On Sun, Jul 24, 2016 at 06:38:46AM +0800, Chao Yu wrote:
...
> >> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> >> index de6c41c..ec17096 100644
> >> --- a/fs/f2fs/gc.c
> >> +++ b/fs/f2fs/gc.c
> >> @@ -908,10 +908,14 @@ gc_more:
> >> * enough free sections, we should flush dent/node blocks and do
> >> * garbage collections.
> >> */
> >> - if (__get_victim(sbi, &segno, gc_type) || prefree_segments(sbi))
> >> + if (__get_victim(sbi, &segno, gc_type) ||
> >> prefree_segments(sbi)) {
> >> write_checkpoint(sbi, &cpc);
> >> - else if (has_not_enough_free_secs(sbi, 0))
> >
> > If segno is NULL_SEGNO, we get a panic when checking the below conditions.
> > Anyway, I don't think we need this condition at all.
>
> I thinks the condition which trigger our f2fs_bug_on is really a corner case,
> we'd better not waste the victim we found everytime, especially for these
> victims from last background gc's victims.
>
> What about checking segno first?
>
> if(segno != NULL_SEGNO && (!get_valid_blocks(sbi, segno, sbi->segs_per_sec) ||
> IS_CURSEC(sbi, GET_SECNO(sbi, segno)))
> segno = NULL_SEGNO;
My viewpoint is write_checkpoint() flushes node and dentry pages, which provides
another better victims. Another concern is get_valid_blocks and IS_CURSEG are
not covered by any lock.
Thanks,
>
> Thanks,
>
> > Let me remove them and just set NULL_SEGNO only after checkpoint.
> > Please check the dev-test repo.
> >
> > Thanks,
> >
> >> + if(!get_valid_blocks(sbi, segno, sbi->segs_per_sec)
> >> + || IS_CURSEC(sbi, segno /
> >> sbi->segs_per_sec))
> >> + segno = NULL_SEGNO;
> >> + } else if (has_not_enough_free_secs(sbi, 0)) {
> >> write_checkpoint(sbi, &cpc);
> >> + }
> >> }
> >>
> >> if (segno == NULL_SEGNO && !__get_victim(sbi, &segno, gc_type))
> >> --
> >> 1.9.1
> >
> > ------------------------------------------------------------------------------
> > What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
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> > are
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> > planning
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------------------------------------------------------------------------------
What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
patterns at an interface-level. Reveals which users, apps, and protocols are
consuming the most bandwidth. Provides multi-vendor support for NetFlow,
J-Flow, sFlow and other flows. Make informed decisions using capacity planning
reports.http://sdm.link/zohodev2dev
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