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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_2 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 A9A2ECA9EB6 for ; Wed, 23 Oct 2019 15:51:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 619B22064A for ; Wed, 23 Oct 2019 15:51:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lca.pw header.i=@lca.pw header.b="skavQFPt" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 619B22064A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lca.pw Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id F00616B0003; Wed, 23 Oct 2019 11:51:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id EAFE66B0005; Wed, 23 Oct 2019 11:51:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D77936B0006; Wed, 23 Oct 2019 11:51:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0031.hostedemail.com [216.40.44.31]) by kanga.kvack.org (Postfix) with ESMTP id B32C46B0003 for ; Wed, 23 Oct 2019 11:51:48 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 5D5348249980 for ; Wed, 23 Oct 2019 15:51:48 +0000 (UTC) X-FDA: 76075489896.17.scarf74_841eb65bc0c2d X-HE-Tag: scarf74_841eb65bc0c2d X-Filterd-Recvd-Size: 4390 Received: from mail-qt1-f193.google.com (mail-qt1-f193.google.com [209.85.160.193]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Wed, 23 Oct 2019 15:51:47 +0000 (UTC) Received: by mail-qt1-f193.google.com with SMTP id c17so29979864qtn.8 for ; Wed, 23 Oct 2019 08:51:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lca.pw; s=google; h=message-id:subject:from:to:cc:date:in-reply-to:references :mime-version:content-transfer-encoding; bh=MxZvQ5ahYDyvo9zRmiCgox63DQt65JRMrjon3hrPmgU=; b=skavQFPt7lvx7dsxZg2sUqnDpF2yvxFgElf7B/R1pymBsjEs5w9lH2buBsjIAMjEl6 b2i+Zfs8l8hzJ5VJjSa9mqKk27YmQF5XMjYMAu1EhOderwR/zFbCj/I1xJKPM+wHXD5N l3+wMI6W0rvZnR5MuxVWazlHZs5YA9sQ+/O91xsLnH4CEAENIIYG1maEi9Nsw1BhnNrN BVKaxef7M3DH6kNmhi9xhTkC2IVenP3EiJ36E3tndqMhOEE07U9Bif7+WJKMjxasyZn6 R4SeyBahLSmgd5Ra17i19Fu0yXSsHnESJypkP6kI1LlH1lu/G9bFylZ76AoSAe/m8Z1A wM2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:mime-version:content-transfer-encoding; bh=MxZvQ5ahYDyvo9zRmiCgox63DQt65JRMrjon3hrPmgU=; b=bpVsIidE7kWQlaUw5o/Z2vdXDWx6rg0J6AFjN367zfR07RQTzeZwEsSmzMJFMbICrf cPAliC9SV7K4y/0au4zxYrSSWSKNUssmIyWhCBwPT96xb4C12KHNQdOsrI1Z02/JHzIL 7XxVyqrNNL5RMm76YPZGy5wrvtpYP72etHt1MrUDE3fJWR2d1UWdcmDXsUt81aAsMBDF hMZ7LnLxiW8QZ+GeynTACSqTbiemLPBs+zxkS4tp9XqY8uVrOYIDoH/55x4P0cJJUCnL eG7PBmQuje/sISumprx/DWlqK30upYT8UaTePNA5JPJ4gyZMU2eAlg5E4dpHEgLCHlP/ lk7w== X-Gm-Message-State: APjAAAW5RvqkgBkec+lubtZPPwyEmqZwCyGbWjJDvARtpcoTyJqvJjE7 YiD6k52hXJ3hTUa/aEfJbQR4bQ== X-Google-Smtp-Source: APXvYqxgRE1MSPCporiCYj6UuGJ4GgaFhDKdNNDojsygw+b3NW02XupzgPK+ACzdKNGC2OwjYi4tPw== X-Received: by 2002:ad4:53c8:: with SMTP id k8mr9677187qvv.240.1571845907082; Wed, 23 Oct 2019 08:51:47 -0700 (PDT) Received: from dhcp-41-57.bos.redhat.com (nat-pool-bos-t.redhat.com. [66.187.233.206]) by smtp.gmail.com with ESMTPSA id r36sm10713980qta.27.2019.10.23.08.51.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 23 Oct 2019 08:51:46 -0700 (PDT) Message-ID: <1571845904.5937.89.camel@lca.pw> Subject: Re: [PATCH] mm/vmstat: Reduce zone lock hold time when reading /proc/pagetypeinfo From: Qian Cai To: Rafael Aquini Cc: Waiman Long , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Johannes Weiner , Michal Hocko , Roman Gushchin , Vlastimil Babka , Konstantin Khlebnikov , Jann Horn , Song Liu , Greg Kroah-Hartman Date: Wed, 23 Oct 2019 11:51:44 -0400 In-Reply-To: <20191023150319.GD22601@optiplex-lnx> References: <20191022162156.17316-1-longman@redhat.com> <20191022145902.d9c4a719c0b32175e06e4eee@linux-foundation.org> <2236495a-ead0-e08e-3fb6-f3ab906b75b6@redhat.com> <1571842093.5937.84.camel@lca.pw> <20191023150319.GD22601@optiplex-lnx> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6 (3.22.6-10.el7) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, 2019-10-23 at 11:03 -0400, Rafael Aquini wrote: > > > > this still isn't a bulletproof fix. Maybe just terminate the list > > > > walk if freecount reaches 1024. Would anyone really care? > > > > > > > > Sigh. I wonder if anyone really uses this thing for anything > > > > important. Can we just remove it all? > > > > > > > > > > Removing it will be a breakage of kernel API. > > > > Who cares about breaking this part of the API that essentially nobody will use > > this file? > > > > Seems that _some_ are using it, aren't they? Otherwise we wouldn't be > seeing complaints. Moving it out of /proc to /sys/kernel/debug looks > like a reasonable compromise with those that care about the interface. No, there are some known testing tools will blindly read this file just because it exists which is not important to keep the file.