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8f6e39a7 MC |
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/version.h> | |
8a0aba73 | 21 | #include <linux/blkdev.h> |
920313a7 | 22 | #include <linux/mutex.h> |
8f6e39a7 MC |
23 | #include "ext4_jbd2.h" |
24 | #include "ext4.h" | |
8f6e39a7 MC |
25 | |
26 | /* | |
27 | * with AGGRESSIVE_CHECK allocator runs consistency checks over | |
28 | * structures. these checks slow things down a lot | |
29 | */ | |
30 | #define AGGRESSIVE_CHECK__ | |
31 | ||
32 | /* | |
33 | * with DOUBLE_CHECK defined mballoc creates persistent in-core | |
34 | * bitmaps, maintains and uses them to check for double allocations | |
35 | */ | |
36 | #define DOUBLE_CHECK__ | |
37 | ||
38 | /* | |
39 | */ | |
40 | #define MB_DEBUG__ | |
41 | #ifdef MB_DEBUG | |
42 | #define mb_debug(fmt, a...) printk(fmt, ##a) | |
43 | #else | |
44 | #define mb_debug(fmt, a...) | |
45 | #endif | |
46 | ||
47 | /* | |
48 | * with EXT4_MB_HISTORY mballoc stores last N allocations in memory | |
49 | * and you can monitor it in /proc/fs/ext4/<dev>/mb_history | |
50 | */ | |
51 | #define EXT4_MB_HISTORY | |
52 | #define EXT4_MB_HISTORY_ALLOC 1 /* allocation */ | |
53 | #define EXT4_MB_HISTORY_PREALLOC 2 /* preallocated blocks used */ | |
54 | #define EXT4_MB_HISTORY_DISCARD 4 /* preallocation discarded */ | |
55 | #define EXT4_MB_HISTORY_FREE 8 /* free */ | |
56 | ||
57 | #define EXT4_MB_HISTORY_DEFAULT (EXT4_MB_HISTORY_ALLOC | \ | |
58 | EXT4_MB_HISTORY_PREALLOC) | |
59 | ||
60 | /* | |
61 | * How long mballoc can look for a best extent (in found extents) | |
62 | */ | |
63 | #define MB_DEFAULT_MAX_TO_SCAN 200 | |
64 | ||
65 | /* | |
66 | * How long mballoc must look for a best extent | |
67 | */ | |
68 | #define MB_DEFAULT_MIN_TO_SCAN 10 | |
69 | ||
70 | /* | |
71 | * How many groups mballoc will scan looking for the best chunk | |
72 | */ | |
73 | #define MB_DEFAULT_MAX_GROUPS_TO_SCAN 5 | |
74 | ||
75 | /* | |
76 | * with 'ext4_mb_stats' allocator will collect stats that will be | |
77 | * shown at umount. The collecting costs though! | |
78 | */ | |
79 | #define MB_DEFAULT_STATS 1 | |
80 | ||
81 | /* | |
82 | * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served | |
83 | * by the stream allocator, which purpose is to pack requests | |
84 | * as close each to other as possible to produce smooth I/O traffic | |
85 | * We use locality group prealloc space for stream request. | |
86 | * We can tune the same via /proc/fs/ext4/<parition>/stream_req | |
87 | */ | |
88 | #define MB_DEFAULT_STREAM_THRESHOLD 16 /* 64K */ | |
89 | ||
90 | /* | |
91 | * for which requests use 2^N search using buddies | |
92 | */ | |
93 | #define MB_DEFAULT_ORDER2_REQS 2 | |
94 | ||
95 | /* | |
96 | * default group prealloc size 512 blocks | |
97 | */ | |
98 | #define MB_DEFAULT_GROUP_PREALLOC 512 | |
99 | ||
8f6e39a7 | 100 | |
c894058d AK |
101 | struct ext4_free_data { |
102 | /* this links the free block information from group_info */ | |
103 | struct rb_node node; | |
8f6e39a7 | 104 | |
c894058d | 105 | /* this links the free block information from ext4_sb_info */ |
8f6e39a7 | 106 | struct list_head list; |
c894058d AK |
107 | |
108 | /* group which free block extent belongs */ | |
109 | ext4_group_t group; | |
110 | ||
111 | /* free block extent */ | |
112 | ext4_grpblk_t start_blk; | |
113 | ext4_grpblk_t count; | |
114 | ||
115 | /* transaction which freed this extent */ | |
116 | tid_t t_tid; | |
8f6e39a7 MC |
117 | }; |
118 | ||
8f6e39a7 MC |
119 | struct ext4_prealloc_space { |
120 | struct list_head pa_inode_list; | |
121 | struct list_head pa_group_list; | |
122 | union { | |
123 | struct list_head pa_tmp_list; | |
124 | struct rcu_head pa_rcu; | |
125 | } u; | |
126 | spinlock_t pa_lock; | |
127 | atomic_t pa_count; | |
128 | unsigned pa_deleted; | |
129 | ext4_fsblk_t pa_pstart; /* phys. block */ | |
130 | ext4_lblk_t pa_lstart; /* log. block */ | |
131 | unsigned short pa_len; /* len of preallocated chunk */ | |
132 | unsigned short pa_free; /* how many blocks are free */ | |
cc0fb9ad | 133 | unsigned short pa_type; /* pa type. inode or group */ |
8f6e39a7 MC |
134 | spinlock_t *pa_obj_lock; |
135 | struct inode *pa_inode; /* hack, for history only */ | |
136 | }; | |
137 | ||
cc0fb9ad AK |
138 | enum { |
139 | MB_INODE_PA = 0, | |
140 | MB_GROUP_PA = 1 | |
141 | }; | |
8f6e39a7 MC |
142 | |
143 | struct ext4_free_extent { | |
144 | ext4_lblk_t fe_logical; | |
145 | ext4_grpblk_t fe_start; | |
146 | ext4_group_t fe_group; | |
147 | int fe_len; | |
148 | }; | |
149 | ||
150 | /* | |
151 | * Locality group: | |
152 | * we try to group all related changes together | |
153 | * so that writeback can flush/allocate them together as well | |
6be2ded1 AK |
154 | * Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC |
155 | * (512). We store prealloc space into the hash based on the pa_free blocks | |
156 | * order value.ie, fls(pa_free)-1; | |
8f6e39a7 | 157 | */ |
6be2ded1 | 158 | #define PREALLOC_TB_SIZE 10 |
8f6e39a7 MC |
159 | struct ext4_locality_group { |
160 | /* for allocator */ | |
6be2ded1 AK |
161 | /* to serialize allocates */ |
162 | struct mutex lg_mutex; | |
163 | /* list of preallocations */ | |
164 | struct list_head lg_prealloc_list[PREALLOC_TB_SIZE]; | |
8f6e39a7 MC |
165 | spinlock_t lg_prealloc_lock; |
166 | }; | |
167 | ||
168 | struct ext4_allocation_context { | |
169 | struct inode *ac_inode; | |
170 | struct super_block *ac_sb; | |
171 | ||
172 | /* original request */ | |
173 | struct ext4_free_extent ac_o_ex; | |
174 | ||
175 | /* goal request (after normalization) */ | |
176 | struct ext4_free_extent ac_g_ex; | |
177 | ||
178 | /* the best found extent */ | |
179 | struct ext4_free_extent ac_b_ex; | |
180 | ||
181 | /* copy of the bext found extent taken before preallocation efforts */ | |
182 | struct ext4_free_extent ac_f_ex; | |
183 | ||
184 | /* number of iterations done. we have to track to limit searching */ | |
185 | unsigned long ac_ex_scanned; | |
186 | __u16 ac_groups_scanned; | |
187 | __u16 ac_found; | |
188 | __u16 ac_tail; | |
189 | __u16 ac_buddy; | |
190 | __u16 ac_flags; /* allocation hints */ | |
191 | __u8 ac_status; | |
192 | __u8 ac_criteria; | |
193 | __u8 ac_repeats; | |
194 | __u8 ac_2order; /* if request is to allocate 2^N blocks and | |
195 | * N > 0, the field stores N, otherwise 0 */ | |
196 | __u8 ac_op; /* operation, for history only */ | |
197 | struct page *ac_bitmap_page; | |
198 | struct page *ac_buddy_page; | |
8556e8f3 AK |
199 | /* |
200 | * pointer to the held semaphore upon successful | |
201 | * block allocation | |
202 | */ | |
203 | struct rw_semaphore *alloc_semp; | |
8f6e39a7 MC |
204 | struct ext4_prealloc_space *ac_pa; |
205 | struct ext4_locality_group *ac_lg; | |
206 | }; | |
207 | ||
208 | #define AC_STATUS_CONTINUE 1 | |
209 | #define AC_STATUS_FOUND 2 | |
210 | #define AC_STATUS_BREAK 3 | |
211 | ||
212 | struct ext4_mb_history { | |
213 | struct ext4_free_extent orig; /* orig allocation */ | |
214 | struct ext4_free_extent goal; /* goal allocation */ | |
215 | struct ext4_free_extent result; /* result allocation */ | |
216 | unsigned pid; | |
217 | unsigned ino; | |
218 | __u16 found; /* how many extents have been found */ | |
219 | __u16 groups; /* how many groups have been scanned */ | |
220 | __u16 tail; /* what tail broke some buddy */ | |
221 | __u16 buddy; /* buddy the tail ^^^ broke */ | |
222 | __u16 flags; | |
223 | __u8 cr:3; /* which phase the result extent was found at */ | |
224 | __u8 op:4; | |
225 | __u8 merged:1; | |
226 | }; | |
227 | ||
228 | struct ext4_buddy { | |
229 | struct page *bd_buddy_page; | |
230 | void *bd_buddy; | |
231 | struct page *bd_bitmap_page; | |
232 | void *bd_bitmap; | |
233 | struct ext4_group_info *bd_info; | |
234 | struct super_block *bd_sb; | |
235 | __u16 bd_blkbits; | |
236 | ext4_group_t bd_group; | |
920313a7 | 237 | struct rw_semaphore *alloc_semp; |
8f6e39a7 MC |
238 | }; |
239 | #define EXT4_MB_BITMAP(e4b) ((e4b)->bd_bitmap) | |
240 | #define EXT4_MB_BUDDY(e4b) ((e4b)->bd_buddy) | |
241 | ||
242 | #ifndef EXT4_MB_HISTORY | |
243 | static inline void ext4_mb_store_history(struct ext4_allocation_context *ac) | |
244 | { | |
245 | return; | |
246 | } | |
8f6e39a7 MC |
247 | #endif |
248 | ||
249 | #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) | |
250 | ||
c3a326a6 | 251 | static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb, |
8f6e39a7 MC |
252 | struct ext4_free_extent *fex) |
253 | { | |
254 | ext4_fsblk_t block; | |
255 | ||
256 | block = (ext4_fsblk_t) fex->fe_group * EXT4_BLOCKS_PER_GROUP(sb) | |
257 | + fex->fe_start | |
258 | + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block); | |
259 | return block; | |
260 | } | |
261 | #endif |