netdev - Re: [Patch v2] skbuff: Hide GFP_ATOMIC page allocation failures for dropped packets

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Message-ID: <51A4D4AD.2010507@candelatech.com>
Date:	Tue, 28 May 2013 09:00:45 -0700
From:	Ben Greear <greearb@...delatech.com>
To:	Francois Romieu <romieu@...zoreil.com>
CC:	atomlin@...hat.com, netdev@...r.kernel.org, davem@...emloft.net,
	edumazet@...gle.com, pshelar@...ira.com, mst@...hat.com,
	alexander.h.duyck@...el.com, riel@...hat.com, aquini@...hat.com,
	sergei.shtylyov@...entembedded.com, linux-kernel@...r.kernel.org
Subject: Re: [Patch v2] skbuff: Hide GFP_ATOMIC page allocation failures for
 dropped packets

On 05/27/2013 03:41 PM, Francois Romieu wrote:
> atomlin@...hat.com <atomlin@...hat.com> :
> [...]
>> Failed GFP_ATOMIC allocations by the network stack result in dropped
>> packets, which will be received on a subsequent retransmit, and an
>> unnecessary, noisy warning with a kernel backtrace.
>>
>> These warnings are harmless, but they still cause users to panic and
>> file bug reports over dropped packets. It would be better to hide the
>> failed allocation warnings and backtraces, and let retransmits handle
>> dropped packets quietly.
>
> Linux VM may be perfect but device drivers do stupid things.
>
> Please don't paper over it just because some shit ends in your backyard.

We should rate-limit these messages at least.  When a system is low on memory
the logs can quickly fill up with useless OOM messages, further slowing
the system...

Ben

>


-- 
Ben Greear <greearb@...delatech.com>
Candela Technologies Inc  http://www.candelatech.com

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