xref: /openbmc/linux/fs/ext4/mballoc.h (revision ecc23d0a422a3118fcf6e4f0a46e17a6c2047b02)
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 's_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   * Number of groups to search linearly before performing group scanning
78   * optimization.
79   */
80  #define MB_DEFAULT_LINEAR_LIMIT		4
81  
82  /*
83   * Minimum number of groups that should be present in the file system to perform
84   * group scanning optimizations.
85   */
86  #define MB_DEFAULT_LINEAR_SCAN_THRESHOLD	16
87  
88  /*
89   * The maximum order upto which CR_BEST_AVAIL_LEN can trim a particular
90   * allocation request. Example, if we have an order 7 request and max trim order
91   * of 3, we can trim this request upto order 4.
92   */
93  #define MB_DEFAULT_BEST_AVAIL_TRIM_ORDER	3
94  
95  /*
96   * Number of valid buddy orders
97   */
98  #define MB_NUM_ORDERS(sb)		((sb)->s_blocksize_bits + 2)
99  
100  struct ext4_free_data {
101  	/* this links the free block information from sb_info */
102  	struct list_head		efd_list;
103  
104  	/* this links the free block information from group_info */
105  	struct rb_node			efd_node;
106  
107  	/* group which free block extent belongs */
108  	ext4_group_t			efd_group;
109  
110  	/* free block extent */
111  	ext4_grpblk_t			efd_start_cluster;
112  	ext4_grpblk_t			efd_count;
113  
114  	/* transaction which freed this extent */
115  	tid_t				efd_tid;
116  };
117  
118  struct ext4_prealloc_space {
119  	union {
120  		struct rb_node	inode_node;		/* for inode PA rbtree */
121  		struct list_head	lg_list;	/* for lg PAs */
122  	} pa_node;
123  	struct list_head	pa_group_list;
124  	union {
125  		struct list_head pa_tmp_list;
126  		struct rcu_head	pa_rcu;
127  	} u;
128  	spinlock_t		pa_lock;
129  	atomic_t		pa_count;
130  	unsigned		pa_deleted;
131  	ext4_fsblk_t		pa_pstart;	/* phys. block */
132  	ext4_lblk_t		pa_lstart;	/* log. block */
133  	ext4_grpblk_t		pa_len;		/* len of preallocated chunk */
134  	ext4_grpblk_t		pa_free;	/* how many blocks are free */
135  	unsigned short		pa_type;	/* pa type. inode or group */
136  	union {
137  		rwlock_t		*inode_lock;	/* locks the rbtree holding this PA */
138  		spinlock_t		*lg_lock;	/* locks the lg list holding this PA */
139  	} pa_node_lock;
140  	struct inode		*pa_inode;	/* used to get the inode during group discard */
141  };
142  
143  enum {
144  	MB_INODE_PA = 0,
145  	MB_GROUP_PA = 1
146  };
147  
148  struct ext4_free_extent {
149  	ext4_lblk_t fe_logical;
150  	ext4_grpblk_t fe_start;	/* In cluster units */
151  	ext4_group_t fe_group;
152  	ext4_grpblk_t fe_len;	/* In cluster units */
153  };
154  
155  /*
156   * Locality group:
157   *   we try to group all related changes together
158   *   so that writeback can flush/allocate them together as well
159   *   Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC
160   *   (512). We store prealloc space into the hash based on the pa_free blocks
161   *   order value.ie, fls(pa_free)-1;
162   */
163  #define PREALLOC_TB_SIZE 10
164  struct ext4_locality_group {
165  	/* for allocator */
166  	/* to serialize allocates */
167  	struct mutex		lg_mutex;
168  	/* list of preallocations */
169  	struct list_head	lg_prealloc_list[PREALLOC_TB_SIZE];
170  	spinlock_t		lg_prealloc_lock;
171  };
172  
173  struct ext4_allocation_context {
174  	struct inode *ac_inode;
175  	struct super_block *ac_sb;
176  
177  	/* original request */
178  	struct ext4_free_extent ac_o_ex;
179  
180  	/* goal request (normalized ac_o_ex) */
181  	struct ext4_free_extent ac_g_ex;
182  
183  	/* the best found extent */
184  	struct ext4_free_extent ac_b_ex;
185  
186  	/* copy of the best found extent taken before preallocation efforts */
187  	struct ext4_free_extent ac_f_ex;
188  
189  	/*
190  	 * goal len can change in CR1.5, so save the original len. This is
191  	 * used while adjusting the PA window and for accounting.
192  	 */
193  	ext4_grpblk_t	ac_orig_goal_len;
194  
195  	__u32 ac_groups_considered;
196  	__u32 ac_flags;		/* allocation hints */
197  	__u32 ac_groups_linear_remaining;
198  	__u16 ac_groups_scanned;
199  	__u16 ac_found;
200  	__u16 ac_cX_found[EXT4_MB_NUM_CRS];
201  	__u16 ac_tail;
202  	__u16 ac_buddy;
203  	__u8 ac_status;
204  	__u8 ac_criteria;
205  	__u8 ac_2order;		/* if request is to allocate 2^N blocks and
206  				 * N > 0, the field stores N, otherwise 0 */
207  	__u8 ac_op;		/* operation, for history only */
208  	struct page *ac_bitmap_page;
209  	struct page *ac_buddy_page;
210  	struct ext4_prealloc_space *ac_pa;
211  	struct ext4_locality_group *ac_lg;
212  };
213  
214  #define AC_STATUS_CONTINUE	1
215  #define AC_STATUS_FOUND		2
216  #define AC_STATUS_BREAK		3
217  
218  struct ext4_buddy {
219  	struct page *bd_buddy_page;
220  	void *bd_buddy;
221  	struct page *bd_bitmap_page;
222  	void *bd_bitmap;
223  	struct ext4_group_info *bd_info;
224  	struct super_block *bd_sb;
225  	__u16 bd_blkbits;
226  	ext4_group_t bd_group;
227  };
228  
ext4_grp_offs_to_block(struct super_block * sb,struct ext4_free_extent * fex)229  static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
230  					struct ext4_free_extent *fex)
231  {
232  	return ext4_group_first_block_no(sb, fex->fe_group) +
233  		(fex->fe_start << EXT4_SB(sb)->s_cluster_bits);
234  }
235  
extent_logical_end(struct ext4_sb_info * sbi,struct ext4_free_extent * fex)236  static inline loff_t extent_logical_end(struct ext4_sb_info *sbi,
237  					struct ext4_free_extent *fex)
238  {
239  	/* Use loff_t to avoid end exceeding ext4_lblk_t max. */
240  	return (loff_t)fex->fe_logical + EXT4_C2B(sbi, fex->fe_len);
241  }
242  
pa_logical_end(struct ext4_sb_info * sbi,struct ext4_prealloc_space * pa)243  static inline loff_t pa_logical_end(struct ext4_sb_info *sbi,
244  				    struct ext4_prealloc_space *pa)
245  {
246  	/* Use loff_t to avoid end exceeding ext4_lblk_t max. */
247  	return (loff_t)pa->pa_lstart + EXT4_C2B(sbi, pa->pa_len);
248  }
249  
250  typedef int (*ext4_mballoc_query_range_fn)(
251  	struct super_block		*sb,
252  	ext4_group_t			agno,
253  	ext4_grpblk_t			start,
254  	ext4_grpblk_t			len,
255  	void				*priv);
256  
257  int
258  ext4_mballoc_query_range(
259  	struct super_block		*sb,
260  	ext4_group_t			agno,
261  	ext4_grpblk_t			start,
262  	ext4_grpblk_t			end,
263  	ext4_mballoc_query_range_fn	meta_formatter,
264  	ext4_mballoc_query_range_fn	formatter,
265  	void				*priv);
266  
267  #endif
268