From: Peter Zijlstra <peterz@infradead.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>,
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,
Peter Zijlstra <peterz@infradead.org>
Subject: [PATCH 02/16] sched/wait: Change timeout logic
Date: Wed, 02 Oct 2013 11:22:19 +0200 [thread overview]
Message-ID: <20131002092528.028892896@infradead.org> (raw)
In-Reply-To: <20131002092217.784439754@infradead.org>
[-- Attachment #1: peterz-wait-change-sched-timo.patch --]
[-- Type: text/plain, Size: 2543 bytes --]
Commit 4c663cf ("wait: fix false timeouts when using
wait_event_timeout()") introduced an additional condition check after
a timeout but there's a few issues;
- it forgot one site
- it put the check after the main loop; not at the actual timeout
check.
Cure both; by wrapping the condition (as suggested by Oleg), this
avoids double evaluation of 'condition' which could be quite big.
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
---
include/linux/wait.h | 24 +++++++++++-------------
1 file changed, 11 insertions(+), 13 deletions(-)
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -179,6 +179,14 @@ wait_queue_head_t *bit_waitqueue(void *,
#define wake_up_interruptible_sync_poll(x, m) \
__wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
+#define ___wait_cond_timeout(condition, ret) \
+({ \
+ bool __cond = (condition); \
+ if (__cond && !ret) \
+ ret = 1; \
+ __cond || !ret; \
+})
+
#define __wait_event(wq, condition) \
do { \
DEFINE_WAIT(__wait); \
@@ -217,14 +225,10 @@ do { \
\
for (;;) { \
prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
- if (condition) \
+ if (___wait_cond_timeout(condition, ret)) \
break; \
ret = schedule_timeout(ret); \
- if (!ret) \
- break; \
} \
- if (!ret && (condition)) \
- ret = 1; \
finish_wait(&wq, &__wait); \
} while (0)
@@ -299,18 +303,14 @@ do { \
\
for (;;) { \
prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
- if (condition) \
+ if (___wait_cond_timeout(condition, ret)) \
break; \
if (signal_pending(current)) { \
ret = -ERESTARTSYS; \
break; \
} \
ret = schedule_timeout(ret); \
- if (!ret) \
- break; \
} \
- if (!ret && (condition)) \
- ret = 1; \
finish_wait(&wq, &__wait); \
} while (0)
@@ -815,7 +815,7 @@ do { \
\
for (;;) { \
prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
- if (condition) \
+ if (___wait_cond_timeout(condition, ret)) \
break; \
if (signal_pending(current)) { \
ret = -ERESTARTSYS; \
@@ -824,8 +824,6 @@ do { \
spin_unlock_irq(&lock); \
ret = schedule_timeout(ret); \
spin_lock_irq(&lock); \
- if (!ret) \
- break; \
} \
finish_wait(&wq, &__wait); \
} while (0)
next prev parent reply other threads:[~2013-10-02 9:53 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-02 9:22 [PATCH 00/16] sched/wait: Collapse __wait_event macros -v5 Peter Zijlstra
2013-10-02 9:22 ` [PATCH 01/16] sched/wait: Make the signal_pending() checks consistent Peter Zijlstra
2013-10-04 17:33 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2013-10-02 9:22 ` Peter Zijlstra [this message]
2013-10-04 17:33 ` [tip:sched/core] sched/wait: Change timeout logic tip-bot for Peter Zijlstra
2013-10-02 9:22 ` [PATCH 03/16] sched/wait: Change the wait_exclusive control flow Peter Zijlstra
2013-10-04 17:33 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2013-10-02 9:22 ` [PATCH 04/16] sched/wait: Introduce ___wait_event() Peter Zijlstra
2013-10-04 17:33 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2013-10-02 9:22 ` [PATCH 05/16] sched/wait: Collapse __wait_event() Peter Zijlstra
2013-10-04 17:34 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2013-10-02 9:22 ` [PATCH 06/16] sched/wait: Collapse __wait_event_timeout() Peter Zijlstra
2013-10-04 17:34 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2013-10-02 9:22 ` [PATCH 07/16] sched/wait: Collapse __wait_event_interruptible() Peter Zijlstra
2013-10-04 17:34 ` [tip:sched/core] sched/wait: Collapse __wait_event_interruptible( ) tip-bot for Peter Zijlstra
2013-10-02 9:22 ` [PATCH 08/16] sched/wait: Collapse __wait_event_interruptible_timeout() Peter Zijlstra
2013-10-04 17:34 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2013-10-02 9:22 ` [PATCH 09/16] sched/wait: Collapse __wait_event_interruptible_exclusive() Peter Zijlstra
2013-10-04 17:34 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2013-10-02 9:22 ` [PATCH 10/16] sched/wait: Collapse __wait_event_lock_irq() Peter Zijlstra
2013-10-04 17:34 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2013-10-02 9:22 ` [PATCH 11/16] sched/wait: Collapse __wait_event_interruptible_lock_irq() Peter Zijlstra
2013-10-04 17:35 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2013-10-02 9:22 ` [PATCH 12/16] sched/wait: Collapse __wait_event_interruptible_lock_irq_timeout() Peter Zijlstra
2013-10-04 17:35 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2013-10-02 9:22 ` [PATCH 13/16] sched/wait: Collapse __wait_event_interruptible_tty() Peter Zijlstra
2013-10-04 17:35 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2013-10-02 9:22 ` [PATCH 14/16] sched/wait: Collapse __wait_event_killable() Peter Zijlstra
2013-10-04 17:35 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2013-10-02 9:22 ` [PATCH 15/16] sched/wait: Collapse __wait_event_hrtimeout() Peter Zijlstra
2013-10-04 17:35 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2013-10-02 9:22 ` [PATCH 16/16] sched/wait: Make the __wait_event*() interface more friendly Peter Zijlstra
2013-10-04 17:35 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2013-10-04 20:44 ` [PATCH 00/16] sched/wait: Collapse __wait_event macros -v5 Peter Zijlstra
2013-10-04 20:44 ` Peter Zijlstra
2013-10-05 8:04 ` Ingo Molnar
2013-10-08 9:59 ` Peter Zijlstra
2013-10-08 10:23 ` Ingo Molnar
2013-10-08 14:16 ` Paul E. McKenney
2013-10-08 19:47 ` Ingo Molnar
2013-10-08 20:01 ` Peter Zijlstra
2013-10-08 20:41 ` Paul E. McKenney
2013-10-08 21:06 ` Peter Zijlstra
2013-10-08 21:43 ` Paul E. McKenney
2013-10-08 20:40 ` Paul E. McKenney
2013-10-09 3:28 ` Paul E. McKenney
2013-10-09 3:35 ` Paul E. McKenney
2013-10-09 6:08 ` Ingo Molnar
2013-10-09 14:21 ` Paul E. McKenney
2013-10-10 2:59 ` Paul E. McKenney
2013-10-10 8:05 ` Ingo Molnar
2013-10-10 17:11 ` Paul E. McKenney
2013-10-10 17:39 ` Ingo Molnar
2013-10-10 18:58 ` Paul E. McKenney
2013-10-11 7:26 ` Ingo Molnar
2013-10-11 15:59 ` Paul E. McKenney
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