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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 E02B2C2BB1D for ; Sun, 15 Mar 2020 12:22:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B7DE720578 for ; Sun, 15 Mar 2020 12:22:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="chYAt6y0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728514AbgCOMWV (ORCPT ); Sun, 15 Mar 2020 08:22:21 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:39333 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728480AbgCOMWV (ORCPT ); Sun, 15 Mar 2020 08:22:21 -0400 Received: by mail-wr1-f66.google.com with SMTP id r15so17766812wrx.6 for ; Sun, 15 Mar 2020 05:22:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:reply-to:references:mime-version :content-disposition:in-reply-to:user-agent; bh=/Kx5mSt5kBh7FsLH+0N/pfeCSX6lxtBaeY/mUDaY9J4=; b=chYAt6y0eCvcUVZE3gi3UBUzNUzKL+vQ1CMKCFG1y5sNExXx+3T8iGg0e83kjBmxrm YWmLFF335HRNA7cfnN7z9efqWMpah8o9G5+f28jKF1e4G4yCwB83Q2nieWSKqsz8zf4f +WtQUcWBgizHrzbXLH6FYcUPSIulaR8QifpA6Hn8IoGSYYJMBfR+tKDtX765FwgXq93R PX67+DjGRSnNHhNZYg0a7qjblj627lIvZ6g/JDDcMXNWzIP7GqbemQvAsJP4stqJEv4s pH+LeEsvuP8ljdQg0TjWtOVX2zyy5XDMgasvecY67rK/oc+2X0CrzzzWi9WkG/amCziB 6iow== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:reply-to :references:mime-version:content-disposition:in-reply-to:user-agent; bh=/Kx5mSt5kBh7FsLH+0N/pfeCSX6lxtBaeY/mUDaY9J4=; b=qJdqq2N44mNGqNro1ZgB3WTOJvgGdRBTDMPjYxCvDycwDmeO7Ky9oxW4fWRbNUxMsf aj0lXnNHP8mKqaWCohHvvUdeyb4OZk9XkX5MhVHxWa8cPNXFv/dWdaA08K064ZVdzjdQ 92kXsfcKsDvR3+/dTp/jbYxnT6OkAW2kBo8mXrgUBviqIPyMoWCcRgKnJ3rp7BCaSDxW KBwZhLA+K+qXmJSIzhGvZbKd3Y1zX7jovsgsFJaCMHlZ9A5rCs5uT4siHPEOqOlIke3c 5lh+rn7hrVq4o8qt8PUejt8Oh+ljruL98YdJTXqa+6SrnLdwd6kjbOPrTvPuwZZ/4qct 5teA== X-Gm-Message-State: ANhLgQ199SLudcxtP1OMKUBey9Y4yK3GQCdrleqrhpM1Bj1+2lbGet34 FdrAS30dSDHc5KuVhbygIc1pW1ES X-Google-Smtp-Source: ADFU+vt66/Ql4uCVh3eduLr+kYFsxKgtN259zBw/vcwySrA50rU0Bvrq10gHgvRGjWQI7Jq7qzwsIg== X-Received: by 2002:a5d:6a8d:: with SMTP id s13mr29885645wru.260.1584274939361; Sun, 15 Mar 2020 05:22:19 -0700 (PDT) Received: from localhost ([185.92.221.13]) by smtp.gmail.com with ESMTPSA id x16sm23743836wrg.44.2020.03.15.05.22.18 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sun, 15 Mar 2020 05:22:18 -0700 (PDT) Date: Sun, 15 Mar 2020 12:22:17 +0000 From: Wei Yang To: Mika Penttil?? Cc: Wei Yang , "Huang, Ying" , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Dave Hansen , David Hildenbrand , Mel Gorman , Vlastimil Babka , Zi Yan , Michal Hocko , Peter Zijlstra , Minchan Kim , Johannes Weiner , Hugh Dickins Subject: Re: [RFC 2/3] mm: Add a new page flag PageLayzyFree() for MADV_FREE Message-ID: <20200315122217.45mioaxzuulwvx2f@master> Reply-To: Wei Yang References: <20200228033819.3857058-1-ying.huang@intel.com> <20200228033819.3857058-3-ying.huang@intel.com> <20200315081854.rcqlmfckeqrh7fbt@master> <92d4b0fe-f592-8da6-0282-2ea8a015b247@nextfour.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <92d4b0fe-f592-8da6-0282-2ea8a015b247@nextfour.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Mar 15, 2020 at 10:54:03AM +0200, Mika Penttil?? wrote: > > >On 15.3.2020 10.18, Wei Yang wrote: >> On Fri, Feb 28, 2020 at 11:38:18AM +0800, Huang, Ying wrote: >> > From: Huang Ying >> > >> > Now !PageSwapBacked() is used as the flag for the pages freed lazily >> > via MADV_FREE. This isn't obvious enough. So Dave suggested to add a >> > new page flag for that to improve the code readability. >> I am confused with the usage of PageSwapBacked(). >> >> Previously I thought this flag means the page is swapin, set in >> swapin_readahead(). While I found page_add_new_anon_rmap() would set it too. >> This means every anon page would carry this flag. Then what is this flag >> means? >> >> > >But not all PageSwapBacked() pages are anon, like shmem. > Yes, while it looks shmem is the only exception. I am still struggling to understand the meaning of this flag. > >--Mika -- Wei Yang Help you, Help me