocation_context *ac);
269 #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
271 struct buffer_head *read_block_bitmap(struct super_block *, ext4_group_t);
273 static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
275 static void ext4_mb_return_to_preallocation(struct inode *inode,
276 struct ext4_buddy *e4b, sector_t block,
278 static void ext4_mb_put_pa(struct ext4_allocation_context *,
279 struct super_block *, struct ext4_prealloc_space *pa);
280 static int ext4_mb_init_per_dev_proc(struct super_block *sb);
281 static int ext4_mb_destroy_per_dev_proc(struct super_block *sb);
282 static void release_blocks_on_commit(journal_t *journal, transaction_t *txn);
285 static inline void ext4_lock_group(struct super_block *sb, ext4_group_t group)
287 struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);
289 bit_spin_lock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state));
292 static inline void ext4_unlock_group(struct super_block *sb,
295 struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);
297 bit_spin_unlock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state));
300 static inline int ext4_is_group_locked(struct super_block *sb,
303 struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);
305 return bit_spin_is_locked(EXT4_GROUP_INFO_LOCKED_BIT,
306 &(grinfo->bb_state));
309 static ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
310 struct ext4_free_extent *fex)
314 block = (ext4_fsblk_t) fex->fe_group * EXT4_BLOCKS_PER_GROUP(sb)
316 + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);