From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B3C5C433EF for ; Wed, 29 Jun 2022 16:30:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230209AbiF2QaW (ORCPT ); Wed, 29 Jun 2022 12:30:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43040 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229582AbiF2QaQ (ORCPT ); Wed, 29 Jun 2022 12:30:16 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BB37E2C11C for ; Wed, 29 Jun 2022 09:30:15 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6153761CC2 for ; Wed, 29 Jun 2022 16:30:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AA426C34114; Wed, 29 Jun 2022 16:30:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1656520214; bh=Ty+fLcDrCUsxl2YZ2pxLl0PoHycLZyiCQ/QvpV3W9X0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Rqis4yST0n3Rm594Q7375njijGRebK9yXVpUBqRMNOO0+Dm1EN18uHHYYF8vJ1bTY C0KfkndWMWRX9fYcN0Y8XcjmEgZ31WpB7oaTw/zdJydtX86ZrajGucVqDMUxrUZVvB ayisW+7Sb/mBzt/b7KOXNoUEDeY0fa5WFVHBZNVF2MbuUcv4H1aNVk2k3apuXaXwZn cFtVm93C2o70lOs6PA+QUyfnpqIuKC9lf/f0XJQ6W0ZCKaIdwzxJzpszNjiOtzNsyw mbNzkNOpYLToQ1IqM+fq8U7BDgD8o9/5XdppGQ18f5getWPzNaTdxVViur23ujKX7s 8chhmLrnSc9eQ== Date: Wed, 29 Jun 2022 09:30:13 -0700 From: Jaegeuk Kim To: Chao Yu Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: Re: [f2fs-dev] [PATCH 2/3] f2fs: run GCs synchronously given user requests Message-ID: References: <20220617223106.3517374-1-jaegeuk@kernel.org> <20220617223106.3517374-2-jaegeuk@kernel.org> <27138a10-a6b2-edad-1985-687a95b9039b@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/28, Jaegeuk Kim wrote: > 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. Let me drop this patch, since [1] series could fix the GC issue. [1] https://lore.kernel.org/linux-f2fs-devel/20220628234733.3330502-1-jaegeuk@kernel.org/T/#t > > > > > /* > > * 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 > > > > > > > --- > > > > > > > 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) > > > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel