Received: by 2002:a25:1506:0:0:0:0:0 with SMTP id 6csp4332895ybv;
        Mon, 10 Feb 2020 17:16:33 -0800 (PST)
X-Google-Smtp-Source: APXvYqx/mLIEESAEyjjF7LYi+9YzQ8ETqPW9Qo+rqtp1GxZosAP9PP4eVX156doQ1lA/TLW1wY+1
X-Received: by 2002:aca:48cd:: with SMTP id v196mr1399233oia.102.1581383793750;
        Mon, 10 Feb 2020 17:16:33 -0800 (PST)
ARC-Seal: i=1; a=rsa-sha256; t=1581383793; cv=none;
        d=google.com; s=arc-20160816;
        b=HWgpQOX7vCyA3hicqlFFeIxx8LKtcA+sYVBOp/nQ1r1V6FB3s3PtZuiq8YNoyAW71R
         C+IpD7VzDx4MWt0SEVYpbb24jxyca2S2j5xpFraGWc8QS02nkl7jpX/wu6ODHuipiuWO
         xlFcfVq/0rTmm2l3kU30+/3eKlstPEqeeaevrGs9wLyeffs9VZlde6emPkHIxj3rwNzw
         G44sd9hN5qDRUsUi+4Gv7Mz8t2s40GlRFhHskxdbOdFek0MERqnHRIf1FnPhu31j4AGL
         MeXODvWcDClUmg28cs8IZ+gUuIaUQzuPP812XFnZkvVO/yp4fMVfHymFhT4xdW1il8tL
         caxg==
ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816;
        h=list-id:precedence:sender:in-reply-to:content-disposition
         :mime-version:references:message-id:subject:cc:to:from:date
         :dkim-signature;
        bh=Vtx3GuoucCB7GHmDuyJEH6fVHqrp/1ZumwqI2mL1l24=;
        b=BGWzXD0QjiR9oOUuP4Vf86ImDAPHhPRaXmQip/qNvx7ZI1xtk1cyK17rwpTVK66z2+
         jXTy6f897eEikNkOEc2BFOVytPv93NdVwTZ+8dta4kG84HiarD5iNc+YjXlms3OAhmRW
         /wujZuZVRSvbV6oPrHfnGe72OAx59zK7cwCnsLVD0JS0kvsuPnJ3pc1oDfyZ8luWQntN
         A0m77CH2FdPdm9OJvEo57RIf6P32S7oWZrdE3yTbByIc0wepNLtHhq8V9r+cLkjV7pr2
         hh8zSKM7BIdg1nSmKt93DosoCikPzC8kHkgdkCkeKN32KmKH30XgtlzHf+IxdRJ6glcr
         m62Q==
ARC-Authentication-Results: i=1; mx.google.com;
       dkim=fail header.i=@infradead.org header.s=bombadil.20170209 header.b=UfzGHdBQ;
       spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67])
        by mx.google.com with ESMTP id q189si974119oic.235.2020.02.10.17.16.18;
        Mon, 10 Feb 2020 17:16:33 -0800 (PST)
Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Authentication-Results: mx.google.com;
       dkim=fail header.i=@infradead.org header.s=bombadil.20170209 header.b=UfzGHdBQ;
       spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1727652AbgBKBK0 (ORCPT <rfc822;zcyberian@gmail.com> + 99 others);
        Mon, 10 Feb 2020 20:10:26 -0500
Received: from bombadil.infradead.org ([198.137.202.133]:55358 "EHLO
        bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1727575AbgBKBKZ (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Mon, 10 Feb 2020 20:10:25 -0500
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed;
        d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version
        :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To:
        Content-Transfer-Encoding:Content-ID:Content-Description;
        bh=Vtx3GuoucCB7GHmDuyJEH6fVHqrp/1ZumwqI2mL1l24=; b=UfzGHdBQv58rdN0fTCxFUQMUML
        6aRCWb0mQMzxLmctfZv4Ar0eK3ud5abaYIYVXGCl1FKucrkL/b5S7X2fUWzhrUnFHqVVWWhjA0ApF
        GDYvAfbLvR57bnyvmU04VGEpKQFlLek+UlkWrybi/bTUnUoGb5IZW7+y565jQJcnlh5NIDWVPxjro
        7E8PY24rHv6x8BoXdWCmdICj3E43+/8MKOq5UPX+NiuDLYqbZlwN/quukXUzzuDNx3Ht3KNZbachV
        nNQOiM2P5WHVen9pJWoWQ5Z/ildtTuAA/En9XeDOtJiV7aptvCQIFS5RFUasjGqUj+VtGoYSh8TwV
        C/rL77aw==;
Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux))
        id 1j1K4E-00053D-0Q; Tue, 11 Feb 2020 01:10:22 +0000
Date:   Mon, 10 Feb 2020 17:10:21 -0800
From:   Matthew Wilcox <willy@infradead.org>
To:     Minchan Kim <minchan@kernel.org>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        linux-mm <linux-mm@kvack.org>,
        Josef Bacik <josef@toxicpanda.com>,
        Johannes Weiner <hannes@cmpxchg.org>, Jan Kara <jack@suse.cz>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: fix long time stall from mm_populate
Message-ID: <20200211011021.GP8731@bombadil.infradead.org>
References: <20200211001958.170261-1-minchan@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20200211001958.170261-1-minchan@kernel.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Mon, Feb 10, 2020 at 04:19:58PM -0800, Minchan Kim wrote:
>       filemap_fault
>         find a page form page(PG_uptodate|PG_readahead|PG_writeback)

Uh ... That shouldn't be possible.

        /*
         * Same bit is used for PG_readahead and PG_reclaim.
         */
        if (PageWriteback(page))
                return;

        ClearPageReadahead(page);