sched: Add a preempt count base offset to __might_sleep()
Add a preempt count base offset to compare against the current preempt level count. It prepares to pull up the might_sleep check from cond_resched() to cond_resched_lock() and cond_resched_bh(). For these two helpers, we need to respectively ensure that once we'll unlock the given spinlock / reenable local softirqs, we will reach a sleepable state. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> [ Move and rename preempt_count_equals() ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1247725694-6082-4-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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@ -125,7 +125,7 @@ extern int _cond_resched(void);
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#endif
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#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
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void __might_sleep(char *file, int line);
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void __might_sleep(char *file, int line, int preempt_offset);
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/**
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* might_sleep - annotation for functions that can sleep
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*
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@ -137,9 +137,9 @@ extern int _cond_resched(void);
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* supposed to.
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*/
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# define might_sleep() \
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do { __might_sleep(__FILE__, __LINE__); might_resched(); } while (0)
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do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
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#else
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static inline void __might_sleep(char *file, int line) { }
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static inline void __might_sleep(char *file, int line, int preempt_offset) { }
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# define might_sleep() do { might_resched(); } while (0)
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#endif
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@ -6610,7 +6610,7 @@ static inline int should_resched(void)
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static void __cond_resched(void)
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{
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__might_sleep(__FILE__, __LINE__);
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__might_sleep(__FILE__, __LINE__, 0);
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add_preempt_count(PREEMPT_ACTIVE);
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schedule();
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@ -9429,13 +9429,20 @@ void __init sched_init(void)
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}
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#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
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void __might_sleep(char *file, int line)
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static inline int preempt_count_equals(int preempt_offset)
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{
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int nested = preempt_count() & ~PREEMPT_ACTIVE;
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return (nested == PREEMPT_INATOMIC_BASE + preempt_offset);
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}
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void __might_sleep(char *file, int line, int preempt_offset)
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{
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#ifdef in_atomic
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static unsigned long prev_jiffy; /* ratelimiting */
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if ((!in_atomic() && !irqs_disabled()) ||
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system_state != SYSTEM_RUNNING || oops_in_progress)
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if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
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system_state != SYSTEM_RUNNING || oops_in_progress)
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return;
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if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
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return;
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