From: Minchan Kim <minchan@kernel.org>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Mel Gorman <mgorman@suse.de>, Michal Hocko <mhocko@suse.cz>
Subject: Re: [PATCH] mm: do not use page_count without a page pin
Date: Thu, 14 Jun 2012 10:49:48 +0900 [thread overview]
Message-ID: <4FD9433C.4060503@kernel.org> (raw)
In-Reply-To: <20120614012103.GY3094@redhat.com>
On 06/14/2012 10:21 AM, Andrea Arcangeli wrote:
> On Tue, Jun 12, 2012 at 07:49:34AM +0900, Minchan Kim wrote:
>> If THP page isn't LRU and it's still PageTransHuge, I think it's rather rare and
>> although it happens, it means migration/reclaimer is about to split or isolate/putback
>> so it ends up making THP page movable pages.
>>
>> IMHO, it would be better to account it by movable pages.
>> What do you think about it?
>
> Agreed. Besides THP don't fragment pageblocks. It was just about
> speeding up the scanning the same way it happens with the pagebuddy
> check, but probably not worth it because we're in a racy area here not
> holding locks. pagebuddy is safe because the zone lock is hold, or
> it'd run in the same problem.
Yeb. zone lock is already hold so pagebuddy check is safe but THP still in a racy so let's leave it as it is.
If you don't have concern about this patch any more, could you add Acked-by in my latest patch for Andrew
to pick up? Although you have a concern, let's make it as separate patch because it's optimization patch and
other patch is pending by this.
Thanks, Andrea.
--
Kind regards,
Minchan Kim
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prev parent reply other threads:[~2012-06-14 1:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-11 0:17 [PATCH] mm: do not use page_count without a page pin Minchan Kim
2012-06-11 0:23 ` Wanpeng Li
2012-06-11 2:09 ` Minchan Kim
2012-06-11 7:20 ` Kamezawa Hiroyuki
2012-06-11 7:44 ` Andrea Arcangeli
2012-06-11 8:48 ` Kamezawa Hiroyuki
2012-06-11 13:30 ` Minchan Kim
2012-06-11 14:41 ` Andrea Arcangeli
2012-06-11 22:49 ` Minchan Kim
2012-06-14 1:21 ` Andrea Arcangeli
2012-06-14 1:49 ` Minchan Kim [this message]
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