Re: [f2fs-dev] [PATCH 4/5 v2] f2fs: do not stop GC when requiring a free section
From: Chao Yu
Date: Sun May 15 2022 - 10:28:08 EST
On 2022/5/13 4:50, Jaegeuk Kim wrote:
The f2fs_gc uses a bitmap to indicate pinned sections, but when disabling
chckpoint, we call f2fs_gc() with NULL_SEGNO which selects the same dirty
segment as a victim all the time, resulting in checkpoint=disable failure,
for example. Let's pick another one, if we fail to collect it.
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
Change log from v1:
- refactor the code path to avoid ambiguous condition like BG_GC/sec_freed
fs/f2fs/f2fs.h | 1 +
fs/f2fs/file.c | 12 ++++++++----
fs/f2fs/gc.c | 14 +++++++++-----
fs/f2fs/segment.c | 3 ++-
fs/f2fs/super.c | 3 ++-
include/trace/events/f2fs.h | 11 ++++++++---
6 files changed, 30 insertions(+), 14 deletions(-)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 9920b2d6af8f..492af5b96de1 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1271,6 +1271,7 @@ struct f2fs_gc_control {
bool no_bg_gc; /* check the space and stop bg_gc */
bool should_migrate_blocks; /* should migrate blocks */
bool err_gc_skipped; /* return EAGAIN if GC skipped */
+ unsigned int nr_free_secs; /* # of free sections to do GC */
};
/* For s_flag in struct f2fs_sb_info */
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index d0547bef0851..216081ea8c81 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1650,7 +1650,8 @@ static int expand_inode_data(struct inode *inode, loff_t offset,
struct f2fs_gc_control gc_control = { .victim_segno = NULL_SEGNO,
.init_gc_type = FG_GC,
.should_migrate_blocks = false,
- .err_gc_skipped = true };
+ .err_gc_skipped = true,
+ .nr_free_secs = 0 };
pgoff_t pg_start, pg_end;
loff_t new_size = i_size_read(inode);
loff_t off_end;
@@ -2350,7 +2351,8 @@ static int f2fs_ioc_gc(struct file *filp, unsigned long arg)
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
struct f2fs_gc_control gc_control = { .victim_segno = NULL_SEGNO,
.no_bg_gc = false,
- .should_migrate_blocks = false };
+ .should_migrate_blocks = false,
+ .nr_free_secs = 0 };
__u32 sync;
int ret;
@@ -2391,7 +2393,8 @@ static int __f2fs_ioc_gc_range(struct file *filp, struct f2fs_gc_range *range)
.init_gc_type = range->sync ? FG_GC : BG_GC,
.no_bg_gc = false,
.should_migrate_blocks = false,
- .err_gc_skipped = range->sync };
+ .err_gc_skipped = range->sync,
+ .nr_free_secs = 0 };
u64 end;
int ret;
@@ -2837,7 +2840,8 @@ static int f2fs_ioc_flush_device(struct file *filp, unsigned long arg)
struct f2fs_gc_control gc_control = {
.init_gc_type = FG_GC,
.should_migrate_blocks = true,
- .err_gc_skipped = true };
+ .err_gc_skipped = true,
+ .nr_free_secs = 0 };
int ret;
if (!capable(CAP_SYS_ADMIN))
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index e275b72bc65f..10b24b0f13a5 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -147,6 +147,7 @@ static int gc_thread_func(void *data)
gc_control.init_gc_type = sync_mode ? FG_GC : BG_GC;
gc_control.no_bg_gc = foreground;
+ gc_control.nr_free_secs = foreground ? 1 : 0;
/* if return value is not zero, no victim was selected */
if (f2fs_gc(sbi, &gc_control))
@@ -1761,6 +1762,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
unsigned int skipped_round = 0, round = 0;
trace_f2fs_gc_begin(sbi->sb, gc_type, gc_control->no_bg_gc,
+ gc_control->nr_free_secs,
get_pages(sbi, F2FS_DIRTY_NODES),
get_pages(sbi, F2FS_DIRTY_DENTS),
get_pages(sbi, F2FS_DIRTY_IMETA),
@@ -1823,12 +1825,13 @@ int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
if (gc_type == FG_GC)
sbi->cur_victim_sec = NULL_SEGNO;
- if (gc_control->init_gc_type == FG_GC)
- goto stop;
-
- if (!has_not_enough_free_secs(sbi,
- (gc_type == FG_GC) ? sec_freed : 0, 0))
+ if (gc_control->init_gc_type == FG_GC ||
+ !has_not_enough_free_secs(sbi,
+ (gc_type == FG_GC) ? sec_freed : 0, 0)) {
In all gc_control->init_gc_type = BG_GC cases, gc_control->no_bg_gc is true,
if gc_type = BG_GC, then it should break out due to below condition.
/* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
if (gc_type == BG_GC && gc_control->no_bg_gc) {
ret = -EINVAL;
goto stop;
}
Otherwise gc_type should always be FG_GC in
!has_not_enough_free_secs(sbi, (gc_type == FG_GC) ? sec_freed : 0, 0), right?
Thanks,
+ if (gc_mode == FG_GC && sec_freed < gc_control->nr_free_secs)
+ goto go_gc_more;
goto stop;
+ }
/* FG_GC stops GC by skip_count */
if (gc_type == FG_GC) {
@@ -1849,6 +1852,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
if (ret)
goto stop;
}
+go_gc_more:
segno = NULL_SEGNO;
goto gc_more;
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 8b4f2b1d2cca..0a4180f64291 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -404,7 +404,8 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need)
.init_gc_type = BG_GC,
.no_bg_gc = true,
.should_migrate_blocks = false,
- .err_gc_skipped = false };
+ .err_gc_skipped = false,
+ .nr_free_secs = 1 };
f2fs_down_write(&sbi->gc_lock);
f2fs_gc(sbi, &gc_control);
}
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index a28c27eed6d0..63daae67a9d9 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2080,7 +2080,8 @@ static int f2fs_disable_checkpoint(struct f2fs_sb_info *sbi)
.victim_segno = NULL_SEGNO,
.init_gc_type = FG_GC,
.should_migrate_blocks = false,
- .err_gc_skipped = true };
+ .err_gc_skipped = true,
+ .nr_free_secs = 1 };
f2fs_down_write(&sbi->gc_lock);
err = f2fs_gc(sbi, &gc_control);
diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
index 54ec9e543f09..16c67ede85b6 100644
--- a/include/trace/events/f2fs.h
+++ b/include/trace/events/f2fs.h
@@ -645,18 +645,21 @@ TRACE_EVENT(f2fs_background_gc,
TRACE_EVENT(f2fs_gc_begin,
TP_PROTO(struct super_block *sb, int gc_type, bool no_bg_gc,
+ unsigned int nr_free_secs,
long long dirty_nodes, long long dirty_dents,
long long dirty_imeta, unsigned int free_sec,
unsigned int free_seg, int reserved_seg,
unsigned int prefree_seg),
- TP_ARGS(sb, gc_type, no_bg_gc, dirty_nodes, dirty_dents, dirty_imeta,
+ TP_ARGS(sb, gc_type, no_bg_gc, nr_free_secs, dirty_nodes,
+ dirty_dents, dirty_imeta,
free_sec, free_seg, reserved_seg, prefree_seg),
TP_STRUCT__entry(
__field(dev_t, dev)
__field(int, gc_type)
__field(bool, no_bg_gc)
+ __field(unsigned int, nr_free_secs)
__field(long long, dirty_nodes)
__field(long long, dirty_dents)
__field(long long, dirty_imeta)
@@ -670,6 +673,7 @@ TRACE_EVENT(f2fs_gc_begin,
__entry->dev = sb->s_dev;
__entry->gc_type = gc_type;
__entry->no_bg_gc = no_bg_gc;
+ __entry->nr_free_secs = nr_free_secs;
__entry->dirty_nodes = dirty_nodes;
__entry->dirty_dents = dirty_dents;
__entry->dirty_imeta = dirty_imeta;
@@ -679,12 +683,13 @@ TRACE_EVENT(f2fs_gc_begin,
__entry->prefree_seg = prefree_seg;
),
- TP_printk("dev = (%d,%d), gc_type = %s, no_background_GC = %d, nodes = %lld, "
- "dents = %lld, imeta = %lld, free_sec:%u, free_seg:%u, "
+ TP_printk("dev = (%d,%d), gc_type = %s, no_background_GC = %d, nr_free_secs = %u, "
+ "nodes = %lld, dents = %lld, imeta = %lld, free_sec:%u, free_seg:%u, "
"rsv_seg:%d, prefree_seg:%u",
show_dev(__entry->dev),
show_gc_type(__entry->gc_type),
(__entry->gc_type == BG_GC) ? __entry->no_bg_gc : -1,
+ __entry->nr_free_secs,
__entry->dirty_nodes,
__entry->dirty_dents,
__entry->dirty_imeta,