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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 A9680C433E0 for ; Thu, 18 Jun 2020 02:28:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7D75A2192A for ; Thu, 18 Jun 2020 02:28:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592447291; bh=Il+45iujVCYEqM5m6qUHQmdBDfODZnNhkilSBuA698g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZeV2FIKDEudC28MqNK6QntMWsJbL2lQdhF3pKEIadOZbenA2DCMRGNGPsFr/5vMl0 lJLR/kTHanc+oH/R/EZ3vzgDrPyQe4wuTh6BQbd04aI3zdzQEaJuDAZ4KcCrF3P5/+ tmXWiWs0PsRgz3Wlw8XcU26guA8gzWW9ZA+xlpqE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728775AbgFRBQ1 (ORCPT ); Wed, 17 Jun 2020 21:16:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:46498 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728503AbgFRBQT (ORCPT ); Wed, 17 Jun 2020 21:16:19 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 94565206F1; Thu, 18 Jun 2020 01:16:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592442979; bh=Il+45iujVCYEqM5m6qUHQmdBDfODZnNhkilSBuA698g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FEVSBByQ2cWOjSfASPgx2tKY2JMj3drUnppnVLGC63TV1FZrvMGZ4fynMFL9DyXdr AVZ3xV6HzY0KUSivqbz9k5PEsrDxPd0HiUgp1iMFwecrHgjEfHB+tDah/XdirmWW8A HCTZ8hwPvqWD0QRRms1U7E4z8cyYP2etxr7BLZrY= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Chuck Lever , Anna Schumaker , Sasha Levin , linux-nfs@vger.kernel.org Subject: [PATCH AUTOSEL 5.7 381/388] NFS: Fix direct WRITE throughput regression Date: Wed, 17 Jun 2020 21:07:58 -0400 Message-Id: <20200618010805.600873-381-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200618010805.600873-1-sashal@kernel.org> References: <20200618010805.600873-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org From: Chuck Lever [ Upstream commit ba838a75e73f55a780f1ee896b8e3ecb032dba0f ] I measured a 50% throughput regression for large direct writes. The observed on-the-wire behavior is that the client sends every NFS WRITE twice: once as an UNSTABLE WRITE plus a COMMIT, and once as a FILE_SYNC WRITE. This is because the nfs_write_match_verf() check in nfs_direct_commit_complete() fails for every WRITE. Buffered writes use nfs_write_completion(), which sets req->wb_verf correctly. Direct writes use nfs_direct_write_completion(), which does not set req->wb_verf at all. This leaves req->wb_verf set to all zeroes for every direct WRITE, and thus nfs_direct_commit_completion() always sets NFS_ODIRECT_RESCHED_WRITES. This fix appears to restore nearly all of the lost performance. Fixes: 1f28476dcb98 ("NFS: Fix O_DIRECT commit verifier handling") Signed-off-by: Chuck Lever Signed-off-by: Anna Schumaker Signed-off-by: Sasha Levin --- fs/nfs/direct.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index a57e7c72c7f4..d49b1d197908 100644 --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -731,6 +731,8 @@ static void nfs_direct_write_completion(struct nfs_pgio_header *hdr) nfs_list_remove_request(req); if (request_commit) { kref_get(&req->wb_kref); + memcpy(&req->wb_verf, &hdr->verf.verifier, + sizeof(req->wb_verf)); nfs_mark_request_commit(req, hdr->lseg, &cinfo, hdr->ds_commit_idx); } -- 2.25.1