linux-kernel - Re: [PATCH 0/8][for -mm] mem

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Message-Id: <20080417182121.A8CA.KOSAKI.MOTOHIRO@jp.fujitsu.com>
Date:	Thu, 17 Apr 2008 18:30:11 +0900
From:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
To:	"Tom May" <tom@...may.com>
Cc:	kosaki.motohiro@...fujitsu.com, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/8][for -mm] mem_notify v6

Hi Tom

> Here's a test program that allocates memory and frees on notification.
>  It takes an argument which is the number of pages to use; use a
> number considerably higher than the amount of memory in the system.
> I'm running this on a system without swap.  Each time it gets a
> notification, it frees memory and writes out the /proc/meminfo
> contents.  What I see is that Cached gradually decreases, then Mapped
> decreases, and eventually the kernel invokes the oom killer.  It may
> be necessary to tune some of the constants that control the allocation
> and free rates and latency; these values work for my system.

may be...

I think you misunderstand madvise(MADV_DONTNEED).  
madvise(DONTNEED) indicate drop process page table.
it mean become easily swap.

when run on system without swap, madvise(DONTNEED) almost doesn't work
as your expected.

I am sorry for being not able to help you. ;)



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