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=-0.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_SBL,URIBL_SBL_A 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 7DD0AC43381 for ; Fri, 8 Mar 2019 23:15:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4AFA62064A for ; Fri, 8 Mar 2019 23:15:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726588AbfCHXPQ (ORCPT ); Fri, 8 Mar 2019 18:15:16 -0500 Received: from trent.utfs.org ([94.185.90.103]:41336 "EHLO trent.utfs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726379AbfCHXPQ (ORCPT ); Fri, 8 Mar 2019 18:15:16 -0500 Received: from localhost (localhost [IPv6:::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by trent.utfs.org (Postfix) with ESMTPS id 0F87D602A3; Sat, 9 Mar 2019 00:15:14 +0100 (CET) Date: Fri, 8 Mar 2019 15:15:14 -0800 (PST) From: Christian Kujau To: David Howells cc: linux-kernel@vger.kernel.org, Anna Schumaker , Steve Dickson Subject: Re: FS-Cache: Duplicate cookie detected In-Reply-To: <17155.1552056554@warthog.procyon.org.uk> Message-ID: References: <22096.1551878195@warthog.procyon.org.uk> <10106.1551892803@warthog.procyon.org.uk> <17155.1552056554@warthog.procyon.org.uk> User-Agent: Alpine 2.21.999 (DEB 277 2018-05-20) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 8 Mar 2019, David Howells wrote: > See the attached for a patch that helps with certain kinds of collision, > though I can't see that it should help with what you're seeing since the > RELINQUISHED flag isn't set on the old cookie (fl=222, but 0x10 isn't in > there). You can monitor the number of waits by looking in > /proc/fs/fscache/stats for the: > > Acquire: n=289166 nul=0 noc=0 ok=286331 nbf=2 oom=0 wrq=23748 Running Linux v5.0 with this patch applied does indeed still produce the "Duplicate cookie detected" messages, but I only ever see wrq=0 when running nfstest_cache: https://paste.fedoraproject.org/paste/dkav0FQzYZxE9-V7GphjAQ (Scroll down until the messages start to appear again) Only the n= field seems to change during that test: fedora0# grep wrq n2.log | sort | uniq -c | sort -n 28 Acquire: n=8 nul=0 noc=0 ok=1 nbf=0 oom=0 wrq=0 29 Acquire: n=7 nul=0 noc=0 ok=1 nbf=0 oom=0 wrq=0 34 Acquire: n=6 nul=0 noc=0 ok=1 nbf=0 oom=0 wrq=0 82 Acquire: n=9 nul=0 noc=0 ok=1 nbf=0 oom=0 wrq=0 93 Acquire: n=5 nul=0 noc=0 ok=1 nbf=0 oom=0 wrq=0 HTH, Christian. -- BOFH excuse #5: static from plastic slide rules