Re: [RFC] [PATCH 3/4] Reclaim from groups over their soft limit under memory pressure

[Balbir Singh <balbir@linux.vnet.ibm.com>]

KAMEZAWA Hiroyuki wrote:
> On Thu, 14 Feb 2008 13:10:35 +0530
> Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
> 
>>> And I think it's big workload to relclaim all excessed pages at once.
>>>
>>> How about just reclaiming small # of pages ? like
>>> ==
>>> if (nr_bytes_over_sl <= 0)
>>> 	goto next;
>>> nr_pages = SWAP_CLUSTER_MAX;
>> I thought about this, but wanted to push back all groups over their soft limit
>> back to their soft limit quickly. I'll experiment with your suggestion and see
>> how the system behaves when we push back pages slowly. Thanks for the suggestion.
> 
> My point is an unlucky process may have to reclaim tons of pages even if
> what he wants is just 1 page. It's not good, IMO.
> 

Yes, that makes sense.

> Probably backgound-reclaim patch will be able to help this soft-limit situation,
> if a daemon can know it should reclaim or not.
> 

Yes, I agree. I might just need to schedule the daemon under memory pressure.

> Thanks,
> -Kame

-- 
	Warm Regards,
	Balbir Singh
	Linux Technology Center
	IBM, ISTL

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