On 02/19, Chao Yu wrote: > On 2020/2/19 11:04, Jaegeuk Kim wrote: > > On 02/19, Chao Yu wrote: > >> On 2020/2/19 7:27, Jaegeuk Kim wrote: > >>> On 02/17, Chao Yu wrote: > >>>> On 2020/2/15 2:58, Jaegeuk Kim wrote: > >>>>> FG_GC needs to move entire section more quickly. > >>>>> > >>>>> Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org> > >>>>> --- > >>>>> fs/f2fs/gc.c | 2 +- > >>>>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>>>> > >>>>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c > >>>>> index bbf4db3f6bb4..1676eebc8c8b 100644 > >>>>> --- a/fs/f2fs/gc.c > >>>>> +++ b/fs/f2fs/gc.c > >>>>> @@ -1203,7 +1203,7 @@ static int do_garbage_collect(struct f2fs_sb_info > >>>>> *sbi, > >>>>> > >>>>> if (get_valid_blocks(sbi, segno, false) == 0) > >>>>> goto freed; > >>>>> - if (__is_large_section(sbi) && > >>>>> + if (gc_type == BG_GC && __is_large_section(sbi) && > >>>>> migrated >= sbi->migration_granularity) > >>>> > >>>> I knew migrating one large section is a more efficient way, but this can > >>>> increase long-tail latency of f2fs_balance_fs() occasionally, especially > >>>> in > >>>> extreme fragmented space. > >>> > >>> FG_GC requires to wait for whole section migration which shows the entire > >>> latency. > >> > >> That will cause long-tail latency for single f2fs_balance_fs() procedure, > >> which it looks a very long hang when userspace call f2fs syscall, so why > >> not splitting total elapsed time into several f2fs_balance_fs() to avoid > >> that. > > > > Then, other ops can easily make more dirty segments. The intention of FG_GC > > is > > Yup, that's a problem, if there are more dirty datas being made, reserved > segments > may be ran out during FG_GC. > > > to block everything and make min. free segments as a best shot. > > I just try to simulate write GC's logic in FTL to mitigate single op's max > latency, > otherwise benchmark looks hang during FG_GC (in a 500mb+ section).
Hmm, I think we may need to think another way like doing BG_GC more aggressively. > > Thanks, > > > > >> > >> Thanks, > >> > >>> > >>>> > >>>> Thanks, > >>>> > >>>>> goto skip; > >>>>> if (!PageUptodate(sum_page) || > >>>>> unlikely(f2fs_cp_error(sbi))) > >>>>> > >>> . > >>> > > . > > _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
