From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Pekka Enberg <penberg@cs.helsinki.fi>,
Greg Kroah-Hartman <gregkh@suse.de>,
Christoph Lameter <cl@linux-foundation.org>,
Frans Pop <elendil@planet.nl>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Mel Gorman <mel@skynet.ie>
Subject: Re: Memory management woes - order 1 allocation failures
Date: Tue, 2 Mar 2010 18:34:51 +0000 [thread overview]
Message-ID: <20100302183451.75d44f03@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <20100302172606.GA11355@csn.ul.ie>
> For reasons that are not particularly clear to me, tty_buffer_alloc() is
> called far more frequently in 2.6.33 than in 2.6.24. I instrumented the
> function to print out the size of the buffers allocated, booted under
> qemu and would just "cat /bin/ls" to see what buffers were allocated.
> 2.6.33 allocates loads, including high-order allocations. 2.6.24
> appeared to allocate once and keep silent.
The pty layer is using them now and didn't before. That will massively
distort your numhers.
> While there have been snags recently with respect to high-order
> allocation failures in recent kernels, this might be one of the cases
> where it's due to subsystems requesting high-order allocations more.
The pty code certainly triggered more such allocations. I've sent Greg
patches to make the tty buffering layer allocate sensible sizes as it
doesn't need multiple page allocations in the first place.
Alan
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next prev parent reply other threads:[~2010-03-02 18:32 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-26 11:32 Memory management woes - order 1 allocation failures Frans Pop
2010-02-26 12:24 ` Frans Pop
2010-02-26 14:01 ` Pekka Enberg
2010-02-26 15:33 ` Frans Pop
2010-02-26 16:43 ` Christoph Lameter
2010-02-26 17:17 ` Pekka Enberg
2010-03-01 1:42 ` KOSAKI Motohiro
2010-03-02 17:26 ` Mel Gorman
2010-03-02 18:34 ` Alan Cox [this message]
2010-03-02 19:11 ` Mel Gorman
2010-03-02 19:29 ` Greg KH
2010-03-02 21:16 ` Mel Gorman
2010-03-02 22:17 ` Alan Cox
2010-03-02 22:29 ` Mel Gorman
2010-03-12 3:32 ` Frans Pop
2010-03-02 23:31 ` KOSAKI Motohiro
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