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Date: Tue, 27 Apr 2004 22:42:39 -0700
From: Andrew Morton <akpm@osdl.org>
To: Brad Allen <Ulmo-Usenet@Usenet.Q.Net>
Cc: linux-kernel@vger.kernel.org
Subject: Re: allocation failures with CBQ bandwidth limiting & high net use
 (was Re: Filesystem kernel hangup, 2.6.3 (bad: scheduling while atomic!))
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Brad Allen <Ulmo-Usenet@Usenet.Q.Net> wrote:
>
>  My MTU for GbE (e1000) is 9000, and NFS block size 8192 bytes.
>  That GbE is a consumer grade Intel model.
> ....
>  swapper: page allocation failure. order:3, mode:0x20

The kernel simply doesn't have a hope of being able to find eight
physically-contiguous free pages at interrupt time.

You'll get some benefit from increasing /proc/sys/vm/min_free_kbytes

But it's beginning to look like we need separately-managed higher-order
page pools for this.  At least.