[Xen-devel] [PATCH v2 8/9] xen/sched: eliminate sched_tick_suspend() and sched_tick_resume()

[Juergen Gross <jgross@suse.com>]

sched_tick_suspend() and sched_tick_resume() only call rcu related
functions, so eliminate them and do the rcu_idle_timer*() calling in
rcu_idle_[enter|exit]().

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Dario Faggioli <dfaggioli@suse.com>
Acked-by: Julien Grall <julien@xen.org>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
 xen/arch/arm/domain.c         |  6 +++---
 xen/arch/x86/acpi/cpu_idle.c  | 15 ++++++++-------
 xen/arch/x86/cpu/mwait-idle.c |  8 ++++----
 xen/common/rcupdate.c         |  7 +++++--
 xen/common/sched/core.c       | 12 ------------
 xen/include/xen/rcupdate.h    |  3 ---
 xen/include/xen/sched.h       |  2 --
 7 files changed, 20 insertions(+), 33 deletions(-)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index c0a13aa0ab..aa3df3b3ba 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -46,8 +46,8 @@ static void do_idle(void)
 {
     unsigned int cpu = smp_processor_id();
 
-    sched_tick_suspend();
-    /* sched_tick_suspend() can raise TIMER_SOFTIRQ. Process it now. */
+    rcu_idle_enter(cpu);
+    /* rcu_idle_enter() can raise TIMER_SOFTIRQ. Process it now. */
     process_pending_softirqs();
 
     local_irq_disable();
@@ -58,7 +58,7 @@ static void do_idle(void)
     }
     local_irq_enable();
 
-    sched_tick_resume();
+    rcu_idle_exit(cpu);
 }
 
 void idle_loop(void)
diff --git a/xen/arch/x86/acpi/cpu_idle.c b/xen/arch/x86/acpi/cpu_idle.c
index 5edd1844f4..2676f0d7da 100644
--- a/xen/arch/x86/acpi/cpu_idle.c
+++ b/xen/arch/x86/acpi/cpu_idle.c
@@ -599,7 +599,8 @@ void update_idle_stats(struct acpi_processor_power *power,
 
 static void acpi_processor_idle(void)
 {
-    struct acpi_processor_power *power = processor_powers[smp_processor_id()];
+    unsigned int cpu = smp_processor_id();
+    struct acpi_processor_power *power = processor_powers[cpu];
     struct acpi_processor_cx *cx = NULL;
     int next_state;
     uint64_t t1, t2 = 0;
@@ -648,8 +649,8 @@ static void acpi_processor_idle(void)
 
     cpufreq_dbs_timer_suspend();
 
-    sched_tick_suspend();
-    /* sched_tick_suspend() can raise TIMER_SOFTIRQ. Process it now. */
+    rcu_idle_enter(cpu);
+    /* rcu_idle_enter() can raise TIMER_SOFTIRQ. Process it now. */
     process_pending_softirqs();
 
     /*
@@ -658,10 +659,10 @@ static void acpi_processor_idle(void)
      */
     local_irq_disable();
 
-    if ( !cpu_is_haltable(smp_processor_id()) )
+    if ( !cpu_is_haltable(cpu) )
     {
         local_irq_enable();
-        sched_tick_resume();
+        rcu_idle_exit(cpu);
         cpufreq_dbs_timer_resume();
         return;
     }
@@ -786,7 +787,7 @@ static void acpi_processor_idle(void)
         /* Now in C0 */
         power->last_state = &power->states[0];
         local_irq_enable();
-        sched_tick_resume();
+        rcu_idle_exit(cpu);
         cpufreq_dbs_timer_resume();
         return;
     }
@@ -794,7 +795,7 @@ static void acpi_processor_idle(void)
     /* Now in C0 */
     power->last_state = &power->states[0];
 
-    sched_tick_resume();
+    rcu_idle_exit(cpu);
     cpufreq_dbs_timer_resume();
 
     if ( cpuidle_current_governor->reflect )
diff --git a/xen/arch/x86/cpu/mwait-idle.c b/xen/arch/x86/cpu/mwait-idle.c
index 52413e6da1..f49b04c45b 100644
--- a/xen/arch/x86/cpu/mwait-idle.c
+++ b/xen/arch/x86/cpu/mwait-idle.c
@@ -755,8 +755,8 @@ static void mwait_idle(void)
 
 	cpufreq_dbs_timer_suspend();
 
-	sched_tick_suspend();
-	/* sched_tick_suspend() can raise TIMER_SOFTIRQ. Process it now. */
+	rcu_idle_enter(cpu);
+	/* rcu_idle_enter() can raise TIMER_SOFTIRQ. Process it now. */
 	process_pending_softirqs();
 
 	/* Interrupts must be disabled for C2 and higher transitions. */
@@ -764,7 +764,7 @@ static void mwait_idle(void)
 
 	if (!cpu_is_haltable(cpu)) {
 		local_irq_enable();
-		sched_tick_resume();
+		rcu_idle_exit(cpu);
 		cpufreq_dbs_timer_resume();
 		return;
 	}
@@ -806,7 +806,7 @@ static void mwait_idle(void)
 	if (!(lapic_timer_reliable_states & (1 << cstate)))
 		lapic_timer_on();
 
-	sched_tick_resume();
+	rcu_idle_exit(cpu);
 	cpufreq_dbs_timer_resume();
 
 	if ( cpuidle_current_governor->reflect )
diff --git a/xen/common/rcupdate.c b/xen/common/rcupdate.c
index a56103c6f7..cb712c8690 100644
--- a/xen/common/rcupdate.c
+++ b/xen/common/rcupdate.c
@@ -459,7 +459,7 @@ int rcu_needs_cpu(int cpu)
  * periodically poke rcu_pedning(), so that it will invoke the callback
  * not too late after the end of the grace period.
  */
-void rcu_idle_timer_start()
+static void rcu_idle_timer_start(void)
 {
     struct rcu_data *rdp = &this_cpu(rcu_data);
 
@@ -475,7 +475,7 @@ void rcu_idle_timer_start()
     rdp->idle_timer_active = true;
 }
 
-void rcu_idle_timer_stop()
+static void rcu_idle_timer_stop(void)
 {
     struct rcu_data *rdp = &this_cpu(rcu_data);
 
@@ -633,10 +633,13 @@ void rcu_idle_enter(unsigned int cpu)
      * Se the comment before cpumask_andnot() in  rcu_start_batch().
      */
     smp_mb();
+
+    rcu_idle_timer_start();
 }
 
 void rcu_idle_exit(unsigned int cpu)
 {
+    rcu_idle_timer_stop();
     ASSERT(cpumask_test_cpu(cpu, &rcu_ctrlblk.idle_cpumask));
     cpumask_clear_cpu(cpu, &rcu_ctrlblk.idle_cpumask);
 }
diff --git a/xen/common/sched/core.c b/xen/common/sched/core.c
index 896f82f4d2..d32b9b1baa 100644
--- a/xen/common/sched/core.c
+++ b/xen/common/sched/core.c
@@ -3268,18 +3268,6 @@ void schedule_dump(struct cpupool *c)
     rcu_read_unlock(&sched_res_rculock);
 }
 
-void sched_tick_suspend(void)
-{
-    rcu_idle_enter(smp_processor_id());
-    rcu_idle_timer_start();
-}
-
-void sched_tick_resume(void)
-{
-    rcu_idle_timer_stop();
-    rcu_idle_exit(smp_processor_id());
-}
-
 void wait(void)
 {
     schedule();
diff --git a/xen/include/xen/rcupdate.h b/xen/include/xen/rcupdate.h
index 13850865ed..174d058113 100644
--- a/xen/include/xen/rcupdate.h
+++ b/xen/include/xen/rcupdate.h
@@ -148,7 +148,4 @@ int rcu_barrier(void);
 void rcu_idle_enter(unsigned int cpu);
 void rcu_idle_exit(unsigned int cpu);
 
-void rcu_idle_timer_start(void);
-void rcu_idle_timer_stop(void);
-
 #endif /* __XEN_RCUPDATE_H */
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index d8e961095f..cf7aa39844 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -690,8 +690,6 @@ void sched_destroy_domain(struct domain *d);
 long sched_adjust(struct domain *, struct xen_domctl_scheduler_op *);
 long sched_adjust_global(struct xen_sysctl_scheduler_op *);
 int  sched_id(void);
-void sched_tick_suspend(void);
-void sched_tick_resume(void);
 void vcpu_wake(struct vcpu *v);
 long vcpu_yield(void);
 void vcpu_sleep_nosync(struct vcpu *v);
-- 
2.16.4


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