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From: Frederic Weisbecker <frederic@kernel.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Frederic Weisbecker <frederic@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Chris Metcalf <cmetcalf@mellanox.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Luiz Capitulino <lcapitulino@redhat.com>,
	Christoph Lameter <cl@linux.com>,
	"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
	Mike Galbraith <efault@gmx.de>, Rik van Riel <riel@redhat.com>,
	Wanpeng Li <kernellwp@gmail.com>
Subject: [PATCH 07/12] housekeeping: Move it under its own config, independent from NO_HZ
Date: Fri, 27 Oct 2017 04:42:34 +0200
Message-ID: <1509072159-31808-8-git-send-email-frederic@kernel.org> (raw)
In-Reply-To: <1509072159-31808-1-git-send-email-frederic@kernel.org>

Split housekeeping config from CONFIG_NO_HZ_FULL. This way we finally
separate the isolation code from nohz.

Although a dependency to CONFIG_NO_HZ_FULL remains for now until the
housekeeping code doesn't deal anymore with nohz internals directly.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <kernellwp@gmail.com>
---
 include/linux/sched/isolation.h | 6 +++---
 init/Kconfig                    | 8 ++++++++
 kernel/sched/Makefile           | 2 +-
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h
index ad0f5d9..93ac2367 100644
--- a/include/linux/sched/isolation.h
+++ b/include/linux/sched/isolation.h
@@ -5,7 +5,7 @@
 #include <linux/init.h>
 #include <linux/tick.h>
 
-#ifdef CONFIG_NO_HZ_FULL
+#ifdef CONFIG_CPU_ISOLATION
 DECLARE_STATIC_KEY_FALSE(housekeeping_overriden);
 extern int housekeeping_any_cpu(void);
 extern const struct cpumask *housekeeping_cpumask(void);
@@ -27,11 +27,11 @@ static inline const struct cpumask *housekeeping_cpumask(void)
 
 static inline void housekeeping_affine(struct task_struct *t) { }
 static inline void housekeeping_init(void) { }
-#endif /* CONFIG_NO_HZ_FULL */
+#endif /* CONFIG_CPU_ISOLATION */
 
 static inline bool housekeeping_cpu(int cpu)
 {
-#ifdef CONFIG_NO_HZ_FULL
+#ifdef CONFIG_CPU_ISOLATION
 	if (static_branch_unlikely(&housekeeping_overriden))
 		return housekeeping_test_cpu(cpu);
 #endif
diff --git a/init/Kconfig b/init/Kconfig
index 78cb246..6f52e6f 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -472,6 +472,14 @@ config TASK_IO_ACCOUNTING
 
 endmenu # "CPU/Task time and stats accounting"
 
+config CPU_ISOLATION
+	bool "CPU isolation"
+	depends on NO_HZ_FULL
+	help
+	  Make sure that CPUs running critical tasks are not disturbed by
+	  any source of "noise" such as unbound workqueues, timers, kthreads...
+	  Unbound jobs get offloaded to housekeeping CPUs.
+
 source "kernel/rcu/Kconfig"
 
 config BUILD_BIN2C
diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
index 871d43d..dbe6130 100644
--- a/kernel/sched/Makefile
+++ b/kernel/sched/Makefile
@@ -26,4 +26,4 @@ obj-$(CONFIG_CGROUP_CPUACCT) += cpuacct.o
 obj-$(CONFIG_CPU_FREQ) += cpufreq.o
 obj-$(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) += cpufreq_schedutil.o
 obj-$(CONFIG_MEMBARRIER) += membarrier.o
-obj-$(CONFIG_NO_HZ_FULL) += isolation.o
+obj-$(CONFIG_CPU_ISOLATION) += isolation.o
-- 
2.7.4

  parent reply index

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-27  2:42 [GIT PULL] Housekeeping subsystem v6 Frederic Weisbecker
2017-10-27  2:42 ` [PATCH 01/12] housekeeping: Move housekeeping related code to its own file Frederic Weisbecker
2017-10-27 12:01   ` [tip:sched/core] sched/isolation: " tip-bot for Frederic Weisbecker
2017-10-27  2:42 ` [PATCH 02/12] watchdog: Use housekeeping_cpumask() instead of ad-hoc version Frederic Weisbecker
2017-10-27 12:02   ` [tip:sched/core] sched/isolation, " tip-bot for Frederic Weisbecker
2017-10-27  2:42 ` [PATCH 03/12] housekeeping: Provide a dynamic off-case to housekeeping_any_cpu() Frederic Weisbecker
2017-10-27 12:02   ` [tip:sched/core] sched/isolation: " tip-bot for Frederic Weisbecker
2017-10-27  2:42 ` [PATCH 04/12] housekeeping: Make housekeeping cpumask private Frederic Weisbecker
2017-10-27 12:03   ` [tip:sched/core] sched/isolation: Make the " tip-bot for Frederic Weisbecker
2017-10-27  2:42 ` [PATCH 05/12] housekeeping: Use its own static key Frederic Weisbecker
2017-10-27 12:03   ` [tip:sched/core] sched/isolation: " tip-bot for Frederic Weisbecker
2017-10-27  2:42 ` [PATCH 06/12] housekeeping: Rename is_housekeeping_cpu to housekeeping_cpu Frederic Weisbecker
2017-10-27 12:03   ` [tip:sched/core] sched/isolation: Rename is_housekeeping_cpu() to housekeeping_cpu() tip-bot for Frederic Weisbecker
2017-10-27  2:42 ` Frederic Weisbecker [this message]
2017-10-27 12:04   ` [tip:sched/core] sched/isolation: Split out new CONFIG_CPU_ISOLATION=y config from CONFIG_NO_HZ_FULL tip-bot for Frederic Weisbecker
2017-10-27  2:42 ` [PATCH 08/12] housekeeping: Introduce housekeeping flags Frederic Weisbecker
2017-10-27 12:04   ` [tip:sched/core] sched/isolation: " tip-bot for Frederic Weisbecker
2017-10-27  2:42 ` [PATCH 09/12] housekeeping: Handle the nohz_full= parameter Frederic Weisbecker
2017-10-27 12:05   ` [tip:sched/core] sched/isolation: " tip-bot for Frederic Weisbecker
2017-10-27  2:42 ` [PATCH 10/12] housekeeping: Move isolcpus to housekeeping Frederic Weisbecker
2017-10-27 12:05   ` [tip:sched/core] sched/isolation: Move isolcpus= handling to the housekeeping code tip-bot for Frederic Weisbecker
2017-10-27  2:42 ` [PATCH 11/12] housekeeping: Add basic isolcpus flags Frederic Weisbecker
2017-10-27 12:05   ` [tip:sched/core] sched/isolation: " tip-bot for Frederic Weisbecker
2017-10-27  2:42 ` [PATCH 12/12] housekeeping: Document " Frederic Weisbecker
2017-10-27 12:06   ` [tip:sched/core] sched/isolation: Document the isolcpus= flags tip-bot for Frederic Weisbecker
2017-10-27 13:58     ` Peter Zijlstra
2017-10-27 14:36       ` Frederic Weisbecker
2017-10-27 17:06         ` Ingo Molnar
2017-10-27 17:33           ` Frederic Weisbecker
2017-10-27 18:21             ` Ingo Molnar
2017-10-27 18:39               ` Frederic Weisbecker
2017-10-27 19:04                 ` Ingo Molnar
2017-10-27 14:38       ` Mike Galbraith
2017-10-30 15:48       ` Christopher Lameter
2017-10-30 16:11         ` Peter Zijlstra
2017-10-30 16:30           ` Christopher Lameter
2017-10-30 16:58             ` Peter Zijlstra
2017-10-30 16:56           ` Mike Galbraith

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