From: Larry Finger <Larry.Finger@lwfinger.net>
To: Igor Plyatov <plyatov@gmail.com>
Cc: linux-wireless@vger.kernel.org
Subject: Re: rt2800usb: page allocation failure
Date: Tue, 12 Apr 2011 13:00:18 -0500 [thread overview]
Message-ID: <4DA49332.8000403@lwfinger.net> (raw)
In-Reply-To: <4DA471DC.7080308@gmail.com>
On 04/12/2011 10:38 AM, Igor Plyatov wrote:
> kworker/u:1: page allocation failure. order:1, mode:0x20
--snip--
> [<c0279450>] (dev_alloc_skb+0x0/0x44) from [<c0226698>]
> (rt2x00queue_alloc_rxskb+0x4c/0xc4)
> [<c022664c>] (rt2x00queue_alloc_rxskb+0x0/0xc4) from [<c0223480>]
> (rt2x00lib_rxdone+0x44/0x298)
--snip--
> Normal: 403*4kB 2*8kB 2*16kB 2*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB
> 0*2048kB 0*4096kB = 1724kB
Your system is failing to get a receive buffer of size 8kB (order:1). If we look
at the last line above, you have quite a bit of memory free, but it is highly
fragmented - almost all of it is in 4kB pieces. This condition is not fatal, but
it can be avoided by changing the NIC parameters so that each RX buffer fits in 4k.
If you look at the ifconfig output for this device, the MTU is likely 1500. By
reducing this, you should be able to get all buffers to be of order 0. I would
start with 1400 to see if it makes the problem go away. Reducing this quantity
has the potential to slow the network transfers, but you won't see it as the
default block size for dd is 512. Any such slowdown will be much less severe
than the delay causes by missing a buffer allocation.
Larry
next prev parent reply other threads:[~2011-04-12 18:00 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-12 15:38 rt2800usb: page allocation failure Igor Plyatov
2011-04-12 18:00 ` Larry Finger [this message]
2011-04-12 21:22 ` Johannes Stezenbach
2011-04-13 1:38 ` Larry Finger
2011-04-13 7:54 ` Helmut Schaa
2011-04-13 7:55 ` Johannes Stezenbach
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