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/init.h>
15 #include <linux/f2fs_fs.h>
16 #include <linux/kthread.h>
17 #include <linux/delay.h>
18 #include <linux/freezer.h>
19 #include <linux/blkdev.h>
25 #include <trace/events/f2fs.h>
27 static struct kmem_cache
*winode_slab
;
29 static int gc_thread_func(void *data
)
31 struct f2fs_sb_info
*sbi
= data
;
32 struct f2fs_gc_kthread
*gc_th
= sbi
->gc_thread
;
33 wait_queue_head_t
*wq
= &sbi
->gc_thread
->gc_wait_queue_head
;
36 wait_ms
= gc_th
->min_sleep_time
;
42 wait_event_interruptible_timeout(*wq
,
43 kthread_should_stop(),
44 msecs_to_jiffies(wait_ms
));
45 if (kthread_should_stop())
48 if (sbi
->sb
->s_writers
.frozen
>= SB_FREEZE_WRITE
) {
49 wait_ms
= increase_sleep_time(gc_th
, wait_ms
);
54 * [GC triggering condition]
55 * 0. GC is not conducted currently.
56 * 1. There are enough dirty segments.
57 * 2. IO subsystem is idle by checking the # of writeback pages.
58 * 3. IO subsystem is idle by checking the # of requests in
59 * bdev's request list.
61 * Note) We have to avoid triggering GCs frequently.
62 * Because it is possible that some segments can be
63 * invalidated soon after by user update or deletion.
64 * So, I'd like to wait some time to collect dirty segments.
66 if (!mutex_trylock(&sbi
->gc_mutex
))
70 wait_ms
= increase_sleep_time(gc_th
, wait_ms
);
71 mutex_unlock(&sbi
->gc_mutex
);
75 if (has_enough_invalid_blocks(sbi
))
76 wait_ms
= decrease_sleep_time(gc_th
, wait_ms
);
78 wait_ms
= increase_sleep_time(gc_th
, wait_ms
);
80 stat_inc_bggc_count(sbi
);
82 /* if return value is not zero, no victim was selected */
84 wait_ms
= gc_th
->no_gc_sleep_time
;
86 /* balancing f2fs's metadata periodically */
87 f2fs_balance_fs_bg(sbi
);
89 } while (!kthread_should_stop());
93 int start_gc_thread(struct f2fs_sb_info
*sbi
)
95 struct f2fs_gc_kthread
*gc_th
;
96 dev_t dev
= sbi
->sb
->s_bdev
->bd_dev
;
99 if (!test_opt(sbi
, BG_GC
))
101 gc_th
= kmalloc(sizeof(struct f2fs_gc_kthread
), GFP_KERNEL
);
107 gc_th
->min_sleep_time
= DEF_GC_THREAD_MIN_SLEEP_TIME
;
108 gc_th
->max_sleep_time
= DEF_GC_THREAD_MAX_SLEEP_TIME
;
109 gc_th
->no_gc_sleep_time
= DEF_GC_THREAD_NOGC_SLEEP_TIME
;
113 sbi
->gc_thread
= gc_th
;
114 init_waitqueue_head(&sbi
->gc_thread
->gc_wait_queue_head
);
115 sbi
->gc_thread
->f2fs_gc_task
= kthread_run(gc_thread_func
, sbi
,
116 "f2fs_gc-%u:%u", MAJOR(dev
), MINOR(dev
));
117 if (IS_ERR(gc_th
->f2fs_gc_task
)) {
118 err
= PTR_ERR(gc_th
->f2fs_gc_task
);
120 sbi
->gc_thread
= NULL
;
126 void stop_gc_thread(struct f2fs_sb_info
*sbi
)
128 struct f2fs_gc_kthread
*gc_th
= sbi
->gc_thread
;
131 kthread_stop(gc_th
->f2fs_gc_task
);
133 sbi
->gc_thread
= NULL
;
136 static int select_gc_type(struct f2fs_gc_kthread
*gc_th
, int gc_type
)
138 int gc_mode
= (gc_type
== BG_GC
) ? GC_CB
: GC_GREEDY
;
140 if (gc_th
&& gc_th
->gc_idle
) {
141 if (gc_th
->gc_idle
== 1)
143 else if (gc_th
->gc_idle
== 2)
149 static void select_policy(struct f2fs_sb_info
*sbi
, int gc_type
,
150 int type
, struct victim_sel_policy
*p
)
152 struct dirty_seglist_info
*dirty_i
= DIRTY_I(sbi
);
154 if (p
->alloc_mode
== SSR
) {
155 p
->gc_mode
= GC_GREEDY
;
156 p
->dirty_segmap
= dirty_i
->dirty_segmap
[type
];
157 p
->max_search
= dirty_i
->nr_dirty
[type
];
160 p
->gc_mode
= select_gc_type(sbi
->gc_thread
, gc_type
);
161 p
->dirty_segmap
= dirty_i
->dirty_segmap
[DIRTY
];
162 p
->max_search
= dirty_i
->nr_dirty
[DIRTY
];
163 p
->ofs_unit
= sbi
->segs_per_sec
;
166 if (p
->max_search
> sbi
->max_victim_search
)
167 p
->max_search
= sbi
->max_victim_search
;
169 p
->offset
= sbi
->last_victim
[p
->gc_mode
];
172 static unsigned int get_max_cost(struct f2fs_sb_info
*sbi
,
173 struct victim_sel_policy
*p
)
175 /* SSR allocates in a segment unit */
176 if (p
->alloc_mode
== SSR
)
177 return 1 << sbi
->log_blocks_per_seg
;
178 if (p
->gc_mode
== GC_GREEDY
)
179 return (1 << sbi
->log_blocks_per_seg
) * p
->ofs_unit
;
180 else if (p
->gc_mode
== GC_CB
)
182 else /* No other gc_mode */
186 static unsigned int check_bg_victims(struct f2fs_sb_info
*sbi
)
188 struct dirty_seglist_info
*dirty_i
= DIRTY_I(sbi
);
192 * If the gc_type is FG_GC, we can select victim segments
193 * selected by background GC before.
194 * Those segments guarantee they have small valid blocks.
196 for_each_set_bit(secno
, dirty_i
->victim_secmap
, MAIN_SECS(sbi
)) {
197 if (sec_usage_check(sbi
, secno
))
199 clear_bit(secno
, dirty_i
->victim_secmap
);
200 return secno
* sbi
->segs_per_sec
;
205 static unsigned int get_cb_cost(struct f2fs_sb_info
*sbi
, unsigned int segno
)
207 struct sit_info
*sit_i
= SIT_I(sbi
);
208 unsigned int secno
= GET_SECNO(sbi
, segno
);
209 unsigned int start
= secno
* sbi
->segs_per_sec
;
210 unsigned long long mtime
= 0;
211 unsigned int vblocks
;
212 unsigned char age
= 0;
216 for (i
= 0; i
< sbi
->segs_per_sec
; i
++)
217 mtime
+= get_seg_entry(sbi
, start
+ i
)->mtime
;
218 vblocks
= get_valid_blocks(sbi
, segno
, sbi
->segs_per_sec
);
220 mtime
= div_u64(mtime
, sbi
->segs_per_sec
);
221 vblocks
= div_u64(vblocks
, sbi
->segs_per_sec
);
223 u
= (vblocks
* 100) >> sbi
->log_blocks_per_seg
;
225 /* Handle if the system time has changed by the user */
226 if (mtime
< sit_i
->min_mtime
)
227 sit_i
->min_mtime
= mtime
;
228 if (mtime
> sit_i
->max_mtime
)
229 sit_i
->max_mtime
= mtime
;
230 if (sit_i
->max_mtime
!= sit_i
->min_mtime
)
231 age
= 100 - div64_u64(100 * (mtime
- sit_i
->min_mtime
),
232 sit_i
->max_mtime
- sit_i
->min_mtime
);
234 return UINT_MAX
- ((100 * (100 - u
) * age
) / (100 + u
));
237 static inline unsigned int get_gc_cost(struct f2fs_sb_info
*sbi
,
238 unsigned int segno
, struct victim_sel_policy
*p
)
240 if (p
->alloc_mode
== SSR
)
241 return get_seg_entry(sbi
, segno
)->ckpt_valid_blocks
;
243 /* alloc_mode == LFS */
244 if (p
->gc_mode
== GC_GREEDY
)
245 return get_valid_blocks(sbi
, segno
, sbi
->segs_per_sec
);
247 return get_cb_cost(sbi
, segno
);
251 * This function is called from two paths.
252 * One is garbage collection and the other is SSR segment selection.
253 * When it is called during GC, it just gets a victim segment
254 * and it does not remove it from dirty seglist.
255 * When it is called from SSR segment selection, it finds a segment
256 * which has minimum valid blocks and removes it from dirty seglist.
258 static int get_victim_by_default(struct f2fs_sb_info
*sbi
,
259 unsigned int *result
, int gc_type
, int type
, char alloc_mode
)
261 struct dirty_seglist_info
*dirty_i
= DIRTY_I(sbi
);
262 struct victim_sel_policy p
;
263 unsigned int secno
, max_cost
;
266 mutex_lock(&dirty_i
->seglist_lock
);
268 p
.alloc_mode
= alloc_mode
;
269 select_policy(sbi
, gc_type
, type
, &p
);
271 p
.min_segno
= NULL_SEGNO
;
272 p
.min_cost
= max_cost
= get_max_cost(sbi
, &p
);
274 if (p
.alloc_mode
== LFS
&& gc_type
== FG_GC
) {
275 p
.min_segno
= check_bg_victims(sbi
);
276 if (p
.min_segno
!= NULL_SEGNO
)
284 segno
= find_next_bit(p
.dirty_segmap
, MAIN_SEGS(sbi
), p
.offset
);
285 if (segno
>= MAIN_SEGS(sbi
)) {
286 if (sbi
->last_victim
[p
.gc_mode
]) {
287 sbi
->last_victim
[p
.gc_mode
] = 0;
294 p
.offset
= segno
+ p
.ofs_unit
;
296 p
.offset
-= segno
% p
.ofs_unit
;
298 secno
= GET_SECNO(sbi
, segno
);
300 if (sec_usage_check(sbi
, secno
))
302 if (gc_type
== BG_GC
&& test_bit(secno
, dirty_i
->victim_secmap
))
305 cost
= get_gc_cost(sbi
, segno
, &p
);
307 if (p
.min_cost
> cost
) {
310 } else if (unlikely(cost
== max_cost
)) {
314 if (nsearched
++ >= p
.max_search
) {
315 sbi
->last_victim
[p
.gc_mode
] = segno
;
319 if (p
.min_segno
!= NULL_SEGNO
) {
321 if (p
.alloc_mode
== LFS
) {
322 secno
= GET_SECNO(sbi
, p
.min_segno
);
323 if (gc_type
== FG_GC
)
324 sbi
->cur_victim_sec
= secno
;
326 set_bit(secno
, dirty_i
->victim_secmap
);
328 *result
= (p
.min_segno
/ p
.ofs_unit
) * p
.ofs_unit
;
330 trace_f2fs_get_victim(sbi
->sb
, type
, gc_type
, &p
,
332 prefree_segments(sbi
), free_segments(sbi
));
334 mutex_unlock(&dirty_i
->seglist_lock
);
336 return (p
.min_segno
== NULL_SEGNO
) ? 0 : 1;
339 static const struct victim_selection default_v_ops
= {
340 .get_victim
= get_victim_by_default
,
343 static struct inode
*find_gc_inode(nid_t ino
, struct list_head
*ilist
)
345 struct inode_entry
*ie
;
347 list_for_each_entry(ie
, ilist
, list
)
348 if (ie
->inode
->i_ino
== ino
)
353 static void add_gc_inode(struct inode
*inode
, struct list_head
*ilist
)
355 struct inode_entry
*new_ie
;
357 if (inode
== find_gc_inode(inode
->i_ino
, ilist
)) {
362 new_ie
= f2fs_kmem_cache_alloc(winode_slab
, GFP_NOFS
);
363 new_ie
->inode
= inode
;
364 list_add_tail(&new_ie
->list
, ilist
);
367 static void put_gc_inode(struct list_head
*ilist
)
369 struct inode_entry
*ie
, *next_ie
;
370 list_for_each_entry_safe(ie
, next_ie
, ilist
, list
) {
373 kmem_cache_free(winode_slab
, ie
);
377 static int check_valid_map(struct f2fs_sb_info
*sbi
,
378 unsigned int segno
, int offset
)
380 struct sit_info
*sit_i
= SIT_I(sbi
);
381 struct seg_entry
*sentry
;
384 mutex_lock(&sit_i
->sentry_lock
);
385 sentry
= get_seg_entry(sbi
, segno
);
386 ret
= f2fs_test_bit(offset
, sentry
->cur_valid_map
);
387 mutex_unlock(&sit_i
->sentry_lock
);
392 * This function compares node address got in summary with that in NAT.
393 * On validity, copy that node with cold status, otherwise (invalid node)
396 static void gc_node_segment(struct f2fs_sb_info
*sbi
,
397 struct f2fs_summary
*sum
, unsigned int segno
, int gc_type
)
400 struct f2fs_summary
*entry
;
406 for (off
= 0; off
< sbi
->blocks_per_seg
; off
++, entry
++) {
407 nid_t nid
= le32_to_cpu(entry
->nid
);
408 struct page
*node_page
;
410 /* stop BG_GC if there is not enough free sections. */
411 if (gc_type
== BG_GC
&& has_not_enough_free_secs(sbi
, 0))
414 if (check_valid_map(sbi
, segno
, off
) == 0)
418 ra_node_page(sbi
, nid
);
421 node_page
= get_node_page(sbi
, nid
);
422 if (IS_ERR(node_page
))
425 /* block may become invalid during get_node_page */
426 if (check_valid_map(sbi
, segno
, off
) == 0) {
427 f2fs_put_page(node_page
, 1);
431 /* set page dirty and write it */
432 if (gc_type
== FG_GC
) {
433 f2fs_wait_on_page_writeback(node_page
, NODE
);
434 set_page_dirty(node_page
);
436 if (!PageWriteback(node_page
))
437 set_page_dirty(node_page
);
439 f2fs_put_page(node_page
, 1);
440 stat_inc_node_blk_count(sbi
, 1);
448 if (gc_type
== FG_GC
) {
449 struct writeback_control wbc
= {
450 .sync_mode
= WB_SYNC_ALL
,
451 .nr_to_write
= LONG_MAX
,
454 sync_node_pages(sbi
, 0, &wbc
);
457 * In the case of FG_GC, it'd be better to reclaim this victim
460 if (get_valid_blocks(sbi
, segno
, 1) != 0)
466 * Calculate start block index indicating the given node offset.
467 * Be careful, caller should give this node offset only indicating direct node
468 * blocks. If any node offsets, which point the other types of node blocks such
469 * as indirect or double indirect node blocks, are given, it must be a caller's
472 block_t
start_bidx_of_node(unsigned int node_ofs
, struct f2fs_inode_info
*fi
)
474 unsigned int indirect_blks
= 2 * NIDS_PER_BLOCK
+ 4;
482 } else if (node_ofs
<= indirect_blks
) {
483 int dec
= (node_ofs
- 4) / (NIDS_PER_BLOCK
+ 1);
484 bidx
= node_ofs
- 2 - dec
;
486 int dec
= (node_ofs
- indirect_blks
- 3) / (NIDS_PER_BLOCK
+ 1);
487 bidx
= node_ofs
- 5 - dec
;
489 return bidx
* ADDRS_PER_BLOCK
+ ADDRS_PER_INODE(fi
);
492 static int check_dnode(struct f2fs_sb_info
*sbi
, struct f2fs_summary
*sum
,
493 struct node_info
*dni
, block_t blkaddr
, unsigned int *nofs
)
495 struct page
*node_page
;
497 unsigned int ofs_in_node
;
498 block_t source_blkaddr
;
500 nid
= le32_to_cpu(sum
->nid
);
501 ofs_in_node
= le16_to_cpu(sum
->ofs_in_node
);
503 node_page
= get_node_page(sbi
, nid
);
504 if (IS_ERR(node_page
))
507 get_node_info(sbi
, nid
, dni
);
509 if (sum
->version
!= dni
->version
) {
510 f2fs_put_page(node_page
, 1);
514 *nofs
= ofs_of_node(node_page
);
515 source_blkaddr
= datablock_addr(node_page
, ofs_in_node
);
516 f2fs_put_page(node_page
, 1);
518 if (source_blkaddr
!= blkaddr
)
523 static void move_data_page(struct inode
*inode
, struct page
*page
, int gc_type
)
525 struct f2fs_io_info fio
= {
530 if (gc_type
== BG_GC
) {
531 if (PageWriteback(page
))
533 set_page_dirty(page
);
536 f2fs_wait_on_page_writeback(page
, DATA
);
538 if (clear_page_dirty_for_io(page
))
539 inode_dec_dirty_pages(inode
);
541 do_write_data_page(page
, &fio
);
542 clear_cold_data(page
);
545 f2fs_put_page(page
, 1);
549 * This function tries to get parent node of victim data block, and identifies
550 * data block validity. If the block is valid, copy that with cold status and
551 * modify parent node.
552 * If the parent node is not valid or the data block address is different,
553 * the victim data block is ignored.
555 static void gc_data_segment(struct f2fs_sb_info
*sbi
, struct f2fs_summary
*sum
,
556 struct list_head
*ilist
, unsigned int segno
, int gc_type
)
558 struct super_block
*sb
= sbi
->sb
;
559 struct f2fs_summary
*entry
;
564 start_addr
= START_BLOCK(sbi
, segno
);
569 for (off
= 0; off
< sbi
->blocks_per_seg
; off
++, entry
++) {
570 struct page
*data_page
;
572 struct node_info dni
; /* dnode info for the data */
573 unsigned int ofs_in_node
, nofs
;
576 /* stop BG_GC if there is not enough free sections. */
577 if (gc_type
== BG_GC
&& has_not_enough_free_secs(sbi
, 0))
580 if (check_valid_map(sbi
, segno
, off
) == 0)
584 ra_node_page(sbi
, le32_to_cpu(entry
->nid
));
588 /* Get an inode by ino with checking validity */
589 if (check_dnode(sbi
, entry
, &dni
, start_addr
+ off
, &nofs
) == 0)
593 ra_node_page(sbi
, dni
.ino
);
597 ofs_in_node
= le16_to_cpu(entry
->ofs_in_node
);
600 inode
= f2fs_iget(sb
, dni
.ino
);
601 if (IS_ERR(inode
) || is_bad_inode(inode
))
604 start_bidx
= start_bidx_of_node(nofs
, F2FS_I(inode
));
606 data_page
= find_data_page(inode
,
607 start_bidx
+ ofs_in_node
, false);
608 if (IS_ERR(data_page
))
611 f2fs_put_page(data_page
, 0);
612 add_gc_inode(inode
, ilist
);
614 inode
= find_gc_inode(dni
.ino
, ilist
);
616 start_bidx
= start_bidx_of_node(nofs
,
618 data_page
= get_lock_data_page(inode
,
619 start_bidx
+ ofs_in_node
);
620 if (IS_ERR(data_page
))
622 move_data_page(inode
, data_page
, gc_type
);
623 stat_inc_data_blk_count(sbi
, 1);
634 if (gc_type
== FG_GC
) {
635 f2fs_submit_merged_bio(sbi
, DATA
, WRITE
);
638 * In the case of FG_GC, it'd be better to reclaim this victim
641 if (get_valid_blocks(sbi
, segno
, 1) != 0) {
648 static int __get_victim(struct f2fs_sb_info
*sbi
, unsigned int *victim
,
649 int gc_type
, int type
)
651 struct sit_info
*sit_i
= SIT_I(sbi
);
653 mutex_lock(&sit_i
->sentry_lock
);
654 ret
= DIRTY_I(sbi
)->v_ops
->get_victim(sbi
, victim
, gc_type
, type
, LFS
);
655 mutex_unlock(&sit_i
->sentry_lock
);
659 static void do_garbage_collect(struct f2fs_sb_info
*sbi
, unsigned int segno
,
660 struct list_head
*ilist
, int gc_type
)
662 struct page
*sum_page
;
663 struct f2fs_summary_block
*sum
;
664 struct blk_plug plug
;
666 /* read segment summary of victim */
667 sum_page
= get_sum_page(sbi
, segno
);
669 blk_start_plug(&plug
);
671 sum
= page_address(sum_page
);
673 switch (GET_SUM_TYPE((&sum
->footer
))) {
675 gc_node_segment(sbi
, sum
->entries
, segno
, gc_type
);
678 gc_data_segment(sbi
, sum
->entries
, ilist
, segno
, gc_type
);
681 blk_finish_plug(&plug
);
683 stat_inc_seg_count(sbi
, GET_SUM_TYPE((&sum
->footer
)));
684 stat_inc_call_count(sbi
->stat_info
);
686 f2fs_put_page(sum_page
, 1);
689 int f2fs_gc(struct f2fs_sb_info
*sbi
)
691 struct list_head ilist
;
692 unsigned int segno
, i
;
696 struct cp_control cpc
= {
700 INIT_LIST_HEAD(&ilist
);
702 if (unlikely(!(sbi
->sb
->s_flags
& MS_ACTIVE
)))
704 if (unlikely(f2fs_cp_error(sbi
)))
707 if (gc_type
== BG_GC
&& has_not_enough_free_secs(sbi
, nfree
)) {
709 write_checkpoint(sbi
, &cpc
);
712 if (!__get_victim(sbi
, &segno
, gc_type
, NO_CHECK_TYPE
))
716 /* readahead multi ssa blocks those have contiguous address */
717 if (sbi
->segs_per_sec
> 1)
718 ra_meta_pages(sbi
, GET_SUM_BLOCK(sbi
, segno
), sbi
->segs_per_sec
,
721 for (i
= 0; i
< sbi
->segs_per_sec
; i
++)
722 do_garbage_collect(sbi
, segno
+ i
, &ilist
, gc_type
);
724 if (gc_type
== FG_GC
) {
725 sbi
->cur_victim_sec
= NULL_SEGNO
;
727 WARN_ON(get_valid_blocks(sbi
, segno
, sbi
->segs_per_sec
));
730 if (has_not_enough_free_secs(sbi
, nfree
))
733 if (gc_type
== FG_GC
)
734 write_checkpoint(sbi
, &cpc
);
736 mutex_unlock(&sbi
->gc_mutex
);
738 put_gc_inode(&ilist
);
742 void build_gc_manager(struct f2fs_sb_info
*sbi
)
744 DIRTY_I(sbi
)->v_ops
= &default_v_ops
;
747 int __init
create_gc_caches(void)
749 winode_slab
= f2fs_kmem_cache_create("f2fs_gc_inodes",
750 sizeof(struct inode_entry
));
756 void destroy_gc_caches(void)
758 kmem_cache_destroy(winode_slab
);