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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 13432C433DF for ; Sun, 17 May 2020 11:12:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBC8A206F4 for ; Sun, 17 May 2020 11:12:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lca.pw header.i=@lca.pw header.b="gVfUAYDo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727907AbgEQLMh (ORCPT ); Sun, 17 May 2020 07:12:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57618 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727832AbgEQLMg (ORCPT ); Sun, 17 May 2020 07:12:36 -0400 Received: from mail-qt1-x82e.google.com (mail-qt1-x82e.google.com [IPv6:2607:f8b0:4864:20::82e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4F2A7C061A0C for ; Sun, 17 May 2020 04:12:36 -0700 (PDT) Received: by mail-qt1-x82e.google.com with SMTP id c24so5811367qtw.7 for ; Sun, 17 May 2020 04:12:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lca.pw; s=google; h=content-transfer-encoding:from:mime-version:subject:date:message-id :references:cc:in-reply-to:to; bh=Zyl3SarFIasLxbZ+RIzpA3l1T3ELrj/FBTllereD9vE=; b=gVfUAYDorbrrcavuF+7jzMivSWiuHH+HWijoJzN3x7+36DiWCaaXZeshs+HeYjbaVn sGCIdzXE40/UKgJpzhp6xtYBzBttOR1dp0VfiBDyCwjXB0YfyAe6xiHM89fH0ZP3ahLL UhcWS/esXKCSeQcqrLW+7fpfza1HvO8lSghtmjsxG8/YGZCa3aOtGDgCrymKSfNZOQBf nA7McKvnwl3+7T8j+oBVAMFpmLWFAUusLSQ1cNwHflYRsvbUIfre1u0PiJc1Olkvk+NY wxqDt8f4P1AJMRy/r8DBlmxXn+MNt/9s24JKgmQAGONF0XNS4AUhbTlErFPS7ie6dOyR zkkw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:content-transfer-encoding:from:mime-version :subject:date:message-id:references:cc:in-reply-to:to; bh=Zyl3SarFIasLxbZ+RIzpA3l1T3ELrj/FBTllereD9vE=; b=PuWjLAlCxhEaLP+Db+dANv6h2+EV1Sq+yfCpTNBkRPyVC3ITeX2BVqeekaabTbD15G ELQQGRkgyHQup3Ar+fZtWbUIMlGSJmEgI0iK8d2Tmpj7+/v8YtIred6Bcl3gGcR3xYT+ foIS9xUAMH51o2rrsjTlJFvTZiQZXbLuGZIrxFDF6kRkKIGxgZl+xMyYUG0gnPfQeSTR ogWsBXnrl29e+vhi5ci8w0U68OGzGl+GbKdirSY31H8o910H7lY5theJ3Sive6u3Jz7x c0N0+u6+CzmgLRp6MhbjZr+UsY/meod1aeVFqBkKzBjdUETy99hgZ56MgQZsBTjmaq94 hkjg== X-Gm-Message-State: AOAM5323eRx+JDUiAveOW5Hkyfrmy5sGp5ah0R4dERU2JMHdZihVffxS 1DGooWMXo663vmpdkl+hhiuCew== X-Google-Smtp-Source: ABdhPJxm+Z6psJVh1daO567GdnW4roVUxYUbV5oTdCairc5qpsrr0Ja8dmh8CYKiFCVFihyKb1Eg+w== X-Received: by 2002:ac8:4650:: with SMTP id f16mr11496052qto.168.1589713954634; Sun, 17 May 2020 04:12:34 -0700 (PDT) Received: from [192.168.1.183] (pool-71-184-117-43.bstnma.fios.verizon.net. [71.184.117.43]) by smtp.gmail.com with ESMTPSA id h22sm6512975qtn.23.2020.05.17.04.12.33 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 17 May 2020 04:12:33 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable From: Qian Cai Mime-Version: 1.0 (1.0) Subject: Re: "BUG: MAX_LOCKDEP_ENTRIES too low" with 6979 "&type->s_umount_key" Date: Sun, 17 May 2020 07:12:33 -0400 Message-Id: <06E43DA0-9976-4D44-AC72-5ED8A7022FA3@lca.pw> References: Cc: Peter Zijlstra , Will Deacon , Ingo Molnar , David Howells , Alexander Viro , linux-fsdevel@vger.kernel.org, Linux Kernel Mailing List In-Reply-To: To: Waiman Long X-Mailer: iPhone Mail (17E262) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On May 16, 2020, at 9:16 PM, Waiman Long wrote: >=20 > The lock_list table entries are for tracking a lock's forward and backward= dependencies. The lockdep_chains isn't the right lockdep file to look at. I= nstead, check the lockdep files for entries with the maximum BD (backward de= pendency) + FD (forward dependency). That will give you a better view of whi= ch locks are consuming most of the lock_list entries. Also take a look at lo= ckdep_stats for an overall view of how much various table entries are being c= onsumed. Thanks for the hint. It seems something in vfs is the culprit because every s= ingle one of those triggering from path_openat() (vfs_open()) or vfs_get_tre= e() When the system after boot, lock_list entries is around 10000. After running= LTP syscalls and mm tests, the number is around 20000. Then, it will go all= the way over the max (32700) while running LTP fs tests. Most of the time f= rom a test that would read every single file in sysfs. I=E2=80=99ll decode the lockdep file to see if there is any more clues.=