From patchwork Tue Jun 23 19:56:10 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 223153 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_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 3A3E7C433E0 for ; Tue, 23 Jun 2020 21:26:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 14C2220781 for ; Tue, 23 Jun 2020 21:26:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592947598; bh=aOUdI9uRoCxAKootm2RDpqEy5nNznUOHDF9tGkse2iQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=CGkWxSgH6Z+Eiq6gbp8TZkLJBXL+R+qX20P+tVmFGDoG2PQbrbhdrnYukO7KnXdjw FxMpsu73n+/4Wd/Noo6IlKnEmQUKoHkKlAqy0COEdofHBHoZHulWZBstT2iwaGKURZ 3Yk2tmc1FSZsLnFOvvVstIfZ9I/NH5+HeQeAPka0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391064AbgFWV0f (ORCPT ); Tue, 23 Jun 2020 17:26:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:34202 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389592AbgFWURr (ORCPT ); Tue, 23 Jun 2020 16:17:47 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 BF1E32137B; Tue, 23 Jun 2020 20:17:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592943467; bh=aOUdI9uRoCxAKootm2RDpqEy5nNznUOHDF9tGkse2iQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cIOJS2o/btazfsd6IMzkDz4jPs256F3SRvg1/rRsKCpenM4SdEXF7P3P2dkiFnI62 Zw3y7qpyrZboX2hU0Rsp1cjVVS4UEnZUbQosdf+i8qmO2s+lYBa3MXYyHT2MMMy2RQ rXVRnFMGBR+74Iuf/gnEAJakOJdHcyjDC8T6YlEI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chuck Lever , Anna Schumaker , Sasha Levin Subject: [PATCH 5.7 373/477] NFS: Fix direct WRITE throughput regression Date: Tue, 23 Jun 2020 21:56:10 +0200 Message-Id: <20200623195425.160972368@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200623195407.572062007@linuxfoundation.org> References: <20200623195407.572062007@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 a57e7c72c7f47..d49b1d1979084 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); }