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 39D54CA9EB9 for ; Wed, 23 Oct 2019 15:51:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0F4932086D for ; Wed, 23 Oct 2019 15:51:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lca.pw header.i=@lca.pw header.b="skavQFPt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406854AbfJWPvs (ORCPT ); Wed, 23 Oct 2019 11:51:48 -0400 Received: from mail-qt1-f193.google.com ([209.85.160.193]:36809 "EHLO mail-qt1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403945AbfJWPvs (ORCPT ); Wed, 23 Oct 2019 11:51:48 -0400 Received: by mail-qt1-f193.google.com with SMTP id d17so18378321qto.3 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=W6aM8920/IsPLxWFaYnYTR//WZ+Lc1LmXoDsjZt0v1tOdZJW2uJhclnZ10YTi7Y/A2 lAiCUXShADBmDY8iMgv3jMt9ryBqSQowyTc5Fyto6IKNnq017RAfyQvPeF0xQC1Yfgyv ur0/k26xLnq4mSasCBzuz5ZIueIEJmvLBGFX0oSRtCxTNQAyh48pgMPnXqpwPt06kQFJ Z5rhw2FBUaaofg9JYM3mulZT5X7JCYxKvshGGH8VnrtlvZLwLE0NQH0x/wpRAT3fw4VE Uoo7F01Fv5FUWthSUnjY7ox27fvedP5Eg+lxIZdTj3O/WsaRUXEq1tKDJ6YJfszT0xtr m/pw== X-Gm-Message-State: APjAAAWbEWZG8aQKZNUIW9WMq/X6xz7ynWkXD8smgCkKmGUaqsSMK+mL M+844DK7be0HzVX+WZ0wp59r7Q== 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 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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.