linux-kernel - Re: [PATCH v2] trace: Set __GFP_NORETRY flag for ring buffer allocating process

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Date:	Thu, 09 Jun 2011 15:52:42 -0400
From:	Steven Rostedt <rostedt@...dmis.org>
To:	David Rientjes <rientjes@...gle.com>
Cc:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	vnagarnaik@...gle.com, mingo@...hat.com, fweisbec@...il.com,
	mrubin@...gle.com, dhsharp@...gle.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] trace: Set __GFP_NORETRY flag for ring buffer
 allocating process

On Thu, 2011-06-09 at 12:42 -0700, David Rientjes wrote:

> It would only happen if there was an antagonist that stole the reclaimed 
> pages before your __GFP_NORETRY allocation could allocate them, resulting 
> in the system being oom again as it was before reclaim occurred.  Without 
> __GFP_NORETRY, we'd automatically retry these allocations in a loop until 
> we found the memory since they are order-0, so the only side effect would 
> be an increased latency in the allocation.  I think if we still end up oom 
> after reclaiming memory that was allocated by another thread that we 
> probably don't want to be expanding the ring buffer and, thus, I see no 
> problem with just failing.

Agreed, which is why I already pushed the patch.

-- Steve


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