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 */
28 #ifdef CONFIG_EXT4_DEBUG
29 extern ushort ext4_mballoc_debug;
30
31 #define mb_debug(n, fmt, ...) \
32 do { \
33 if ((n) <= ext4_mballoc_debug) { \
34 printk(KERN_DEBUG "(%s, %d): %s: " fmt, \
35 __FILE__, __LINE__, __func__, ##__VA_ARGS__); \
36 } \
37 } while (0)
38 #else
39 #define mb_debug(n, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
40 #endif
41
42 #define EXT4_MB_HISTORY_ALLOC 1 /* allocation */
43 #define EXT4_MB_HISTORY_PREALLOC 2 /* preallocated blocks used */
44
45 /*
46 * How long mballoc can look for a best extent (in found extents)
47 */
48 #define MB_DEFAULT_MAX_TO_SCAN 200
49
50 /*
51 * How long mballoc must look for a best extent
52 */
53 #define MB_DEFAULT_MIN_TO_SCAN 10
54
55 /*
56 * with 'ext4_mb_stats' allocator will collect stats that will be
57 * shown at umount. The collecting costs though!
58 */
59 #define MB_DEFAULT_STATS 0
60
61 /*
62 * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served
63 * by the stream allocator, which purpose is to pack requests
64 * as close each to other as possible to produce smooth I/O traffic
65 * We use locality group prealloc space for stream request.
66 * We can tune the same via /proc/fs/ext4/<parition>/stream_req
67 */
68 #define MB_DEFAULT_STREAM_THRESHOLD 16 /* 64K */
69
70 /*
71 * for which requests use 2^N search using buddies
72 */
73 #define MB_DEFAULT_ORDER2_REQS 2
74
75 /*
76 * default group prealloc size 512 blocks
77 */
78 #define MB_DEFAULT_GROUP_PREALLOC 512
79
80
81 struct ext4_free_data {
82 /* this links the free block information from sb_info */
83 struct list_head efd_list;
84
85 /* this links the free block information from group_info */
86 struct rb_node efd_node;
87
88 /* group which free block extent belongs */
89 ext4_group_t efd_group;
90
91 /* free block extent */
92 ext4_grpblk_t efd_start_cluster;
93 ext4_grpblk_t efd_count;
94
95 /* transaction which freed this extent */
96 tid_t efd_tid;
97 };
98
99 struct ext4_prealloc_space {
100 struct list_head pa_inode_list;
101 struct list_head pa_group_list;
102 union {
103 struct list_head pa_tmp_list;
104 struct rcu_head pa_rcu;
105 } u;
106 spinlock_t pa_lock;
107 atomic_t pa_count;
108 unsigned pa_deleted;
109 ext4_fsblk_t pa_pstart; /* phys. block */
110 ext4_lblk_t pa_lstart; /* log. block */
111 ext4_grpblk_t pa_len; /* len of preallocated chunk */
112 ext4_grpblk_t pa_free; /* how many blocks are free */
113 unsigned short pa_type; /* pa type. inode or group */
114 spinlock_t *pa_obj_lock;
115 struct inode *pa_inode; /* hack, for history only */
116 };
117
118 enum {
119 MB_INODE_PA = 0,
120 MB_GROUP_PA = 1
121 };
122
123 struct ext4_free_extent {
124 ext4_lblk_t fe_logical;
125 ext4_grpblk_t fe_start; /* In cluster units */
126 ext4_group_t fe_group;
127 ext4_grpblk_t fe_len; /* In cluster units */
128 };
129
130 /*
131 * Locality group:
132 * we try to group all related changes together
133 * so that writeback can flush/allocate them together as well
134 * Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC
135 * (512). We store prealloc space into the hash based on the pa_free blocks
136 * order value.ie, fls(pa_free)-1;
137 */
138 #define PREALLOC_TB_SIZE 10
139 struct ext4_locality_group {
140 /* for allocator */
141 /* to serialize allocates */
142 struct mutex lg_mutex;
143 /* list of preallocations */
144 struct list_head lg_prealloc_list[PREALLOC_TB_SIZE];
145 spinlock_t lg_prealloc_lock;
146 };
147
148 struct ext4_allocation_context {
149 struct inode *ac_inode;
150 struct super_block *ac_sb;
151
152 /* original request */
153 struct ext4_free_extent ac_o_ex;
154
155 /* goal request (normalized ac_o_ex) */
156 struct ext4_free_extent ac_g_ex;
157
158 /* the best found extent */
159 struct ext4_free_extent ac_b_ex;
160
161 /* copy of the best found extent taken before preallocation efforts */
162 struct ext4_free_extent ac_f_ex;
163
164 __u16 ac_groups_scanned;
165 __u16 ac_found;
166 __u16 ac_tail;
167 __u16 ac_buddy;
168 __u16 ac_flags; /* allocation hints */
169 __u8 ac_status;
170 __u8 ac_criteria;
171 __u8 ac_2order; /* if request is to allocate 2^N blocks and
172 * N > 0, the field stores N, otherwise 0 */
173 __u8 ac_op; /* operation, for history only */
174 struct page *ac_bitmap_page;
175 struct page *ac_buddy_page;
176 struct ext4_prealloc_space *ac_pa;
177 struct ext4_locality_group *ac_lg;
178 };
179
180 #define AC_STATUS_CONTINUE 1
181 #define AC_STATUS_FOUND 2
182 #define AC_STATUS_BREAK 3
183
184 struct ext4_buddy {
185 struct page *bd_buddy_page;
186 void *bd_buddy;
187 struct page *bd_bitmap_page;
188 void *bd_bitmap;
189 struct ext4_group_info *bd_info;
190 struct super_block *bd_sb;
191 __u16 bd_blkbits;
192 ext4_group_t bd_group;
193 };
194
ext4_grp_offs_to_block(struct super_block * sb,struct ext4_free_extent * fex)195 static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
196 struct ext4_free_extent *fex)
197 {
198 return ext4_group_first_block_no(sb, fex->fe_group) +
199 (fex->fe_start << EXT4_SB(sb)->s_cluster_bits);
200 }
201
202 typedef int (*ext4_mballoc_query_range_fn)(
203 struct super_block *sb,
204 ext4_group_t agno,
205 ext4_grpblk_t start,
206 ext4_grpblk_t len,
207 void *priv);
208
209 int
210 ext4_mballoc_query_range(
211 struct super_block *sb,
212 ext4_group_t agno,
213 ext4_grpblk_t start,
214 ext4_grpblk_t end,
215 ext4_mballoc_query_range_fn formatter,
216 void *priv);
217
218 #endif
219