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From: Benjamin LaHaise <bcrl@redhat.com>
To: Rik van Riel <riel@conectiva.com.br>
Cc: kernelnewbies@nl.linux.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: [CFT][PATCH] smoother VM for -ac
Date: Wed, 10 Oct 2001 16:48:23 -0400	[thread overview]
Message-ID: <20011010164823.A17860@redhat.com> (raw)
In-Reply-To: <Pine.LNX.4.33L.0110101710150.26495-100000@duckman.distro.conectiva>
In-Reply-To: <Pine.LNX.4.33L.0110101710150.26495-100000@duckman.distro.conectiva>; from riel@conectiva.com.br on Wed, Oct 10, 2001 at 05:25:30PM -0300

On Wed, Oct 10, 2001 at 05:25:30PM -0300, Rik van Riel wrote:
> 4) in page_alloc.c, the "slowdown" reschedule has been
>    made stronger by turning it into a try_to_free_pages(),
>    under memory load, this results in allocators calling
>    try_to_free_pages() when the amount of work to be done
>    isn't too bad yet and pretty much guarantees them they'll
>    get to do their allocation immediately afterwards ...
>    statistics make sure that the memory hogs are slowed down
>    much more than well-behaved programs

There's a small problem with this one: I know that during testing of 
earlier 2.4 kernels we saw a livelock which was caused by the vm 
subsystem spinning without scheduling.  This can happen in a couple of 
cases like NFS where another task has to be allowed to run in order to 
make progress in clearing pages.

		-ben

WARNING: multiple messages have this Message-ID (diff)
From: Benjamin LaHaise <bcrl@redhat.com>
To: Rik van Riel <riel@conectiva.com.br>
Cc: kernelnewbies@nl.linux.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: [CFT][PATCH] smoother VM for -ac
Date: Wed, 10 Oct 2001 16:48:23 -0400	[thread overview]
Message-ID: <20011010164823.A17860@redhat.com> (raw)
In-Reply-To: <Pine.LNX.4.33L.0110101710150.26495-100000@duckman.distro.conectiva>; from riel@conectiva.com.br on Wed, Oct 10, 2001 at 05:25:30PM -0300

On Wed, Oct 10, 2001 at 05:25:30PM -0300, Rik van Riel wrote:
> 4) in page_alloc.c, the "slowdown" reschedule has been
>    made stronger by turning it into a try_to_free_pages(),
>    under memory load, this results in allocators calling
>    try_to_free_pages() when the amount of work to be done
>    isn't too bad yet and pretty much guarantees them they'll
>    get to do their allocation immediately afterwards ...
>    statistics make sure that the memory hogs are slowed down
>    much more than well-behaved programs

There's a small problem with this one: I know that during testing of 
earlier 2.4 kernels we saw a livelock which was caused by the vm 
subsystem spinning without scheduling.  This can happen in a couple of 
cases like NFS where another task has to be allowed to run in order to 
make progress in clearing pages.

		-ben
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  reply	other threads:[~2001-10-10 20:48 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-10-10 20:25 [CFT][PATCH] smoother VM for -ac Rik van Riel
2001-10-10 20:25 ` Rik van Riel
2001-10-10 20:48 ` Benjamin LaHaise [this message]
2001-10-10 20:48   ` Benjamin LaHaise
2001-10-10 21:25   ` Rik van Riel
2001-10-10 21:25     ` Rik van Riel
2001-10-10 21:44     ` Rik van Riel
2001-10-10 21:44       ` Rik van Riel
     [not found] <Pine.LNX.4.33L.0110101710150.26495-100000@duckman.distro.c onectiva>
2001-10-11  8:46 ` Lorenzo Allegrucci
2001-10-11  8:46   ` Lorenzo Allegrucci
  -- strict thread matches above, loose matches on Subject: below --
2001-10-12  4:41 Re[02]: " Robert Love
2001-10-12  5:09 ` Andrea Arcangeli
     [not found]   ` <3BC64882.27834.2D200B0@localhost>
2001-10-12  5:54     ` Andrea Arcangeli
2001-10-12  5:54       ` Andrea Arcangeli

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