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Date: Thu, 27 Apr 2017 09:59:22 +0200
From: Michal Hocko <mhocko@kernel.org>
To: linux-mm@kvack.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Mel Gorman <mgorman@suse.de>, Vlastimil Babka <vbabka@suse.cz>,
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        Igor Mammedov <imammedo@redhat.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 08/13] mm, compaction: skip over holes in
 __reset_isolation_suitable
Message-ID: <20170427075922.GC4706@dhcp22.suse.cz>
References: <20170421120512.23960-1-mhocko@kernel.org>
 <20170421120512.23960-9-mhocko@kernel.org>
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On Fri 21-04-17 14:05:11, Michal Hocko wrote:
> From: Michal Hocko <mhocko@suse.com>
> 
> __reset_isolation_suitable walks the whole zone pfn range and it tries
> to jump over holes by checking the zone for each page. It might still
> stumble over offline pages, though. Skip those by checking PageReserved.

ups, forgot to update the changelog here. s@PageReserved@pfn_to_online_page()@
 
> Signed-off-by: Michal Hocko <mhocko@suse.com>
> ---
>  mm/compaction.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/compaction.c b/mm/compaction.c
> index 613c59e928cb..fb548e4c7bd4 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -236,10 +236,9 @@ static void __reset_isolation_suitable(struct zone *zone)
>  
>  		cond_resched();
>  
> -		if (!pfn_valid(pfn))
> +		page = pfn_to_online_page(pfn);
> +		if (!page)
>  			continue;
> -
> -		page = pfn_to_page(pfn);
>  		if (zone != page_zone(page))
>  			continue;
>  
> -- 
> 2.11.0
> 

-- 
Michal Hocko
SUSE Labs