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Subject: Re: [PATCH] Add kmemleak annotations to lmb.c
From: Catalin Marinas <catalin.marinas@arm.com>
To: David Miller <davem@davemloft.net>
In-Reply-To: <20090814.124933.146642945.davem@davemloft.net>
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Date: Fri, 14 Aug 2009 22:57:51 +0100
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On Fri, 2009-08-14 at 12:49 -0700, David Miller wrote:
> From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Date: Fri, 14 Aug 2009 17:56:40 +1000
> 
> > On Thu, 2009-08-13 at 16:40 +0100, Catalin Marinas wrote:
> >> On Thu, 2009-08-13 at 13:01 +1000, Michael Ellerman wrote:
> >> > We don't actually want kmemleak to track the lmb allocations, so we
> >> > pass min_count as 0. However telling kmemleak about lmb allocations
> >> > allows it to scan that memory for pointers to other memory that is
> >> > tracked by kmemleak, ie. slab allocations etc.
> >> 
> >> Looks alright to me (though I haven't tested it). You can add a
> >> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> > 
> > Actually, Milton pointed to me that we may not want to allow all
> > LMB chunks to be scanned by kmemleaks, things like the DART hole
> > that's taken out of the linear mapping for example may need to
> > be avoided, though I'm not sure what would be the right way to
> > do it.
> 
> I think that annotating LMB for kmemleak may be more problems
> that it's worth.

BTW, are there many LMB allocations used for storing pointers to other
objects? If not, it may be worth just annotating those with
kmemleak_alloc() if you get false positives.

-- 
Catalin