From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S965148AbcFMJid (ORCPT <rfc822;w@1wt.eu>);
	Mon, 13 Jun 2016 05:38:33 -0400
Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:62851 "EHLO
	mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL)
	by vger.kernel.org with ESMTP id S964895AbcFMJib (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Mon, 13 Jun 2016 05:38:31 -0400
X-IBM-Helo: d23dlp02.au.ibm.com
X-IBM-MailFrom: khandual@linux.vnet.ibm.com
X-IBM-RcptTo: linux-kernel@vger.kernel.org
Date: Mon, 13 Jun 2016 15:08:19 +0530
From: Anshuman Khandual <khandual@linux.vnet.ibm.com>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0
MIME-Version: 1.0
To: Minchan Kim <minchan@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>
CC: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Rik van Riel <riel@redhat.com>, Vlastimil Babka <vbabka@suse.cz>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>, Mel Gorman <mgorman@suse.de>,
        Hugh Dickins <hughd@google.com>, Rafael Aquini <aquini@redhat.com>,
        virtualization@lists.linux-foundation.org,
        Jonathan Corbet <corbet@lwn.net>,
        John Einar Reitan <john.reitan@foss.arm.com>,
        dri-devel@lists.freedesktop.org,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Gioh Kim <gi-oh.kim@profitbricks.com>
Subject: Re: [PATCH v6v3 02/12] mm: migrate: support non-lru movable page
 migration
References: <1463754225-31311-1-git-send-email-minchan@kernel.org> <1463754225-31311-3-git-send-email-minchan@kernel.org> <20160530013926.GB8683@bbox> <20160531000117.GB18314@bbox>
In-Reply-To: <20160531000117.GB18314@bbox>
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit
X-TM-AS-MML: disable
X-Content-Scanned: Fidelis XPS MAILER
x-cbid: 16061309-0016-0000-0000-000001A4D78A
X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused
x-cbparentid: 16061309-0017-0000-0000-000004D00C7D
Message-Id: <575E7F0B.8010201@linux.vnet.ibm.com>
X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-06-13_05:,,
 signatures=0
X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0
 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam
 adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000
 definitions=main-1606130107
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 05/31/2016 05:31 AM, Minchan Kim wrote:
> @@ -791,6 +921,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
>  	int rc = -EAGAIN;
>  	int page_was_mapped = 0;
>  	struct anon_vma *anon_vma = NULL;
> +	bool is_lru = !__PageMovable(page);
>  
>  	if (!trylock_page(page)) {
>  		if (!force || mode == MIGRATE_ASYNC)
> @@ -871,6 +1002,11 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
>  		goto out_unlock_both;
>  	}
>  
> +	if (unlikely(!is_lru)) {
> +		rc = move_to_new_page(newpage, page, mode);
> +		goto out_unlock_both;
> +	}
> +

Hello Minchan,

I might be missing something here but does this implementation support the
scenario where these non LRU pages owned by the driver mapped as PTE into
process page table ? Because the "goto out_unlock_both" statement above
skips all the PTE unmap, putting a migration PTE and removing the migration
PTE steps.

Regards
Anshuman