4 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
5 * http://www.samsung.com/
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
12 #include <linux/module.h>
13 #include <linux/backing-dev.h>
14 #include <linux/proc_fs.h>
15 #include <linux/init.h>
16 #include <linux/f2fs_fs.h>
17 #include <linux/kthread.h>
18 #include <linux/delay.h>
19 #include <linux/freezer.h>
20 #include <linux/blkdev.h>
27 static struct kmem_cache
*winode_slab
;
29 static int gc_thread_func(void *data
)
31 struct f2fs_sb_info
*sbi
= data
;
32 wait_queue_head_t
*wq
= &sbi
->gc_thread
->gc_wait_queue_head
;
35 wait_ms
= GC_THREAD_MIN_SLEEP_TIME
;
41 wait_event_interruptible_timeout(*wq
,
42 kthread_should_stop(),
43 msecs_to_jiffies(wait_ms
));
44 if (kthread_should_stop())
47 if (sbi
->sb
->s_writers
.frozen
>= SB_FREEZE_WRITE
) {
48 wait_ms
= GC_THREAD_MAX_SLEEP_TIME
;
53 * [GC triggering condition]
54 * 0. GC is not conducted currently.
55 * 1. There are enough dirty segments.
56 * 2. IO subsystem is idle by checking the # of writeback pages.
57 * 3. IO subsystem is idle by checking the # of requests in
58 * bdev's request list.
60 * Note) We have to avoid triggering GCs too much frequently.
61 * Because it is possible that some segments can be
62 * invalidated soon after by user update or deletion.
63 * So, I'd like to wait some time to collect dirty segments.
65 if (!mutex_trylock(&sbi
->gc_mutex
))
69 wait_ms
= increase_sleep_time(wait_ms
);
70 mutex_unlock(&sbi
->gc_mutex
);
74 if (has_enough_invalid_blocks(sbi
))
75 wait_ms
= decrease_sleep_time(wait_ms
);
77 wait_ms
= increase_sleep_time(wait_ms
);
81 /* if return value is not zero, no victim was selected */
83 wait_ms
= GC_THREAD_NOGC_SLEEP_TIME
;
84 else if (wait_ms
== GC_THREAD_NOGC_SLEEP_TIME
)
85 wait_ms
= GC_THREAD_MAX_SLEEP_TIME
;
87 } while (!kthread_should_stop());
91 int start_gc_thread(struct f2fs_sb_info
*sbi
)
93 struct f2fs_gc_kthread
*gc_th
;
94 dev_t dev
= sbi
->sb
->s_bdev
->bd_dev
;
96 if (!test_opt(sbi
, BG_GC
))
98 gc_th
= kmalloc(sizeof(struct f2fs_gc_kthread
), GFP_KERNEL
);
102 sbi
->gc_thread
= gc_th
;
103 init_waitqueue_head(&sbi
->gc_thread
->gc_wait_queue_head
);
104 sbi
->gc_thread
->f2fs_gc_task
= kthread_run(gc_thread_func
, sbi
,
105 "f2fs_gc-%u:%u", MAJOR(dev
), MINOR(dev
));
106 if (IS_ERR(gc_th
->f2fs_gc_task
)) {
108 sbi
->gc_thread
= NULL
;
114 void stop_gc_thread(struct f2fs_sb_info
*sbi
)
116 struct f2fs_gc_kthread
*gc_th
= sbi
->gc_thread
;
119 kthread_stop(gc_th
->f2fs_gc_task
);
121 sbi
->gc_thread
= NULL
;
124 static int select_gc_type(int gc_type
)
126 return (gc_type
== BG_GC
) ? GC_CB
: GC_GREEDY
;
129 static void select_policy(struct f2fs_sb_info
*sbi
, int gc_type
,
130 int type
, struct victim_sel_policy
*p
)
132 struct dirty_seglist_info
*dirty_i
= DIRTY_I(sbi
);
135 p
->gc_mode
= GC_GREEDY
;
136 p
->dirty_segmap
= dirty_i
->dirty_segmap
[type
];
139 p
->gc_mode
= select_gc_type(gc_type
);
140 p
->dirty_segmap
= dirty_i
->dirty_segmap
[DIRTY
];
141 p
->ofs_unit
= sbi
->segs_per_sec
;
143 p
->offset
= sbi
->last_victim
[p
->gc_mode
];
146 static unsigned int get_max_cost(struct f2fs_sb_info
*sbi
,
147 struct victim_sel_policy
*p
)
149 /* SSR allocates in a segment unit */
150 if (p
->alloc_mode
== SSR
)
151 return 1 << sbi
->log_blocks_per_seg
;
152 if (p
->gc_mode
== GC_GREEDY
)
153 return (1 << sbi
->log_blocks_per_seg
) * p
->ofs_unit
;
154 else if (p
->gc_mode
== GC_CB
)
156 else /* No other gc_mode */
160 static unsigned int check_bg_victims(struct f2fs_sb_info
*sbi
)
162 struct dirty_seglist_info
*dirty_i
= DIRTY_I(sbi
);
166 * If the gc_type is FG_GC, we can select victim segments
167 * selected by background GC before.
168 * Those segments guarantee they have small valid blocks.
170 segno
= find_next_bit(dirty_i
->victim_segmap
[BG_GC
],
172 if (segno
< TOTAL_SEGS(sbi
)) {
173 clear_bit(segno
, dirty_i
->victim_segmap
[BG_GC
]);
179 static unsigned int get_cb_cost(struct f2fs_sb_info
*sbi
, unsigned int segno
)
181 struct sit_info
*sit_i
= SIT_I(sbi
);
182 unsigned int secno
= GET_SECNO(sbi
, segno
);
183 unsigned int start
= secno
* sbi
->segs_per_sec
;
184 unsigned long long mtime
= 0;
185 unsigned int vblocks
;
186 unsigned char age
= 0;
190 for (i
= 0; i
< sbi
->segs_per_sec
; i
++)
191 mtime
+= get_seg_entry(sbi
, start
+ i
)->mtime
;
192 vblocks
= get_valid_blocks(sbi
, segno
, sbi
->segs_per_sec
);
194 mtime
= div_u64(mtime
, sbi
->segs_per_sec
);
195 vblocks
= div_u64(vblocks
, sbi
->segs_per_sec
);
197 u
= (vblocks
* 100) >> sbi
->log_blocks_per_seg
;
199 /* Handle if the system time is changed by user */
200 if (mtime
< sit_i
->min_mtime
)
201 sit_i
->min_mtime
= mtime
;
202 if (mtime
> sit_i
->max_mtime
)
203 sit_i
->max_mtime
= mtime
;
204 if (sit_i
->max_mtime
!= sit_i
->min_mtime
)
205 age
= 100 - div64_u64(100 * (mtime
- sit_i
->min_mtime
),
206 sit_i
->max_mtime
- sit_i
->min_mtime
);
208 return UINT_MAX
- ((100 * (100 - u
) * age
) / (100 + u
));
211 static unsigned int get_gc_cost(struct f2fs_sb_info
*sbi
, unsigned int segno
,
212 struct victim_sel_policy
*p
)
214 if (p
->alloc_mode
== SSR
)
215 return get_seg_entry(sbi
, segno
)->ckpt_valid_blocks
;
217 /* alloc_mode == LFS */
218 if (p
->gc_mode
== GC_GREEDY
)
219 return get_valid_blocks(sbi
, segno
, sbi
->segs_per_sec
);
221 return get_cb_cost(sbi
, segno
);
225 * This function is called from two pathes.
226 * One is garbage collection and the other is SSR segment selection.
227 * When it is called during GC, it just gets a victim segment
228 * and it does not remove it from dirty seglist.
229 * When it is called from SSR segment selection, it finds a segment
230 * which has minimum valid blocks and removes it from dirty seglist.
232 static int get_victim_by_default(struct f2fs_sb_info
*sbi
,
233 unsigned int *result
, int gc_type
, int type
, char alloc_mode
)
235 struct dirty_seglist_info
*dirty_i
= DIRTY_I(sbi
);
236 struct victim_sel_policy p
;
240 p
.alloc_mode
= alloc_mode
;
241 select_policy(sbi
, gc_type
, type
, &p
);
243 p
.min_segno
= NULL_SEGNO
;
244 p
.min_cost
= get_max_cost(sbi
, &p
);
246 mutex_lock(&dirty_i
->seglist_lock
);
248 if (p
.alloc_mode
== LFS
&& gc_type
== FG_GC
) {
249 p
.min_segno
= check_bg_victims(sbi
);
250 if (p
.min_segno
!= NULL_SEGNO
)
257 segno
= find_next_bit(p
.dirty_segmap
,
258 TOTAL_SEGS(sbi
), p
.offset
);
259 if (segno
>= TOTAL_SEGS(sbi
)) {
260 if (sbi
->last_victim
[p
.gc_mode
]) {
261 sbi
->last_victim
[p
.gc_mode
] = 0;
267 p
.offset
= ((segno
/ p
.ofs_unit
) * p
.ofs_unit
) + p
.ofs_unit
;
269 if (test_bit(segno
, dirty_i
->victim_segmap
[FG_GC
]))
271 if (gc_type
== BG_GC
&&
272 test_bit(segno
, dirty_i
->victim_segmap
[BG_GC
]))
274 if (IS_CURSEC(sbi
, GET_SECNO(sbi
, segno
)))
277 cost
= get_gc_cost(sbi
, segno
, &p
);
279 if (p
.min_cost
> cost
) {
284 if (cost
== get_max_cost(sbi
, &p
))
287 if (nsearched
++ >= MAX_VICTIM_SEARCH
) {
288 sbi
->last_victim
[p
.gc_mode
] = segno
;
293 if (p
.min_segno
!= NULL_SEGNO
) {
294 *result
= (p
.min_segno
/ p
.ofs_unit
) * p
.ofs_unit
;
295 if (p
.alloc_mode
== LFS
) {
297 for (i
= 0; i
< p
.ofs_unit
; i
++)
299 dirty_i
->victim_segmap
[gc_type
]);
302 mutex_unlock(&dirty_i
->seglist_lock
);
304 return (p
.min_segno
== NULL_SEGNO
) ? 0 : 1;
307 static const struct victim_selection default_v_ops
= {
308 .get_victim
= get_victim_by_default
,
311 static struct inode
*find_gc_inode(nid_t ino
, struct list_head
*ilist
)
313 struct list_head
*this;
314 struct inode_entry
*ie
;
316 list_for_each(this, ilist
) {
317 ie
= list_entry(this, struct inode_entry
, list
);
318 if (ie
->inode
->i_ino
== ino
)
324 static void add_gc_inode(struct inode
*inode
, struct list_head
*ilist
)
326 struct list_head
*this;
327 struct inode_entry
*new_ie
, *ie
;
329 list_for_each(this, ilist
) {
330 ie
= list_entry(this, struct inode_entry
, list
);
331 if (ie
->inode
== inode
) {
337 new_ie
= kmem_cache_alloc(winode_slab
, GFP_NOFS
);
342 new_ie
->inode
= inode
;
343 list_add_tail(&new_ie
->list
, ilist
);
346 static void put_gc_inode(struct list_head
*ilist
)
348 struct inode_entry
*ie
, *next_ie
;
349 list_for_each_entry_safe(ie
, next_ie
, ilist
, list
) {
352 kmem_cache_free(winode_slab
, ie
);
356 static int check_valid_map(struct f2fs_sb_info
*sbi
,
357 unsigned int segno
, int offset
)
359 struct sit_info
*sit_i
= SIT_I(sbi
);
360 struct seg_entry
*sentry
;
363 mutex_lock(&sit_i
->sentry_lock
);
364 sentry
= get_seg_entry(sbi
, segno
);
365 ret
= f2fs_test_bit(offset
, sentry
->cur_valid_map
);
366 mutex_unlock(&sit_i
->sentry_lock
);
371 * This function compares node address got in summary with that in NAT.
372 * On validity, copy that node with cold status, otherwise (invalid node)
375 static void gc_node_segment(struct f2fs_sb_info
*sbi
,
376 struct f2fs_summary
*sum
, unsigned int segno
, int gc_type
)
379 struct f2fs_summary
*entry
;
384 for (off
= 0; off
< sbi
->blocks_per_seg
; off
++, entry
++) {
385 nid_t nid
= le32_to_cpu(entry
->nid
);
386 struct page
*node_page
;
388 /* stop BG_GC if there is not enough free sections. */
389 if (gc_type
== BG_GC
&& has_not_enough_free_secs(sbi
, 0))
392 if (check_valid_map(sbi
, segno
, off
) == 0)
396 ra_node_page(sbi
, nid
);
399 node_page
= get_node_page(sbi
, nid
);
400 if (IS_ERR(node_page
))
403 /* set page dirty and write it */
404 if (!PageWriteback(node_page
))
405 set_page_dirty(node_page
);
406 f2fs_put_page(node_page
, 1);
407 stat_inc_node_blk_count(sbi
, 1);
414 if (gc_type
== FG_GC
) {
415 struct writeback_control wbc
= {
416 .sync_mode
= WB_SYNC_ALL
,
417 .nr_to_write
= LONG_MAX
,
420 sync_node_pages(sbi
, 0, &wbc
);
425 * Calculate start block index indicating the given node offset.
426 * Be careful, caller should give this node offset only indicating direct node
427 * blocks. If any node offsets, which point the other types of node blocks such
428 * as indirect or double indirect node blocks, are given, it must be a caller's
431 block_t
start_bidx_of_node(unsigned int node_ofs
)
433 unsigned int indirect_blks
= 2 * NIDS_PER_BLOCK
+ 4;
441 } else if (node_ofs
<= indirect_blks
) {
442 int dec
= (node_ofs
- 4) / (NIDS_PER_BLOCK
+ 1);
443 bidx
= node_ofs
- 2 - dec
;
445 int dec
= (node_ofs
- indirect_blks
- 3) / (NIDS_PER_BLOCK
+ 1);
446 bidx
= node_ofs
- 5 - dec
;
448 return bidx
* ADDRS_PER_BLOCK
+ ADDRS_PER_INODE
;
451 static int check_dnode(struct f2fs_sb_info
*sbi
, struct f2fs_summary
*sum
,
452 struct node_info
*dni
, block_t blkaddr
, unsigned int *nofs
)
454 struct page
*node_page
;
456 unsigned int ofs_in_node
;
457 block_t source_blkaddr
;
459 nid
= le32_to_cpu(sum
->nid
);
460 ofs_in_node
= le16_to_cpu(sum
->ofs_in_node
);
462 node_page
= get_node_page(sbi
, nid
);
463 if (IS_ERR(node_page
))
466 get_node_info(sbi
, nid
, dni
);
468 if (sum
->version
!= dni
->version
) {
469 f2fs_put_page(node_page
, 1);
473 *nofs
= ofs_of_node(node_page
);
474 source_blkaddr
= datablock_addr(node_page
, ofs_in_node
);
475 f2fs_put_page(node_page
, 1);
477 if (source_blkaddr
!= blkaddr
)
482 static void move_data_page(struct inode
*inode
, struct page
*page
, int gc_type
)
484 if (page
->mapping
!= inode
->i_mapping
)
487 if (inode
!= page
->mapping
->host
)
490 if (PageWriteback(page
))
493 if (gc_type
== BG_GC
) {
494 set_page_dirty(page
);
497 struct f2fs_sb_info
*sbi
= F2FS_SB(inode
->i_sb
);
498 mutex_lock_op(sbi
, DATA_WRITE
);
499 if (clear_page_dirty_for_io(page
) &&
500 S_ISDIR(inode
->i_mode
)) {
501 dec_page_count(sbi
, F2FS_DIRTY_DENTS
);
502 inode_dec_dirty_dents(inode
);
505 do_write_data_page(page
);
506 mutex_unlock_op(sbi
, DATA_WRITE
);
507 clear_cold_data(page
);
510 f2fs_put_page(page
, 1);
514 * This function tries to get parent node of victim data block, and identifies
515 * data block validity. If the block is valid, copy that with cold status and
516 * modify parent node.
517 * If the parent node is not valid or the data block address is different,
518 * the victim data block is ignored.
520 static void gc_data_segment(struct f2fs_sb_info
*sbi
, struct f2fs_summary
*sum
,
521 struct list_head
*ilist
, unsigned int segno
, int gc_type
)
523 struct super_block
*sb
= sbi
->sb
;
524 struct f2fs_summary
*entry
;
529 start_addr
= START_BLOCK(sbi
, segno
);
533 for (off
= 0; off
< sbi
->blocks_per_seg
; off
++, entry
++) {
534 struct page
*data_page
;
536 struct node_info dni
; /* dnode info for the data */
537 unsigned int ofs_in_node
, nofs
;
540 /* stop BG_GC if there is not enough free sections. */
541 if (gc_type
== BG_GC
&& has_not_enough_free_secs(sbi
, 0))
544 if (check_valid_map(sbi
, segno
, off
) == 0)
548 ra_node_page(sbi
, le32_to_cpu(entry
->nid
));
552 /* Get an inode by ino with checking validity */
553 if (check_dnode(sbi
, entry
, &dni
, start_addr
+ off
, &nofs
) == 0)
557 ra_node_page(sbi
, dni
.ino
);
561 start_bidx
= start_bidx_of_node(nofs
);
562 ofs_in_node
= le16_to_cpu(entry
->ofs_in_node
);
565 inode
= f2fs_iget(sb
, dni
.ino
);
569 data_page
= find_data_page(inode
,
570 start_bidx
+ ofs_in_node
);
571 if (IS_ERR(data_page
))
574 f2fs_put_page(data_page
, 0);
575 add_gc_inode(inode
, ilist
);
577 inode
= find_gc_inode(dni
.ino
, ilist
);
579 data_page
= get_lock_data_page(inode
,
580 start_bidx
+ ofs_in_node
);
581 if (IS_ERR(data_page
))
583 move_data_page(inode
, data_page
, gc_type
);
584 stat_inc_data_blk_count(sbi
, 1);
594 if (gc_type
== FG_GC
)
595 f2fs_submit_bio(sbi
, DATA
, true);
598 static int __get_victim(struct f2fs_sb_info
*sbi
, unsigned int *victim
,
599 int gc_type
, int type
)
601 struct sit_info
*sit_i
= SIT_I(sbi
);
603 mutex_lock(&sit_i
->sentry_lock
);
604 ret
= DIRTY_I(sbi
)->v_ops
->get_victim(sbi
, victim
, gc_type
, type
, LFS
);
605 mutex_unlock(&sit_i
->sentry_lock
);
609 static void do_garbage_collect(struct f2fs_sb_info
*sbi
, unsigned int segno
,
610 struct list_head
*ilist
, int gc_type
)
612 struct page
*sum_page
;
613 struct f2fs_summary_block
*sum
;
615 /* read segment summary of victim */
616 sum_page
= get_sum_page(sbi
, segno
);
617 if (IS_ERR(sum_page
))
621 * CP needs to lock sum_page. In this time, we don't need
622 * to lock this page, because this summary page is not gone anywhere.
623 * Also, this page is not gonna be updated before GC is done.
625 unlock_page(sum_page
);
626 sum
= page_address(sum_page
);
628 switch (GET_SUM_TYPE((&sum
->footer
))) {
630 gc_node_segment(sbi
, sum
->entries
, segno
, gc_type
);
633 gc_data_segment(sbi
, sum
->entries
, ilist
, segno
, gc_type
);
636 stat_inc_seg_count(sbi
, GET_SUM_TYPE((&sum
->footer
)));
637 stat_inc_call_count(sbi
->stat_info
);
639 f2fs_put_page(sum_page
, 0);
642 int f2fs_gc(struct f2fs_sb_info
*sbi
)
644 struct list_head ilist
;
645 unsigned int segno
, i
;
650 INIT_LIST_HEAD(&ilist
);
652 if (!(sbi
->sb
->s_flags
& MS_ACTIVE
))
655 if (gc_type
== BG_GC
&& has_not_enough_free_secs(sbi
, nfree
))
658 if (!__get_victim(sbi
, &segno
, gc_type
, NO_CHECK_TYPE
))
662 for (i
= 0; i
< sbi
->segs_per_sec
; i
++)
663 do_garbage_collect(sbi
, segno
+ i
, &ilist
, gc_type
);
665 if (gc_type
== FG_GC
&&
666 get_valid_blocks(sbi
, segno
, sbi
->segs_per_sec
) == 0)
669 if (has_not_enough_free_secs(sbi
, nfree
))
672 if (gc_type
== FG_GC
)
673 write_checkpoint(sbi
, false);
675 mutex_unlock(&sbi
->gc_mutex
);
677 put_gc_inode(&ilist
);
681 void build_gc_manager(struct f2fs_sb_info
*sbi
)
683 DIRTY_I(sbi
)->v_ops
= &default_v_ops
;
686 int __init
create_gc_caches(void)
688 winode_slab
= f2fs_kmem_cache_create("f2fs_gc_inodes",
689 sizeof(struct inode_entry
), NULL
);
695 void destroy_gc_caches(void)
697 kmem_cache_destroy(winode_slab
);