From: Peter Zijlstra <peterz@infradead.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>,
Fabian Frederick <fabf@skynet.be>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Jan \"Yenya\" Kasprzak" <kas@fi.muni.cz>,
netdev@vger.kernel.org
Subject: Re: [PATCH 6/7 linux-next] wan: cosa: replace current->state by set_current_state()
Date: Fri, 20 Feb 2015 21:02:26 +0100 [thread overview]
Message-ID: <20150220200226.GD23367@worktop.ger.corp.intel.com> (raw)
In-Reply-To: <1424460713.5565.28.camel@edumazet-glaptop2.roam.corp.google.com>
On Fri, Feb 20, 2015 at 11:31:53AM -0800, Eric Dumazet wrote:
> On Fri, 2015-02-20 at 19:58 +0100, Peter Zijlstra wrote:
> Maybe this might be self documented in set_current_state(),
> as we have about 120 calls to __set_current_state(TASK_RUNNING)
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 41c60e5302d7..26133da6445e 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -275,7 +275,11 @@ extern char ___assert_task_state[1 - 2*!!(
> #define set_current_state(state_value) \
> do { \
> current->task_state_change = _THIS_IP_; \
> - set_mb(current->state, (state_value)); \
> + if (__builtin_constant_p(state_value) && \
> + (state_value) == TASK_RUNNING) \
> + current->state = (state_value); \
> + else \
> + set_mb(current->state, (state_value)); \
> } while (0)
lkml.kernel.org/r/20150206163947.GR21418@twins.programming.kicks-ass.net
The problem is that there _might_ be someone relying on that barrier.
Its (very) unlikely, but you don't want to risk subtle borkage just
because. And I'm too lazy to go audit all of them :/
next prev parent reply other threads:[~2015-02-20 20:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-20 18:12 [PATCH 1/7 linux-next] swim: replace current->state by set_current_state() Fabian Frederick
2015-02-20 18:12 ` [PATCH 2/7 linux-next] mISDN: " Fabian Frederick
2015-02-22 20:24 ` David Miller
2015-02-20 18:12 ` [PATCH 3/7 linux-next] powerpc/pmac: " Fabian Frederick
2015-02-20 18:12 ` Fabian Frederick
2015-02-20 18:12 ` [PATCH 4/7 linux-next] saa7146: " Fabian Frederick
2015-02-20 18:12 ` [PATCH 5/7 linux-next] hso: replace current->state by __set_current_state() Fabian Frederick
2015-02-22 20:25 ` David Miller
2015-02-20 18:12 ` [PATCH 6/7 linux-next] wan: cosa: replace current->state by set_current_state() Fabian Frederick
2015-02-20 18:26 ` Jan Yenya Kasprzak
2015-02-20 18:34 ` Sergei Shtylyov
2015-02-20 18:51 ` Fabian Frederick
2015-02-20 19:15 ` Sergei Shtylyov
2015-02-20 18:58 ` Peter Zijlstra
2015-02-20 19:31 ` Eric Dumazet
2015-02-20 19:44 ` Eric Dumazet
2015-02-20 20:02 ` Peter Zijlstra [this message]
2015-02-21 7:42 ` Fabian Frederick
2015-02-22 20:25 ` David Miller
2015-02-20 18:12 ` [PATCH 7/7 linux-next] serial: core: replace current->state by __set_current_state() Fabian Frederick
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