sched/isolation: Split out new CONFIG_CPU_ISOLATION=y config from CONFIG_NO_HZ_FULL

Split the 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, while the
housekeeping code still deals with NOHZ internals.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
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: Wanpeng Li <kernellwp@gmail.com>
Link: http://lkml.kernel.org/r/1509072159-31808-8-git-send-email-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>

diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h
index ad0f5d986a2e3d7610d5636aa4dedcaf5b1baede..93ac2367a520cec2eb098d289a756284736364ce 100644 (file)
--- 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 46075327c165dd798b0283dd8600b21e2396a61b..87e5d2676d100c001c38175ef79e58a3a88bb979 100644 (file)
--- 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 bebd97a6ddfe78455e8f7f5aba3c7e697214a255..e2f9d4feff4015dd747a3dea06a345076b7709fd 100644 (file)
--- a/kernel/sched/Makefile
+++ b/kernel/sched/Makefile
@@ -27,4 +27,4 @@ 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