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=-7.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 77BB4C56202 for ; Sun, 22 Nov 2020 00:02:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3179D20BED for ; Sun, 22 Nov 2020 00:02:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fieldses.org header.i=@fieldses.org header.b="jfh63sDn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726365AbgKVACT (ORCPT ); Sat, 21 Nov 2020 19:02:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59270 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726175AbgKVACT (ORCPT ); Sat, 21 Nov 2020 19:02:19 -0500 Received: from fieldses.org (fieldses.org [IPv6:2600:3c00:e000:2f7::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C2306C0613CF for ; Sat, 21 Nov 2020 16:02:18 -0800 (PST) Received: by fieldses.org (Postfix, from userid 2815) id ACC146E9D; Sat, 21 Nov 2020 19:02:16 -0500 (EST) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org ACC146E9D DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1606003336; bh=kWiXqsqeeKzuPgJ9oSmEHy6qJ3vVeCE9G6JG2XvAEcA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jfh63sDn1EXARSSRVaTExaxnub3oSs4zE40opNkYx/XWm9kAMn2mp8XVr1SDePhXE BDrhDH64yIZktuj9Q4uIU21X9DKF2DGQ3PsaOGZYkBE4BuX7wyRxits/Cj9tKIqHkc h+ZCc0hKwobvx3vhVAverFqtsJ288J41MTkTGZFQ= Date: Sat, 21 Nov 2020 19:02:16 -0500 From: bfields To: Daire Byrne Cc: Jeff Layton , "J. Bruce Fields" , Trond Myklebust , linux-cachefs , linux-nfs Subject: Re: [PATCH 2/4] nfsd: pre/post attr is using wrong change attribute Message-ID: <20201122000216.GE3476@fieldses.org> References: <20201117031601.GB10526@fieldses.org> <1605583086-19869-2-git-send-email-bfields@redhat.com> <20201117152636.GC4556@fieldses.org> <725499c144317aac1a03f0334a22005588dbdefc.camel@kernel.org> <20201120223831.GB7705@fieldses.org> <20201120224438.GC7705@fieldses.org> <5f8e9e0cb53c89a7d1c156a6799c6dbc6db96dae.camel@kernel.org> <1758069641.91412432.1605995069116.JavaMail.zimbra@dneg.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1758069641.91412432.1605995069116.JavaMail.zimbra@dneg.com> User-Agent: Mutt/1.5.21 (2010-09-15) Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Sat, Nov 21, 2020 at 09:44:29PM +0000, Daire Byrne wrote: > ----- On 21 Nov, 2020, at 01:03, Jeff Layton jlayton@kernel.org wrote: > > On Fri, 2020-11-20 at 17:44 -0500, J. Bruce Fields wrote: > >> On Fri, Nov 20, 2020 at 05:38:31PM -0500, J. Bruce Fields wrote: > >> > I think the first one's all that's needed to fix the problem Daire > >> > identified. I'm a little less sure of the rest. > > I can confirm that patch 1/8 alone does indeed address the reported revalidation issue for us (as did the previous patch). The re-export server's client cache seems to remain intact and can serve the same cached results to multiple clients. Thanks again for the testing. > I should also mention that I still see a lot of unexpected repeat > lookups even with the iversion optimisation patches with certain > workloads. For example, looking at a network capture on the re-export > server I might see 100s of getattr calls to the originating server for > the same filehandle within 30 seconds which I would have expected the > client cache to serve. But it could also be that the client cache is > under memory pressure and not holding that data for very long. That sounds weird. Is the filehandle for a file or a directory? Is the file or directory actually changing at the time, and if so, is it the client that's changing it? Remind me what the setup is--a v3 re-export of a v4 mount? --b. > But now I do wonder if these NFSv4 directory modifications and > pre/post change attributes could be one potential contributor? I might > run some production loads with a v3 re-export of a v3 server to see if > that changes anything. > > Many thanks again for the patches, I will take the entire set and run > them through our production re-export workloads to see if anything > shakes out. > > Daire