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/mutex.h>
23 #include "ext4_jbd2.h"
27 * with AGGRESSIVE_CHECK allocator runs consistency checks over
28 * structures. these checks slow things down a lot
30 #define AGGRESSIVE_CHECK__
33 * with DOUBLE_CHECK defined mballoc creates persistent in-core
34 * bitmaps, maintains and uses them to check for double allocations
36 #define DOUBLE_CHECK__
40 #ifdef CONFIG_EXT4_DEBUG
41 extern u8 mb_enable_debug
;
43 #define mb_debug(n, fmt, a...) \
45 if ((n) <= mb_enable_debug) { \
46 printk(KERN_DEBUG "(%s, %d): %s: ", \
47 __FILE__, __LINE__, __func__); \
52 #define mb_debug(n, fmt, a...)
56 * with EXT4_MB_HISTORY mballoc stores last N allocations in memory
57 * and you can monitor it in /proc/fs/ext4/<dev>/mb_history
59 #define EXT4_MB_HISTORY
60 #define EXT4_MB_HISTORY_ALLOC 1 /* allocation */
61 #define EXT4_MB_HISTORY_PREALLOC 2 /* preallocated blocks used */
62 #define EXT4_MB_HISTORY_DISCARD 4 /* preallocation discarded */
63 #define EXT4_MB_HISTORY_FREE 8 /* free */
65 #define EXT4_MB_HISTORY_DEFAULT (EXT4_MB_HISTORY_ALLOC | \
66 EXT4_MB_HISTORY_PREALLOC)
69 * How long mballoc can look for a best extent (in found extents)
71 #define MB_DEFAULT_MAX_TO_SCAN 200
74 * How long mballoc must look for a best extent
76 #define MB_DEFAULT_MIN_TO_SCAN 10
79 * How many groups mballoc will scan looking for the best chunk
81 #define MB_DEFAULT_MAX_GROUPS_TO_SCAN 5
84 * with 'ext4_mb_stats' allocator will collect stats that will be
85 * shown at umount. The collecting costs though!
87 #define MB_DEFAULT_STATS 1
90 * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served
91 * by the stream allocator, which purpose is to pack requests
92 * as close each to other as possible to produce smooth I/O traffic
93 * We use locality group prealloc space for stream request.
94 * We can tune the same via /proc/fs/ext4/<parition>/stream_req
96 #define MB_DEFAULT_STREAM_THRESHOLD 16 /* 64K */
99 * for which requests use 2^N search using buddies
101 #define MB_DEFAULT_ORDER2_REQS 2
104 * default group prealloc size 512 blocks
106 #define MB_DEFAULT_GROUP_PREALLOC 512
109 struct ext4_free_data
{
110 /* this links the free block information from group_info */
113 /* this links the free block information from ext4_sb_info */
114 struct list_head list
;
116 /* group which free block extent belongs */
119 /* free block extent */
120 ext4_grpblk_t start_blk
;
123 /* transaction which freed this extent */
127 struct ext4_prealloc_space
{
128 struct list_head pa_inode_list
;
129 struct list_head pa_group_list
;
131 struct list_head pa_tmp_list
;
132 struct rcu_head pa_rcu
;
137 ext4_fsblk_t pa_pstart
; /* phys. block */
138 ext4_lblk_t pa_lstart
; /* log. block */
139 ext4_grpblk_t pa_len
; /* len of preallocated chunk */
140 ext4_grpblk_t pa_free
; /* how many blocks are free */
141 unsigned short pa_type
; /* pa type. inode or group */
142 spinlock_t
*pa_obj_lock
;
143 struct inode
*pa_inode
; /* hack, for history only */
151 struct ext4_free_extent
{
152 ext4_lblk_t fe_logical
;
153 ext4_grpblk_t fe_start
;
154 ext4_group_t fe_group
;
155 ext4_grpblk_t fe_len
;
160 * we try to group all related changes together
161 * so that writeback can flush/allocate them together as well
162 * Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC
163 * (512). We store prealloc space into the hash based on the pa_free blocks
164 * order value.ie, fls(pa_free)-1;
166 #define PREALLOC_TB_SIZE 10
167 struct ext4_locality_group
{
169 /* to serialize allocates */
170 struct mutex lg_mutex
;
171 /* list of preallocations */
172 struct list_head lg_prealloc_list
[PREALLOC_TB_SIZE
];
173 spinlock_t lg_prealloc_lock
;
176 struct ext4_allocation_context
{
177 struct inode
*ac_inode
;
178 struct super_block
*ac_sb
;
180 /* original request */
181 struct ext4_free_extent ac_o_ex
;
183 /* goal request (after normalization) */
184 struct ext4_free_extent ac_g_ex
;
186 /* the best found extent */
187 struct ext4_free_extent ac_b_ex
;
189 /* copy of the bext found extent taken before preallocation efforts */
190 struct ext4_free_extent ac_f_ex
;
192 /* number of iterations done. we have to track to limit searching */
193 unsigned long ac_ex_scanned
;
194 __u16 ac_groups_scanned
;
198 __u16 ac_flags
; /* allocation hints */
202 __u8 ac_2order
; /* if request is to allocate 2^N blocks and
203 * N > 0, the field stores N, otherwise 0 */
204 __u8 ac_op
; /* operation, for history only */
205 struct page
*ac_bitmap_page
;
206 struct page
*ac_buddy_page
;
208 * pointer to the held semaphore upon successful
211 struct rw_semaphore
*alloc_semp
;
212 struct ext4_prealloc_space
*ac_pa
;
213 struct ext4_locality_group
*ac_lg
;
216 #define AC_STATUS_CONTINUE 1
217 #define AC_STATUS_FOUND 2
218 #define AC_STATUS_BREAK 3
220 struct ext4_mb_history
{
221 struct ext4_free_extent orig
; /* orig allocation */
222 struct ext4_free_extent goal
; /* goal allocation */
223 struct ext4_free_extent result
; /* result allocation */
226 __u16 found
; /* how many extents have been found */
227 __u16 groups
; /* how many groups have been scanned */
228 __u16 tail
; /* what tail broke some buddy */
229 __u16 buddy
; /* buddy the tail ^^^ broke */
231 __u8 cr
:3; /* which phase the result extent was found at */
237 struct page
*bd_buddy_page
;
239 struct page
*bd_bitmap_page
;
241 struct ext4_group_info
*bd_info
;
242 struct super_block
*bd_sb
;
244 ext4_group_t bd_group
;
245 struct rw_semaphore
*alloc_semp
;
247 #define EXT4_MB_BITMAP(e4b) ((e4b)->bd_bitmap)
248 #define EXT4_MB_BUDDY(e4b) ((e4b)->bd_buddy)
250 #ifndef EXT4_MB_HISTORY
251 static inline void ext4_mb_store_history(struct ext4_allocation_context
*ac
)
257 #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
259 static inline ext4_fsblk_t
ext4_grp_offs_to_block(struct super_block
*sb
,
260 struct ext4_free_extent
*fex
)
264 block
= (ext4_fsblk_t
) fex
->fe_group
* EXT4_BLOCKS_PER_GROUP(sb
)
266 + le32_to_cpu(EXT4_SB(sb
)->s_es
->s_first_data_block
);