From fe32d3cd5e8eb0f82e459763374aa80797023403 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() 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 --- include/asm-generic/preempt.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include/asm-generic') diff --git a/include/asm-generic/preempt.h b/include/asm-generic/preempt.h index d0a7a4753db2..0bec580a4885 100644 --- a/include/asm-generic/preempt.h +++ b/include/asm-generic/preempt.h @@ -71,9 +71,10 @@ static __always_inline bool __preempt_count_dec_and_test(void) /* * Returns true when we need to resched and can (barring IRQ state). */ -static __always_inline bool should_resched(void) +static __always_inline bool should_resched(int preempt_offset) { - return unlikely(!preempt_count() && tif_need_resched()); + return unlikely(preempt_count() == preempt_offset && + tif_need_resched()); } #ifdef CONFIG_PREEMPT -- cgit v1.2.3