linux-kernel - Re: [PATCH 2/4] kmemleak: Handle percpu memory allocation

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Message-ID: <20111004170628.GD13865@e102109-lin.cambridge.arm.com>
Date:	Tue, 4 Oct 2011 18:06:29 +0100
From:	Catalin Marinas <catalin.marinas@....com>
To:	Tejun Heo <htejun@...il.com>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Huajun Li <huajun.li.lee@...il.com>,
	Christoph Lameter <cl@...ux-foundation.org>
Subject: Re: [PATCH 2/4] kmemleak: Handle percpu memory allocation

On Tue, Oct 04, 2011 at 05:59:58PM +0100, Tejun Heo wrote:
> Hello, Catalin.
> 
> On Tue, Oct 04, 2011 at 10:26:24AM +0100, Catalin Marinas wrote:
> > Before kmemleak is initialised we still get memory allocations that
> > kmemleak stores in an early_log buffer (via the log_early() function
> > called from kmemleak_alloc_percpu). Later when kmemleak has all the data
> > structures in place, the kmemleak_init() function goes through the
> > early_log array and replays the previously recorded requests. The
> > early_alloc_percpu() function is used during early_log replaying and it
> > indeed registers every percpu memory block but the early_log is always
> > O(#PCPU_ALLOCS).
> > 
> > The reason we don't call kmemleak_alloc_percpu() directly during
> > replaying is that early_alloc() also copies the previously recorded
> > stack trace into the newly created object (otherwise all early
> > allocations would be shown as done by kmemleak_init).
> 
> Ah, okay, I was misreading the patch.  For some reason, log_early()
> was nested inside for_each_possible_cpu(), but one other thing.
> kmemleak_free_percpu() is calling log_early() w/ KMEMLEAK_FREE.
> Shouldn't it be KMEMLEAK_FREE_PERCPU?

Good point, I updated the patch.

Thanks.

-- 
Catalin
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