From: Oleg Nesterov <oleg@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>,
Paul McKenney <paulmck@linux.vnet.ibm.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/6] sched, wait: Collapse __wait_event macros -v4
Date: Tue, 1 Oct 2013 16:09:40 +0200 [thread overview]
Message-ID: <20131001140940.GA32328@redhat.com> (raw)
In-Reply-To: <20130930181358.GA29544@redhat.com>
On 09/30, Oleg Nesterov wrote:
>
> On 09/30, Peter Zijlstra wrote:
> >
> > On Mon, Sep 30, 2013 at 07:40:54PM +0200, Oleg Nesterov wrote:
> > > Once again, of course I do not blame this series, but
> > > wait_event_timeout(wq, true, 0) still returns 0.
> >
> > So we have:
> >
> > [...snip...]
>
> > So wait_event_timeout(wq, true, 0) turns into:
>
> Not really, because of fast-path check,
>
> #define wait_event_timeout(wq, condition, timeout) \
> ({ \
> long __ret = timeout; \
> if (!(condition)) \
> __ret = __wait_event_timeout(wq, condition, timeout); \
> __ret; \
> })
>
> we do not even call __wait_event_timeout() if "condition" is already
> true at the start.
But somehow I didn't realize that ___wait_cond_timeout() can be used
as is, so the simple patch below should work?
Oleg.
--- x/include/linux/wait.h
+++ x/include/linux/wait.h
@@ -270,7 +270,7 @@ do { \
#define wait_event_timeout(wq, condition, timeout) \
({ \
long __ret = timeout; \
- if (!(condition)) \
+ if (!___wait_cond_timeout(condition)) \
__ret = __wait_event_timeout(wq, condition, timeout); \
__ret; \
})
@@ -328,7 +328,7 @@ do { \
#define wait_event_interruptible_timeout(wq, condition, timeout) \
({ \
long __ret = timeout; \
- if (!(condition)) \
+ if (!___wait_cond_timeout(condition)) \
__ret = __wait_event_interruptible_timeout(wq, \
condition, timeout); \
__ret; \
@@ -770,7 +770,7 @@ do { \
timeout) \
({ \
long __ret = timeout; \
- if (!(condition)) \
+ if (!___wait_cond_timeout(condition)) \
__ret = __wait_event_interruptible_lock_irq_timeout( \
wq, condition, lock, timeout); \
__ret; \
next prev parent reply other threads:[~2013-10-01 14:16 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-30 15:22 [PATCH 0/6] sched, wait: Collapse __wait_event macros -v4 Peter Zijlstra
2013-09-30 15:22 ` [PATCH 1/6] sched, wait: Make the signal_pending() checks consistent Peter Zijlstra
2013-09-30 15:22 ` [PATCH 2/6] sched, wait: Change timeout logic Peter Zijlstra
2013-09-30 15:48 ` Linus Torvalds
2013-09-30 16:09 ` Peter Zijlstra
2013-09-30 15:22 ` [PATCH 3/6] sched, wait: Change the wait_exclusive control flow Peter Zijlstra
2013-09-30 15:22 ` [PATCH 4/6] sched, wait: Collapse __wait_event macros Peter Zijlstra
2013-09-30 15:22 ` [PATCH 5/6] sched, wait: Also use ___wait_event() for __wait_event_hrtimeout Peter Zijlstra
2013-09-30 15:22 ` [PATCH 6/6] sched, wait: Make the __wait_event*() interface more friendly Peter Zijlstra
2013-10-01 6:39 ` Ingo Molnar
2013-09-30 15:50 ` [PATCH 0/6] sched, wait: Collapse __wait_event macros -v4 Linus Torvalds
2013-09-30 16:11 ` Peter Zijlstra
2013-09-30 17:40 ` Oleg Nesterov
2013-09-30 18:00 ` Oleg Nesterov
2013-09-30 18:09 ` Peter Zijlstra
2013-09-30 18:13 ` Oleg Nesterov
2013-10-01 14:09 ` Oleg Nesterov [this message]
2013-10-01 14:39 ` Peter Zijlstra
2013-10-01 15:16 ` Oleg Nesterov
2013-10-01 17:01 ` [RFC] introduce prepare_to_wait_event() Oleg Nesterov
2013-10-01 17:25 ` Peter Zijlstra
2013-10-01 17:33 ` Oleg Nesterov
2013-10-01 17:44 ` Peter Zijlstra
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