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/blkdev.h>
21 #include <linux/mutex.h>
22 #include "ext4_jbd2.h"
23 #include "ext4.h"
24
25 /*
26 */
27 #ifdef CONFIG_EXT4_DEBUG
28 extern ushort ext4_mballoc_debug;
29
30 #define mb_debug(n, fmt, ...) \
31 do { \
32 if ((n) <= ext4_mballoc_debug) { \
33 printk(KERN_DEBUG "(%s, %d): %s: " fmt, \
34 __FILE__, __LINE__, __func__, ##__VA_ARGS__); \
35 } \
36 } while (0)
37 #else
38 #define mb_debug(n, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
39 #endif
40
41 #define EXT4_MB_HISTORY_ALLOC 1 /* allocation */
42 #define EXT4_MB_HISTORY_PREALLOC 2 /* preallocated blocks used */
43
44 /*
45 * How long mballoc can look for a best extent (in found extents)
46 */
47 #define MB_DEFAULT_MAX_TO_SCAN 200
48
49 /*
50 * How long mballoc must look for a best extent
51 */
52 #define MB_DEFAULT_MIN_TO_SCAN 10
53
54 /*
55 * with 'ext4_mb_stats' allocator will collect stats that will be
56 * shown at umount. The collecting costs though!
57 */
58 #define MB_DEFAULT_STATS 0
59
60 /*
61 * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served
62 * by the stream allocator, which purpose is to pack requests
63 * as close each to other as possible to produce smooth I/O traffic
64 * We use locality group prealloc space for stream request.
65 * We can tune the same via /proc/fs/ext4/<parition>/stream_req
66 */
67 #define MB_DEFAULT_STREAM_THRESHOLD 16 /* 64K */
68
69 /*
70 * for which requests use 2^N search using buddies
71 */
72 #define MB_DEFAULT_ORDER2_REQS 2
73
74 /*
75 * default group prealloc size 512 blocks
76 */
77 #define MB_DEFAULT_GROUP_PREALLOC 512
78
79
80 struct ext4_free_data {
81 /* MUST be the first member */
82 struct ext4_journal_cb_entry efd_jce;
83
84 /* ext4_free_data private data starts from here */
85
86 /* this links the free block information from group_info */
87 struct rb_node efd_node;
88
89 /* group which free block extent belongs */
90 ext4_group_t efd_group;
91
92 /* free block extent */
93 ext4_grpblk_t efd_start_cluster;
94 ext4_grpblk_t efd_count;
95
96 /* transaction which freed this extent */
97 tid_t efd_tid;
98 };
99
100 struct ext4_prealloc_space {
101 struct list_head pa_inode_list;
102 struct list_head pa_group_list;
103 union {
104 struct list_head pa_tmp_list;
105 struct rcu_head pa_rcu;
106 } u;
107 spinlock_t pa_lock;
108 atomic_t pa_count;
109 unsigned pa_deleted;
110 ext4_fsblk_t pa_pstart; /* phys. block */
111 ext4_lblk_t pa_lstart; /* log. block */
112 ext4_grpblk_t pa_len; /* len of preallocated chunk */
113 ext4_grpblk_t pa_free; /* how many blocks are free */
114 unsigned short pa_type; /* pa type. inode or group */
115 spinlock_t *pa_obj_lock;
116 struct inode *pa_inode; /* hack, for history only */
117 };
118
119 enum {
120 MB_INODE_PA = 0,
121 MB_GROUP_PA = 1
122 };
123
124 struct ext4_free_extent {
125 ext4_lblk_t fe_logical;
126 ext4_grpblk_t fe_start; /* In cluster units */
127 ext4_group_t fe_group;
128 ext4_grpblk_t fe_len; /* In cluster units */
129 };
130
131 /*
132 * Locality group:
133 * we try to group all related changes together
134 * so that writeback can flush/allocate them together as well
135 * Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC
136 * (512). We store prealloc space into the hash based on the pa_free blocks
137 * order value.ie, fls(pa_free)-1;
138 */
139 #define PREALLOC_TB_SIZE 10
140 struct ext4_locality_group {
141 /* for allocator */
142 /* to serialize allocates */
143 struct mutex lg_mutex;
144 /* list of preallocations */
145 struct list_head lg_prealloc_list[PREALLOC_TB_SIZE];
146 spinlock_t lg_prealloc_lock;
147 };
148
149 struct ext4_allocation_context {
150 struct inode *ac_inode;
151 struct super_block *ac_sb;
152
153 /* original request */
154 struct ext4_free_extent ac_o_ex;
155
156 /* goal request (normalized ac_o_ex) */
157 struct ext4_free_extent ac_g_ex;
158
159 /* the best found extent */
160 struct ext4_free_extent ac_b_ex;
161
162 /* copy of the best found extent taken before preallocation efforts */
163 struct ext4_free_extent ac_f_ex;
164
165 __u16 ac_groups_scanned;
166 __u16 ac_found;
167 __u16 ac_tail;
168 __u16 ac_buddy;
169 __u16 ac_flags; /* allocation hints */
170 __u8 ac_status;
171 __u8 ac_criteria;
172 __u8 ac_2order; /* if request is to allocate 2^N blocks and
173 * N > 0, the field stores N, otherwise 0 */
174 __u8 ac_op; /* operation, for history only */
175 struct page *ac_bitmap_page;
176 struct page *ac_buddy_page;
177 struct ext4_prealloc_space *ac_pa;
178 struct ext4_locality_group *ac_lg;
179 };
180
181 #define AC_STATUS_CONTINUE 1
182 #define AC_STATUS_FOUND 2
183 #define AC_STATUS_BREAK 3
184
185 struct ext4_buddy {
186 struct page *bd_buddy_page;
187 void *bd_buddy;
188 struct page *bd_bitmap_page;
189 void *bd_bitmap;
190 struct ext4_group_info *bd_info;
191 struct super_block *bd_sb;
192 __u16 bd_blkbits;
193 ext4_group_t bd_group;
194 };
195
ext4_grp_offs_to_block(struct super_block * sb,struct ext4_free_extent * fex)196 static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
197 struct ext4_free_extent *fex)
198 {
199 return ext4_group_first_block_no(sb, fex->fe_group) +
200 (fex->fe_start << EXT4_SB(sb)->s_cluster_bits);
201 }
202 #endif
203