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From: Frederic Weisbecker <frederic@kernel.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>,
	Jacek Anaszewski <jacek.anaszewski@gmail.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Wanpeng Li <wanpengli@tencent.com>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Rik van Riel <riel@surriel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Yauheni Kaliuta <yauheni.kaliuta@redhat.com>,
	Ingo Molnar <mingo@kernel.org>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Pavel Machek <pavel@ucw.cz>
Subject: [PATCH 10/14] context_tracking: Check static key on context_tracking_enabled_*cpu()
Date: Wed, 16 Oct 2019 04:56:56 +0200	[thread overview]
Message-ID: <20191016025700.31277-11-frederic@kernel.org> (raw)
In-Reply-To: <20191016025700.31277-1-frederic@kernel.org>

guest_enter() doesn't call context_tracking_enabled() before calling
context_tracking_enabled_this_cpu(). Therefore the guest code doesn't
benefit from the static key on the fast path.

Just make sure that context_tracking_enabled_*cpu() functions check
the static key by themselves to propagate the optimization.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Ingo Molnar <mingo@kernel.org>
---
 include/linux/context_tracking_state.h | 4 ++--
 include/linux/vtime.h                  | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/linux/context_tracking_state.h b/include/linux/context_tracking_state.h
index 587717705727..e7fe6678b7ad 100644
--- a/include/linux/context_tracking_state.h
+++ b/include/linux/context_tracking_state.h
@@ -33,12 +33,12 @@ static inline bool context_tracking_enabled(void)
 
 static inline bool context_tracking_enabled_cpu(int cpu)
 {
-	return per_cpu(context_tracking.active, cpu);
+	return context_tracking_enabled() && per_cpu(context_tracking.active, cpu);
 }
 
 static inline bool context_tracking_enabled_this_cpu(void)
 {
-	return __this_cpu_read(context_tracking.active);
+	return context_tracking_enabled() && __this_cpu_read(context_tracking.active);
 }
 
 static inline bool context_tracking_in_user(void)
diff --git a/include/linux/vtime.h b/include/linux/vtime.h
index e2733bf33541..2cdeca062db3 100644
--- a/include/linux/vtime.h
+++ b/include/linux/vtime.h
@@ -33,12 +33,12 @@ static inline bool vtime_accounting_enabled(void)
 
 static inline bool vtime_accounting_enabled_cpu(int cpu)
 {
-	return (vtime_accounting_enabled() && context_tracking_enabled_cpu(cpu));
+	return context_tracking_enabled_cpu(cpu);
 }
 
 static inline bool vtime_accounting_enabled_this_cpu(void)
 {
-	return (vtime_accounting_enabled() && context_tracking_enabled_this_cpu());
+	return context_tracking_enabled_this_cpu();
 }
 
 extern void vtime_task_switch_generic(struct task_struct *prev);
-- 
2.23.0


  parent reply	other threads:[~2019-10-16  2:57 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-16  2:56 [PATCH 00/14] sched/nohz: Make kcpustat's CPUTIME_SYSTEM vtime aware v2 (Partially fix kcpustat on nohz_full) Frederic Weisbecker
2019-10-16  2:56 ` [PATCH 01/14] sched/vtime: Record CPU under seqcount for kcpustat needs Frederic Weisbecker
2019-10-29  9:52   ` [tip: sched/core] " tip-bot2 for Frederic Weisbecker
2019-10-16  2:56 ` [PATCH 02/14] sched/cputime: Add vtime idle task state Frederic Weisbecker
2019-10-29  9:52   ` [tip: sched/core] " tip-bot2 for Frederic Weisbecker
2019-10-16  2:56 ` [PATCH 03/14] sched/cputime: Add vtime guest " Frederic Weisbecker
2019-10-29  9:52   ` [tip: sched/core] " tip-bot2 for Frederic Weisbecker
2019-10-16  2:56 ` [PATCH 04/14] context_tracking: Remove context_tracking_active() Frederic Weisbecker
2019-10-29  9:52   ` [tip: sched/core] " tip-bot2 for Frederic Weisbecker
2019-10-16  2:56 ` [PATCH 05/14] context_tracking: s/context_tracking_is_enabled/context_tracking_enabled() Frederic Weisbecker
2019-10-29  9:52   ` [tip: sched/core] context_tracking: Rename context_tracking_is_enabled() => context_tracking_enabled() tip-bot2 for Frederic Weisbecker
2019-10-16  2:56 ` [PATCH 06/14] context_tracking: Rename context_tracking_is_cpu_enabled() to context_tracking_enabled_this_cpu() Frederic Weisbecker
2019-10-29  9:52   ` [tip: sched/core] " tip-bot2 for Frederic Weisbecker
2019-10-16  2:56 ` [PATCH 07/14] context_tracking: Introduce context_tracking_enabled_cpu() Frederic Weisbecker
2019-10-29  9:52   ` [tip: sched/core] " tip-bot2 for Frederic Weisbecker
2019-10-16  2:56 ` [PATCH 08/14] sched/vtime: Rename vtime_accounting_cpu_enabled() to vtime_accounting_enabled_this_cpu() Frederic Weisbecker
2019-10-29  9:52   ` [tip: sched/core] " tip-bot2 for Frederic Weisbecker
2019-10-16  2:56 ` [PATCH 09/14] sched/vtime: Introduce vtime_accounting_enabled_cpu() Frederic Weisbecker
2019-10-29  9:52   ` [tip: sched/core] " tip-bot2 for Frederic Weisbecker
2019-10-16  2:56 ` Frederic Weisbecker [this message]
2019-10-29  9:52   ` [tip: sched/core] context_tracking: Check static key on context_tracking_enabled_*cpu() tip-bot2 for Frederic Weisbecker
2019-10-16  2:56 ` [PATCH 11/14] sched/kcpustat: Introduce vtime-aware kcpustat accessor for CPUTIME_SYSTEM Frederic Weisbecker
2019-10-24 11:50   ` Peter Zijlstra
2019-10-25  1:25     ` Frederic Weisbecker
2019-10-25  2:03   ` [PATCH 11/14 v2] " Frederic Weisbecker
2019-10-29  9:52     ` [tip: sched/core] " tip-bot2 for Frederic Weisbecker
2019-10-16  2:56 ` [PATCH 12/14] procfs: Use vtime aware kcpustat accessor to fetch CPUTIME_SYSTEM Frederic Weisbecker
2019-10-29  9:52   ` [tip: sched/core] " tip-bot2 for Frederic Weisbecker
2019-10-16  2:56 ` [PATCH 13/14] cpufreq: " Frederic Weisbecker
2019-10-16  3:40   ` Viresh Kumar
2019-10-29  9:52   ` [tip: sched/core] " tip-bot2 for Frederic Weisbecker
2019-10-16  2:57 ` [PATCH 14/14] leds: " Frederic Weisbecker
2019-10-29  9:52   ` [tip: sched/core] " tip-bot2 for Frederic Weisbecker
2019-10-24  0:45 ` [GIT PULL] sched/nohz: Make kcpustat's CPUTIME_SYSTEM vtime aware Frederic Weisbecker

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