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Mingming Cao8f6e39a2008-04-29 22:01:31 -04001/*
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/version.h>
Theodore Ts'o8a0aba72008-10-16 10:06:27 -040021#include <linux/blkdev.h>
22#include <linux/marker.h>
Aneesh Kumar K.V920313a2009-01-05 21:36:19 -050023#include <linux/mutex.h>
Mingming Cao8f6e39a2008-04-29 22:01:31 -040024#include "ext4_jbd2.h"
25#include "ext4.h"
26#include "group.h"
27
28/*
29 * with AGGRESSIVE_CHECK allocator runs consistency checks over
30 * structures. these checks slow things down a lot
31 */
32#define AGGRESSIVE_CHECK__
33
34/*
35 * with DOUBLE_CHECK defined mballoc creates persistent in-core
36 * bitmaps, maintains and uses them to check for double allocations
37 */
38#define DOUBLE_CHECK__
39
40/*
41 */
42#define MB_DEBUG__
43#ifdef MB_DEBUG
44#define mb_debug(fmt, a...) printk(fmt, ##a)
45#else
46#define mb_debug(fmt, a...)
47#endif
48
49/*
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
52 */
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 */
58
59#define EXT4_MB_HISTORY_DEFAULT (EXT4_MB_HISTORY_ALLOC | \
60 EXT4_MB_HISTORY_PREALLOC)
61
62/*
63 * How long mballoc can look for a best extent (in found extents)
64 */
65#define MB_DEFAULT_MAX_TO_SCAN 200
66
67/*
68 * How long mballoc must look for a best extent
69 */
70#define MB_DEFAULT_MIN_TO_SCAN 10
71
72/*
73 * How many groups mballoc will scan looking for the best chunk
74 */
75#define MB_DEFAULT_MAX_GROUPS_TO_SCAN 5
76
77/*
78 * with 'ext4_mb_stats' allocator will collect stats that will be
79 * shown at umount. The collecting costs though!
80 */
81#define MB_DEFAULT_STATS 1
82
83/*
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
89 */
90#define MB_DEFAULT_STREAM_THRESHOLD 16 /* 64K */
91
92/*
93 * for which requests use 2^N search using buddies
94 */
95#define MB_DEFAULT_ORDER2_REQS 2
96
97/*
98 * default group prealloc size 512 blocks
99 */
100#define MB_DEFAULT_GROUP_PREALLOC 512
101
Mingming Cao8f6e39a2008-04-29 22:01:31 -0400102
Aneesh Kumar K.Vc8940582008-10-16 10:14:27 -0400103struct ext4_free_data {
104 /* this links the free block information from group_info */
105 struct rb_node node;
Mingming Cao8f6e39a2008-04-29 22:01:31 -0400106
Aneesh Kumar K.Vc8940582008-10-16 10:14:27 -0400107 /* this links the free block information from ext4_sb_info */
Mingming Cao8f6e39a2008-04-29 22:01:31 -0400108 struct list_head list;
Aneesh Kumar K.Vc8940582008-10-16 10:14:27 -0400109
110 /* group which free block extent belongs */
111 ext4_group_t group;
112
113 /* free block extent */
114 ext4_grpblk_t start_blk;
115 ext4_grpblk_t count;
116
117 /* transaction which freed this extent */
118 tid_t t_tid;
Mingming Cao8f6e39a2008-04-29 22:01:31 -0400119};
120
Mingming Cao8f6e39a2008-04-29 22:01:31 -0400121struct ext4_prealloc_space {
122 struct list_head pa_inode_list;
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 unsigned short pa_len; /* len of preallocated chunk */
134 unsigned short pa_free; /* how many blocks are free */
Aneesh Kumar K.Vcc0fb9a2009-03-27 17:16:58 -0400135 unsigned short pa_type; /* pa type. inode or group */
Mingming Cao8f6e39a2008-04-29 22:01:31 -0400136 spinlock_t *pa_obj_lock;
137 struct inode *pa_inode; /* hack, for history only */
138};
139
Aneesh Kumar K.Vcc0fb9a2009-03-27 17:16:58 -0400140enum {
141 MB_INODE_PA = 0,
142 MB_GROUP_PA = 1
143};
Mingming Cao8f6e39a2008-04-29 22:01:31 -0400144
145struct ext4_free_extent {
146 ext4_lblk_t fe_logical;
147 ext4_grpblk_t fe_start;
148 ext4_group_t fe_group;
149 int fe_len;
150};
151
152/*
153 * Locality group:
154 * we try to group all related changes together
155 * so that writeback can flush/allocate them together as well
Aneesh Kumar K.V6be2ded2008-07-23 14:14:05 -0400156 * Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC
157 * (512). We store prealloc space into the hash based on the pa_free blocks
158 * order value.ie, fls(pa_free)-1;
Mingming Cao8f6e39a2008-04-29 22:01:31 -0400159 */
Aneesh Kumar K.V6be2ded2008-07-23 14:14:05 -0400160#define PREALLOC_TB_SIZE 10
Mingming Cao8f6e39a2008-04-29 22:01:31 -0400161struct ext4_locality_group {
162 /* for allocator */
Aneesh Kumar K.V6be2ded2008-07-23 14:14:05 -0400163 /* to serialize allocates */
164 struct mutex lg_mutex;
165 /* list of preallocations */
166 struct list_head lg_prealloc_list[PREALLOC_TB_SIZE];
Mingming Cao8f6e39a2008-04-29 22:01:31 -0400167 spinlock_t lg_prealloc_lock;
168};
169
170struct ext4_allocation_context {
171 struct inode *ac_inode;
172 struct super_block *ac_sb;
173
174 /* original request */
175 struct ext4_free_extent ac_o_ex;
176
177 /* goal request (after normalization) */
178 struct ext4_free_extent ac_g_ex;
179
180 /* the best found extent */
181 struct ext4_free_extent ac_b_ex;
182
183 /* copy of the bext found extent taken before preallocation efforts */
184 struct ext4_free_extent ac_f_ex;
185
186 /* number of iterations done. we have to track to limit searching */
187 unsigned long ac_ex_scanned;
188 __u16 ac_groups_scanned;
189 __u16 ac_found;
190 __u16 ac_tail;
191 __u16 ac_buddy;
192 __u16 ac_flags; /* allocation hints */
193 __u8 ac_status;
194 __u8 ac_criteria;
195 __u8 ac_repeats;
196 __u8 ac_2order; /* if request is to allocate 2^N blocks and
197 * N > 0, the field stores N, otherwise 0 */
198 __u8 ac_op; /* operation, for history only */
199 struct page *ac_bitmap_page;
200 struct page *ac_buddy_page;
Aneesh Kumar K.V8556e8f2009-01-05 21:46:55 -0500201 /*
202 * pointer to the held semaphore upon successful
203 * block allocation
204 */
205 struct rw_semaphore *alloc_semp;
Mingming Cao8f6e39a2008-04-29 22:01:31 -0400206 struct ext4_prealloc_space *ac_pa;
207 struct ext4_locality_group *ac_lg;
208};
209
210#define AC_STATUS_CONTINUE 1
211#define AC_STATUS_FOUND 2
212#define AC_STATUS_BREAK 3
213
214struct ext4_mb_history {
215 struct ext4_free_extent orig; /* orig allocation */
216 struct ext4_free_extent goal; /* goal allocation */
217 struct ext4_free_extent result; /* result allocation */
218 unsigned pid;
219 unsigned ino;
220 __u16 found; /* how many extents have been found */
221 __u16 groups; /* how many groups have been scanned */
222 __u16 tail; /* what tail broke some buddy */
223 __u16 buddy; /* buddy the tail ^^^ broke */
224 __u16 flags;
225 __u8 cr:3; /* which phase the result extent was found at */
226 __u8 op:4;
227 __u8 merged:1;
228};
229
230struct ext4_buddy {
231 struct page *bd_buddy_page;
232 void *bd_buddy;
233 struct page *bd_bitmap_page;
234 void *bd_bitmap;
235 struct ext4_group_info *bd_info;
236 struct super_block *bd_sb;
237 __u16 bd_blkbits;
238 ext4_group_t bd_group;
Aneesh Kumar K.V920313a2009-01-05 21:36:19 -0500239 struct rw_semaphore *alloc_semp;
Mingming Cao8f6e39a2008-04-29 22:01:31 -0400240};
241#define EXT4_MB_BITMAP(e4b) ((e4b)->bd_bitmap)
242#define EXT4_MB_BUDDY(e4b) ((e4b)->bd_buddy)
243
244#ifndef EXT4_MB_HISTORY
245static inline void ext4_mb_store_history(struct ext4_allocation_context *ac)
246{
247 return;
248}
Mingming Cao8f6e39a2008-04-29 22:01:31 -0400249#endif
250
251#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
252
Aneesh Kumar K.Vc3a326a2008-11-25 15:11:52 -0500253static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
Mingming Cao8f6e39a2008-04-29 22:01:31 -0400254 struct ext4_free_extent *fex)
255{
256 ext4_fsblk_t block;
257
258 block = (ext4_fsblk_t) fex->fe_group * EXT4_BLOCKS_PER_GROUP(sb)
259 + fex->fe_start
260 + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
261 return block;
262}
263#endif