sched/isolation: Move housekeeping related code to its own file

The housekeeping code is currently tied to the NOHZ code. As we are
planning to make housekeeping independent from it, start with moving
the relevant code to its own file.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wanpeng Li <kernellwp@gmail.com>
Link: http://lkml.kernel.org/r/1509072159-31808-2-git-send-email-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

drivers/net/ethernet/tile/tilegx.c

@@ -40,7 +40,7 @@
 #include <linux/tcp.h>
 #include <linux/net_tstamp.h>
 #include <linux/ptp_clock_kernel.h>
-#include <linux/tick.h>
+#include <linux/sched/isolation.h>
 
 #include <asm/checksum.h>
 #include <asm/homecache.h>

include/linux/sched/isolation.h

@@ -0,0 +1,56 @@
+#ifndef _LINUX_SCHED_ISOLATION_H
+#define _LINUX_SCHED_ISOLATION_H
+
+#include <linux/cpumask.h>
+#include <linux/init.h>
+#include <linux/tick.h>
+
+#ifdef CONFIG_NO_HZ_FULL
+extern cpumask_var_t housekeeping_mask;
+
+static inline int housekeeping_any_cpu(void)
+{
+	return cpumask_any_and(housekeeping_mask, cpu_online_mask);
+}
+
+extern void __init housekeeping_init(void);
+
+#else
+
+static inline int housekeeping_any_cpu(void)
+{
+	return smp_processor_id();
+}
+
+static inline void housekeeping_init(void) { }
+#endif /* CONFIG_NO_HZ_FULL */
+
+
+static inline const struct cpumask *housekeeping_cpumask(void)
+{
+#ifdef CONFIG_NO_HZ_FULL
+	if (tick_nohz_full_enabled())
+		return housekeeping_mask;
+#endif
+	return cpu_possible_mask;
+}
+
+static inline bool is_housekeeping_cpu(int cpu)
+{
+#ifdef CONFIG_NO_HZ_FULL
+	if (tick_nohz_full_enabled())
+		return cpumask_test_cpu(cpu, housekeeping_mask);
+#endif
+	return true;
+}
+
+static inline void housekeeping_affine(struct task_struct *t)
+{
+#ifdef CONFIG_NO_HZ_FULL
+	if (tick_nohz_full_enabled())
+		set_cpus_allowed_ptr(t, housekeeping_mask);
+
+#endif
+}
+
+#endif /* _LINUX_SCHED_ISOLATION_H */

include/linux/tick.h

@@ -137,7 +137,6 @@ static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
 #ifdef CONFIG_NO_HZ_FULL
 extern bool tick_nohz_full_running;
 extern cpumask_var_t tick_nohz_full_mask;
-extern cpumask_var_t housekeeping_mask;
 
 static inline bool tick_nohz_full_enabled(void)
 {
@@ -161,11 +160,6 @@ static inline void tick_nohz_full_add_cpus_to(struct cpumask *mask)
 		cpumask_or(mask, mask, tick_nohz_full_mask);
 }
 
-static inline int housekeeping_any_cpu(void)
-{
-	return cpumask_any_and(housekeeping_mask, cpu_online_mask);
-}
-
 extern void tick_nohz_dep_set(enum tick_dep_bits bit);
 extern void tick_nohz_dep_clear(enum tick_dep_bits bit);
 extern void tick_nohz_dep_set_cpu(int cpu, enum tick_dep_bits bit);
@@ -235,10 +229,6 @@ static inline void tick_dep_clear_signal(struct signal_struct *signal,
 extern void tick_nohz_full_kick_cpu(int cpu);
 extern void __tick_nohz_task_switch(void);
 #else
-static inline int housekeeping_any_cpu(void)
-{
-	return smp_processor_id();
-}
 static inline bool tick_nohz_full_enabled(void) { return false; }
 static inline bool tick_nohz_full_cpu(int cpu) { return false; }
 static inline void tick_nohz_full_add_cpus_to(struct cpumask *mask) { }
@@ -260,33 +250,6 @@ static inline void tick_nohz_full_kick_cpu(int cpu) { }
 static inline void __tick_nohz_task_switch(void) { }
 #endif
 
-static inline const struct cpumask *housekeeping_cpumask(void)
-{
-#ifdef CONFIG_NO_HZ_FULL
-	if (tick_nohz_full_enabled())
-		return housekeeping_mask;
-#endif
-	return cpu_possible_mask;
-}
-
-static inline bool is_housekeeping_cpu(int cpu)
-{
-#ifdef CONFIG_NO_HZ_FULL
-	if (tick_nohz_full_enabled())
-		return cpumask_test_cpu(cpu, housekeeping_mask);
-#endif
-	return true;
-}
-
-static inline void housekeeping_affine(struct task_struct *t)
-{
-#ifdef CONFIG_NO_HZ_FULL
-	if (tick_nohz_full_enabled())
-		set_cpus_allowed_ptr(t, housekeeping_mask);
-
-#endif
-}
-
 static inline void tick_nohz_task_switch(void)
 {
 	if (tick_nohz_full_enabled())

init/main.c

@@ -46,6 +46,7 @@
 #include <linux/cgroup.h>
 #include <linux/efi.h>
 #include <linux/tick.h>
+#include <linux/sched/isolation.h>
 #include <linux/interrupt.h>
 #include <linux/taskstats_kern.h>
 #include <linux/delayacct.h>
@@ -606,6 +607,7 @@ asmlinkage __visible void __init start_kernel(void)
 	early_irq_init();
 	init_IRQ();
 	tick_init();
+	housekeeping_init();
 	rcu_init_nohz();
 	init_timers();
 	hrtimers_init();

kernel/rcu/tree_plugin.h

@@ -29,6 +29,7 @@
 #include <linux/oom.h>
 #include <linux/sched/debug.h>
 #include <linux/smpboot.h>
+#include <linux/sched/isolation.h>
 #include <uapi/linux/sched/types.h>
 #include "../time/tick-internal.h"
 

kernel/rcu/update.c

@@ -51,6 +51,7 @@
 #include <linux/kthread.h>
 #include <linux/tick.h>
 #include <linux/rcupdate_wait.h>
+#include <linux/sched/isolation.h>
 
 #define CREATE_TRACE_POINTS
 

kernel/sched/Makefile

@@ -26,3 +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

kernel/sched/core.c

@@ -26,6 +26,7 @@
 #include <linux/profile.h>
 #include <linux/security.h>
 #include <linux/syscalls.h>
+#include <linux/sched/isolation.h>
 
 #include <asm/switch_to.h>
 #include <asm/tlb.h>

kernel/sched/fair.c

@@ -32,6 +32,7 @@
 #include <linux/mempolicy.h>
 #include <linux/migrate.h>
 #include <linux/task_work.h>
+#include <linux/sched/isolation.h>
 
 #include <trace/events/sched.h>
 

kernel/sched/isolation.c

@@ -0,0 +1,33 @@
+/*
+ *  Housekeeping management. Manage the targets for routine code that can run on
+ *  any CPU: unbound workqueues, timers, kthreads and any offloadable work.
+ *
+ * Copyright (C) 2017 Red Hat, Inc., Frederic Weisbecker
+ *
+ */
+
+#include <linux/sched/isolation.h>
+#include <linux/tick.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+
+cpumask_var_t housekeeping_mask;
+
+void __init housekeeping_init(void)
+{
+	if (!tick_nohz_full_enabled())
+		return;
+
+	if (!alloc_cpumask_var(&housekeeping_mask, GFP_KERNEL)) {
+		WARN(1, "NO_HZ: Can't allocate not-full dynticks cpumask\n");
+		cpumask_clear(tick_nohz_full_mask);
+		tick_nohz_full_running = false;
+		return;
+	}
+
+	cpumask_andnot(housekeeping_mask,
+		       cpu_possible_mask, tick_nohz_full_mask);
+
+	/* We need at least one CPU to handle housekeeping work */
+	WARN_ON_ONCE(cpumask_empty(housekeeping_mask));
+}

kernel/time/tick-sched.c

@@ -166,7 +166,6 @@ static void tick_sched_handle(struct tick_sched *ts, struct pt_regs *regs)
 
 #ifdef CONFIG_NO_HZ_FULL
 cpumask_var_t tick_nohz_full_mask;
-cpumask_var_t housekeeping_mask;
 bool tick_nohz_full_running;
 static atomic_t tick_dep_mask;
 
@@ -438,13 +437,6 @@ void __init tick_nohz_init(void)
 			return;
 	}
 
-	if (!alloc_cpumask_var(&housekeeping_mask, GFP_KERNEL)) {
-		WARN(1, "NO_HZ: Can't allocate not-full dynticks cpumask\n");
-		cpumask_clear(tick_nohz_full_mask);
-		tick_nohz_full_running = false;
-		return;
-	}
-
 	/*
 	 * Full dynticks uses irq work to drive the tick rescheduling on safe
 	 * locking contexts. But then we need irq work to raise its own
@@ -453,7 +445,6 @@ void __init tick_nohz_init(void)
 	if (!arch_irq_work_has_interrupt()) {
 		pr_warn("NO_HZ: Can't run full dynticks because arch doesn't support irq work self-IPIs\n");
 		cpumask_clear(tick_nohz_full_mask);
-		cpumask_copy(housekeeping_mask, cpu_possible_mask);
 		tick_nohz_full_running = false;
 		return;
 	}
@@ -466,9 +457,6 @@ void __init tick_nohz_init(void)
 		cpumask_clear_cpu(cpu, tick_nohz_full_mask);
 	}
 
-	cpumask_andnot(housekeeping_mask,
-		       cpu_possible_mask, tick_nohz_full_mask);
-
 	for_each_cpu(cpu, tick_nohz_full_mask)
 		context_tracking_cpu_set(cpu);
 
@@ -478,12 +466,6 @@ void __init tick_nohz_init(void)
 	WARN_ON(ret < 0);
 	pr_info("NO_HZ: Full dynticks CPUs: %*pbl.\n",
 		cpumask_pr_args(tick_nohz_full_mask));
-
-	/*
-	 * We need at least one CPU to handle housekeeping work such
-	 * as timekeeping, unbound timers, workqueues, ...
-	 */
-	WARN_ON_ONCE(cpumask_empty(housekeeping_mask));
 }
 #endif
 

kernel/watchdog.c

@@ -24,6 +24,7 @@
 #include <linux/workqueue.h>
 #include <linux/sched/clock.h>
 #include <linux/sched/debug.h>
+#include <linux/sched/isolation.h>
 
 #include <asm/irq_regs.h>
 #include <linux/kvm_para.h>