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 A2B3CC433F5 for ; Tue, 3 May 2022 22:25:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243649AbiECW2k (ORCPT ); Tue, 3 May 2022 18:28:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41528 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235020AbiECW2g (ORCPT ); Tue, 3 May 2022 18:28:36 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2FF57424AF; Tue, 3 May 2022 15:25:03 -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 C221261743; Tue, 3 May 2022 22:25:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED467C385A9; Tue, 3 May 2022 22:25:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1651616702; bh=Gq/fueWpXLku85WUlyGq7Fe4Dx3APSdMq6q4gayT7PM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Xxr/MaWDJqiadPMG7VGDJpekoL14jhrzBzbHxiLQ0q8CJwi41o1G230jImRmQRWdx Q4of6lxctHxejbnevqTjyFSWGWlqx7WF26O4p2/ardn6n47tByAcpnrSwT/xAhUF8C kXsxoBdtCnANrlpHbzxETth9Jymp/8ZEsHhRYCcb3NS6uA+qW96HXjlSMLpiP8IIv8 yEoSuzPl4+HDUkZJzvalQpQj5lkvIaL7RjIWYEG4M/4khabFgFU2Tu+7U38VdPEXz/ HkaU/+5LSTiwE0VVWJcqXyYQb/k3F91/VIgTC/Lug2NH89VIeK7ad87/JhHlmIUeCu zoJjGr5G5ybGQ== Date: Tue, 3 May 2022 15:25:00 -0700 From: Jaegeuk Kim To: Chao Yu Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Ming Yan , Chao Yu Subject: Re: [PATCH] f2fs: fix deadloop in foreground GC Message-ID: References: <20220429204631.7241-1-chao@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220429204631.7241-1-chao@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/30, Chao Yu wrote: > As Yanming reported in bugzilla: > > https://bugzilla.kernel.org/show_bug.cgi?id=215914 > > The root cause is: in a very small sized image, it's very easy to > exceed threshold of foreground GC, if we calculate free space and > dirty data based on section granularity, in corner case, > has_not_enough_free_secs() will always return true, result in > deadloop in f2fs_gc(). Performance regression was reported. Can we check this for very small sized image only? > > So this patch refactors has_not_enough_free_secs() as below to fix > this issue: > 1. calculate needed space based on block granularity, and separate > all blocks to two parts, section part, and block part, comparing > section part to free section, and comparing block part to free space > in openned log. > 2. account F2FS_DIRTY_NODES, F2FS_DIRTY_IMETA and F2FS_DIRTY_DENTS > as node block consumer; > 3. account F2FS_DIRTY_DENTS as data block consumer; > > Cc: stable@vger.kernel.org > Reported-by: Ming Yan > Signed-off-by: Chao Yu > --- > fs/f2fs/segment.h | 30 +++++++++++++++++------------- > 1 file changed, 17 insertions(+), 13 deletions(-) > > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h > index 8a591455d796..28f7aa9b40bf 100644 > --- a/fs/f2fs/segment.h > +++ b/fs/f2fs/segment.h > @@ -575,11 +575,10 @@ static inline int reserved_sections(struct f2fs_sb_info *sbi) > return GET_SEC_FROM_SEG(sbi, reserved_segments(sbi)); > } > > -static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi) > +static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi, > + unsigned int node_blocks, unsigned int dent_blocks) > { > - unsigned int node_blocks = get_pages(sbi, F2FS_DIRTY_NODES) + > - get_pages(sbi, F2FS_DIRTY_DENTS); > - unsigned int dent_blocks = get_pages(sbi, F2FS_DIRTY_DENTS); > + > unsigned int segno, left_blocks; > int i; > > @@ -605,19 +604,24 @@ static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi) > static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi, > int freed, int needed) > { > - int node_secs = get_blocktype_secs(sbi, F2FS_DIRTY_NODES); > - int dent_secs = get_blocktype_secs(sbi, F2FS_DIRTY_DENTS); > - int imeta_secs = get_blocktype_secs(sbi, F2FS_DIRTY_IMETA); > + unsigned int total_node_blocks = get_pages(sbi, F2FS_DIRTY_NODES) + > + get_pages(sbi, F2FS_DIRTY_DENTS) + > + get_pages(sbi, F2FS_DIRTY_IMETA); > + unsigned int total_dent_blocks = get_pages(sbi, F2FS_DIRTY_DENTS); > + unsigned int node_secs = total_node_blocks / BLKS_PER_SEC(sbi); > + unsigned int dent_secs = total_dent_blocks / BLKS_PER_SEC(sbi); > + unsigned int node_blocks = total_node_blocks % BLKS_PER_SEC(sbi); > + unsigned int dent_blocks = total_dent_blocks % BLKS_PER_SEC(sbi); > > if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING))) > return false; > > - if (free_sections(sbi) + freed == reserved_sections(sbi) + needed && > - has_curseg_enough_space(sbi)) > - return false; > - return (free_sections(sbi) + freed) <= > - (node_secs + 2 * dent_secs + imeta_secs + > - reserved_sections(sbi) + needed); > + if (free_sections(sbi) + freed <= > + node_secs + dent_secs + reserved_sections(sbi) + needed) > + return true; > + if (!has_curseg_enough_space(sbi, node_blocks, dent_blocks)) > + return true; > + return false; > } > > static inline bool f2fs_is_checkpoint_ready(struct f2fs_sb_info *sbi) > -- > 2.32.0 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 lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 15FD3C433EF for ; Tue, 3 May 2022 22:25:27 +0000 (UTC) Received: from [127.0.0.1] (helo=sfs-ml-1.v29.lw.sourceforge.com) by sfs-ml-1.v29.lw.sourceforge.com with esmtp (Exim 4.94.2) (envelope-from ) id 1nm0xP-0006sA-Vh; 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Tue, 3 May 2022 22:25:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED467C385A9; Tue, 3 May 2022 22:25:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1651616702; bh=Gq/fueWpXLku85WUlyGq7Fe4Dx3APSdMq6q4gayT7PM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Xxr/MaWDJqiadPMG7VGDJpekoL14jhrzBzbHxiLQ0q8CJwi41o1G230jImRmQRWdx Q4of6lxctHxejbnevqTjyFSWGWlqx7WF26O4p2/ardn6n47tByAcpnrSwT/xAhUF8C kXsxoBdtCnANrlpHbzxETth9Jymp/8ZEsHhRYCcb3NS6uA+qW96HXjlSMLpiP8IIv8 yEoSuzPl4+HDUkZJzvalQpQj5lkvIaL7RjIWYEG4M/4khabFgFU2Tu+7U38VdPEXz/ HkaU/+5LSTiwE0VVWJcqXyYQb/k3F91/VIgTC/Lug2NH89VIeK7ad87/JhHlmIUeCu zoJjGr5G5ybGQ== Date: Tue, 3 May 2022 15:25:00 -0700 From: Jaegeuk Kim To: Chao Yu Message-ID: References: <20220429204631.7241-1-chao@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220429204631.7241-1-chao@kernel.org> X-Headers-End: 1nm0xJ-00012k-NU Subject: Re: [f2fs-dev] [PATCH] f2fs: fix deadloop in foreground GC X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ming Yan , linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On 04/30, Chao Yu wrote: > As Yanming reported in bugzilla: > > https://bugzilla.kernel.org/show_bug.cgi?id=215914 > > The root cause is: in a very small sized image, it's very easy to > exceed threshold of foreground GC, if we calculate free space and > dirty data based on section granularity, in corner case, > has_not_enough_free_secs() will always return true, result in > deadloop in f2fs_gc(). Performance regression was reported. Can we check this for very small sized image only? > > So this patch refactors has_not_enough_free_secs() as below to fix > this issue: > 1. calculate needed space based on block granularity, and separate > all blocks to two parts, section part, and block part, comparing > section part to free section, and comparing block part to free space > in openned log. > 2. account F2FS_DIRTY_NODES, F2FS_DIRTY_IMETA and F2FS_DIRTY_DENTS > as node block consumer; > 3. account F2FS_DIRTY_DENTS as data block consumer; > > Cc: stable@vger.kernel.org > Reported-by: Ming Yan > Signed-off-by: Chao Yu > --- > fs/f2fs/segment.h | 30 +++++++++++++++++------------- > 1 file changed, 17 insertions(+), 13 deletions(-) > > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h > index 8a591455d796..28f7aa9b40bf 100644 > --- a/fs/f2fs/segment.h > +++ b/fs/f2fs/segment.h > @@ -575,11 +575,10 @@ static inline int reserved_sections(struct f2fs_sb_info *sbi) > return GET_SEC_FROM_SEG(sbi, reserved_segments(sbi)); > } > > -static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi) > +static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi, > + unsigned int node_blocks, unsigned int dent_blocks) > { > - unsigned int node_blocks = get_pages(sbi, F2FS_DIRTY_NODES) + > - get_pages(sbi, F2FS_DIRTY_DENTS); > - unsigned int dent_blocks = get_pages(sbi, F2FS_DIRTY_DENTS); > + > unsigned int segno, left_blocks; > int i; > > @@ -605,19 +604,24 @@ static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi) > static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi, > int freed, int needed) > { > - int node_secs = get_blocktype_secs(sbi, F2FS_DIRTY_NODES); > - int dent_secs = get_blocktype_secs(sbi, F2FS_DIRTY_DENTS); > - int imeta_secs = get_blocktype_secs(sbi, F2FS_DIRTY_IMETA); > + unsigned int total_node_blocks = get_pages(sbi, F2FS_DIRTY_NODES) + > + get_pages(sbi, F2FS_DIRTY_DENTS) + > + get_pages(sbi, F2FS_DIRTY_IMETA); > + unsigned int total_dent_blocks = get_pages(sbi, F2FS_DIRTY_DENTS); > + unsigned int node_secs = total_node_blocks / BLKS_PER_SEC(sbi); > + unsigned int dent_secs = total_dent_blocks / BLKS_PER_SEC(sbi); > + unsigned int node_blocks = total_node_blocks % BLKS_PER_SEC(sbi); > + unsigned int dent_blocks = total_dent_blocks % BLKS_PER_SEC(sbi); > > if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING))) > return false; > > - if (free_sections(sbi) + freed == reserved_sections(sbi) + needed && > - has_curseg_enough_space(sbi)) > - return false; > - return (free_sections(sbi) + freed) <= > - (node_secs + 2 * dent_secs + imeta_secs + > - reserved_sections(sbi) + needed); > + if (free_sections(sbi) + freed <= > + node_secs + dent_secs + reserved_sections(sbi) + needed) > + return true; > + if (!has_curseg_enough_space(sbi, node_blocks, dent_blocks)) > + return true; > + return false; > } > > static inline bool f2fs_is_checkpoint_ready(struct f2fs_sb_info *sbi) > -- > 2.32.0 _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel