Re: [patch] slob: fix gfp flags for order-0 page allocations

From: Matt Mackall <mpm@selenic.com>
To: David Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>,
	Christoph Lameter <cl@linux-foundation.org>,
	linux-mm@kvack.org
Subject: Re: [patch] slob: fix gfp flags for order-0 page allocations
Date: Mon, 23 Aug 2010 23:26:34 -0500	[thread overview]
Message-ID: <1282623994.10679.921.camel@calx> (raw)
In-Reply-To: <alpine.DEB.2.00.1008221615350.29062@chino.kir.corp.google.com>

On Sun, 2010-08-22 at 16:16 -0700, David Rientjes wrote:
> kmalloc_node() may allocate higher order slob pages, but the __GFP_COMP
> bit is only passed to the page allocator and not represented in the
> tracepoint event.  The bit should be passed to trace_kmalloc_node() as
> well.
> 
> Signed-off-by: David Rientjes <rientjes@google.com>

>  		unsigned int order = get_order(size);
>  
> -		ret = slob_new_pages(gfp | __GFP_COMP, get_order(size), node);
> +		if (likely(order))
> +			gfp |= __GFP_COMP;

Why is it likely? I would hope that the majority of page allocations are
in fact order 0.

-- 
Mathematics is the supreme nostalgia of our time.

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