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 3AB39EB64DA for ; Mon, 3 Jul 2023 01:28:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229923AbjGCB2T (ORCPT ); Sun, 2 Jul 2023 21:28:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41600 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229958AbjGCB2R (ORCPT ); Sun, 2 Jul 2023 21:28:17 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B74A010CE for ; Sun, 2 Jul 2023 18:27:58 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 675CA60CA5 for ; Mon, 3 Jul 2023 01:27:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DE039C433C8; Mon, 3 Jul 2023 01:27:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1688347676; bh=bY6ntNsjmwD2TqbWSTRt+J7FYU10yDNtD/OTzg/NXhY=; h=Date:To:References:From:Cc:Subject:In-Reply-To:From; b=CHSn1Drzc7D4OdHtlIrflJTh8I9B2FqdguwHOgxXkOKZjuJTHbYDyE8CnCbfXB0EW pv7f7Cz3KDrbpE7o6TTLxHBfaA6Q/RZgG+pn6gF35FTkEslRnO8iIfNdJQoLz9i9qp KxR97JuGL4PTcQhHhBy39Z0nP2z3qK3G7JTQrVgVThtT/JUgSDPZnjiGOUiKRh1BDj L2EAgRUnV3BJCCxfzc+ZEsfoNLAJVzHQBu5unHwS3doL1xYPWZDA9JLgP/WnCDDkpy S0QhgtnEqOoHBGdkGnOmGdgbPkRtasdSi0Htw+27/CSwf+2CJVULXCbrkb366wan0w +nqU24rHagxew== Message-ID: <50d5fa8c-4fe9-8a03-be78-0b5383e55b62@kernel.org> Date: Mon, 3 Jul 2023 09:27:53 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 To: Jaegeuk Kim , Daejun Park References: <20230613203947.2745943-1-jaegeuk@kernel.org> Content-Language: en-US From: Chao Yu Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [f2fs-dev] [PATCH v2] f2fs: do not issue small discard commands during checkpoint In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/6/15 0:10, Jaegeuk Kim wrote: > If there're huge # of small discards, this will increase checkpoint latency > insanely. Let's issue small discards only by trim. > > Signed-off-by: Jaegeuk Kim > --- > > Change log from v1: > - move the skip logic to avoid dangling objects > > fs/f2fs/segment.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index 8c7af8b4fc47..0457d620011f 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -2193,7 +2193,7 @@ void f2fs_clear_prefree_segments(struct f2fs_sb_info *sbi, > len = next_pos - cur_pos; > > if (f2fs_sb_has_blkzoned(sbi) || > - (force && len < cpc->trim_minlen)) > + !force || len < cpc->trim_minlen) > goto skip; Sorry for late reply. We have a configuration for such case, what do you think of setting max_small_discards to zero? otherwise, w/ above change, max_small_discards logic may be broken? What: /sys/fs/f2fs//max_small_discards Date: November 2013 Contact: "Jaegeuk Kim" Description: Controls the issue rate of discard commands that consist of small blocks less than 2MB. The candidates to be discarded are cached until checkpoint is triggered, and issued during the checkpoint. By default, it is disabled with 0. Or, if we prefer to disable small_discards by default, what about below change: From eb89d9b56e817e3046d7fa17165b12416f09d456 Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Mon, 3 Jul 2023 09:06:53 +0800 Subject: [PATCH] Revert "f2fs: enable small discard by default" This reverts commit d618ebaf0aa83d175658aea5291e0c459d471d39 in order to disable small discard by default, so that if there're huge number of small discards, it will decrease checkpoint's latency obviously. Also, this patch reverts 9ac00e7cef10 ("f2fs: do not issue small discard commands during checkpoint"), due to it breaks small discard feature which may be configured via sysfs entry max_small_discards. Fixes: 9ac00e7cef10 ("f2fs: do not issue small discard commands during checkpoint") Signed-off-by: Chao Yu --- fs/f2fs/segment.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 14c822e5c9c9..0a313368f18b 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -2193,7 +2193,7 @@ void f2fs_clear_prefree_segments(struct f2fs_sb_info *sbi, len = next_pos - cur_pos; if (f2fs_sb_has_blkzoned(sbi) || - !force || len < cpc->trim_minlen) + (force && len < cpc->trim_minlen)) goto skip; f2fs_issue_discard(sbi, entry->start_blkaddr + cur_pos, @@ -2269,7 +2269,7 @@ static int create_discard_cmd_control(struct f2fs_sb_info *sbi) atomic_set(&dcc->queued_discard, 0); atomic_set(&dcc->discard_cmd_cnt, 0); dcc->nr_discards = 0; - dcc->max_discards = MAIN_SEGS(sbi) << sbi->log_blocks_per_seg; + dcc->max_discards = 0; dcc->max_discard_request = DEF_MAX_DISCARD_REQUEST; dcc->min_discard_issue_time = DEF_MIN_DISCARD_ISSUE_TIME; dcc->mid_discard_issue_time = DEF_MID_DISCARD_ISSUE_TIME; -- 2.40.1 > > f2fs_issue_discard(sbi, entry->start_blkaddr + cur_pos,