Re: [PATCH v2 1/2] compaction: handle active and inactive fairly in too_many_isolated

From: Minchan Kim
Date: Thu Aug 26 2010 - 05:39:56 EST


On Thu, Aug 26, 2010 at 6:03 PM, Mel Gorman <mel@xxxxxxxxx> wrote:
> On Wed, Aug 25, 2010 at 12:31:18AM +0900, Minchan Kim wrote:
>> Iram reported compaction's too_many_isolated loops forever.
>> (http://www.spinics.net/lists/linux-mm/msg08123.html)
>>
>> The meminfo of situation happened was inactive anon is zero.
>> That's because the system has no memory pressure until then.
>> While all anon pages was in active lru, compaction could select
>> active lru as well as inactive lru. That's different things
>> with vmscan's isolated. So we has been two too_many_isolated.
>>
>> While compaction can isolated pages in both active and inactive,
>> current implementation of too_many_isolated only considers inactive.
>> It made Iram's problem.
>>
>> This patch handles active and inactive with fair.
>> That's because we can't expect where from and how many compaction would
>> isolated pages.
>>
>> This patch changes (nr_isolated > nr_inactive) with
>> nr_isolated > (nr_active + nr_inactive) / 2.
>>
>> Cc: Iram Shahzad <iram.shahzad@xxxxxxxxxxxxxx>
>> Acked-by: Mel Gorman <mel@xxxxxxxxx>
>> Acked-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
>> Signed-off-by: Minchan Kim <minchan.kim@xxxxxxxxx>
>
> Please send this patch on its own as it looks like it should be merged and
> arguably is a stable candidate for 2.6.35. Alternatively, Andrew, can you pick
> up just this patch? It seems unrelated to the second patch on COMPACTPAGEFAILED.

I thought it's not urgent and next patch would apply based on this
patch without HUNK.
If Andrew doesn't have a response, I will resend as a standalone.
Thanks.

--
Kind regards,
Minchan Kim
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