On Fri, Sep 25, 2015 at 05:50:55PM +0800, Chao Yu wrote:
> This patch fixes to maintain the right section count freed in garbage
> collecting when triggering a foreground gc.
>
> Besides, when a foreground gc is running on current selected section, once
> we fail to gc one segment, it's better to abandon gcing the left segments
> in current section, because anyway we will select next victim for
> foreground gc, so gc on the left segments in previous section will become
> overhead and also cause the long latency for caller.
>
> Signed-off-by: Chao Yu <chao2...@samsung.com>
> ---
> v2:
> o avoid calc the wrong value when freed segments across sections.
> fs/f2fs/gc.c | 22 +++++++++++++++++-----
> 1 file changed, 17 insertions(+), 5 deletions(-)
>
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index e932740..256ebd4 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -802,7 +802,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi)
> unsigned int segno = NULL_SEGNO;
> unsigned int i;
> int gc_type = BG_GC;
> - int nfree = 0;
> + int sec_freed = 0, seg_freed;
> int ret = -1;
> struct cp_control cpc;
> struct gc_inode_list gc_list = {
> @@ -817,7 +817,7 @@ gc_more:
> if (unlikely(f2fs_cp_error(sbi)))
> goto stop;
>
> - if (gc_type == BG_GC && has_not_enough_free_secs(sbi, nfree)) {
> + if (gc_type == BG_GC && has_not_enough_free_secs(sbi, sec_freed)) {
> gc_type = FG_GC;
> if (__get_victim(sbi, &segno, gc_type) || prefree_segments(sbi))
> write_checkpoint(sbi, &cpc);
> @@ -833,13 +833,25 @@ gc_more:
> ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno), sbi->segs_per_sec,
> META_SSA);
>
> - for (i = 0; i < sbi->segs_per_sec; i++)
> - nfree += do_garbage_collect(sbi, segno + i, &gc_list, gc_type);
> + for (i = 0, seg_freed = 0; i < sbi->segs_per_sec; i++) {
> + /*
> + * for FG_GC case, halt gcing left segments once failed one
> + * of segments in selected section to avoid long latency.
> + */
> + if (!do_garbage_collect(sbi, segno + i, &gc_list, gc_type) &&
> + gc_type == FG_GC)
> + break;
> + if (gc_type == FG_GC)
> + seg_freed++;
> + }
How about?
if (i == sbi->segs_per_sec && gc_type == FG_GC)
sec_free++;
> +
> + if (seg_freed == sbi->segs_per_sec)
> + sec_freed++;
>
> if (gc_type == FG_GC)
> sbi->cur_victim_sec = NULL_SEGNO;
>
> - if (has_not_enough_free_secs(sbi, nfree))
> + if (has_not_enough_free_secs(sbi, sec_freed))
> goto gc_more;
>
> if (gc_type == FG_GC)
> --
> 2.5.2
------------------------------------------------------------------------------
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
