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 'ext4_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 * maximum length of inode prealloc list
78 */
79 #define MB_DEFAULT_MAX_INODE_PREALLOC 512
80
81 /*
82 * Number of groups to search linearly before performing group scanning
83 * optimization.
84 */
85 #define MB_DEFAULT_LINEAR_LIMIT 4
86
87 /*
88 * Minimum number of groups that should be present in the file system to perform
89 * group scanning optimizations.
90 */
91 #define MB_DEFAULT_LINEAR_SCAN_THRESHOLD 16
92
93 /*
94 * Number of valid buddy orders
95 */
96 #define MB_NUM_ORDERS(sb) ((sb)->s_blocksize_bits + 2)
97
98 struct ext4_free_data {
99 /* this links the free block information from sb_info */
100 struct list_head efd_list;
101
102 /* this links the free block information from group_info */
103 struct rb_node efd_node;
104
105 /* group which free block extent belongs */
106 ext4_group_t efd_group;
107
108 /* free block extent */
109 ext4_grpblk_t efd_start_cluster;
110 ext4_grpblk_t efd_count;
111
112 /* transaction which freed this extent */
113 tid_t efd_tid;
114 };
115
116 struct ext4_prealloc_space {
117 struct list_head pa_inode_list;
118 struct list_head pa_group_list;
119 union {
120 struct list_head pa_tmp_list;
121 struct rcu_head pa_rcu;
122 } u;
123 spinlock_t pa_lock;
124 atomic_t pa_count;
125 unsigned pa_deleted;
126 ext4_fsblk_t pa_pstart; /* phys. block */
127 ext4_lblk_t pa_lstart; /* log. block */
128 ext4_grpblk_t pa_len; /* len of preallocated chunk */
129 ext4_grpblk_t pa_free; /* how many blocks are free */
130 unsigned short pa_type; /* pa type. inode or group */
131 spinlock_t *pa_obj_lock;
132 struct inode *pa_inode; /* hack, for history only */
133 };
134
135 enum {
136 MB_INODE_PA = 0,
137 MB_GROUP_PA = 1
138 };
139
140 struct ext4_free_extent {
141 ext4_lblk_t fe_logical;
142 ext4_grpblk_t fe_start; /* In cluster units */
143 ext4_group_t fe_group;
144 ext4_grpblk_t fe_len; /* In cluster units */
145 };
146
147 /*
148 * Locality group:
149 * we try to group all related changes together
150 * so that writeback can flush/allocate them together as well
151 * Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC
152 * (512). We store prealloc space into the hash based on the pa_free blocks
153 * order value.ie, fls(pa_free)-1;
154 */
155 #define PREALLOC_TB_SIZE 10
156 struct ext4_locality_group {
157 /* for allocator */
158 /* to serialize allocates */
159 struct mutex lg_mutex;
160 /* list of preallocations */
161 struct list_head lg_prealloc_list[PREALLOC_TB_SIZE];
162 spinlock_t lg_prealloc_lock;
163 };
164
165 struct ext4_allocation_context {
166 struct inode *ac_inode;
167 struct super_block *ac_sb;
168
169 /* original request */
170 struct ext4_free_extent ac_o_ex;
171
172 /* goal request (normalized ac_o_ex) */
173 struct ext4_free_extent ac_g_ex;
174
175 /* the best found extent */
176 struct ext4_free_extent ac_b_ex;
177
178 /* copy of the best found extent taken before preallocation efforts */
179 struct ext4_free_extent ac_f_ex;
180
181 __u32 ac_groups_considered;
182 __u32 ac_flags; /* allocation hints */
183 __u16 ac_groups_scanned;
184 __u16 ac_groups_linear_remaining;
185 __u16 ac_found;
186 __u16 ac_tail;
187 __u16 ac_buddy;
188 __u8 ac_status;
189 __u8 ac_criteria;
190 __u8 ac_2order; /* if request is to allocate 2^N blocks and
191 * N > 0, the field stores N, otherwise 0 */
192 __u8 ac_op; /* operation, for history only */
193 struct page *ac_bitmap_page;
194 struct page *ac_buddy_page;
195 struct ext4_prealloc_space *ac_pa;
196 struct ext4_locality_group *ac_lg;
197 };
198
199 #define AC_STATUS_CONTINUE 1
200 #define AC_STATUS_FOUND 2
201 #define AC_STATUS_BREAK 3
202
203 struct ext4_buddy {
204 struct page *bd_buddy_page;
205 void *bd_buddy;
206 struct page *bd_bitmap_page;
207 void *bd_bitmap;
208 struct ext4_group_info *bd_info;
209 struct super_block *bd_sb;
210 __u16 bd_blkbits;
211 ext4_group_t bd_group;
212 };
213
ext4_grp_offs_to_block(struct super_block * sb,struct ext4_free_extent * fex)214 static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
215 struct ext4_free_extent *fex)
216 {
217 return ext4_group_first_block_no(sb, fex->fe_group) +
218 (fex->fe_start << EXT4_SB(sb)->s_cluster_bits);
219 }
220
221 typedef int (*ext4_mballoc_query_range_fn)(
222 struct super_block *sb,
223 ext4_group_t agno,
224 ext4_grpblk_t start,
225 ext4_grpblk_t len,
226 void *priv);
227
228 int
229 ext4_mballoc_query_range(
230 struct super_block *sb,
231 ext4_group_t agno,
232 ext4_grpblk_t start,
233 ext4_grpblk_t end,
234 ext4_mballoc_query_range_fn formatter,
235 void *priv);
236
237 #endif
238