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). 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
