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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Minchan Kim <minchan.kim@gmail.com>
Cc: kosaki.motohiro@jp.fujitsu.com, Ying Han <yinghan@google.com>,
	Rik van Riel <riel@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Venkatesh Pallipadi <venki@google.com>,
	Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH] vmscan: prevent background aging of anon page in no swap system
Date: Tue, 31 Aug 2010 10:38:10 +0900 (JST)	[thread overview]
Message-ID: <20100831102557.87D3.A69D9226@jp.fujitsu.com> (raw)
In-Reply-To: <AANLkTin4-NomOoNFYCKgi7oE+MCUiC0o0ftAkOwLKez_@mail.gmail.com>

> > I think both Ying's and Minchan's opnion are right and makes sense.  however I _personally_
> > like Ying version because 1) this version is simpler 2) swap full is very rarely event 3)
> > no swap mounting is very common on HPC. so this version could have a chance to
> > improvement hpc workload too.
> 
> I agree.
> 
> >
> > In the other word, both avoiding unnecessary TLB flush and keeping proper page aging are
> > performance matter. so when we are talking performance, we always need to think frequency
> > of the event.
> 
> Ying's one and mine both has a same effect.
> Only difference happens swap is full. My version maintains old
> behavior but Ying's one changes the behavior. I admit swap full is
> rare event but I hoped not changed old behavior if we doesn't find any
> problem.
> If kswapd does aging when swap full happens, is it a problem?
> We have been used to it from 2.6.28.
> 
> If we regard a code consistency is more important than _unexpected_
> result, Okay. I don't mind it. :)

To be honest, I don't mind the difference between you and Ying's version. because
_practically_ swap full occur mean the application has a bug. so, proper page aging
doesn't help so much. That's the reason why I said I prefer simper. I don't have 
strong opinion. I think it's not big matter.


> But at least we should do more thing to make the patch to compile out
> for non-swap configurable system.

Yes, It makes embedded happy :)



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  reply	other threads:[~2010-08-31  1:38 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-29 15:43 Minchan Kim
2010-08-29 15:49 ` Rik van Riel
2010-08-29 17:45 ` Ying Han
2010-08-29 20:03   ` Rik van Riel
2010-08-29 20:56     ` Ying Han
2010-08-29 21:23     ` Ying Han
2010-08-29 22:26       ` Rik van Riel
2010-08-30  0:18       ` Minchan Kim
2010-08-30  5:40         ` Ying Han
2010-08-30  6:16           ` Minchan Kim
2010-08-31  0:56             ` KOSAKI Motohiro
2010-08-31  1:10               ` Minchan Kim
2010-08-31  1:18                 ` KOSAKI Motohiro
2010-08-31  1:36                   ` Minchan Kim
2010-08-31  1:41                     ` KOSAKI Motohiro
2010-08-31  0:56           ` KOSAKI Motohiro
2010-08-31  1:23             ` Minchan Kim
2010-08-31  1:38               ` KOSAKI Motohiro [this message]
2010-08-31  2:02                 ` Minchan Kim
2010-08-31  2:09                   ` KOSAKI Motohiro
2010-08-31  3:47                     ` Minchan Kim
2010-08-31  2:30               ` Rik van Riel
2010-08-31  3:46                 ` Minchan Kim
2010-09-03 21:06 ` Andrew Morton
2010-09-03 21:23   ` Rik van Riel
2010-09-03 21:45   ` Ying Han
2010-09-03 21:47   ` Ying Han
2010-09-03 21:56     ` Andrew Morton
2010-09-04  1:12       ` Venkatesh Pallipadi

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