Message-ID: <544E1F70.1030106@suse.cz>
Date: Mon, 27 Oct 2014 11:33:20 +0100
From: Vlastimil Babka <vbabka@suse.cz>
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To: Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>
CC: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Rik van Riel <riel@redhat.com>, Peter Zijlstra <peterz@infradead.org>,
        Mel Gorman <mgorman@suse.de>, Johannes Weiner <hannes@cmpxchg.org>,
        Minchan Kim <minchan@kernel.org>,
        Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>,
        Zhang Yanfei <zhangyanfei@cn.fujitsu.com>,
        Tang Chen <tangchen@cn.fujitsu.com>,
        Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        Wen Congyang <wency@cn.fujitsu.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Michal Nazarewicz <mina86@mina86.com>,
        Laura Abbott <lauraa@codeaurora.org>,
        Heesub Shin <heesub.shin@samsung.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
        Ritesh Harjani <ritesh.list@gmail.com>, t.stanislaws@samsung.com,
        Gioh Kim <gioh.kim@lge.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH v4 1/4] mm/page_alloc: fix incorrect isolation behavior
 by rechecking migratetype
References: <1414051821-12769-1-git-send-email-iamjoonsoo.kim@lge.com> <1414051821-12769-2-git-send-email-iamjoonsoo.kim@lge.com>
In-Reply-To: <1414051821-12769-2-git-send-email-iamjoonsoo.kim@lge.com>
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Sender: linux-kernel-owner@vger.kernel.org

On 10/23/2014 10:10 AM, Joonsoo Kim wrote:
> Changes from v3:
> Add one more check in free_one_page() that checks whether migratetype is
> MIGRATE_ISOLATE or not. Without this, abovementioned case 1 could happens.

Good catch.

> Cc: <stable@vger.kernel.org>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

Acked-by: Vlastimil Babka <vbabka@suse.cz>

(minor suggestion below)

> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -749,9 +749,16 @@ static void free_one_page(struct zone *zone,
>  	if (nr_scanned)
>  		__mod_zone_page_state(zone, NR_PAGES_SCANNED, -nr_scanned);
>  
> +	if (unlikely(has_isolate_pageblock(zone) ||

Would it make any difference if this was read just once and not in each
loop iteration?


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