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authorThomas Gleixner <tglx@linutronix.de>2011-03-21 13:32:17 +0100
committerIngo Molnar <mingo@elte.hu>2012-03-01 10:28:04 +0100
commitba74c1448f127649046615ec017bded7b2a76f29 (patch)
tree33eceaf0c4b35aca095e3e1a678bdbab23006650
parentbd2f55361f18347e890d52ff9cfd8895455ec11b (diff)
downloadlinux-ba74c1448f127649046615ec017bded7b2a76f29.tar.bz2
sched/rt: Document scheduler related skip-resched-check sites
Create a distinction between scheduler related preempt_enable_no_resched() calls and the nearly one hundred other places in the kernel that do not want to reschedule, for one reason or another. This distinction matters for -rt, where the scheduler and the non-scheduler preempt models (and checks) are different. For upstream it's purely documentational. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/n/tip-gs88fvx2mdv5psnzxnv575ke@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--arch/powerpc/kernel/idle.c2
-rw-r--r--arch/sparc/kernel/process_64.c2
-rw-r--r--include/linux/preempt.h5
-rw-r--r--kernel/sched/core.c6
-rw-r--r--kernel/softirq.c4
5 files changed, 11 insertions, 8 deletions
diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c
index 65035141552b..c97fc60c790c 100644
--- a/arch/powerpc/kernel/idle.c
+++ b/arch/powerpc/kernel/idle.c
@@ -102,7 +102,7 @@ void cpu_idle(void)
rcu_idle_exit();
tick_nohz_idle_exit();
if (cpu_should_die()) {
- preempt_enable_no_resched();
+ sched_preempt_enable_no_resched();
cpu_die();
}
schedule_preempt_disabled();
diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c
index ab9a29268213..06b5b5fc20c7 100644
--- a/arch/sparc/kernel/process_64.c
+++ b/arch/sparc/kernel/process_64.c
@@ -106,7 +106,7 @@ void cpu_idle(void)
#ifdef CONFIG_HOTPLUG_CPU
if (cpu_is_offline(cpu)) {
- preempt_enable_no_resched();
+ sched_preempt_enable_no_resched();
cpu_play_dead();
}
#endif
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 58969b2a8a82..5a710b9c578e 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -48,12 +48,14 @@ do { \
barrier(); \
} while (0)
-#define preempt_enable_no_resched() \
+#define sched_preempt_enable_no_resched() \
do { \
barrier(); \
dec_preempt_count(); \
} while (0)
+#define preempt_enable_no_resched() sched_preempt_enable_no_resched()
+
#define preempt_enable() \
do { \
preempt_enable_no_resched(); \
@@ -92,6 +94,7 @@ do { \
#else /* !CONFIG_PREEMPT_COUNT */
#define preempt_disable() do { } while (0)
+#define sched_preempt_enable_no_resched() do { } while (0)
#define preempt_enable_no_resched() do { } while (0)
#define preempt_enable() do { } while (0)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 73022395c00e..643cc37fcb23 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3220,7 +3220,7 @@ need_resched:
post_schedule(rq);
- preempt_enable_no_resched();
+ sched_preempt_enable_no_resched();
if (need_resched())
goto need_resched;
}
@@ -3253,7 +3253,7 @@ EXPORT_SYMBOL(schedule);
*/
void __sched schedule_preempt_disabled(void)
{
- preempt_enable_no_resched();
+ sched_preempt_enable_no_resched();
schedule();
preempt_disable();
}
@@ -4486,7 +4486,7 @@ SYSCALL_DEFINE0(sched_yield)
__release(rq->lock);
spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
do_raw_spin_unlock(&rq->lock);
- preempt_enable_no_resched();
+ sched_preempt_enable_no_resched();
schedule();
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 79b524767a24..f268369ebe1f 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -353,7 +353,7 @@ void irq_exit(void)
tick_nohz_irq_exit();
#endif
rcu_irq_exit();
- preempt_enable_no_resched();
+ sched_preempt_enable_no_resched();
}
/*
@@ -759,7 +759,7 @@ static int run_ksoftirqd(void * __bind_cpu)
if (local_softirq_pending())
__do_softirq();
local_irq_enable();
- preempt_enable_no_resched();
+ sched_preempt_enable_no_resched();
cond_resched();
preempt_disable();
rcu_note_context_switch((long)__bind_cpu);