From: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
To: Tejun Heo <tj@kernel.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>,
Ingo Molnar <mingo@elte.hu>,
rusty@rustcorp.com.au, tglx@linutronix.de, x86@kernel.org,
linux-kernel@vger.kernel.org, hpa@zytor.com,
Paul Mundt <lethal@linux-sh.org>,
rmk@arm.linux.org.uk, starvik@axis.com, ralf@linux-mips.org,
davem@davemloft.net, cooloney@kernel.org, kyle@mcmartin.ca,
matthew@wil.cx, grundler@parisc-linux.org, takata@linux-m32r.org,
benh@kernel.crashing.org, rth@twiddle.net,
heiko.carstens@de.ibm.com
Subject: Re: [GIT RFC] percpu: use dynamic percpu allocator as the default percpu allocator
Date: Thu, 9 Apr 2009 13:47:14 +0400 [thread overview]
Message-ID: <20090409094713.GA6538@jurassic.park.msu.ru> (raw)
In-Reply-To: <49DD068F.8040102@kernel.org>
On Wed, Apr 08, 2009 at 01:18:23PM -0700, Tejun Heo wrote:
> > #define DEFINE_PER_CPU_SECTION(type, name, section) \
> > __attribute__((__section__(".garbage"), __unused__)) \
> > char __dummy__##name; \
> > __attribute__((__section__(PER_CPU_BASE_SECTION section))) \
> > __weak __typeof__(type) per_cpu__##name
>
> Nice. I think .discard would suit better for the dummy variable tho
> (x86 discards the section and it seems to be more common name with
> ldscript using /DISCARD/ identifier for things to throw away). Also,
Indeed, .discard sounds better.
> it seems like if two different files happen to use static percpu
> variables with the same name, they would end up sharing it, right?
> That looks a tad bit dangerous.
True. One of possible solutions is to add another dummy variable,
like this:
#define DEFINE_PER_CPU_SECTION(type, name, section) \
__attribute__((__section__(".discard"), __unused__)) \
char __dummy__##name; \
+ __attribute__((__section__(".discard"))) \
+ char __per_cpu_multiple_def__##name; \
__attribute__((__section__(PER_CPU_BASE_SECTION section))) \
__weak __typeof__(type) per_cpu__##name
so in that situation we'll get a link failure.
Ivan.
next prev parent reply other threads:[~2009-04-09 9:47 UTC|newest]
Thread overview: 95+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-10 7:53 [GIT RFC] percpu: use dynamic percpu allocator as the default percpu allocator Tejun Heo
2009-03-10 7:53 ` [PATCH 1/5] linker script: define __per_cpu_load on all SMP capable archs Tejun Heo
2009-03-10 7:53 ` [PATCH 2/5] percpu: make x86 addr <-> pcpu ptr conversion macros generic Tejun Heo
2009-03-10 7:53 ` [PATCH 3/5] percpu: more flexibility for @dyn_size of pcpu_setup_first_chunk() Tejun Heo
2009-03-10 7:53 ` [PATCH 4/5] percpu: generalize embedding first chunk setup helper Tejun Heo
2009-03-10 7:53 ` [PATCH 5/5] percpu: use dynamic percpu allocator as the default percpu allocator Tejun Heo
2009-03-10 7:57 ` test module to verify " Tejun Heo
2009-03-10 10:59 ` [GIT RFC] percpu: use dynamic percpu allocator as the default " David Miller
2009-03-11 6:03 ` Tejun Heo
2009-03-11 5:56 ` [GIT PULL] pull request for safe part Tejun Heo
2009-03-16 18:01 ` [GIT RFC] percpu: use dynamic percpu allocator as the default percpu allocator Martin Schwidefsky
2009-03-20 2:35 ` Tejun Heo
2009-03-24 15:22 ` Tejun Heo
2009-03-25 11:27 ` Martin Schwidefsky
2009-03-25 11:51 ` Tejun Heo
2009-03-25 12:22 ` Ingo Molnar
2009-03-25 12:27 ` Tejun Heo
2009-03-25 12:39 ` Ingo Molnar
2009-03-25 13:13 ` Martin Schwidefsky
2009-03-25 13:21 ` Tejun Heo
2009-03-25 13:25 ` Martin Schwidefsky
2009-03-25 13:34 ` Tejun Heo
2009-03-31 16:54 ` Martin Schwidefsky
2009-03-31 17:20 ` Christoph Lameter
2009-03-31 20:18 ` Martin Schwidefsky
2009-03-31 21:10 ` Christoph Lameter
2009-04-01 8:01 ` Martin Schwidefsky
2009-03-31 19:17 ` Ivan Kokshaysky
2009-03-31 20:19 ` Martin Schwidefsky
2009-03-31 20:29 ` Ivan Kokshaysky
2009-04-01 0:07 ` Tejun Heo
2009-04-01 8:10 ` Martin Schwidefsky
2009-04-01 8:17 ` Tejun Heo
2009-04-01 8:32 ` Martin Schwidefsky
2009-04-01 8:37 ` David Miller
2009-04-01 8:47 ` Martin Schwidefsky
2009-04-01 8:50 ` Tejun Heo
2009-04-01 9:08 ` Martin Schwidefsky
2009-04-02 1:54 ` Tejun Heo
2009-04-01 8:53 ` David Miller
2009-04-01 8:53 ` Tejun Heo
2009-04-01 11:07 ` Martin Schwidefsky
2009-04-02 1:57 ` Tejun Heo
2009-04-02 7:24 ` Ivan Kokshaysky
2009-04-02 11:13 ` Martin Schwidefsky
2009-04-03 0:31 ` Tejun Heo
2009-04-07 16:09 ` Ivan Kokshaysky
2009-04-08 20:18 ` Tejun Heo
2009-04-09 9:47 ` Ivan Kokshaysky [this message]
2009-04-09 11:53 ` Tejun Heo
2009-04-11 1:38 ` Rusty Russell
2009-04-11 1:52 ` Tejun Heo
2009-04-02 0:20 ` Rusty Russell
2009-03-25 14:00 ` Martin Schwidefsky
2009-03-25 14:14 ` Tejun Heo
2009-03-30 10:07 ` [PATCH UPDATED] " Tejun Heo
2009-03-30 10:42 ` Martin Schwidefsky
2009-04-01 0:08 ` Tejun Heo
2009-03-30 11:49 ` Ingo Molnar
2009-03-30 14:50 ` Christoph Lameter
2009-03-31 16:12 ` Christoph Lameter
2009-04-01 0:15 ` Tejun Heo
2009-04-01 13:49 ` Christoph Lameter
2009-04-01 15:49 ` Ingo Molnar
2009-04-01 18:06 ` Christoph Lameter
2009-04-01 19:01 ` Ingo Molnar
2009-04-01 19:39 ` Linus Torvalds
2009-04-01 20:12 ` Matthew Wilcox
2009-04-02 2:13 ` Ingo Molnar
2009-04-01 22:32 ` Ingo Molnar
2009-04-01 22:57 ` Matthew Wilcox
2009-04-02 2:10 ` Ingo Molnar
2009-04-02 2:21 ` Christoph Lameter
2009-04-02 3:25 ` Ingo Molnar
2009-04-02 3:28 ` Christoph Lameter
2009-04-02 2:30 ` Tejun Heo
2009-04-02 2:18 ` Christoph Lameter
2009-04-02 3:42 ` Ingo Molnar
2009-04-02 13:53 ` Christoph Lameter
2009-04-08 16:26 ` Ingo Molnar
2009-04-13 18:18 ` Christoph Lameter
2009-04-14 14:04 ` Ingo Molnar
2009-04-14 16:48 ` Christoph Lameter
2009-04-14 17:12 ` Ingo Molnar
2009-04-02 2:15 ` Christoph Lameter
2009-04-02 4:19 ` [PATCH 1/2 x86#core/percpu] percpu: don't put the first chunk in reverse-map rbtree Tejun Heo
2009-04-02 4:21 ` [PATCH 2/2 x86#core/percpu] percpu: remove rbtree and use page->index instead Tejun Heo
2009-04-08 17:03 ` [tip:core/percpu] " Christoph Lameter
2009-04-08 17:03 ` [tip:core/percpu] percpu: don't put the first chunk in reverse-map rbtree Tejun Heo
2009-03-31 16:14 ` [PATCH UPDATED] percpu: use dynamic percpu allocator as the default percpu allocator Christoph Lameter
2009-04-01 0:18 ` Tejun Heo
2009-03-31 1:34 ` Rusty Russell
2009-03-31 22:57 ` David Miller
2009-03-31 23:49 ` Benjamin Herrenschmidt
2009-04-01 0:19 ` Tejun Heo
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