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 * with AGGRESSIVE_CHECK allocator runs consistency checks over
27 * structures. these checks slow things down a lot
28 */
29 #define AGGRESSIVE_CHECK__
30
31 /*
32 * with DOUBLE_CHECK defined mballoc creates persistent in-core
33 * bitmaps, maintains and uses them to check for double allocations
34 */
35 #define DOUBLE_CHECK__
36
37 /*
38 */
39 #ifdef CONFIG_EXT4_DEBUG
40 extern ushort ext4_mballoc_debug;
41
42 #define mb_debug(n, fmt, a...) \
43 do { \
44 if ((n) <= ext4_mballoc_debug) { \
45 printk(KERN_DEBUG "(%s, %d): %s: ", \
46 __FILE__, __LINE__, __func__); \
47 printk(fmt, ## a); \
48 } \
49 } while (0)
50 #else
51 #define mb_debug(n, fmt, a...) no_printk(fmt, ## a)
52 #endif
53
54 #define EXT4_MB_HISTORY_ALLOC 1 /* allocation */
55 #define EXT4_MB_HISTORY_PREALLOC 2 /* preallocated blocks used */
56
57 /*
58 * How long mballoc can look for a best extent (in found extents)
59 */
60 #define MB_DEFAULT_MAX_TO_SCAN 200
61
62 /*
63 * How long mballoc must look for a best extent
64 */
65 #define MB_DEFAULT_MIN_TO_SCAN 10
66
67 /*
68 * with 'ext4_mb_stats' allocator will collect stats that will be
69 * shown at umount. The collecting costs though!
70 */
71 #define MB_DEFAULT_STATS 0
72
73 /*
74 * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served
75 * by the stream allocator, which purpose is to pack requests
76 * as close each to other as possible to produce smooth I/O traffic
77 * We use locality group prealloc space for stream request.
78 * We can tune the same via /proc/fs/ext4/<parition>/stream_req
79 */
80 #define MB_DEFAULT_STREAM_THRESHOLD 16 /* 64K */
81
82 /*
83 * for which requests use 2^N search using buddies
84 */
85 #define MB_DEFAULT_ORDER2_REQS 2
86
87 /*
88 * default group prealloc size 512 blocks
89 */
90 #define MB_DEFAULT_GROUP_PREALLOC 512
91
92
93 struct ext4_free_data {
94 /* MUST be the first member */
95 struct ext4_journal_cb_entry efd_jce;
96
97 /* ext4_free_data private data starts from here */
98
99 /* this links the free block information from group_info */
100 struct rb_node efd_node;
101
102 /* group which free block extent belongs */
103 ext4_group_t efd_group;
104
105 /* free block extent */
106 ext4_grpblk_t efd_start_cluster;
107 ext4_grpblk_t efd_count;
108
109 /* transaction which freed this extent */
110 tid_t efd_tid;
111 };
112
113 struct ext4_prealloc_space {
114 struct list_head pa_inode_list;
115 struct list_head pa_group_list;
116 union {
117 struct list_head pa_tmp_list;
118 struct rcu_head pa_rcu;
119 } u;
120 spinlock_t pa_lock;
121 atomic_t pa_count;
122 unsigned pa_deleted;
123 ext4_fsblk_t pa_pstart; /* phys. block */
124 ext4_lblk_t pa_lstart; /* log. block */
125 ext4_grpblk_t pa_len; /* len of preallocated chunk */
126 ext4_grpblk_t pa_free; /* how many blocks are free */
127 unsigned short pa_type; /* pa type. inode or group */
128 spinlock_t *pa_obj_lock;
129 struct inode *pa_inode; /* hack, for history only */
130 };
131
132 enum {
133 MB_INODE_PA = 0,
134 MB_GROUP_PA = 1
135 };
136
137 struct ext4_free_extent {
138 ext4_lblk_t fe_logical;
139 ext4_grpblk_t fe_start; /* In cluster units */
140 ext4_group_t fe_group;
141 ext4_grpblk_t fe_len; /* In cluster units */
142 };
143
144 /*
145 * Locality group:
146 * we try to group all related changes together
147 * so that writeback can flush/allocate them together as well
148 * Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC
149 * (512). We store prealloc space into the hash based on the pa_free blocks
150 * order value.ie, fls(pa_free)-1;
151 */
152 #define PREALLOC_TB_SIZE 10
153 struct ext4_locality_group {
154 /* for allocator */
155 /* to serialize allocates */
156 struct mutex lg_mutex;
157 /* list of preallocations */
158 struct list_head lg_prealloc_list[PREALLOC_TB_SIZE];
159 spinlock_t lg_prealloc_lock;
160 };
161
162 struct ext4_allocation_context {
163 struct inode *ac_inode;
164 struct super_block *ac_sb;
165
166 /* original request */
167 struct ext4_free_extent ac_o_ex;
168
169 /* goal request (normalized ac_o_ex) */
170 struct ext4_free_extent ac_g_ex;
171
172 /* the best found extent */
173 struct ext4_free_extent ac_b_ex;
174
175 /* copy of the best found extent taken before preallocation efforts */
176 struct ext4_free_extent ac_f_ex;
177
178 __u16 ac_groups_scanned;
179 __u16 ac_found;
180 __u16 ac_tail;
181 __u16 ac_buddy;
182 __u16 ac_flags; /* allocation hints */
183 __u8 ac_status;
184 __u8 ac_criteria;
185 __u8 ac_2order; /* if request is to allocate 2^N blocks and
186 * N > 0, the field stores N, otherwise 0 */
187 __u8 ac_op; /* operation, for history only */
188 struct page *ac_bitmap_page;
189 struct page *ac_buddy_page;
190 struct ext4_prealloc_space *ac_pa;
191 struct ext4_locality_group *ac_lg;
192 };
193
194 #define AC_STATUS_CONTINUE 1
195 #define AC_STATUS_FOUND 2
196 #define AC_STATUS_BREAK 3
197
198 struct ext4_buddy {
199 struct page *bd_buddy_page;
200 void *bd_buddy;
201 struct page *bd_bitmap_page;
202 void *bd_bitmap;
203 struct ext4_group_info *bd_info;
204 struct super_block *bd_sb;
205 __u16 bd_blkbits;
206 ext4_group_t bd_group;
207 };
208
ext4_grp_offs_to_block(struct super_block * sb,struct ext4_free_extent * fex)209 static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
210 struct ext4_free_extent *fex)
211 {
212 return ext4_group_first_block_no(sb, fex->fe_group) +
213 (fex->fe_start << EXT4_SB(sb)->s_cluster_bits);
214 }
215 #endif
216