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=-9.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 5D8AFC433DF for ; Wed, 24 Jun 2020 01:22:03 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 29A012098B; Wed, 24 Jun 2020 01:22:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=sourceforge.net header.i=@sourceforge.net header.b="QYMV1EsY"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=sf.net header.i=@sf.net header.b="Th8qzPWD"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="PrCwI/LG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 29A012098B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linux-f2fs-devel-bounces@lists.sourceforge.net Received: from [127.0.0.1] (helo=sfs-ml-4.v29.lw.sourceforge.com) by sfs-ml-4.v29.lw.sourceforge.com with esmtp (Exim 4.90_1) (envelope-from ) id 1jnu70-000735-Pc; Wed, 24 Jun 2020 01:22:02 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-4.v29.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jnu70-00072z-C9 for linux-f2fs-devel@lists.sourceforge.net; Wed, 24 Jun 2020 01:22:02 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=Content-Transfer-Encoding:MIME-Version:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:In-Reply-To:References:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=3D2Pjzl6zLc6+mLJTP+WGzveq780PCi0s+2HpfDKIdg=; b=QYMV1EsYOhRiO9l6XH3x21j79J 8qDr9iolP4xwaiq4zJMYxAIF/nKwrAKQr7cmuMxaHYs9+g0pkofSj0+iConXC432yYSFs1ughBzMq qRZJatqZWZZvbBWCwlF4NPBC6zGAbU7OcbpuSBXDHo+QhrpGYO3+gTTWl67SX8MCEU4s=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=Content-Transfer-Encoding:MIME-Version:Message-Id:Date:Subject:Cc:To:From :Sender:Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Id:List-Help:List-Unsubscribe:List-Subscribe:List-Post: List-Owner:List-Archive; bh=3D2Pjzl6zLc6+mLJTP+WGzveq780PCi0s+2HpfDKIdg=; b=T h8qzPWD3wY/Sen7dxiQpsd9hTfTReJEQZHk12m/lHlNYKlC8U5qKmM4uBVmQrglkwV6MM/r9fm2D/ eCNVfPe1BrleovE6qaYCXSRe10/IP4r8IYXJLzifjrlS+mJge5nh4aeLmWaBYGl3XLbDV2nEOlEmW UehpJ2l1PTVj/vaM=; Received: from mail.kernel.org ([198.145.29.99]) by sfi-mx-4.v28.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92.2) id 1jnu6u-00GXZ5-3Y for linux-f2fs-devel@lists.sourceforge.net; Wed, 24 Jun 2020 01:22:02 +0000 Received: from localhost (unknown [104.132.1.66]) (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 A54C72098B; Wed, 24 Jun 2020 01:21:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592961710; bh=q4Pi3kNmO4FJ+5AKsS68CryMsRDMWC3DAutTzeZ9fAw=; h=From:To:Cc:Subject:Date:From; b=PrCwI/LGSBreBr49BTTIywyZJN9Dvn7jpBRbXUfo97cuaDA0tll3lTbCSa8SyErdt XuDZKR49M8rDSLypdOALdd8kR/vt0GIEwvgIbUhLmZmbruoNlznbt+oR0advniYmzz GeZivfeGLVLerbasPB+phfMIVySvy24cSljoJUSU= From: Jaegeuk Kim To: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com Date: Tue, 23 Jun 2020 18:21:48 -0700 Message-Id: <20200624012148.180050-1-jaegeuk@kernel.org> X-Mailer: git-send-email 2.27.0.111.gc72c7da667-goog MIME-Version: 1.0 X-Headers-End: 1jnu6u-00GXZ5-3Y Subject: [f2fs-dev] [PATCH] f2fs: avoid readahead race condition 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: Jaegeuk Kim Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net If two readahead threads having same offset enter in readpages, every read IOs are split and issued to the disk which giving lower bandwidth. This patch tries to avoid redundant readahead calls. Signed-off-by: Jaegeuk Kim --- fs/f2fs/data.c | 15 +++++++++++++++ fs/f2fs/f2fs.h | 1 + fs/f2fs/super.c | 2 ++ 3 files changed, 18 insertions(+) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index dfd3225153570..1886d83bc5f15 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -2292,6 +2292,7 @@ static int f2fs_mpage_readpages(struct inode *inode, unsigned nr_pages = rac ? readahead_count(rac) : 1; unsigned max_nr_pages = nr_pages; int ret = 0; + bool drop_ra = false; map.m_pblk = 0; map.m_lblk = 0; @@ -2302,6 +2303,17 @@ static int f2fs_mpage_readpages(struct inode *inode, map.m_seg_type = NO_CHECK_TYPE; map.m_may_create = false; + /* + * Two readahead threads for same address range can cause race condition + * which fragments sequential read IOs. So let's avoid each other. + */ + if (rac && readahead_count(rac)) { + if (F2FS_I(inode)->ra_offset == readahead_index(rac)) + drop_ra = true; + else + F2FS_I(inode)->ra_offset = readahead_index(rac); + } + for (; nr_pages; nr_pages--) { if (rac) { page = readahead_page(rac); @@ -2368,6 +2380,9 @@ static int f2fs_mpage_readpages(struct inode *inode, } if (bio) __submit_bio(F2FS_I_SB(inode), bio, DATA); + + if (rac && readahead_count(rac) && !drop_ra) + F2FS_I(inode)->ra_offset = -1; return ret; } diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 7fb2a1a334388..753782426feac 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -809,6 +809,7 @@ struct f2fs_inode_info { struct list_head inmem_pages; /* inmemory pages managed by f2fs */ struct task_struct *inmem_task; /* store inmemory task */ struct mutex inmem_lock; /* lock for inmemory pages */ + pgoff_t ra_offset; /* ongoing readahead offset */ struct extent_tree *extent_tree; /* cached extent_tree entry */ /* avoid racing between foreground op and gc */ diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 7326522057378..80cb7cd358f84 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -1015,6 +1015,8 @@ static struct inode *f2fs_alloc_inode(struct super_block *sb) /* Will be used by directory only */ fi->i_dir_level = F2FS_SB(sb)->dir_level; + fi->ra_offset = -1; + return &fi->vfs_inode; } -- 2.27.0.111.gc72c7da667-goog _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel