From 36df04bc5273a046f53b5e359febc1225f85aa7b Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 29 Oct 2014 12:21:57 +0100 Subject: [PATCH] sched/wait: Reimplement wait_event_freezable() Provide better implementations of wait_event_freezable() APIs. The problem is with freezer_do_not_count(), it hides the thread from the freezer, even though this thread might not actually freeze/sleep at all. Cc: oleg@redhat.com Cc: Rafael Wysocki Signed-off-by: Peter Zijlstra (Intel) Cc: Len Brown Cc: Linus Torvalds Cc: Pavel Machek Cc: Rafael J. Wysocki Cc: linux-pm@vger.kernel.org Link: http://lkml.kernel.org/n/tip-d86fz1jmso9wjxa8jfpinp8o@git.kernel.org Signed-off-by: Ingo Molnar --- include/linux/freezer.h | 38 --------------------------- include/linux/wait.h | 57 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 57 insertions(+), 38 deletions(-) diff --git a/include/linux/freezer.h b/include/linux/freezer.h index 7fd81b8c4897..e203665c0faa 100644 --- a/include/linux/freezer.h +++ b/include/linux/freezer.h @@ -265,35 +265,6 @@ static inline int freezable_schedule_hrtimeout_range(ktime_t *expires, __retval; \ }) -#define wait_event_freezable(wq, condition) \ -({ \ - int __retval; \ - freezer_do_not_count(); \ - __retval = wait_event_interruptible(wq, (condition)); \ - freezer_count(); \ - __retval; \ -}) - -#define wait_event_freezable_timeout(wq, condition, timeout) \ -({ \ - long __retval = timeout; \ - freezer_do_not_count(); \ - __retval = wait_event_interruptible_timeout(wq, (condition), \ - __retval); \ - freezer_count(); \ - __retval; \ -}) - -#define wait_event_freezable_exclusive(wq, condition) \ -({ \ - int __retval; \ - freezer_do_not_count(); \ - __retval = wait_event_interruptible_exclusive(wq, condition); \ - freezer_count(); \ - __retval; \ -}) - - #else /* !CONFIG_FREEZER */ static inline bool frozen(struct task_struct *p) { return false; } static inline bool freezing(struct task_struct *p) { return false; } @@ -331,15 +302,6 @@ static inline void set_freezable(void) {} #define freezable_schedule_hrtimeout_range(expires, delta, mode) \ schedule_hrtimeout_range(expires, delta, mode) -#define wait_event_freezable(wq, condition) \ - wait_event_interruptible(wq, condition) - -#define wait_event_freezable_timeout(wq, condition, timeout) \ - wait_event_interruptible_timeout(wq, condition, timeout) - -#define wait_event_freezable_exclusive(wq, condition) \ - wait_event_interruptible_exclusive(wq, condition) - #define wait_event_freezekillable(wq, condition) \ wait_event_killable(wq, condition) diff --git a/include/linux/wait.h b/include/linux/wait.h index 0421775e0b9f..2232ed16635a 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -267,6 +267,31 @@ do { \ __wait_event(wq, condition); \ } while (0) +#define __wait_event_freezable(wq, condition) \ + ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0, \ + schedule(); try_to_freeze()) + +/** + * wait_event - sleep (or freeze) until a condition gets true + * @wq: the waitqueue to wait on + * @condition: a C expression for the event to wait for + * + * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute + * to system load) until the @condition evaluates to true. The + * @condition is checked each time the waitqueue @wq is woken up. + * + * wake_up() has to be called after changing any variable that could + * change the result of the wait condition. + */ +#define wait_event_freezable(wq, condition) \ +({ \ + int __ret = 0; \ + might_sleep(); \ + if (!(condition)) \ + __ret = __wait_event_freezable(wq, condition); \ + __ret; \ +}) + #define __wait_event_timeout(wq, condition, timeout) \ ___wait_event(wq, ___wait_cond_timeout(condition), \ TASK_UNINTERRUPTIBLE, 0, timeout, \ @@ -300,6 +325,24 @@ do { \ __ret; \ }) +#define __wait_event_freezable_timeout(wq, condition, timeout) \ + ___wait_event(wq, ___wait_cond_timeout(condition), \ + TASK_INTERRUPTIBLE, 0, timeout, \ + __ret = schedule_timeout(__ret); try_to_freeze()) + +/* + * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid + * increasing load and is freezable. + */ +#define wait_event_freezable_timeout(wq, condition, timeout) \ +({ \ + long __ret = timeout; \ + might_sleep(); \ + if (!___wait_cond_timeout(condition)) \ + __ret = __wait_event_freezable_timeout(wq, condition, timeout); \ + __ret; \ +}) + #define __wait_event_cmd(wq, condition, cmd1, cmd2) \ (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \ cmd1; schedule(); cmd2) @@ -480,6 +523,20 @@ do { \ }) +#define __wait_event_freezable_exclusive(wq, condition) \ + ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \ + schedule(); try_to_freeze()) + +#define wait_event_freezable_exclusive(wq, condition) \ +({ \ + int __ret = 0; \ + might_sleep(); \ + if (!(condition)) \ + __ret = __wait_event_freezable_exclusive(wq, condition);\ + __ret; \ +}) + + #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \ ({ \ int __ret = 0; \