Messages in this thread | | | Date | Wed, 11 May 2022 16:53:41 +0800 | Subject | Re: [f2fs-dev] [PATCH 4/5] f2fs: do not stop GC when requiring a free section | From | Chao Yu <> |
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On 2022/5/10 0:55, Jaegeuk Kim wrote: > On 05/08, Chao Yu wrote: >> On 2022/5/7 7:20, 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@kernel.org> >>> --- >>> fs/f2fs/f2fs.h | 1 + >>> fs/f2fs/file.c | 12 ++++++++---- >>> fs/f2fs/gc.c | 11 +++++++---- >>> fs/f2fs/segment.c | 3 ++- >>> fs/f2fs/super.c | 3 ++- >>> include/trace/events/f2fs.h | 11 ++++++++--- >>> 6 files changed, 28 insertions(+), 13 deletions(-) >>> >>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h >>> index d49b9b476592..27871f6efb01 100644 >>> --- a/fs/f2fs/f2fs.h >>> +++ b/fs/f2fs/f2fs.h >>> @@ -1282,6 +1282,7 @@ 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 0e7d101c3e65..7072c2b86b2f 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; >>> @@ -2453,7 +2454,8 @@ 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; >>> @@ -2494,7 +2496,8 @@ 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; >>> @@ -2940,7 +2943,8 @@ 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 ec3f6f876e76..f63576ff1c2d 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 init_gc_type is BG_GC, sec_freed won't increase for background GC due to >> below statement: >> >> if (gc_type == FG_GC && >> get_valid_blocks(sbi, segno, false) == 0) >> seg_freed++; >> >> It may cause gc thread migrates lots of segments in each round? > > BG_GC include two cases, f2fs_balance_fs and gc thread for GC_MERGE, both of > which are no_bg_gc=true. So, I think this would be enough. Other cases that sets > nr_free_secs to 1 should be FG_GC only.
What I mean is, in below check condition, for BG_GC cases, if !has_not_enough_free_secs(sbi, sec_freed, 0) is true, since sec_freed will never be increased due to above condition, so it will goto gc_more label all the time, result in looping until migrating all dirty segments.
Thanks,
> >> >> if ((gc_control->init_gc_type == FG_GC || >> !has_not_enough_free_secs(sbi, sec_freed, 0))) { >> if (sec_freed < gc_control->nr_free_secs) >> goto gc_more; >> goto stop; >> } >> >>> /* if return value is not zero, no victim was selected */ >>> if (f2fs_gc(sbi, &gc_control)) >>> @@ -1776,6 +1777,7 @@ 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), >>> @@ -1848,11 +1850,12 @@ 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, sec_freed, 0)) >>> + if ((gc_control->init_gc_type == FG_GC || >>> + !has_not_enough_free_secs(sbi, sec_freed, 0))) { >>> + if (sec_freed < gc_control->nr_free_secs) >>> + goto gc_more; >>> goto stop; >>> + } >>> if (skipped_round <= MAX_SKIP_GC_COUNT || skipped_round * 2 < round) { >>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c >>> index bc63f0572c64..d6b9231ab0e1 100644 >>> --- a/fs/f2fs/segment.c >>> +++ b/fs/f2fs/segment.c >>> @@ -528,7 +528,8 @@ 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 }; >> >> .init_gc_type is BG_GC, so !has_not_enough_free_secs(sbi, sec_freed, 0) condition >> should be enough to exit? >> >> if ((gc_control->init_gc_type == FG_GC || >> !has_not_enough_free_secs(sbi, sec_freed, 0))) { >> if (sec_freed < gc_control->nr_free_secs) >> goto gc_more; >> goto stop; >> } >> >> Thanks, >> >>> f2fs_down_write(&sbi->gc_lock); >>> f2fs_gc(sbi, &gc_control); >>> } >>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c >>> index 8b23fa6fc6b7..5d5b35067c3d 100644 >>> --- a/fs/f2fs/super.c >>> +++ b/fs/f2fs/super.c >>> @@ -2084,7 +2084,8 @@ 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 6699174977a3..349679a72301 100644 >>> --- a/include/trace/events/f2fs.h >>> +++ b/include/trace/events/f2fs.h >>> @@ -653,18 +653,21 @@ 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) >>> @@ -678,6 +681,7 @@ 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; >>> @@ -687,12 +691,13 @@ 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->no_bg_gc, >>> + __entry->nr_free_secs, >>> __entry->dirty_nodes, >>> __entry->dirty_dents, >>> __entry->dirty_imeta,
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