mballoc.h

  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
100struct 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
118struct 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
143enum {
144	MB_INODE_PA = 0,
145	MB_GROUP_PA = 1
146};
147
148struct 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
164struct 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
173struct 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 CR_BEST_AVAIL_LEN, so save the original len.
191	 * This is used while adjusting the PA window and for accounting.
192	 */
193	ext4_grpblk_t	ac_orig_goal_len;
194
195	ext4_group_t ac_prefetch_grp;
196	unsigned int ac_prefetch_ios;
197	unsigned int ac_prefetch_nr;
198
199	int ac_first_err;
200
201	__u32 ac_flags;		/* allocation hints */
202	__u16 ac_groups_scanned;
203	__u16 ac_found;
204	__u16 ac_cX_found[EXT4_MB_NUM_CRS];
205	__u16 ac_tail;
206	__u16 ac_buddy;
207	__u8 ac_status;
208	__u8 ac_criteria;
209	__u8 ac_2order;		/* if request is to allocate 2^N blocks and
210				 * N > 0, the field stores N, otherwise 0 */
211	__u8 ac_op;		/* operation, for history only */
212
213	struct ext4_buddy *ac_e4b;
214	struct folio *ac_bitmap_folio;
215	struct folio *ac_buddy_folio;
216	struct ext4_prealloc_space *ac_pa;
217	struct ext4_locality_group *ac_lg;
218};
219
220#define AC_STATUS_CONTINUE	1
221#define AC_STATUS_FOUND		2
222#define AC_STATUS_BREAK		3
223
224struct ext4_buddy {
225	struct folio *bd_buddy_folio;
226	void *bd_buddy;
227	struct folio *bd_bitmap_folio;
228	void *bd_bitmap;
229	struct ext4_group_info *bd_info;
230	struct super_block *bd_sb;
231	__u16 bd_blkbits;
232	ext4_group_t bd_group;
233};
234
235static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
236					struct ext4_free_extent *fex)
237{
238	return ext4_group_first_block_no(sb, fex->fe_group) +
239		(fex->fe_start << EXT4_SB(sb)->s_cluster_bits);
240}
241
242static inline loff_t extent_logical_end(struct ext4_sb_info *sbi,
243					struct ext4_free_extent *fex)
244{
245	/* Use loff_t to avoid end exceeding ext4_lblk_t max. */
246	return (loff_t)fex->fe_logical + EXT4_C2B(sbi, fex->fe_len);
247}
248
249static inline loff_t pa_logical_end(struct ext4_sb_info *sbi,
250				    struct ext4_prealloc_space *pa)
251{
252	/* Use loff_t to avoid end exceeding ext4_lblk_t max. */
253	return (loff_t)pa->pa_lstart + EXT4_C2B(sbi, pa->pa_len);
254}
255
256typedef int (*ext4_mballoc_query_range_fn)(
257	struct super_block		*sb,
258	ext4_group_t			agno,
259	ext4_grpblk_t			start,
260	ext4_grpblk_t			len,
261	void				*priv);
262
263int
264ext4_mballoc_query_range(
265	struct super_block		*sb,
266	ext4_group_t			agno,
267	ext4_grpblk_t			start,
268	ext4_grpblk_t			end,
269	ext4_mballoc_query_range_fn	meta_formatter,
270	ext4_mballoc_query_range_fn	formatter,
271	void				*priv);
272
273extern int ext4_mb_mark_context(handle_t *handle,
274		struct super_block *sb, bool state,
275		ext4_group_t group, ext4_grpblk_t blkoff,
276		ext4_grpblk_t len, int flags,
277		ext4_grpblk_t *ret_changed);
278#if IS_ENABLED(CONFIG_EXT4_KUNIT_TESTS)
279extern void mb_clear_bits_test(void *bm, int cur, int len);
280extern ext4_fsblk_t
281ext4_mb_new_blocks_simple_test(struct ext4_allocation_request *ar,
282			       int *errp);
283extern int mb_find_next_zero_bit_test(void *addr, int max, int start);
284extern int mb_find_next_bit_test(void *addr, int max, int start);
285extern void mb_clear_bit_test(int bit, void *addr);
286extern int mb_test_bit_test(int bit, void *addr);
287extern int
288ext4_mb_mark_diskspace_used_test(struct ext4_allocation_context *ac,
289				 handle_t *handle);
290extern int mb_mark_used_test(struct ext4_buddy *e4b,
291			     struct ext4_free_extent *ex);
292extern void ext4_mb_generate_buddy_test(struct super_block *sb,
293		void *buddy, void *bitmap, ext4_group_t group,
294		struct ext4_group_info *grp);
295extern int ext4_mb_load_buddy_test(struct super_block *sb,
296		ext4_group_t group, struct ext4_buddy *e4b);
297extern void ext4_mb_unload_buddy_test(struct ext4_buddy *e4b);
298extern void mb_free_blocks_test(struct inode *inode,
299		struct ext4_buddy *e4b, int first, int count);
300extern void ext4_free_blocks_simple_test(struct inode *inode,
301		ext4_fsblk_t block, unsigned long count);
302#endif
303#endif