Messages in this thread | | | Date | Tue, 28 Jun 2022 11:17:26 -0700 | From | Jaegeuk Kim <> | Subject | Re: [f2fs-dev] [PATCH 2/3] f2fs: run GCs synchronously given user requests |
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On 06/28, Chao Yu wrote: > On 2022/6/23 0:58, Jaegeuk Kim wrote: > > On 06/22, Chao Yu wrote: > > > On 2022/6/20 6:34, Jaegeuk Kim wrote: > > > > On 06/19, Chao Yu wrote: > > > > > On 2022/6/18 6:31, Jaegeuk Kim wrote: > > > > > > When users set GC_URGENT or GC_MID, they expected to do GCs right away. > > > > > > But, there's a condition to bypass it. Let's indicate we need to do now > > > > > > in the thread. > > > > > > > > > > .should_migrate_blocks is used to force migrating blocks in full > > > > > section, so what is the condition here? GC should not never select > > > > > a full section, right? > > > > > > > > I think it'll move a full section given .victim_segno is not NULL_SEGNO, > > > > as __get_victim will give a dirty segment all the time. wdyt? > > > > > > However, in gc_thread_fun() victim_segno is NULL_SEGNO all the time. > > > > What do you mean? The gc_thread thread sets NULL_SEGNO, which prevents > > from selecting the full section. But, f2fs_ioc_flush_device will set the > > segno to move, and f2fs_resize_fs calls do_garbage_collect directly. > > Yes, but I didn't get why this patch updates .should_migrate_blocks for > gc_thread_func() case? If this is added to avoid breaking from below condition, > I guess it's not necessary, since victim selected from gc_thread_func() will > always be dirty, so get_valid_blocks(sbi, segno, true) == BLKS_PER_SEC(sbi) > will be false anyway? or am I missing something?
I lost the previous test. :( IIRC, once I set GC_URGENT_HIGH, I've seen that f2fs_gc couldn't migrate blocks quickly, even or never succeeded. And, I also suspected the below condition tho, if I give force_migrate, it simply worked. I just realized that that may be caused by large sections having non-2MB-aligned zone capacity. Will check it again, as I found some buggy flows in that case.
> > /* > * stop BG_GC if there is not enough free sections. > * Or, stop GC if the segment becomes fully valid caused by > * race condition along with SSR block allocation. > */ > if ((gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) || > (!force_migrate && get_valid_blocks(sbi, segno, true) == > BLKS_PER_SEC(sbi))) > return submitted; > > Thanks, > > > > > > > > > I guess .should_migrate_blocks should only be set to true for > > > F2FS_IOC_FLUSH_DEVICE/F2FS_IOC_RESIZE_FS case? rather than GC_URGENT or GC_MID > > > case? See commit 7dede88659df ("f2fs: fix to allow migrating fully valid segment"). > > > > > > Thanks, > > > > > > > > > > > > > > > > > Thanks, > > > > > > > > > > > > > > > > > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> > > > > > > --- > > > > > > fs/f2fs/gc.c | 8 ++++++-- > > > > > > 1 file changed, 6 insertions(+), 2 deletions(-) > > > > > > > > > > > > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c > > > > > > index d5fb426e0747..f4aa3c88118b 100644 > > > > > > --- a/fs/f2fs/gc.c > > > > > > +++ b/fs/f2fs/gc.c > > > > > > @@ -37,7 +37,6 @@ static int gc_thread_func(void *data) > > > > > > unsigned int wait_ms; > > > > > > struct f2fs_gc_control gc_control = { > > > > > > .victim_segno = NULL_SEGNO, > > > > > > - .should_migrate_blocks = false, > > > > > > .err_gc_skipped = false }; > > > > > > wait_ms = gc_th->min_sleep_time; > > > > > > @@ -113,7 +112,10 @@ static int gc_thread_func(void *data) > > > > > > sbi->gc_mode == GC_URGENT_MID) { > > > > > > wait_ms = gc_th->urgent_sleep_time; > > > > > > f2fs_down_write(&sbi->gc_lock); > > > > > > + gc_control.should_migrate_blocks = true; > > > > > > goto do_gc; > > > > > > + } else { > > > > > > + gc_control.should_migrate_blocks = false; > > > > > > } > > > > > > if (foreground) { > > > > > > @@ -139,7 +141,9 @@ static int gc_thread_func(void *data) > > > > > > if (!foreground) > > > > > > stat_inc_bggc_count(sbi->stat_info); > > > > > > - sync_mode = F2FS_OPTION(sbi).bggc_mode == BGGC_MODE_SYNC; > > > > > > + sync_mode = F2FS_OPTION(sbi).bggc_mode == BGGC_MODE_SYNC || > > > > > > + sbi->gc_mode == GC_URGENT_HIGH || > > > > > > + sbi->gc_mode == GC_URGENT_MID; > > > > > > /* foreground GC was been triggered via f2fs_balance_fs() */ > > > > > > if (foreground)
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