Commit-ID: e4aafea2d4bde8b44d6500c4ee7195bbfc51269e
Gitweb: http://git.kernel.org/tip/e4aafea2d4bde8b44d6500c4ee7195bbfc51269e
Author: Frederic Weisbecker <fweisbec@xxxxxxxxx>
AuthorDate: Thu, 16 Jul 2009 15:44:29 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Sat, 18 Jul 2009 15:51:42 +0200
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@xxxxxxxxx>
[ Move and rename preempt_count_equals() ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
LKML-Reference: <1247725694-6082-4-git-send-email-fweisbec@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
include/linux/kernel.h | 6 +++---
kernel/sched.c | 15 +++++++++++----
2 files changed, 14 insertions(+), 7 deletions(-)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index b804f69..2b5b1e0 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -125,7 +125,7 @@ extern int _cond_resched(void);
#endif
#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
- void __might_sleep(char *file, int line);
+ void __might_sleep(char *file, int line, int preempt_offset);
/**
* might_sleep - annotation for functions that can sleep
*
@@ -137,9 +137,9 @@ extern int _cond_resched(void);
* supposed to.
*/
# define might_sleep() \
- do { __might_sleep(__FILE__, __LINE__); might_resched(); } while (0)
+ do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
#else
- static inline void __might_sleep(char *file, int line) { }
+ static inline void __might_sleep(char *file, int line, int preempt_offset) { }
# define might_sleep() do { might_resched(); } while (0)
#endif
diff --git a/kernel/sched.c b/kernel/sched.c
index 370a6c3..3ff4d00 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -6610,7 +6610,7 @@ static inline int should_resched(void)
static void __cond_resched(void)
{
- __might_sleep(__FILE__, __LINE__);
+ __might_sleep(__FILE__, __LINE__, 0);
add_preempt_count(PREEMPT_ACTIVE);
schedule();
@@ -9429,13 +9429,20 @@ void __init sched_init(void)
}
#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
-void __might_sleep(char *file, int line)
+static inline int preempt_count_equals(int preempt_offset)
+{
+ int nested = preempt_count() & ~PREEMPT_ACTIVE;
+
+ return (nested == PREEMPT_INATOMIC_BASE + preempt_offset);
+}
+
+void __might_sleep(char *file, int line, int preempt_offset)
{
#ifdef in_atomic
static unsigned long prev_jiffy; /* ratelimiting */
- if ((!in_atomic() && !irqs_disabled()) ||
- system_state != SYSTEM_RUNNING || oops_in_progress)
+ if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
+ system_state != SYSTEM_RUNNING || oops_in_progress)
return;
if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
return;
--
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