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 X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9AA06C43610 for ; Thu, 8 Nov 2018 22:42:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5576920844 for ; Thu, 8 Nov 2018 22:42:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="NjVxXEIK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5576920844 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728618AbeKIIUI (ORCPT ); Fri, 9 Nov 2018 03:20:08 -0500 Received: from mail.kernel.org ([198.145.29.99]:49234 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727653AbeKIHde (ORCPT ); Fri, 9 Nov 2018 02:33:34 -0500 Received: from localhost (unknown [208.72.13.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3F195208E3; Thu, 8 Nov 2018 21:56:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541714167; bh=LmG8jrvRYEADteGhDtfq/THNZao666MAcJGjhN9G11A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NjVxXEIKyxWkLYO5xAV//Ez5dEzclwNHueHGG7G6pWStTOWjAXYrKANJOGTi1bSSa EvmMYzSQLGDB6jCRGBWk5OZWkd71muAlv0gL7OlZPdpaiRS1akOZKrEL1cRYPdy48W pv70ZcUnxolXZY8SBha3dC8c6VMq0ZLpcUM+RGuk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Huang Ying , Filipe Manana , Chris Mason , Sasha Levin Subject: [PATCH 3.18 087/144] Btrfs: avoid syncing log in the fast fsync path when not necessary Date: Thu, 8 Nov 2018 13:50:58 -0800 Message-Id: <20181108215101.703913777@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181108215054.826084593@linuxfoundation.org> References: <20181108215054.826084593@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit b659ef027792219b590d67a2baf1643a93727d29 ] Commit 3a8b36f37806 ("Btrfs: fix data loss in the fast fsync path") added a performance regression for that causes an unnecessary sync of the log trees (fs/subvol and root log trees) when 2 consecutive fsyncs are done against a file, without no writes or any metadata updates to the inode in between them and if a transaction is committed before the second fsync is called. Huang Ying reported this to lkml (https://lkml.org/lkml/2015/3/18/99) after a test sysbench test that measured a -62% decrease of file io requests per second for that tests' workload. The test is: echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor echo performance > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor echo performance > /sys/devices/system/cpu/cpu2/cpufreq/scaling_governor echo performance > /sys/devices/system/cpu/cpu3/cpufreq/scaling_governor mkfs -t btrfs /dev/sda2 mount -t btrfs /dev/sda2 /fs/sda2 cd /fs/sda2 for ((i = 0; i < 1024; i++)); do fallocate -l 67108864 testfile.$i; done sysbench --test=fileio --max-requests=0 --num-threads=4 --max-time=600 \ --file-test-mode=rndwr --file-total-size=68719476736 --file-io-mode=sync \ --file-num=1024 run A test on kvm guest, running a debug kernel gave me the following results: Without 3a8b36f378060d: 16.01 reqs/sec With 3a8b36f378060d: 3.39 reqs/sec With 3a8b36f378060d and this patch: 16.04 reqs/sec Reported-by: Huang Ying Tested-by: Huang, Ying Signed-off-by: Filipe Manana Signed-off-by: Chris Mason Signed-off-by: Sasha Levin --- fs/btrfs/file.c | 9 ++++++--- fs/btrfs/ordered-data.c | 14 ++++++++++++++ fs/btrfs/ordered-data.h | 3 +++ 3 files changed, 23 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 2ad4cb3da8f6..ba37ec6263ca 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1879,6 +1879,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync) struct btrfs_log_ctx ctx; int ret = 0; bool full_sync = 0; + const u64 len = end - start + 1; trace_btrfs_sync_file(file, datasync); @@ -1907,7 +1908,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync) * all extents are persisted and the respective file extent * items are in the fs/subvol btree. */ - ret = btrfs_wait_ordered_range(inode, start, end - start + 1); + ret = btrfs_wait_ordered_range(inode, start, len); } else { /* * Start any new ordered operations before starting to log the @@ -1979,8 +1980,10 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync) */ smp_mb(); if (btrfs_inode_in_log(inode, root->fs_info->generation) || - (full_sync && BTRFS_I(inode)->last_trans <= - root->fs_info->last_trans_committed)) { + (BTRFS_I(inode)->last_trans <= + root->fs_info->last_trans_committed && + (full_sync || + !btrfs_have_ordered_extents_in_range(inode, start, len)))) { /* * We'v had everything committed since the last time we were * modified so clear this flag in case it was set for whatever diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c index b23d024c0234..4c20199cef62 100644 --- a/fs/btrfs/ordered-data.c +++ b/fs/btrfs/ordered-data.c @@ -848,6 +848,20 @@ out: return entry; } +bool btrfs_have_ordered_extents_in_range(struct inode *inode, + u64 file_offset, + u64 len) +{ + struct btrfs_ordered_extent *oe; + + oe = btrfs_lookup_ordered_range(inode, file_offset, len); + if (oe) { + btrfs_put_ordered_extent(oe); + return true; + } + return false; +} + /* * lookup and return any extent before 'file_offset'. NULL is returned * if none is found diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h index 0124bffc775f..a1bce0a5cccc 100644 --- a/fs/btrfs/ordered-data.h +++ b/fs/btrfs/ordered-data.h @@ -191,6 +191,9 @@ btrfs_lookup_first_ordered_extent(struct inode * inode, u64 file_offset); struct btrfs_ordered_extent *btrfs_lookup_ordered_range(struct inode *inode, u64 file_offset, u64 len); +bool btrfs_have_ordered_extents_in_range(struct inode *inode, + u64 file_offset, + u64 len); int btrfs_ordered_update_i_size(struct inode *inode, u64 offset, struct btrfs_ordered_extent *ordered); int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr, -- 2.17.1