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[GIT PULL] Introduce housekeeping subsystem v4

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  [GIT PULL] Introduce housekeeping subsystem v4 Frederic Weisbecker <fweisbec@gmail.com> - 2017-09-18 16:00 +0200
    [PATCH 02/12] watchdog: Use housekeeping_cpumask() instead of ad-hoc version Frederic Weisbecker <fweisbec@gmail.com> - 2017-09-18 16:00 +0200
    [PATCH 10/12] housekeeping: Move isolcpus to housekeeping Frederic Weisbecker <fweisbec@gmail.com> - 2017-09-18 16:00 +0200
    [PATCH 03/12] housekeeping: Provide a dynamic off-case to housekeeping_any_cpu() Frederic Weisbecker <fweisbec@gmail.com> - 2017-09-18 16:00 +0200

#1734156 — [GIT PULL] Introduce housekeeping subsystem v4

Ingo,

Please pull the core/isolation-v4 branch that can be found at:

git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
	core/isolation-v4

HEAD: cf4c55aad44251369c8507c3823f9f9c51d4dc77

Summary of changes:

* Move the housekeeping code that was tied to NO_HZ to its own subsystem.
  Currently NO_HZ governs the other isolation features which is not right
  as dynticks is just an isolation feature like the others. We want to
  centralize the CPU isolation decisions to a subsystem of its own instead.

* Integrate isolcpus code to housekeeping and treat it as a CPU isolation
  feature.

* Reuse the "isolcpus=" kernel parameter to control the CPU isolation.
  For now only tick and domains can be isolated after this patchset:

       isolcpus=1-7         # isolate domains on CPU range 1 to 7
                            # "domain" flag is implicit by default to
                            # keep the current behaviour
                            
       isolcpus=domain,1-7  # do the same

       isolcpus=nohz,1-7    # apply nohz_full to CPU range 1 to 7

       isolcpus=nohz,domain,1-7  # apply nohz_full and isolate domains of
                                 # CPU range 1 to 7

Thanks,
	Frederic
---

Frederic Weisbecker (12):
      housekeeping: Move housekeeping related code to its own file
      watchdog: Use housekeeping_cpumask() instead of ad-hoc version
      housekeeping: Provide a dynamic off-case to housekeeping_any_cpu()
      housekeeping: Make housekeeping cpumask private
      housekeeping: Use its own static key
      housekeeping: Rename is_housekeeping_cpu to housekeeping_cpu
      housekeeping: Move it under its own config, independant from NO_HZ
      housekeeping: Introduce housekeeping flags
      housekeeping: Handle nohz_full= parameter
      housekeeping: Move isolcpus to housekeeping
      housekeeping: Add basic isolcpus flags
      housekeeping: Document isolcpus flags


 Documentation/admin-guide/kernel-parameters.txt |  33 +++---
 drivers/base/cpu.c                              |  11 +-
 drivers/net/ethernet/tile/tilegx.c              |   6 +-
 include/linux/housekeeping.h                    |  51 ++++++++
 include/linux/sched.h                           |   2 -
 include/linux/tick.h                            |  39 +------
 init/Kconfig                                    |   7 ++
 init/main.c                                     |   2 +
 kernel/Makefile                                 |   1 +
 kernel/cgroup/cpuset.c                          |  15 +--
 kernel/housekeeping.c                           | 149 ++++++++++++++++++++++++
 kernel/rcu/tree_plugin.h                        |   3 +-
 kernel/rcu/update.c                             |   3 +-
 kernel/sched/core.c                             |  25 +---
 kernel/sched/fair.c                             |   3 +-
 kernel/sched/topology.c                         |  24 +---
 kernel/time/tick-sched.c                        |  31 +----
 kernel/watchdog.c                               |  13 +--
 18 files changed, 276 insertions(+), 142 deletions(-)

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#1734159 — [PATCH 02/12] watchdog: Use housekeeping_cpumask() instead of ad-hoc version

While trying to disable the watchog on nohz_full CPUs, the watchdog
implements an ad-hoc version of housekeeping_cpumask(). Lets replace
those re-invented lines.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Wanpeng Li <kernellwp@gmail.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
---
 kernel/watchdog.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 3cc5596..e672752 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -942,15 +942,10 @@ void __init lockup_detector_init(void)
 {
 	set_sample_period();
 
-#ifdef CONFIG_NO_HZ_FULL
-	if (tick_nohz_full_enabled()) {
+	if (tick_nohz_full_enabled())
 		pr_info("Disabling watchdog on nohz_full cores by default\n");
-		cpumask_copy(&watchdog_cpumask, housekeeping_mask);
-	} else
-		cpumask_copy(&watchdog_cpumask, cpu_possible_mask);
-#else
-	cpumask_copy(&watchdog_cpumask, cpu_possible_mask);
-#endif
+
+	cpumask_copy(&watchdog_cpumask, housekeeping_cpumask());
 
 	if (watchdog_enabled)
 		watchdog_enable_all_cpus();
-- 
2.7.4

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#1734160 — [PATCH 10/12] housekeeping: Move isolcpus to housekeeping

We want to centralize the isolation features on the housekeeping
subsystem and scheduler domain isolation is a significant part of it.

No intended behaviour change, we just reuse the housekeeping cpumask
and core code.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Wanpeng Li <kernellwp@gmail.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
---
 drivers/base/cpu.c           | 11 ++++++++-
 include/linux/housekeeping.h |  1 +
 include/linux/sched.h        |  2 --
 kernel/cgroup/cpuset.c       | 15 ++++--------
 kernel/housekeeping.c        | 57 +++++++++++++++++++++++++++++++++++---------
 kernel/sched/core.c          | 16 +------------
 kernel/sched/topology.c      | 24 +++++--------------
 7 files changed, 69 insertions(+), 57 deletions(-)

diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 321cd7b..7aa0d12 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -18,6 +18,7 @@
 #include <linux/cpufeature.h>
 #include <linux/tick.h>
 #include <linux/pm_qos.h>
+#include <linux/housekeeping.h>
 
 #include "base.h"
 
@@ -271,8 +272,16 @@ static ssize_t print_cpus_isolated(struct device *dev,
 				  struct device_attribute *attr, char *buf)
 {
 	int n = 0, len = PAGE_SIZE-2;
+	cpumask_var_t isolated;
 
-	n = scnprintf(buf, len, "%*pbl\n", cpumask_pr_args(cpu_isolated_map));
+	if (!alloc_cpumask_var(&isolated, GFP_KERNEL))
+		return -ENOMEM;
+
+	cpumask_andnot(isolated, cpu_possible_mask,
+		       housekeeping_cpumask(HK_FLAG_DOMAIN));
+	n = scnprintf(buf, len, "%*pbl\n", cpumask_pr_args(isolated));
+
+	free_cpumask_var(isolated);
 
 	return n;
 }
diff --git a/include/linux/housekeeping.h b/include/linux/housekeeping.h
index 35fb197..a99466e 100644
--- a/include/linux/housekeeping.h
+++ b/include/linux/housekeeping.h
@@ -11,6 +11,7 @@ enum hk_flags {
 	HK_FLAG_MISC		= (1 << 2),
 	HK_FLAG_SCHED		= (1 << 3),
 	HK_FLAG_TICK		= (1 << 4),
+	HK_FLAG_DOMAIN		= (1 << 5),
 };
 
 #ifdef CONFIG_CPU_ISOLATION
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 92fb8dd..962de00 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -166,8 +166,6 @@ struct task_group;
 /* Task command name length: */
 #define TASK_COMM_LEN			16
 
-extern cpumask_var_t			cpu_isolated_map;
-
 extern void scheduler_tick(void);
 
 #define	MAX_SCHEDULE_TIMEOUT		LONG_MAX
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 4657e29..4156ad9 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -57,7 +57,7 @@
 #include <linux/backing-dev.h>
 #include <linux/sort.h>
 #include <linux/oom.h>
-
+#include <linux/housekeeping.h>
 #include <linux/uaccess.h>
 #include <linux/atomic.h>
 #include <linux/mutex.h>
@@ -656,7 +656,6 @@ static int generate_sched_domains(cpumask_var_t **domains,
 	int csn;		/* how many cpuset ptrs in csa so far */
 	int i, j, k;		/* indices for partition finding loops */
 	cpumask_var_t *doms;	/* resulting partition; i.e. sched domains */
-	cpumask_var_t non_isolated_cpus;  /* load balanced CPUs */
 	struct sched_domain_attr *dattr;  /* attributes for custom domains */
 	int ndoms = 0;		/* number of sched domains in result */
 	int nslot;		/* next empty doms[] struct cpumask slot */
@@ -666,10 +665,6 @@ static int generate_sched_domains(cpumask_var_t **domains,
 	dattr = NULL;
 	csa = NULL;
 
-	if (!alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL))
-		goto done;
-	cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
-
 	/* Special case for the 99% of systems with one, full, sched domain */
 	if (is_sched_load_balance(&top_cpuset)) {
 		ndoms = 1;
@@ -683,7 +678,7 @@ static int generate_sched_domains(cpumask_var_t **domains,
 			update_domain_attr_tree(dattr, &top_cpuset);
 		}
 		cpumask_and(doms[0], top_cpuset.effective_cpus,
-				     non_isolated_cpus);
+			    housekeeping_cpumask(HK_FLAG_DOMAIN));
 
 		goto done;
 	}
@@ -707,7 +702,8 @@ static int generate_sched_domains(cpumask_var_t **domains,
 		 */
 		if (!cpumask_empty(cp->cpus_allowed) &&
 		    !(is_sched_load_balance(cp) &&
-		      cpumask_intersects(cp->cpus_allowed, non_isolated_cpus)))
+		      cpumask_intersects(cp->cpus_allowed,
+					 housekeeping_cpumask(HK_FLAG_DOMAIN))))
 			continue;
 
 		if (is_sched_load_balance(cp))
@@ -789,7 +785,7 @@ static int generate_sched_domains(cpumask_var_t **domains,
 
 			if (apn == b->pn) {
 				cpumask_or(dp, dp, b->effective_cpus);
-				cpumask_and(dp, dp, non_isolated_cpus);
+				cpumask_and(dp, dp, housekeeping_cpumask(HK_FLAG_DOMAIN));
 				if (dattr)
 					update_domain_attr_tree(dattr + nslot, b);
 
@@ -802,7 +798,6 @@ static int generate_sched_domains(cpumask_var_t **domains,
 	BUG_ON(nslot != ndoms);
 
 done:
-	free_cpumask_var(non_isolated_cpus);
 	kfree(csa);
 
 	/*
diff --git a/kernel/housekeeping.c b/kernel/housekeeping.c
index 8fb8d6b..30ee98f 100644
--- a/kernel/housekeeping.c
+++ b/kernel/housekeeping.c
@@ -59,32 +59,67 @@ void __init housekeeping_init(void)
 	WARN_ON_ONCE(cpumask_empty(housekeeping_mask));
 }
 
-#ifdef CONFIG_NO_HZ_FULL
-static int __init housekeeping_nohz_full_setup(char *str)
+static int __init housekeeping_setup(char *str, enum hk_flags flags)
 {
 	cpumask_var_t non_housekeeping_mask;
 
 	alloc_bootmem_cpumask_var(&non_housekeeping_mask);
 	if (cpulist_parse(str, non_housekeeping_mask) < 0) {
-		pr_warn("Housekeeping: Incorrect nohz_full cpumask\n");
+		pr_warn("Housekeeping: nohz_full= or isolcpus= incorrect CPU range\n");
 		free_bootmem_cpumask_var(non_housekeeping_mask);
 		return 0;
 	}
 
-	alloc_bootmem_cpumask_var(&housekeeping_mask);
-	cpumask_andnot(housekeeping_mask, cpu_possible_mask, non_housekeeping_mask);
+	if (!housekeeping_flags) {
+		alloc_bootmem_cpumask_var(&housekeeping_mask);
+		cpumask_andnot(housekeeping_mask,
+			       cpu_possible_mask, non_housekeeping_mask);
+		if (cpumask_empty(housekeeping_mask))
+			cpumask_set_cpu(smp_processor_id(), housekeeping_mask);
+	} else {
+		cpumask_var_t tmp;
 
-	if (cpumask_empty(housekeeping_mask))
-		cpumask_set_cpu(smp_processor_id(), housekeeping_mask);
+		alloc_bootmem_cpumask_var(&tmp);
+		cpumask_andnot(tmp, cpu_possible_mask, non_housekeeping_mask);
+		if (!cpumask_equal(tmp, housekeeping_mask)) {
+			pr_warn("Housekeeping: nohz_full= must match isolcpus=\n");
+			free_bootmem_cpumask_var(tmp);
+			free_bootmem_cpumask_var(non_housekeeping_mask);
+			return 0;
+		}
+		free_bootmem_cpumask_var(tmp);
+	}
 
-	housekeeping_flags = HK_FLAG_TICK | HK_FLAG_TIMER |
-				HK_FLAG_RCU | HK_FLAG_MISC;
+	if ((flags & HK_FLAG_TICK) && !(housekeeping_flags & HK_FLAG_TICK)) {
+		if (IS_ENABLED(CONFIG_NO_HZ_FULL)) {
+			tick_nohz_full_setup(non_housekeeping_mask);
+		} else {
+			pr_warn("Housekeeping: nohz unsupported."
+				" Build with CONFIG_NO_HZ_FULL\n");
+			free_bootmem_cpumask_var(non_housekeeping_mask);
+			return 0;
+		}
+	}
 
-	tick_nohz_full_setup(non_housekeeping_mask);
+	housekeeping_flags |= flags;
 
 	free_bootmem_cpumask_var(non_housekeeping_mask);
 
 	return 1;
 }
+
+static int __init housekeeping_nohz_full_setup(char *str)
+{
+	unsigned int flags;
+
+	flags = HK_FLAG_TICK | HK_FLAG_TIMER | HK_FLAG_RCU | HK_FLAG_MISC;
+
+	return housekeeping_setup(str, flags);
+}
 __setup("nohz_full=", housekeeping_nohz_full_setup);
-#endif
+
+static int __init housekeeping_isolcpus_setup(char *str)
+{
+	return housekeeping_setup(str, HK_FLAG_DOMAIN);
+}
+__setup("isolcpus=", housekeeping_isolcpus_setup);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 4b2c6ce..be124f9 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -84,9 +84,6 @@ __read_mostly int scheduler_running;
  */
 int sysctl_sched_rt_runtime = 950000;
 
-/* CPUs with isolated domains */
-cpumask_var_t cpu_isolated_map;
-
 /*
  * __task_rq_lock - lock the rq @p resides on.
  */
@@ -5705,10 +5702,6 @@ static inline void sched_init_smt(void) { }
 
 void __init sched_init_smp(void)
 {
-	cpumask_var_t non_isolated_cpus;
-
-	alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
-
 	sched_init_numa();
 
 	/*
@@ -5718,16 +5711,12 @@ void __init sched_init_smp(void)
 	 */
 	mutex_lock(&sched_domains_mutex);
 	sched_init_domains(cpu_active_mask);
-	cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
-	if (cpumask_empty(non_isolated_cpus))
-		cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
 	mutex_unlock(&sched_domains_mutex);
 
 	/* Move init over to a non-isolated CPU */
-	if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
+	if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_FLAG_DOMAIN)) < 0)
 		BUG();
 	sched_init_granularity();
-	free_cpumask_var(non_isolated_cpus);
 
 	init_sched_rt_class();
 	init_sched_dl_class();
@@ -5931,9 +5920,6 @@ void __init sched_init(void)
 	calc_load_update = jiffies + LOAD_FREQ;
 
 #ifdef CONFIG_SMP
-	/* May be allocated at isolcpus cmdline parse time */
-	if (cpu_isolated_map == NULL)
-		zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
 	idle_thread_set_boot_cpu();
 	set_cpu_rq_start_time(smp_processor_id());
 #endif
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index f1cf4f3..c6ec01b 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -3,6 +3,7 @@
  */
 #include <linux/sched.h>
 #include <linux/mutex.h>
+#include <linux/housekeeping.h>
 
 #include "sched.h"
 
@@ -463,21 +464,6 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
 	update_top_cache_domain(cpu);
 }
 
-/* Setup the mask of CPUs configured for isolated domains */
-static int __init isolated_cpu_setup(char *str)
-{
-	int ret;
-
-	alloc_bootmem_cpumask_var(&cpu_isolated_map);
-	ret = cpulist_parse(str, cpu_isolated_map);
-	if (ret) {
-		pr_err("sched: Error, all isolcpus= values must be between 0 and %u\n", nr_cpu_ids);
-		return 0;
-	}
-	return 1;
-}
-__setup("isolcpus=", isolated_cpu_setup);
-
 struct s_data {
 	struct sched_domain ** __percpu sd;
 	struct root_domain	*rd;
@@ -1773,7 +1759,7 @@ int sched_init_domains(const struct cpumask *cpu_map)
 	doms_cur = alloc_sched_domains(ndoms_cur);
 	if (!doms_cur)
 		doms_cur = &fallback_doms;
-	cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map);
+	cpumask_and(doms_cur[0], cpu_map, housekeeping_cpumask(HK_FLAG_DOMAIN));
 	err = build_sched_domains(doms_cur[0], NULL);
 	register_sched_domain_sysctl();
 
@@ -1856,7 +1842,8 @@ void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
 		doms_new = alloc_sched_domains(1);
 		if (doms_new) {
 			n = 1;
-			cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
+			cpumask_and(doms_new[0], cpu_active_mask,
+				    housekeeping_cpumask(HK_FLAG_DOMAIN));
 		}
 	} else {
 		n = ndoms_new;
@@ -1879,7 +1866,8 @@ void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
 	if (!doms_new) {
 		n = 0;
 		doms_new = &fallback_doms;
-		cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
+		cpumask_and(doms_new[0], cpu_active_mask,
+			    housekeeping_cpumask(HK_FLAG_DOMAIN));
 	}
 
 	/* Build new domains: */
-- 
2.7.4

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#1734162 — [PATCH 03/12] housekeeping: Provide a dynamic off-case to housekeeping_any_cpu()

housekeeping_any_cpu() doesn't handle correctly the case where
CONFIG_NO_HZ_FULL=y and no CPU is in nohz_full mode. So far no caller
needs this but let's prepare to avoid any future surprise.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Wanpeng Li <kernellwp@gmail.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
---
 include/linux/housekeeping.h | 21 ++++++++-------------
 1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/include/linux/housekeeping.h b/include/linux/housekeeping.h
index 3d6a8e6..64d0ee5 100644
--- a/include/linux/housekeeping.h
+++ b/include/linux/housekeeping.h
@@ -7,24 +7,19 @@
 
 #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 int housekeeping_any_cpu(void)
+{
+#ifdef CONFIG_NO_HZ_FULL
+	if (tick_nohz_full_enabled())
+		return cpumask_any_and(housekeeping_mask, cpu_online_mask);
+#endif
+	return smp_processor_id();
+}
 
 static inline const struct cpumask *housekeeping_cpumask(void)
 {
-- 
2.7.4

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