Merge branch 'sched/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: hrtick_enabled() should use cpu_active()
sched, x86: clean up hrtick implementation
sched: fix build error, provide partition_sched_domains() unconditionally
sched: fix warning in inc_rt_tasks() to not declare variable 'rq' if it's not needed
cpu hotplug: Make cpu_active_map synchronization dependency clear
cpu hotplug, sched: Introduce cpu_active_map and redo sched domain managment (take 2)
sched: rework of "prioritize non-migratable tasks over migratable ones"
sched: reduce stack size in isolated_cpu_setup()
Revert parts of "ftrace: do not trace scheduler functions"
Fixed up conflicts in include/asm-x86/thread_info.h (due to the
TIF_SINGLESTEP unification vs TIF_HRTICK_RESCHED removal) and
kernel/sched_fair.c (due to cpu_active_map vs for_each_cpu_mask_nr()
introduction).
diff --git a/arch/x86/kernel/signal_32.c b/arch/x86/kernel/signal_32.c
index 07faaa5..6fb5bcd 100644
--- a/arch/x86/kernel/signal_32.c
+++ b/arch/x86/kernel/signal_32.c
@@ -661,8 +661,5 @@
if (thread_info_flags & _TIF_SIGPENDING)
do_signal(regs);
- if (thread_info_flags & _TIF_HRTICK_RESCHED)
- hrtick_resched();
-
clear_thread_flag(TIF_IRET);
}
diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c
index bf87684..47c3d24 100644
--- a/arch/x86/kernel/signal_64.c
+++ b/arch/x86/kernel/signal_64.c
@@ -496,9 +496,6 @@
/* deal with pending signal delivery */
if (thread_info_flags & _TIF_SIGPENDING)
do_signal(regs);
-
- if (thread_info_flags & _TIF_HRTICK_RESCHED)
- hrtick_resched();
}
void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
diff --git a/include/asm-x86/thread_info.h b/include/asm-x86/thread_info.h
index 0a8f27d..3f2de10 100644
--- a/include/asm-x86/thread_info.h
+++ b/include/asm-x86/thread_info.h
@@ -79,7 +79,6 @@
#define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
#define TIF_SECCOMP 8 /* secure computing */
#define TIF_MCE_NOTIFY 10 /* notify userspace of an MCE */
-#define TIF_HRTICK_RESCHED 11 /* reprogram hrtick timer */
#define TIF_NOTSC 16 /* TSC is not accessible in userland */
#define TIF_IA32 17 /* 32bit process */
#define TIF_FORK 18 /* ret_from_fork */
@@ -102,7 +101,6 @@
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
#define _TIF_MCE_NOTIFY (1 << TIF_MCE_NOTIFY)
-#define _TIF_HRTICK_RESCHED (1 << TIF_HRTICK_RESCHED)
#define _TIF_NOTSC (1 << TIF_NOTSC)
#define _TIF_IA32 (1 << TIF_IA32)
#define _TIF_FORK (1 << TIF_FORK)
@@ -135,7 +133,7 @@
/* Only used for 64 bit */
#define _TIF_DO_NOTIFY_MASK \
- (_TIF_SIGPENDING|_TIF_MCE_NOTIFY|_TIF_HRTICK_RESCHED)
+ (_TIF_SIGPENDING|_TIF_MCE_NOTIFY)
/* flags to check in __switch_to() */
#define _TIF_WORK_CTXSW \
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 30d59d1..1b5c98e 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -458,13 +458,14 @@
/*
* The following particular system cpumasks and operations manage
- * possible, present and online cpus. Each of them is a fixed size
+ * possible, present, active and online cpus. Each of them is a fixed size
* bitmap of size NR_CPUS.
*
* #ifdef CONFIG_HOTPLUG_CPU
* cpu_possible_map - has bit 'cpu' set iff cpu is populatable
* cpu_present_map - has bit 'cpu' set iff cpu is populated
* cpu_online_map - has bit 'cpu' set iff cpu available to scheduler
+ * cpu_active_map - has bit 'cpu' set iff cpu available to migration
* #else
* cpu_possible_map - has bit 'cpu' set iff cpu is populated
* cpu_present_map - copy of cpu_possible_map
@@ -515,6 +516,7 @@
extern cpumask_t cpu_possible_map;
extern cpumask_t cpu_online_map;
extern cpumask_t cpu_present_map;
+extern cpumask_t cpu_active_map;
#if NR_CPUS > 1
#define num_online_cpus() cpus_weight_nr(cpu_online_map)
@@ -523,6 +525,7 @@
#define cpu_online(cpu) cpu_isset((cpu), cpu_online_map)
#define cpu_possible(cpu) cpu_isset((cpu), cpu_possible_map)
#define cpu_present(cpu) cpu_isset((cpu), cpu_present_map)
+#define cpu_active(cpu) cpu_isset((cpu), cpu_active_map)
#else
#define num_online_cpus() 1
#define num_possible_cpus() 1
@@ -530,6 +533,7 @@
#define cpu_online(cpu) ((cpu) == 0)
#define cpu_possible(cpu) ((cpu) == 0)
#define cpu_present(cpu) ((cpu) == 0)
+#define cpu_active(cpu) ((cpu) == 0)
#endif
#define cpu_is_offline(cpu) unlikely(!cpu_online(cpu))
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index 0385783..e8f450c 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -78,6 +78,8 @@
extern int current_cpuset_is_being_rebound(void);
+extern void rebuild_sched_domains(void);
+
#else /* !CONFIG_CPUSETS */
static inline int cpuset_init_early(void) { return 0; }
@@ -156,6 +158,11 @@
return 0;
}
+static inline void rebuild_sched_domains(void)
+{
+ partition_sched_domains(0, NULL, NULL);
+}
+
#endif /* !CONFIG_CPUSETS */
#endif /* _LINUX_CPUSET_H */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index af443a0..dc7e592 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -825,7 +825,16 @@
struct sched_domain_attr *dattr_new);
extern int arch_reinit_sched_domains(void);
-#endif /* CONFIG_SMP */
+#else /* CONFIG_SMP */
+
+struct sched_domain_attr;
+
+static inline void
+partition_sched_domains(int ndoms_new, cpumask_t *doms_new,
+ struct sched_domain_attr *dattr_new)
+{
+}
+#endif /* !CONFIG_SMP */
struct io_context; /* See blkdev.h */
#define NGROUPS_SMALL 32
diff --git a/init/main.c b/init/main.c
index 756eca4..2769dc0 100644
--- a/init/main.c
+++ b/init/main.c
@@ -415,6 +415,13 @@
{
unsigned int cpu;
+ /*
+ * Set up the current CPU as possible to migrate to.
+ * The other ones will be done by cpu_up/cpu_down()
+ */
+ cpu = smp_processor_id();
+ cpu_set(cpu, cpu_active_map);
+
/* FIXME: This should be done in userspace --RR */
for_each_present_cpu(cpu) {
if (num_online_cpus() >= setup_max_cpus)
diff --git a/kernel/Kconfig.hz b/kernel/Kconfig.hz
index 526128a..2a202a8 100644
--- a/kernel/Kconfig.hz
+++ b/kernel/Kconfig.hz
@@ -55,4 +55,4 @@
default 1000 if HZ_1000
config SCHED_HRTICK
- def_bool HIGH_RES_TIMERS && X86
+ def_bool HIGH_RES_TIMERS
diff --git a/kernel/Makefile b/kernel/Makefile
index 985ddb7..15ab63f 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -11,6 +11,8 @@
hrtimer.o rwsem.o nsproxy.o srcu.o semaphore.o \
notifier.o ksysfs.o pm_qos_params.o sched_clock.o
+CFLAGS_REMOVE_sched.o = -mno-spe
+
ifdef CONFIG_FTRACE
# Do not trace debug files and internal ftrace files
CFLAGS_REMOVE_lockdep.o = -pg
diff --git a/kernel/cpu.c b/kernel/cpu.c
index d26d0b0..2cc409c 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -64,6 +64,8 @@
cpu_hotplug.refcount = 0;
}
+cpumask_t cpu_active_map;
+
#ifdef CONFIG_HOTPLUG_CPU
void get_online_cpus(void)
@@ -291,11 +293,30 @@
int err = 0;
cpu_maps_update_begin();
- if (cpu_hotplug_disabled)
- err = -EBUSY;
- else
- err = _cpu_down(cpu, 0);
+ if (cpu_hotplug_disabled) {
+ err = -EBUSY;
+ goto out;
+ }
+
+ cpu_clear(cpu, cpu_active_map);
+
+ /*
+ * Make sure the all cpus did the reschedule and are not
+ * using stale version of the cpu_active_map.
+ * This is not strictly necessary becuase stop_machine()
+ * that we run down the line already provides the required
+ * synchronization. But it's really a side effect and we do not
+ * want to depend on the innards of the stop_machine here.
+ */
+ synchronize_sched();
+
+ err = _cpu_down(cpu, 0);
+
+ if (cpu_online(cpu))
+ cpu_set(cpu, cpu_active_map);
+
+out:
cpu_maps_update_done();
return err;
}
@@ -355,11 +376,18 @@
}
cpu_maps_update_begin();
- if (cpu_hotplug_disabled)
- err = -EBUSY;
- else
- err = _cpu_up(cpu, 0);
+ if (cpu_hotplug_disabled) {
+ err = -EBUSY;
+ goto out;
+ }
+
+ err = _cpu_up(cpu, 0);
+
+ if (cpu_online(cpu))
+ cpu_set(cpu, cpu_active_map);
+
+out:
cpu_maps_update_done();
return err;
}
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index d2cc67d..d573891 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -564,7 +564,7 @@
* partition_sched_domains().
*/
-static void rebuild_sched_domains(void)
+void rebuild_sched_domains(void)
{
struct kfifo *q; /* queue of cpusets to be scanned */
struct cpuset *cp; /* scans q */
diff --git a/kernel/sched.c b/kernel/sched.c
index df80bae..6acf749 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -571,8 +571,10 @@
#endif
#ifdef CONFIG_SCHED_HRTICK
- unsigned long hrtick_flags;
- ktime_t hrtick_expire;
+#ifdef CONFIG_SMP
+ int hrtick_csd_pending;
+ struct call_single_data hrtick_csd;
+#endif
struct hrtimer hrtick_timer;
#endif
@@ -983,13 +985,6 @@
return rq;
}
-static void __resched_task(struct task_struct *p, int tif_bit);
-
-static inline void resched_task(struct task_struct *p)
-{
- __resched_task(p, TIF_NEED_RESCHED);
-}
-
#ifdef CONFIG_SCHED_HRTICK
/*
* Use HR-timers to deliver accurate preemption points.
@@ -1001,25 +996,6 @@
* When we get rescheduled we reprogram the hrtick_timer outside of the
* rq->lock.
*/
-static inline void resched_hrt(struct task_struct *p)
-{
- __resched_task(p, TIF_HRTICK_RESCHED);
-}
-
-static inline void resched_rq(struct rq *rq)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&rq->lock, flags);
- resched_task(rq->curr);
- spin_unlock_irqrestore(&rq->lock, flags);
-}
-
-enum {
- HRTICK_SET, /* re-programm hrtick_timer */
- HRTICK_RESET, /* not a new slice */
- HRTICK_BLOCK, /* stop hrtick operations */
-};
/*
* Use hrtick when:
@@ -1030,40 +1006,11 @@
{
if (!sched_feat(HRTICK))
return 0;
- if (unlikely(test_bit(HRTICK_BLOCK, &rq->hrtick_flags)))
+ if (!cpu_active(cpu_of(rq)))
return 0;
return hrtimer_is_hres_active(&rq->hrtick_timer);
}
-/*
- * Called to set the hrtick timer state.
- *
- * called with rq->lock held and irqs disabled
- */
-static void hrtick_start(struct rq *rq, u64 delay, int reset)
-{
- assert_spin_locked(&rq->lock);
-
- /*
- * preempt at: now + delay
- */
- rq->hrtick_expire =
- ktime_add_ns(rq->hrtick_timer.base->get_time(), delay);
- /*
- * indicate we need to program the timer
- */
- __set_bit(HRTICK_SET, &rq->hrtick_flags);
- if (reset)
- __set_bit(HRTICK_RESET, &rq->hrtick_flags);
-
- /*
- * New slices are called from the schedule path and don't need a
- * forced reschedule.
- */
- if (reset)
- resched_hrt(rq->curr);
-}
-
static void hrtick_clear(struct rq *rq)
{
if (hrtimer_active(&rq->hrtick_timer))
@@ -1071,32 +1018,6 @@
}
/*
- * Update the timer from the possible pending state.
- */
-static void hrtick_set(struct rq *rq)
-{
- ktime_t time;
- int set, reset;
- unsigned long flags;
-
- WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
-
- spin_lock_irqsave(&rq->lock, flags);
- set = __test_and_clear_bit(HRTICK_SET, &rq->hrtick_flags);
- reset = __test_and_clear_bit(HRTICK_RESET, &rq->hrtick_flags);
- time = rq->hrtick_expire;
- clear_thread_flag(TIF_HRTICK_RESCHED);
- spin_unlock_irqrestore(&rq->lock, flags);
-
- if (set) {
- hrtimer_start(&rq->hrtick_timer, time, HRTIMER_MODE_ABS);
- if (reset && !hrtimer_active(&rq->hrtick_timer))
- resched_rq(rq);
- } else
- hrtick_clear(rq);
-}
-
-/*
* High-resolution timer tick.
* Runs from hardirq context with interrupts disabled.
*/
@@ -1115,27 +1036,37 @@
}
#ifdef CONFIG_SMP
-static void hotplug_hrtick_disable(int cpu)
+/*
+ * called from hardirq (IPI) context
+ */
+static void __hrtick_start(void *arg)
{
- struct rq *rq = cpu_rq(cpu);
- unsigned long flags;
+ struct rq *rq = arg;
- spin_lock_irqsave(&rq->lock, flags);
- rq->hrtick_flags = 0;
- __set_bit(HRTICK_BLOCK, &rq->hrtick_flags);
- spin_unlock_irqrestore(&rq->lock, flags);
-
- hrtick_clear(rq);
+ spin_lock(&rq->lock);
+ hrtimer_restart(&rq->hrtick_timer);
+ rq->hrtick_csd_pending = 0;
+ spin_unlock(&rq->lock);
}
-static void hotplug_hrtick_enable(int cpu)
+/*
+ * Called to set the hrtick timer state.
+ *
+ * called with rq->lock held and irqs disabled
+ */
+static void hrtick_start(struct rq *rq, u64 delay)
{
- struct rq *rq = cpu_rq(cpu);
- unsigned long flags;
+ struct hrtimer *timer = &rq->hrtick_timer;
+ ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
- spin_lock_irqsave(&rq->lock, flags);
- __clear_bit(HRTICK_BLOCK, &rq->hrtick_flags);
- spin_unlock_irqrestore(&rq->lock, flags);
+ timer->expires = time;
+
+ if (rq == this_rq()) {
+ hrtimer_restart(timer);
+ } else if (!rq->hrtick_csd_pending) {
+ __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd);
+ rq->hrtick_csd_pending = 1;
+ }
}
static int
@@ -1150,16 +1081,7 @@
case CPU_DOWN_PREPARE_FROZEN:
case CPU_DEAD:
case CPU_DEAD_FROZEN:
- hotplug_hrtick_disable(cpu);
- return NOTIFY_OK;
-
- case CPU_UP_PREPARE:
- case CPU_UP_PREPARE_FROZEN:
- case CPU_DOWN_FAILED:
- case CPU_DOWN_FAILED_FROZEN:
- case CPU_ONLINE:
- case CPU_ONLINE_FROZEN:
- hotplug_hrtick_enable(cpu);
+ hrtick_clear(cpu_rq(cpu));
return NOTIFY_OK;
}
@@ -1170,46 +1092,45 @@
{
hotcpu_notifier(hotplug_hrtick, 0);
}
+#else
+/*
+ * Called to set the hrtick timer state.
+ *
+ * called with rq->lock held and irqs disabled
+ */
+static void hrtick_start(struct rq *rq, u64 delay)
+{
+ hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay), HRTIMER_MODE_REL);
+}
+
+static void init_hrtick(void)
+{
+}
#endif /* CONFIG_SMP */
static void init_rq_hrtick(struct rq *rq)
{
- rq->hrtick_flags = 0;
+#ifdef CONFIG_SMP
+ rq->hrtick_csd_pending = 0;
+
+ rq->hrtick_csd.flags = 0;
+ rq->hrtick_csd.func = __hrtick_start;
+ rq->hrtick_csd.info = rq;
+#endif
+
hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
rq->hrtick_timer.function = hrtick;
rq->hrtick_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
}
-
-void hrtick_resched(void)
-{
- struct rq *rq;
- unsigned long flags;
-
- if (!test_thread_flag(TIF_HRTICK_RESCHED))
- return;
-
- local_irq_save(flags);
- rq = cpu_rq(smp_processor_id());
- hrtick_set(rq);
- local_irq_restore(flags);
-}
#else
static inline void hrtick_clear(struct rq *rq)
{
}
-static inline void hrtick_set(struct rq *rq)
-{
-}
-
static inline void init_rq_hrtick(struct rq *rq)
{
}
-void hrtick_resched(void)
-{
-}
-
static inline void init_hrtick(void)
{
}
@@ -1228,16 +1149,16 @@
#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
#endif
-static void __resched_task(struct task_struct *p, int tif_bit)
+static void resched_task(struct task_struct *p)
{
int cpu;
assert_spin_locked(&task_rq(p)->lock);
- if (unlikely(test_tsk_thread_flag(p, tif_bit)))
+ if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED)))
return;
- set_tsk_thread_flag(p, tif_bit);
+ set_tsk_thread_flag(p, TIF_NEED_RESCHED);
cpu = task_cpu(p);
if (cpu == smp_processor_id())
@@ -1303,10 +1224,10 @@
#endif /* CONFIG_NO_HZ */
#else /* !CONFIG_SMP */
-static void __resched_task(struct task_struct *p, int tif_bit)
+static void resched_task(struct task_struct *p)
{
assert_spin_locked(&task_rq(p)->lock);
- set_tsk_thread_flag(p, tif_bit);
+ set_tsk_need_resched(p);
}
#endif /* CONFIG_SMP */
@@ -2881,7 +2802,7 @@
rq = task_rq_lock(p, &flags);
if (!cpu_isset(dest_cpu, p->cpus_allowed)
- || unlikely(cpu_is_offline(dest_cpu)))
+ || unlikely(!cpu_active(dest_cpu)))
goto out;
/* force the process onto the specified CPU */
@@ -3849,7 +3770,7 @@
/*
* If we are going offline and still the leader, give up!
*/
- if (cpu_is_offline(cpu) &&
+ if (!cpu_active(cpu) &&
atomic_read(&nohz.load_balancer) == cpu) {
if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
BUG();
@@ -4395,7 +4316,7 @@
struct task_struct *prev, *next;
unsigned long *switch_count;
struct rq *rq;
- int cpu, hrtick = sched_feat(HRTICK);
+ int cpu;
need_resched:
preempt_disable();
@@ -4410,7 +4331,7 @@
schedule_debug(prev);
- if (hrtick)
+ if (sched_feat(HRTICK))
hrtick_clear(rq);
/*
@@ -4457,9 +4378,6 @@
} else
spin_unlock_irq(&rq->lock);
- if (hrtick)
- hrtick_set(rq);
-
if (unlikely(reacquire_kernel_lock(current) < 0))
goto need_resched_nonpreemptible;
@@ -5876,7 +5794,7 @@
struct rq *rq_dest, *rq_src;
int ret = 0, on_rq;
- if (unlikely(cpu_is_offline(dest_cpu)))
+ if (unlikely(!cpu_active(dest_cpu)))
return ret;
rq_src = cpu_rq(src_cpu);
@@ -6768,7 +6686,8 @@
/* Setup the mask of cpus configured for isolated domains */
static int __init isolated_cpu_setup(char *str)
{
- int ints[NR_CPUS], i;
+ static int __initdata ints[NR_CPUS];
+ int i;
str = get_options(str, ARRAY_SIZE(ints), ints);
cpus_clear(cpu_isolated_map);
@@ -7553,18 +7472,6 @@
}
/*
- * Free current domain masks.
- * Called after all cpus are attached to NULL domain.
- */
-static void free_sched_domains(void)
-{
- ndoms_cur = 0;
- if (doms_cur != &fallback_doms)
- kfree(doms_cur);
- doms_cur = &fallback_doms;
-}
-
-/*
* Set up scheduler domains and groups. Callers must hold the hotplug lock.
* For now this just excludes isolated cpus, but could be used to
* exclude other special cases in the future.
@@ -7642,7 +7549,7 @@
* ownership of it and will kfree it when done with it. If the caller
* failed the kmalloc call, then it can pass in doms_new == NULL,
* and partition_sched_domains() will fallback to the single partition
- * 'fallback_doms'.
+ * 'fallback_doms', it also forces the domains to be rebuilt.
*
* Call with hotplug lock held
*/
@@ -7656,12 +7563,8 @@
/* always unregister in case we don't destroy any domains */
unregister_sched_domain_sysctl();
- if (doms_new == NULL) {
- ndoms_new = 1;
- doms_new = &fallback_doms;
- cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map);
- dattr_new = NULL;
- }
+ if (doms_new == NULL)
+ ndoms_new = 0;
/* Destroy deleted domains */
for (i = 0; i < ndoms_cur; i++) {
@@ -7676,6 +7579,14 @@
;
}
+ if (doms_new == NULL) {
+ ndoms_cur = 0;
+ ndoms_new = 1;
+ doms_new = &fallback_doms;
+ cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map);
+ dattr_new = NULL;
+ }
+
/* Build new domains */
for (i = 0; i < ndoms_new; i++) {
for (j = 0; j < ndoms_cur; j++) {
@@ -7706,17 +7617,10 @@
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
int arch_reinit_sched_domains(void)
{
- int err;
-
get_online_cpus();
- mutex_lock(&sched_domains_mutex);
- detach_destroy_domains(&cpu_online_map);
- free_sched_domains();
- err = arch_init_sched_domains(&cpu_online_map);
- mutex_unlock(&sched_domains_mutex);
+ rebuild_sched_domains();
put_online_cpus();
-
- return err;
+ return 0;
}
static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
@@ -7786,59 +7690,49 @@
}
#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
+#ifndef CONFIG_CPUSETS
/*
- * Force a reinitialization of the sched domains hierarchy. The domains
- * and groups cannot be updated in place without racing with the balancing
- * code, so we temporarily attach all running cpus to the NULL domain
- * which will prevent rebalancing while the sched domains are recalculated.
+ * Add online and remove offline CPUs from the scheduler domains.
+ * When cpusets are enabled they take over this function.
*/
static int update_sched_domains(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
+ switch (action) {
+ case CPU_ONLINE:
+ case CPU_ONLINE_FROZEN:
+ case CPU_DEAD:
+ case CPU_DEAD_FROZEN:
+ partition_sched_domains(0, NULL, NULL);
+ return NOTIFY_OK;
+
+ default:
+ return NOTIFY_DONE;
+ }
+}
+#endif
+
+static int update_runtime(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
int cpu = (int)(long)hcpu;
switch (action) {
case CPU_DOWN_PREPARE:
case CPU_DOWN_PREPARE_FROZEN:
disable_runtime(cpu_rq(cpu));
- /* fall-through */
- case CPU_UP_PREPARE:
- case CPU_UP_PREPARE_FROZEN:
- detach_destroy_domains(&cpu_online_map);
- free_sched_domains();
return NOTIFY_OK;
-
case CPU_DOWN_FAILED:
case CPU_DOWN_FAILED_FROZEN:
case CPU_ONLINE:
case CPU_ONLINE_FROZEN:
enable_runtime(cpu_rq(cpu));
- /* fall-through */
- case CPU_UP_CANCELED:
- case CPU_UP_CANCELED_FROZEN:
- case CPU_DEAD:
- case CPU_DEAD_FROZEN:
- /*
- * Fall through and re-initialise the domains.
- */
- break;
+ return NOTIFY_OK;
+
default:
return NOTIFY_DONE;
}
-
-#ifndef CONFIG_CPUSETS
- /*
- * Create default domain partitioning if cpusets are disabled.
- * Otherwise we let cpusets rebuild the domains based on the
- * current setup.
- */
-
- /* The hotplug lock is already held by cpu_up/cpu_down */
- arch_init_sched_domains(&cpu_online_map);
-#endif
-
- return NOTIFY_OK;
}
void __init sched_init_smp(void)
@@ -7858,8 +7752,15 @@
cpu_set(smp_processor_id(), non_isolated_cpus);
mutex_unlock(&sched_domains_mutex);
put_online_cpus();
+
+#ifndef CONFIG_CPUSETS
/* XXX: Theoretical race here - CPU may be hotplugged now */
hotcpu_notifier(update_sched_domains, 0);
+#endif
+
+ /* RT runtime code needs to handle some hotplug events */
+ hotcpu_notifier(update_runtime, 0);
+
init_hrtick();
/* Move init over to a non-isolated CPU */
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index bb61fe2..cf2cd6c 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -878,7 +878,6 @@
#ifdef CONFIG_SCHED_HRTICK
static void hrtick_start_fair(struct rq *rq, struct task_struct *p)
{
- int requeue = rq->curr == p;
struct sched_entity *se = &p->se;
struct cfs_rq *cfs_rq = cfs_rq_of(se);
@@ -899,10 +898,10 @@
* Don't schedule slices shorter than 10000ns, that just
* doesn't make sense. Rely on vruntime for fairness.
*/
- if (!requeue)
+ if (rq->curr != p)
delta = max(10000LL, delta);
- hrtick_start(rq, delta, requeue);
+ hrtick_start(rq, delta);
}
}
#else /* !CONFIG_SCHED_HRTICK */
@@ -1004,6 +1003,8 @@
* not idle and an idle cpu is available. The span of cpus to
* search starts with cpus closest then further out as needed,
* so we always favor a closer, idle cpu.
+ * Domains may include CPUs that are not usable for migration,
+ * hence we need to mask them out (cpu_active_map)
*
* Returns the CPU we should wake onto.
*/
@@ -1031,6 +1032,7 @@
|| ((sd->flags & SD_WAKE_IDLE_FAR)
&& !task_hot(p, task_rq(p)->clock, sd))) {
cpus_and(tmp, sd->span, p->cpus_allowed);
+ cpus_and(tmp, tmp, cpu_active_map);
for_each_cpu_mask_nr(i, tmp) {
if (idle_cpu(i)) {
if (i != task_cpu(p)) {
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 7c96147..f85a763 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -505,7 +505,9 @@
rt_rq->rt_nr_running++;
#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
if (rt_se_prio(rt_se) < rt_rq->highest_prio) {
+#ifdef CONFIG_SMP
struct rq *rq = rq_of_rt_rq(rt_rq);
+#endif
rt_rq->highest_prio = rt_se_prio(rt_se);
#ifdef CONFIG_SMP
@@ -599,11 +601,7 @@
if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running))
return;
- if (rt_se->nr_cpus_allowed == 1)
- list_add(&rt_se->run_list, queue);
- else
- list_add_tail(&rt_se->run_list, queue);
-
+ list_add_tail(&rt_se->run_list, queue);
__set_bit(rt_se_prio(rt_se), array->bitmap);
inc_rt_tasks(rt_se, rt_rq);
@@ -688,32 +686,34 @@
* Put task to the end of the run list without the overhead of dequeue
* followed by enqueue.
*/
-static
-void requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
+static void
+requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se, int head)
{
- struct rt_prio_array *array = &rt_rq->active;
-
if (on_rt_rq(rt_se)) {
- list_del_init(&rt_se->run_list);
- list_add_tail(&rt_se->run_list,
- array->queue + rt_se_prio(rt_se));
+ struct rt_prio_array *array = &rt_rq->active;
+ struct list_head *queue = array->queue + rt_se_prio(rt_se);
+
+ if (head)
+ list_move(&rt_se->run_list, queue);
+ else
+ list_move_tail(&rt_se->run_list, queue);
}
}
-static void requeue_task_rt(struct rq *rq, struct task_struct *p)
+static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head)
{
struct sched_rt_entity *rt_se = &p->rt;
struct rt_rq *rt_rq;
for_each_sched_rt_entity(rt_se) {
rt_rq = rt_rq_of_se(rt_se);
- requeue_rt_entity(rt_rq, rt_se);
+ requeue_rt_entity(rt_rq, rt_se, head);
}
}
static void yield_task_rt(struct rq *rq)
{
- requeue_task_rt(rq, rq->curr);
+ requeue_task_rt(rq, rq->curr, 0);
}
#ifdef CONFIG_SMP
@@ -753,6 +753,30 @@
*/
return task_cpu(p);
}
+
+static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
+{
+ cpumask_t mask;
+
+ if (rq->curr->rt.nr_cpus_allowed == 1)
+ return;
+
+ if (p->rt.nr_cpus_allowed != 1
+ && cpupri_find(&rq->rd->cpupri, p, &mask))
+ return;
+
+ if (!cpupri_find(&rq->rd->cpupri, rq->curr, &mask))
+ return;
+
+ /*
+ * There appears to be other cpus that can accept
+ * current and none to run 'p', so lets reschedule
+ * to try and push current away:
+ */
+ requeue_task_rt(rq, p, 1);
+ resched_task(rq->curr);
+}
+
#endif /* CONFIG_SMP */
/*
@@ -778,18 +802,8 @@
* to move current somewhere else, making room for our non-migratable
* task.
*/
- if((p->prio == rq->curr->prio)
- && p->rt.nr_cpus_allowed == 1
- && rq->curr->rt.nr_cpus_allowed != 1) {
- cpumask_t mask;
-
- if (cpupri_find(&rq->rd->cpupri, rq->curr, &mask))
- /*
- * There appears to be other cpus that can accept
- * current, so lets reschedule to try and push it away
- */
- resched_task(rq->curr);
- }
+ if (p->prio == rq->curr->prio && !need_resched())
+ check_preempt_equal_prio(rq, p);
#endif
}
@@ -922,6 +936,13 @@
return -1; /* No targets found */
/*
+ * Only consider CPUs that are usable for migration.
+ * I guess we might want to change cpupri_find() to ignore those
+ * in the first place.
+ */
+ cpus_and(*lowest_mask, *lowest_mask, cpu_active_map);
+
+ /*
* At this point we have built a mask of cpus representing the
* lowest priority tasks in the system. Now we want to elect
* the best one based on our affinity and topology.
@@ -1415,7 +1436,7 @@
* on the queue:
*/
if (p->rt.run_list.prev != p->rt.run_list.next) {
- requeue_task_rt(rq, p);
+ requeue_task_rt(rq, p, 0);
set_tsk_need_resched(p);
}
}