lkml.org 
[lkml]   [2009]   [Jul]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 6/7 v3] sched: Pull up the might_sleep() check in cond_resched()
Date
might_sleep() is called lately in cond_resched(), after the
need_resched()/preempt enabled/system running tests are checked.

It's better to check the sleeps while atomic earlier and not depend
on some environment datas that reduce the chances to detect a
problem.

Also define cond_resched_*() helpers as macros, so that the FILE/LINE
reported in the sleeping while atomic warning displays the real origin
and not sched.h

Changes in v2:
- call __might_sleep() directly instead of might_sleep() which may call
cond_resched()
- turn cond_resched() into a macro so that the file:line couple reported
refers to the caller of cond_resched() and not __cond_resched() itself.

Changes in v3:
- also propagate this __might_sleep() pull up to cond_resched_lock() and
cond_resched_softirq()

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
fs/dcache.c | 1 +
include/linux/sched.h | 29 +++++++++++++++++++----------
kernel/sched.c | 12 +++++-------
3 files changed, 25 insertions(+), 17 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index 5ecb8e1..64698d6 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -32,6 +32,7 @@
#include <linux/swap.h>
#include <linux/bootmem.h>
#include <linux/fs_struct.h>
+#include <linux/hardirq.h>
#include "internal.h"

int sysctl_vfs_cache_pressure __read_mostly = 100;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index e2bdf18..099408f 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2286,17 +2286,26 @@ static inline int need_resched(void)
*/
extern int _cond_resched(void);

-static inline int cond_resched(void)
-{
- return _cond_resched();
-}
+#define cond_resched() ({ \
+ __might_sleep(__FILE__, __LINE__, 0); \
+ _cond_resched(); \
+})

-extern int cond_resched_lock(spinlock_t * lock);
-extern int cond_resched_softirq(void);
-static inline int cond_resched_bkl(void)
-{
- return _cond_resched();
-}
+extern int __cond_resched_lock(spinlock_t * lock);
+
+#define cond_resched_lock(lock) ({ \
+ __might_sleep(__FILE__, __LINE__, PREEMPT_OFFSET); \
+ __cond_resched_lock(lock); \
+})
+
+extern int __cond_resched_softirq(void);
+
+#define cond_resched_softirq() ({ \
+ __might_sleep(__FILE__, __LINE__, SOFTIRQ_OFFSET); \
+ __cond_resched_softirq(); \
+})
+
+#define cond_resched_bkl() cond_resched()

/*
* Does a critical section need to be broken due to another
diff --git a/kernel/sched.c b/kernel/sched.c
index 847e8fb..b9950b1 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -6610,8 +6610,6 @@ static inline int should_resched(void)

static void __cond_resched(void)
{
- __might_sleep(__FILE__, __LINE__, 0);
-
add_preempt_count(PREEMPT_ACTIVE);
schedule();
sub_preempt_count(PREEMPT_ACTIVE);
@@ -6628,14 +6626,14 @@ int __sched _cond_resched(void)
EXPORT_SYMBOL(_cond_resched);

/*
- * cond_resched_lock() - if a reschedule is pending, drop the given lock,
+ * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
* call schedule, and on return reacquire the lock.
*
* This works OK both with and without CONFIG_PREEMPT. We do strange low-level
* operations here to prevent schedule() from being called twice (once via
* spin_unlock(), once by hand).
*/
-int cond_resched_lock(spinlock_t *lock)
+int __cond_resched_lock(spinlock_t *lock)
{
int resched = should_resched();
int ret = 0;
@@ -6651,9 +6649,9 @@ int cond_resched_lock(spinlock_t *lock)
}
return ret;
}
-EXPORT_SYMBOL(cond_resched_lock);
+EXPORT_SYMBOL(__cond_resched_lock);

-int __sched cond_resched_softirq(void)
+int __sched __cond_resched_softirq(void)
{
BUG_ON(!in_softirq());

@@ -6665,7 +6663,7 @@ int __sched cond_resched_softirq(void)
}
return 0;
}
-EXPORT_SYMBOL(cond_resched_softirq);
+EXPORT_SYMBOL(__cond_resched_softirq);

/**
* yield - yield the current processor to other threads.
--
1.6.2.3


\
 
 \ /
  Last update: 2009-07-16 08:33    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site