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f2fs: get the right gc victim section when section has several segments

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Assume each section has 4 segment:
     .___________________________.
     |_Segment0_|_..._|_Segment3_|
     .                          .
     .                  .
     .__________.
     |_section0_|

Segment 0~2 has 0 valid block, segment 3 has 512 valid blocks.
It will fail if we want to gc section0 in this scenes,
because all 4 segments in section0 is not dirty.
So we should use dirty section bitmap instead of dirty segment bitmap
to get right victim section.

Signed-off-by: Jack Qiu <jack.qiu@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Jack Qiu 2020-06-18 12:37:10 +08:00 committed by Jaegeuk Kim
parent db5ae36329
commit da52f8ade4
3 changed files with 88 additions and 20 deletions
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39
fs/f2fs/gc.c
View file

@ -21,6 +21,9 @@
#include "gc.h"
#include <trace/events/f2fs.h>
static unsigned int count_bits(const unsigned long *addr,
unsigned int offset, unsigned int len);
static int gc_thread_func(void *data)
{
struct f2fs_sb_info *sbi = data;
@ -187,14 +190,20 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
if (p->alloc_mode == SSR) {
p->gc_mode = GC_GREEDY;
p->dirty_segmap = dirty_i->dirty_segmap[type];
p->dirty_bitmap = dirty_i->dirty_segmap[type];
p->max_search = dirty_i->nr_dirty[type];
p->ofs_unit = 1;
} else {
p->gc_mode = select_gc_type(sbi, gc_type);
p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
p->max_search = dirty_i->nr_dirty[DIRTY];
p->ofs_unit = sbi->segs_per_sec;
if (__is_large_section(sbi)) {
p->dirty_bitmap = dirty_i->dirty_secmap;
p->max_search = count_bits(p->dirty_bitmap,
0, MAIN_SECS(sbi));
} else {
p->dirty_bitmap = dirty_i->dirty_segmap[DIRTY];
p->max_search = dirty_i->nr_dirty[DIRTY];
}
}
/*
@ -365,10 +374,14 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
}
while (1) {
unsigned long cost;
unsigned int segno;
unsigned long cost, *dirty_bitmap;
unsigned int unit_no, segno;
segno = find_next_bit(p.dirty_segmap, last_segment, p.offset);
dirty_bitmap = p.dirty_bitmap;
unit_no = find_next_bit(dirty_bitmap,
last_segment / p.ofs_unit,
p.offset / p.ofs_unit);
segno = unit_no * p.ofs_unit;
if (segno >= last_segment) {
if (sm->last_victim[p.gc_mode]) {
last_segment =
@ -381,14 +394,7 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
}
p.offset = segno + p.ofs_unit;
if (p.ofs_unit > 1) {
p.offset -= segno % p.ofs_unit;
nsearched += count_bits(p.dirty_segmap,
p.offset - p.ofs_unit,
p.ofs_unit);
} else {
nsearched++;
}
nsearched++;
#ifdef CONFIG_F2FS_CHECK_FS
/*
@ -421,9 +427,10 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
next:
if (nsearched >= p.max_search) {
if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
sm->last_victim[p.gc_mode] = last_victim + 1;
sm->last_victim[p.gc_mode] =
last_victim + p.ofs_unit;
else
sm->last_victim[p.gc_mode] = segno + 1;
sm->last_victim[p.gc_mode] = segno + p.ofs_unit;
sm->last_victim[p.gc_mode] %=
(MAIN_SECS(sbi) * sbi->segs_per_sec);
break;

61
fs/f2fs/segment.c
View file

@ -796,6 +796,18 @@ static void __locate_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno,
}
if (!test_and_set_bit(segno, dirty_i->dirty_segmap[t]))
dirty_i->nr_dirty[t]++;
if (__is_large_section(sbi)) {
unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
unsigned short valid_blocks =
get_valid_blocks(sbi, segno, true);
f2fs_bug_on(sbi, unlikely(!valid_blocks ||
valid_blocks == BLKS_PER_SEC(sbi)));
if (!IS_CURSEC(sbi, secno))
set_bit(secno, dirty_i->dirty_secmap);
}
}
}
@ -803,6 +815,7 @@ static void __remove_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno,
enum dirty_type dirty_type)
{
struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
unsigned short valid_blocks;
if (test_and_clear_bit(segno, dirty_i->dirty_segmap[dirty_type]))
dirty_i->nr_dirty[dirty_type]--;
@ -814,13 +827,26 @@ static void __remove_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno,
if (test_and_clear_bit(segno, dirty_i->dirty_segmap[t]))
dirty_i->nr_dirty[t]--;
if (get_valid_blocks(sbi, segno, true) == 0) {
valid_blocks = get_valid_blocks(sbi, segno, true);
if (valid_blocks == 0) {
clear_bit(GET_SEC_FROM_SEG(sbi, segno),
dirty_i->victim_secmap);
#ifdef CONFIG_F2FS_CHECK_FS
clear_bit(segno, SIT_I(sbi)->invalid_segmap);
#endif
}
if (__is_large_section(sbi)) {
unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
if (!valid_blocks ||
valid_blocks == BLKS_PER_SEC(sbi)) {
clear_bit(secno, dirty_i->dirty_secmap);
return;
}
if (!IS_CURSEC(sbi, secno))
set_bit(secno, dirty_i->dirty_secmap);
}
}
}
@ -4293,8 +4319,9 @@ static void init_dirty_segmap(struct f2fs_sb_info *sbi)
{
struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
struct free_segmap_info *free_i = FREE_I(sbi);
unsigned int segno = 0, offset = 0;
unsigned int segno = 0, offset = 0, secno;
unsigned short valid_blocks;
unsigned short blks_per_sec = BLKS_PER_SEC(sbi);
while (1) {
/* find dirty segment based on free segmap */
@ -4313,6 +4340,22 @@ static void init_dirty_segmap(struct f2fs_sb_info *sbi)
__locate_dirty_segment(sbi, segno, DIRTY);
mutex_unlock(&dirty_i->seglist_lock);
}
if (!__is_large_section(sbi))
return;
mutex_lock(&dirty_i->seglist_lock);
for (segno = 0; segno < MAIN_SECS(sbi); segno += blks_per_sec) {
valid_blocks = get_valid_blocks(sbi, segno, true);
secno = GET_SEC_FROM_SEG(sbi, segno);
if (!valid_blocks || valid_blocks == blks_per_sec)
continue;
if (IS_CURSEC(sbi, secno))
continue;
set_bit(secno, dirty_i->dirty_secmap);
}
mutex_unlock(&dirty_i->seglist_lock);
}
static int init_victim_secmap(struct f2fs_sb_info *sbi)
@ -4349,6 +4392,14 @@ static int build_dirty_segmap(struct f2fs_sb_info *sbi)
return -ENOMEM;
}
if (__is_large_section(sbi)) {
bitmap_size = f2fs_bitmap_size(MAIN_SECS(sbi));
dirty_i->dirty_secmap = f2fs_kvzalloc(sbi,
bitmap_size, GFP_KERNEL);
if (!dirty_i->dirty_secmap)
return -ENOMEM;
}
init_dirty_segmap(sbi);
return init_victim_secmap(sbi);
}
@ -4775,6 +4826,12 @@ static void destroy_dirty_segmap(struct f2fs_sb_info *sbi)
for (i = 0; i < NR_DIRTY_TYPE; i++)
discard_dirty_segmap(sbi, i);
if (__is_large_section(sbi)) {
mutex_lock(&dirty_i->seglist_lock);
kvfree(dirty_i->dirty_secmap);
mutex_unlock(&dirty_i->seglist_lock);
}
destroy_victim_secmap(sbi);
SM_I(sbi)->dirty_info = NULL;
kvfree(dirty_i);

8
fs/f2fs/segment.h
View file

@ -166,8 +166,11 @@ enum {
struct victim_sel_policy {
int alloc_mode; /* LFS or SSR */
int gc_mode; /* GC_CB or GC_GREEDY */
unsigned long *dirty_segmap; /* dirty segment bitmap */
unsigned int max_search; /* maximum # of segments to search */
unsigned long *dirty_bitmap; /* dirty segment/section bitmap */
unsigned int max_search; /*
* maximum # of segments/sections
* to search
*/
unsigned int offset; /* last scanned bitmap offset */
unsigned int ofs_unit; /* bitmap search unit */
unsigned int min_cost; /* minimum cost */
@ -266,6 +269,7 @@ enum dirty_type {
struct dirty_seglist_info {
const struct victim_selection *v_ops; /* victim selction operation */
unsigned long *dirty_segmap[NR_DIRTY_TYPE];
unsigned long *dirty_secmap;
struct mutex seglist_lock; /* lock for segment bitmaps */
int nr_dirty[NR_DIRTY_TYPE]; /* # of dirty segments */
unsigned long *victim_secmap; /* background GC victims */