From: Christoph Lameter <cl@linux.com>
To: Tejun Heo <tj@kernel.org>
Cc: Dmitry Antipov <dmitry.antipov@linaro.org>,
Rusty Russell <rusty@rustcorp.com.au>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
patches@linaro.org, linaro-dev@lists.linaro.org
Subject: Re: [PATCH 1/3] percpu: use ZERO_SIZE_PTR / ZERO_OR_NULL_PTR
Date: Mon, 30 Jan 2012 11:35:29 -0600 (CST) [thread overview]
Message-ID: <alpine.DEB.2.00.1201301134090.28693@router.home> (raw)
In-Reply-To: <20120130173311.GE3355@google.com>
On Mon, 30 Jan 2012, Tejun Heo wrote:
> I'm pretty sure it never gives out NULL for a dynamic allocation. The
> base might be mapped to zero but we're guaranteed to have some static
> percpu areas there and IIRC the percpu addresses aren't supposed to
> wrap.
True but there is a check for a NULL pointer on free. So a NULL pointer
currently has the semantics of being an unallocated per cpu structure.
If the allocator returns NULL by accident then we cannot free the per cpu
allocation anymore.
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next prev parent reply other threads:[~2012-01-30 17:35 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-30 8:37 Dmitry Antipov
2012-01-30 16:15 ` Christoph Lameter
2012-01-30 17:15 ` Tejun Heo
2012-01-30 17:19 ` Tejun Heo
2012-01-30 17:22 ` Christoph Lameter
2012-01-30 17:33 ` Tejun Heo
2012-01-30 17:35 ` Christoph Lameter [this message]
2012-01-30 17:22 ` Christoph Lameter
2012-01-30 17:42 ` Tejun Heo
2012-01-30 17:52 ` Christoph Lameter
2012-01-30 17:54 ` Tejun Heo
2012-01-30 17:58 ` Christoph Lameter
2012-01-30 18:02 ` Tejun Heo
2012-01-30 18:12 ` Christoph Lameter
2012-01-30 18:16 ` Tejun Heo
2012-01-31 4:48 ` Rusty Russell
2012-01-30 18:13 ` Tejun Heo
2012-01-30 18:15 ` Christoph Lameter
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