linux-kernel - Re: [PATCH] kmemleak: Reduce verbosity when memory allocation fails

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Message-ID: <alpine.DEB.2.00.1101101232580.11969@chino.kir.corp.google.com>
Date:	Mon, 10 Jan 2011 12:36:10 -0800 (PST)
From:	David Rientjes <rientjes@...gle.com>
To:	Catalin Marinas <catalin.marinas@....com>
cc:	linux-kernel@...r.kernel.org,
	Toralf Förster <toralf.foerster@....de>,
	Pekka Enberg <penberg@...helsinki.fi>,
	"Ted Ts'o" <tytso@....edu>
Subject: Re: [PATCH] kmemleak: Reduce verbosity when memory allocation
 fails

On Mon, 10 Jan 2011, Catalin Marinas wrote:

> diff --git a/mm/kmemleak.c b/mm/kmemleak.c
> index bd9bc21..eee8e31 100644
> --- a/mm/kmemleak.c
> +++ b/mm/kmemleak.c
> @@ -113,7 +113,8 @@
>  #define BYTES_PER_POINTER	sizeof(void *)
>  
>  /* GFP bitmask for kmemleak internal allocations */
> -#define GFP_KMEMLEAK_MASK	(GFP_KERNEL | GFP_ATOMIC)
> +#define gfp_kmemleak_mask(gfp)	((gfp) & (GFP_KERNEL | GFP_ATOMIC) | \
> +				 __GFP_NOWARN)

It would be a shame if the allocation were __GFP_NORETRY and kmemleak 
ended up looping forever because it suppresses the bit for a single page, 
it uses __GFP_NOMEMALLOC and kmemleak ends up allocating from memory 
reserves, or it uses __GFP_HARDWALL and kmemleak is allocating metadata in 
a different cpuset.

I'm not sure why you're not just masking __GFP_NOFAIL and __GFP_REPEAT and 
then failing gracefully?  (And __GFP_ZERO and __GFP_COMP, too, of course.)
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