On 04/30, Chao Yu wrote: > As Yanming reported in bugzilla: > > https://bugzilla.kernel.org/show_bug.cgi?id=215914 > > The root cause is: in a very small sized image, it's very easy to > exceed threshold of foreground GC, if we calculate free space and > dirty data based on section granularity, in corner case, > has_not_enough_free_secs() will always return true, result in > deadloop in f2fs_gc(). Performance regression was reported. Can we check this for very small sized image only? > > So this patch refactors has_not_enough_free_secs() as below to fix > this issue: > 1. calculate needed space based on block granularity, and separate > all blocks to two parts, section part, and block part, comparing > section part to free section, and comparing block part to free space > in openned log. > 2. account F2FS_DIRTY_NODES, F2FS_DIRTY_IMETA and F2FS_DIRTY_DENTS > as node block consumer; > 3. account F2FS_DIRTY_DENTS as data block consumer; > > Cc: stable@xxxxxxxxxxxxxxx > Reported-by: Ming Yan <yanming@xxxxxxxxxx> > Signed-off-by: Chao Yu <chao.yu@xxxxxxxx> > --- > fs/f2fs/segment.h | 30 +++++++++++++++++------------- > 1 file changed, 17 insertions(+), 13 deletions(-) > > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h > index 8a591455d796..28f7aa9b40bf 100644 > --- a/fs/f2fs/segment.h > +++ b/fs/f2fs/segment.h > @@ -575,11 +575,10 @@ static inline int reserved_sections(struct f2fs_sb_info *sbi) > return GET_SEC_FROM_SEG(sbi, reserved_segments(sbi)); > } > > -static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi) > +static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi, > + unsigned int node_blocks, unsigned int dent_blocks) > { > - unsigned int node_blocks = get_pages(sbi, F2FS_DIRTY_NODES) + > - get_pages(sbi, F2FS_DIRTY_DENTS); > - unsigned int dent_blocks = get_pages(sbi, F2FS_DIRTY_DENTS); > + > unsigned int segno, left_blocks; > int i; > > @@ -605,19 +604,24 @@ static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi) > static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi, > int freed, int needed) > { > - int node_secs = get_blocktype_secs(sbi, F2FS_DIRTY_NODES); > - int dent_secs = get_blocktype_secs(sbi, F2FS_DIRTY_DENTS); > - int imeta_secs = get_blocktype_secs(sbi, F2FS_DIRTY_IMETA); > + unsigned int total_node_blocks = get_pages(sbi, F2FS_DIRTY_NODES) + > + get_pages(sbi, F2FS_DIRTY_DENTS) + > + get_pages(sbi, F2FS_DIRTY_IMETA); > + unsigned int total_dent_blocks = get_pages(sbi, F2FS_DIRTY_DENTS); > + unsigned int node_secs = total_node_blocks / BLKS_PER_SEC(sbi); > + unsigned int dent_secs = total_dent_blocks / BLKS_PER_SEC(sbi); > + unsigned int node_blocks = total_node_blocks % BLKS_PER_SEC(sbi); > + unsigned int dent_blocks = total_dent_blocks % BLKS_PER_SEC(sbi); > > if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING))) > return false; > > - if (free_sections(sbi) + freed == reserved_sections(sbi) + needed && > - has_curseg_enough_space(sbi)) > - return false; > - return (free_sections(sbi) + freed) <= > - (node_secs + 2 * dent_secs + imeta_secs + > - reserved_sections(sbi) + needed); > + if (free_sections(sbi) + freed <= > + node_secs + dent_secs + reserved_sections(sbi) + needed) > + return true; > + if (!has_curseg_enough_space(sbi, node_blocks, dent_blocks)) > + return true; > + return false; > } > > static inline bool f2fs_is_checkpoint_ready(struct f2fs_sb_info *sbi) > -- > 2.32.0
