From patchwork Thu Aug 3 13:44:57 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Trond Myklebust X-Patchwork-Id: 9879127 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id D709160360 for ; Thu, 3 Aug 2017 13:45:37 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CC6302875C for ; Thu, 3 Aug 2017 13:45:37 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C14AB288FC; Thu, 3 Aug 2017 13:45:37 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.3 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI, RCVD_IN_SORBS_SPAM, T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 544562875C for ; Thu, 3 Aug 2017 13:45:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751696AbdHCNpf (ORCPT ); Thu, 3 Aug 2017 09:45:35 -0400 Received: from mail-it0-f68.google.com ([209.85.214.68]:36473 "EHLO mail-it0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751600AbdHCNpe (ORCPT ); Thu, 3 Aug 2017 09:45:34 -0400 Received: by mail-it0-f68.google.com with SMTP id r9so1312688ita.3 for ; Thu, 03 Aug 2017 06:45:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:subject:date:message-id:in-reply-to:references; bh=0tPBtL9keUvNLTs1GZkxbj0io/qBexCcVC2yNO1P568=; b=T+JF5bT0DG7M8p7m+f5yjrL7avO4wrg2LTlGe6ufpSUhdlC420k9E8wm/JdoBgrIPu DUyWgYdLlIu/JBK9oC/AhjWuZ/Nmvtpp+S0ZfO14ypLsvZ+1ZCmZZigno1eSsiulWmIu bUz3RIw8KWkEgKQIVT2fkPn9qh/dRsD+K7l5bh/FWE7N6s+ofeJJT/YWYkEIId07/7v1 vMnCsZSQ4y6tcoJ1zF8c7Uz8bIcRDfJuraVExltVwZY6POvTbq5O3rKT/QmHA5CeGXRY nwVofB0ubnhqYa3YD/gr7zlis/HEGi3CFx1nFKg/1Sd7Nqqn7Gp3I2qfBkx5uSNpdftt Y/MA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:subject:date:message-id :in-reply-to:references; bh=0tPBtL9keUvNLTs1GZkxbj0io/qBexCcVC2yNO1P568=; b=goCwaMfJK6bdSq7iNOuVHYZ8Fr3lbHxS24ZuDWmmjFRcbTxLjJzBz7af8refAZgp8g WrhxHYSYj4zNfz2AxWM4PG+MgeTnVcrbk/YtXpt4llnonr20U8WNKSDPgPMK0/xuWdqg SSBBGzusO05odJX+W4EMiTKWraR8Zd/ZZwSxETc8rhQqWUgoE/It6D3xvNFwOBA7M2LX lkIytciAV2fq5GdmGL7bN2MLyncW+cKuXHq8pOFH7Ckp3vl5Agv2BUv1i2blQlABDDat yTag220MT951mfhu/yyhYarZMBTkCGM7+P1om0rpbqUYEznpTuLCxNOQ8JGXdjgdSgjS 8LWg== X-Gm-Message-State: AIVw112J7ngtqw0Ebjtg7CMrQTFTlpQF4Yy2zOFeOaEjGRM/9o1Ie3xM XYRMCHc8kYfSKw== X-Received: by 10.36.250.129 with SMTP id v123mr2035106ith.17.1501767933581; Thu, 03 Aug 2017 06:45:33 -0700 (PDT) Received: from localhost.localdomain (50-108-95-251.adr01.mskg.mi.frontiernet.net. [50.108.95.251]) by smtp.gmail.com with ESMTPSA id q90sm5759547ioi.41.2017.08.03.06.45.32 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 03 Aug 2017 06:45:32 -0700 (PDT) From: Trond Myklebust To: Chuck Lever , linux-nfs@vger.kernel.org Subject: [PATCH v2 02/28] NFS: Reduce lock contention in nfs_page_find_head_request() Date: Thu, 3 Aug 2017 09:44:57 -0400 Message-Id: <20170803134523.4922-3-trond.myklebust@primarydata.com> X-Mailer: git-send-email 2.13.3 In-Reply-To: <20170803134523.4922-2-trond.myklebust@primarydata.com> References: <20170803134523.4922-1-trond.myklebust@primarydata.com> <20170803134523.4922-2-trond.myklebust@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add a lockless check for whether or not the page might be carrying an existing writeback before we grab the inode->i_lock. Reported-by: Chuck Lever Signed-off-by: Trond Myklebust --- fs/nfs/write.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 1d447e37f472..06e150c4e315 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -190,9 +190,11 @@ static struct nfs_page *nfs_page_find_head_request(struct page *page) struct inode *inode = page_file_mapping(page)->host; struct nfs_page *req = NULL; - spin_lock(&inode->i_lock); - req = nfs_page_find_head_request_locked(NFS_I(inode), page); - spin_unlock(&inode->i_lock); + if (PagePrivate(page) || PageSwapCache(page)) { + spin_lock(&inode->i_lock); + req = nfs_page_find_head_request_locked(NFS_I(inode), page); + spin_unlock(&inode->i_lock); + } return req; }