Re: [PATCH] vmscan: bail out of page reclaim after swap_cluster_max pages

["KOSAKI Motohiro" <kosaki.motohiro@jp.fujitsu.com>]

2008/11/25 Rik van Riel <riel@redhat.com>:
> KOSAKI Motohiro wrote:
>>>
>>> Sometimes the VM spends the first few priority rounds rotating back
>>> referenced pages and submitting IO.  Once we get to a lower priority,
>>> sometimes the VM ends up freeing way too many pages.
>>>
>>> The fix is relatively simple: in shrink_zone() we can check how many
>>> pages we have already freed, direct reclaim tasks break out of the
>>> scanning loop if they have already freed enough pages and have reached
>>> a lower priority level.
>>>
>>> However, in order to do this we do need to know how many pages we already
>>> freed, so move nr_reclaimed into scan_control.
>>>
>>> Signed-off-by: Rik van Riel <riel@redhat.com>
>>> ---
>>> Kosaki, this should address the zone scanning pressure issue.
>>
>> hmmmm. I still don't like the behavior when priority==DEF_PRIORITY.
>> but I also should explain by code and benchmark.
>
> Well, the behaviour when priority==DEF_PRIORITY is the
> same as the kernel's behaviour without the patch...


Yes, but I think it decrease this patch's valueable...



>> therefore, I'll try to mesure this patch in this week.
>
> Looking forward to it.

thank you.

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