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authorKonstantin Khlebnikov <khlebnikov@yandex-team.ru>2015-07-15 12:52:04 +0300
committerIngo Molnar <mingo@kernel.org>2015-08-03 12:21:24 +0200
commitfe32d3cd5e8eb0f82e459763374aa80797023403 (patch)
tree169ff64d9bb51a7c6c60cd89a9b45a46d2841e1b /include/linux/preempt.h
parentc56dadf39761a6157239cac39e3988998c994f98 (diff)
sched/preempt: Fix cond_resched_lock() and cond_resched_softirq()
These functions check should_resched() before unlocking spinlock/bh-enable: preempt_count always non-zero => should_resched() always returns false. cond_resched_lock() worked iff spin_needbreak is set. This patch adds argument "preempt_offset" to should_resched(). preempt_count offset constants for that: PREEMPT_DISABLE_OFFSET - offset after preempt_disable() PREEMPT_LOCK_OFFSET - offset after spin_lock() SOFTIRQ_DISABLE_OFFSET - offset after local_bh_distable() SOFTIRQ_LOCK_OFFSET - offset after spin_lock_bh() Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Graf <agraf@suse.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: bdb438065890 ("sched: Extract the basic add/sub preempt_count modifiers") Link: http://lkml.kernel.org/r/20150715095204.12246.98268.stgit@buzz Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/preempt.h')
-rw-r--r--include/linux/preempt.h19
1 files changed, 14 insertions, 5 deletions
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 84991f185173..bea8dd8ff5e0 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -84,13 +84,21 @@
*/
#define in_nmi() (preempt_count() & NMI_MASK)
+/*
+ * The preempt_count offset after preempt_disable();
+ */
#if defined(CONFIG_PREEMPT_COUNT)
-# define PREEMPT_DISABLE_OFFSET 1
+# define PREEMPT_DISABLE_OFFSET PREEMPT_OFFSET
#else
-# define PREEMPT_DISABLE_OFFSET 0
+# define PREEMPT_DISABLE_OFFSET 0
#endif
/*
+ * The preempt_count offset after spin_lock()
+ */
+#define PREEMPT_LOCK_OFFSET PREEMPT_DISABLE_OFFSET
+
+/*
* The preempt_count offset needed for things like:
*
* spin_lock_bh()
@@ -103,7 +111,7 @@
*
* Work as expected.
*/
-#define SOFTIRQ_LOCK_OFFSET (SOFTIRQ_DISABLE_OFFSET + PREEMPT_DISABLE_OFFSET)
+#define SOFTIRQ_LOCK_OFFSET (SOFTIRQ_DISABLE_OFFSET + PREEMPT_LOCK_OFFSET)
/*
* Are we running in atomic context? WARNING: this macro cannot
@@ -124,7 +132,8 @@
#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_PREEMPT_TRACER)
extern void preempt_count_add(int val);
extern void preempt_count_sub(int val);
-#define preempt_count_dec_and_test() ({ preempt_count_sub(1); should_resched(); })
+#define preempt_count_dec_and_test() \
+ ({ preempt_count_sub(1); should_resched(0); })
#else
#define preempt_count_add(val) __preempt_count_add(val)
#define preempt_count_sub(val) __preempt_count_sub(val)
@@ -184,7 +193,7 @@ do { \
#define preempt_check_resched() \
do { \
- if (should_resched()) \
+ if (should_resched(0)) \
__preempt_schedule(); \
} while (0)