From e211cb68dd3c951b104ff0b47dbaed2c8b8d2399 Mon Sep 17 00:00:00 2001 From: Konstantin Khlebnikov Date: Wed, 15 Jul 2015 12:52:04 +0300 Subject: sched/preempt: Fix cond_resched_lock() and cond_resched_softirq() commit fe32d3cd5e8eb0f82e459763374aa80797023403 upstream. 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 Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Graf Cc: Boris Ostrovsky Cc: David Vrabel Cc: Linus Torvalds Cc: Mike Galbraith Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Thomas Gleixner 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 Signed-off-by: Mike Galbraith Signed-off-by: Greg Kroah-Hartman --- include/linux/preempt.h | 5 +++-- include/linux/preempt_mask.h | 14 +++++++++++--- include/linux/sched.h | 6 ------ 3 files changed, 14 insertions(+), 11 deletions(-) (limited to 'include/linux') diff --git a/include/linux/preempt.h b/include/linux/preempt.h index 1841b58cf173..411a5c6371da 100644 --- a/include/linux/preempt.h +++ b/include/linux/preempt.h @@ -22,7 +22,8 @@ #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) @@ -61,7 +62,7 @@ do { \ #define preempt_check_resched() \ do { \ - if (should_resched()) \ + if (should_resched(0)) \ __preempt_schedule(); \ } while (0) diff --git a/include/linux/preempt_mask.h b/include/linux/preempt_mask.h index 1f654ee836b7..5cb25f17331a 100644 --- a/include/linux/preempt_mask.h +++ b/include/linux/preempt_mask.h @@ -71,12 +71,20 @@ */ #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: * @@ -90,7 +98,7 @@ * * 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 diff --git a/include/linux/sched.h b/include/linux/sched.h index 91fe6a38b307..ec6000f66e75 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2647,12 +2647,6 @@ extern int _cond_resched(void); extern int __cond_resched_lock(spinlock_t *lock); -#ifdef CONFIG_PREEMPT_COUNT -#define PREEMPT_LOCK_OFFSET PREEMPT_OFFSET -#else -#define PREEMPT_LOCK_OFFSET 0 -#endif - #define cond_resched_lock(lock) ({ \ __might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET); \ __cond_resched_lock(lock); \ -- cgit v1.2.3