Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1033143AbbKEIPG (ORCPT <rfc822;w@1wt.eu>);
	Thu, 5 Nov 2015 03:15:06 -0500
Received: from mx2.suse.de ([195.135.220.15]:60986 "EHLO mx2.suse.de"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1032718AbbKEIPE (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Thu, 5 Nov 2015 03:15:04 -0500
Subject: Re: [PATCH 1/5] mm, page_owner: print migratetype of a page, not
 pageblock
To: Joonsoo Kim <iamjoonsoo.kim@lge.com>
References: <1446649261-27122-1-git-send-email-vbabka@suse.cz>
 <1446649261-27122-2-git-send-email-vbabka@suse.cz>
 <20151105080910.GA25938@js1304-P5Q-DELUXE>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Minchan Kim <minchan@kernel.org>, Sasha Levin <sasha.levin@oracle.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Mel Gorman <mgorman@suse.de>
From: Vlastimil Babka <vbabka@suse.cz>
Message-ID: <563B1005.3070203@suse.cz>
Date: Thu, 5 Nov 2015 09:15:01 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101
 Thunderbird/38.3.0
MIME-Version: 1.0
In-Reply-To: <20151105080910.GA25938@js1304-P5Q-DELUXE>
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 2244
Lines: 56

On 11/05/2015 09:09 AM, Joonsoo Kim wrote:
> On Wed, Nov 04, 2015 at 04:00:57PM +0100, Vlastimil Babka wrote:
>> The information in /sys/kernel/debug/page_owner includes the migratetype
>> declared during the page allocation via gfp_flags. This is also checked against
>> the pageblock's migratetype, and reported as Fallback allocation if these two
>> differ (although in fact fallback allocation is not the only reason why they
>> can differ).
>> 
>> However, the migratetype actually printed is the one of the pageblock, not of
>> the page itself, so it's the same for all pages in the pageblock. This is
>> apparently a bug, noticed when working on other page_owner improvements. Fixed.
> 
> We can guess page migratetype through gfp_mask output although it isn't
> easy task for now. But, there is no way to know pageblock migratetype.
> I used this to know how memory is fragmented.

Ah, I see. How bout just we print both migratetypes then and remove the
"Fallback" part, which can be trivially deduced from them (and as I noted it's
somewhat misleading anyway)?

> Thanks.
> 
>> 
>> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
>> ---
>>  mm/page_owner.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/mm/page_owner.c b/mm/page_owner.c
>> index 983c3a1..a9f16b8 100644
>> --- a/mm/page_owner.c
>> +++ b/mm/page_owner.c
>> @@ -113,7 +113,7 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
>>  			"PFN %lu Block %lu type %d %s Flags %s%s%s%s%s%s%s%s%s%s%s%s\n",
>>  			pfn,
>>  			pfn >> pageblock_order,
>> -			pageblock_mt,
>> +			page_mt,
>>  			pageblock_mt != page_mt ? "Fallback" : "        ",
>>  			PageLocked(page)	? "K" : " ",
>>  			PageError(page)		? "E" : " ",
>> -- 
>> 2.6.2
>> 
>> --
>> To unsubscribe, send a message with 'unsubscribe linux-mm' in
>> the body to majordomo@kvack.org.  For more info on Linux MM,
>> see: http://www.linux-mm.org/ .
>> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
> 

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/