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-rw-r--r--kernel/cpu.c24
-rw-r--r--kernel/cpuset.c2
-rw-r--r--kernel/rcuclassic.c337
-rw-r--r--kernel/rcupreempt.c8
-rw-r--r--kernel/rcupreempt_trace.c7
-rw-r--r--kernel/sched.c377
-rw-r--r--kernel/sched_fair.c234
-rw-r--r--kernel/sched_features.h1
-rw-r--r--kernel/sched_idletask.c6
-rw-r--r--kernel/sched_rt.c57
-rw-r--r--kernel/time/tick-sched.c11
-rw-r--r--kernel/user.c4
12 files changed, 645 insertions, 423 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index f17e985..86d4904 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -199,13 +199,14 @@ static int __ref take_cpu_down(void *_param)
struct take_cpu_down_param *param = _param;
int err;
- raw_notifier_call_chain(&cpu_chain, CPU_DYING | param->mod,
- param->hcpu);
/* Ensure this CPU doesn't handle any more interrupts. */
err = __cpu_disable();
if (err < 0)
return err;
+ raw_notifier_call_chain(&cpu_chain, CPU_DYING | param->mod,
+ param->hcpu);
+
/* Force idle task to run as soon as we yield: it should
immediately notice cpu is offline and die quickly. */
sched_idle_next();
@@ -453,6 +454,25 @@ out:
}
#endif /* CONFIG_PM_SLEEP_SMP */
+/**
+ * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers
+ * @cpu: cpu that just started
+ *
+ * This function calls the cpu_chain notifiers with CPU_STARTING.
+ * It must be called by the arch code on the new cpu, before the new cpu
+ * enables interrupts and before the "boot" cpu returns from __cpu_up().
+ */
+void notify_cpu_starting(unsigned int cpu)
+{
+ unsigned long val = CPU_STARTING;
+
+#ifdef CONFIG_PM_SLEEP_SMP
+ if (cpu_isset(cpu, frozen_cpus))
+ val = CPU_STARTING_FROZEN;
+#endif /* CONFIG_PM_SLEEP_SMP */
+ raw_notifier_call_chain(&cpu_chain, val, (void *)(long)cpu);
+}
+
#endif /* CONFIG_SMP */
/*
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 827cd9ad..eab7bd6 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1921,7 +1921,7 @@ static void remove_tasks_in_empty_cpuset(struct cpuset *cs)
* that has tasks along with an empty 'mems'. But if we did see such
* a cpuset, we'd handle it just like we do if its 'cpus' was empty.
*/
-static void scan_for_empty_cpusets(const struct cpuset *root)
+static void scan_for_empty_cpusets(struct cpuset *root)
{
LIST_HEAD(queue);
struct cpuset *cp; /* scans cpusets being updated */
diff --git a/kernel/rcuclassic.c b/kernel/rcuclassic.c
index aad93cd..37f72e551 100644
--- a/kernel/rcuclassic.c
+++ b/kernel/rcuclassic.c
@@ -47,6 +47,7 @@
#include <linux/notifier.h>
#include <linux/cpu.h>
#include <linux/mutex.h>
+#include <linux/time.h>
#ifdef CONFIG_DEBUG_LOCK_ALLOC
static struct lock_class_key rcu_lock_key;
@@ -60,12 +61,14 @@ EXPORT_SYMBOL_GPL(rcu_lock_map);
static struct rcu_ctrlblk rcu_ctrlblk = {
.cur = -300,
.completed = -300,
+ .pending = -300,
.lock = __SPIN_LOCK_UNLOCKED(&rcu_ctrlblk.lock),
.cpumask = CPU_MASK_NONE,
};
static struct rcu_ctrlblk rcu_bh_ctrlblk = {
.cur = -300,
.completed = -300,
+ .pending = -300,
.lock = __SPIN_LOCK_UNLOCKED(&rcu_bh_ctrlblk.lock),
.cpumask = CPU_MASK_NONE,
};
@@ -83,7 +86,10 @@ static void force_quiescent_state(struct rcu_data *rdp,
{
int cpu;
cpumask_t cpumask;
+ unsigned long flags;
+
set_need_resched();
+ spin_lock_irqsave(&rcp->lock, flags);
if (unlikely(!rcp->signaled)) {
rcp->signaled = 1;
/*
@@ -109,6 +115,7 @@ static void force_quiescent_state(struct rcu_data *rdp,
for_each_cpu_mask_nr(cpu, cpumask)
smp_send_reschedule(cpu);
}
+ spin_unlock_irqrestore(&rcp->lock, flags);
}
#else
static inline void force_quiescent_state(struct rcu_data *rdp,
@@ -118,6 +125,126 @@ static inline void force_quiescent_state(struct rcu_data *rdp,
}
#endif
+static void __call_rcu(struct rcu_head *head, struct rcu_ctrlblk *rcp,
+ struct rcu_data *rdp)
+{
+ long batch;
+
+ head->next = NULL;
+ smp_mb(); /* Read of rcu->cur must happen after any change by caller. */
+
+ /*
+ * Determine the batch number of this callback.
+ *
+ * Using ACCESS_ONCE to avoid the following error when gcc eliminates
+ * local variable "batch" and emits codes like this:
+ * 1) rdp->batch = rcp->cur + 1 # gets old value
+ * ......
+ * 2)rcu_batch_after(rcp->cur + 1, rdp->batch) # gets new value
+ * then [*nxttail[0], *nxttail[1]) may contain callbacks
+ * that batch# = rdp->batch, see the comment of struct rcu_data.
+ */
+ batch = ACCESS_ONCE(rcp->cur) + 1;
+
+ if (rdp->nxtlist && rcu_batch_after(batch, rdp->batch)) {
+ /* process callbacks */
+ rdp->nxttail[0] = rdp->nxttail[1];
+ rdp->nxttail[1] = rdp->nxttail[2];
+ if (rcu_batch_after(batch - 1, rdp->batch))
+ rdp->nxttail[0] = rdp->nxttail[2];
+ }
+
+ rdp->batch = batch;
+ *rdp->nxttail[2] = head;
+ rdp->nxttail[2] = &head->next;
+
+ if (unlikely(++rdp->qlen > qhimark)) {
+ rdp->blimit = INT_MAX;
+ force_quiescent_state(rdp, &rcu_ctrlblk);
+ }
+}
+
+#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
+
+static void record_gp_stall_check_time(struct rcu_ctrlblk *rcp)
+{
+ rcp->gp_start = jiffies;
+ rcp->jiffies_stall = jiffies + RCU_SECONDS_TILL_STALL_CHECK;
+}
+
+static void print_other_cpu_stall(struct rcu_ctrlblk *rcp)
+{
+ int cpu;
+ long delta;
+ unsigned long flags;
+
+ /* Only let one CPU complain about others per time interval. */
+
+ spin_lock_irqsave(&rcp->lock, flags);
+ delta = jiffies - rcp->jiffies_stall;
+ if (delta < 2 || rcp->cur != rcp->completed) {
+ spin_unlock_irqrestore(&rcp->lock, flags);
+ return;
+ }
+ rcp->jiffies_stall = jiffies + RCU_SECONDS_TILL_STALL_RECHECK;
+ spin_unlock_irqrestore(&rcp->lock, flags);
+
+ /* OK, time to rat on our buddy... */
+
+ printk(KERN_ERR "RCU detected CPU stalls:");
+ for_each_possible_cpu(cpu) {
+ if (cpu_isset(cpu, rcp->cpumask))
+ printk(" %d", cpu);
+ }
+ printk(" (detected by %d, t=%ld jiffies)\n",
+ smp_processor_id(), (long)(jiffies - rcp->gp_start));
+}
+
+static void print_cpu_stall(struct rcu_ctrlblk *rcp)
+{
+ unsigned long flags;
+
+ printk(KERN_ERR "RCU detected CPU %d stall (t=%lu/%lu jiffies)\n",
+ smp_processor_id(), jiffies,
+ jiffies - rcp->gp_start);
+ dump_stack();
+ spin_lock_irqsave(&rcp->lock, flags);
+ if ((long)(jiffies - rcp->jiffies_stall) >= 0)
+ rcp->jiffies_stall =
+ jiffies + RCU_SECONDS_TILL_STALL_RECHECK;
+ spin_unlock_irqrestore(&rcp->lock, flags);
+ set_need_resched(); /* kick ourselves to get things going. */
+}
+
+static void check_cpu_stall(struct rcu_ctrlblk *rcp)
+{
+ long delta;
+
+ delta = jiffies - rcp->jiffies_stall;
+ if (cpu_isset(smp_processor_id(), rcp->cpumask) && delta >= 0) {
+
+ /* We haven't checked in, so go dump stack. */
+ print_cpu_stall(rcp);
+
+ } else if (rcp->cur != rcp->completed && delta >= 2) {
+
+ /* They had two seconds to dump stack, so complain. */
+ print_other_cpu_stall(rcp);
+ }
+}
+
+#else /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
+
+static void record_gp_stall_check_time(struct rcu_ctrlblk *rcp)
+{
+}
+
+static inline void check_cpu_stall(struct rcu_ctrlblk *rcp)
+{
+}
+
+#endif /* #else #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
+
/**
* call_rcu - Queue an RCU callback for invocation after a grace period.
* @head: structure to be used for queueing the RCU updates.
@@ -133,18 +260,10 @@ void call_rcu(struct rcu_head *head,
void (*func)(struct rcu_head *rcu))
{
unsigned long flags;
- struct rcu_data *rdp;
head->func = func;
- head->next = NULL;
local_irq_save(flags);
- rdp = &__get_cpu_var(rcu_data);
- *rdp->nxttail = head;
- rdp->nxttail = &head->next;
- if (unlikely(++rdp->qlen > qhimark)) {
- rdp->blimit = INT_MAX;
- force_quiescent_state(rdp, &rcu_ctrlblk);
- }
+ __call_rcu(head, &rcu_ctrlblk, &__get_cpu_var(rcu_data));
local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(call_rcu);
@@ -169,20 +288,10 @@ void call_rcu_bh(struct rcu_head *head,
void (*func)(struct rcu_head *rcu))
{
unsigned long flags;
- struct rcu_data *rdp;
head->func = func;
- head->next = NULL;
local_irq_save(flags);
- rdp = &__get_cpu_var(rcu_bh_data);
- *rdp->nxttail = head;
- rdp->nxttail = &head->next;
-
- if (unlikely(++rdp->qlen > qhimark)) {
- rdp->blimit = INT_MAX;
- force_quiescent_state(rdp, &rcu_bh_ctrlblk);
- }
-
+ __call_rcu(head, &rcu_bh_ctrlblk, &__get_cpu_var(rcu_bh_data));
local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(call_rcu_bh);
@@ -211,12 +320,6 @@ EXPORT_SYMBOL_GPL(rcu_batches_completed_bh);
static inline void raise_rcu_softirq(void)
{
raise_softirq(RCU_SOFTIRQ);
- /*
- * The smp_mb() here is required to ensure that this cpu's
- * __rcu_process_callbacks() reads the most recently updated
- * value of rcu->cur.
- */
- smp_mb();
}
/*
@@ -225,6 +328,7 @@ static inline void raise_rcu_softirq(void)
*/
static void rcu_do_batch(struct rcu_data *rdp)
{
+ unsigned long flags;
struct rcu_head *next, *list;
int count = 0;
@@ -239,9 +343,9 @@ static void rcu_do_batch(struct rcu_data *rdp)
}
rdp->donelist = list;
- local_irq_disable();
+ local_irq_save(flags);
rdp->qlen -= count;
- local_irq_enable();
+ local_irq_restore(flags);
if (rdp->blimit == INT_MAX && rdp->qlen <= qlowmark)
rdp->blimit = blimit;
@@ -269,6 +373,7 @@ static void rcu_do_batch(struct rcu_data *rdp)
* rcu_check_quiescent_state calls rcu_start_batch(0) to start the next grace
* period (if necessary).
*/
+
/*
* Register a new batch of callbacks, and start it up if there is currently no
* active batch and the batch to be registered has not already occurred.
@@ -276,15 +381,10 @@ static void rcu_do_batch(struct rcu_data *rdp)
*/
static void rcu_start_batch(struct rcu_ctrlblk *rcp)
{
- if (rcp->next_pending &&
+ if (rcp->cur != rcp->pending &&
rcp->completed == rcp->cur) {
- rcp->next_pending = 0;
- /*
- * next_pending == 0 must be visible in
- * __rcu_process_callbacks() before it can see new value of cur.
- */
- smp_wmb();
rcp->cur++;
+ record_gp_stall_check_time(rcp);
/*
* Accessing nohz_cpu_mask before incrementing rcp->cur needs a
@@ -322,6 +422,8 @@ static void cpu_quiet(int cpu, struct rcu_ctrlblk *rcp)
static void rcu_check_quiescent_state(struct rcu_ctrlblk *rcp,
struct rcu_data *rdp)
{
+ unsigned long flags;
+
if (rdp->quiescbatch != rcp->cur) {
/* start new grace period: */
rdp->qs_pending = 1;
@@ -345,7 +447,7 @@ static void rcu_check_quiescent_state(struct rcu_ctrlblk *rcp,
return;
rdp->qs_pending = 0;
- spin_lock(&rcp->lock);
+ spin_lock_irqsave(&rcp->lock, flags);
/*
* rdp->quiescbatch/rcp->cur and the cpu bitmap can come out of sync
* during cpu startup. Ignore the quiescent state.
@@ -353,7 +455,7 @@ static void rcu_check_quiescent_state(struct rcu_ctrlblk *rcp,
if (likely(rdp->quiescbatch == rcp->cur))
cpu_quiet(rdp->cpu, rcp);
- spin_unlock(&rcp->lock);
+ spin_unlock_irqrestore(&rcp->lock, flags);
}
@@ -364,33 +466,38 @@ static void rcu_check_quiescent_state(struct rcu_ctrlblk *rcp,
* which is dead and hence not processing interrupts.
*/
static void rcu_move_batch(struct rcu_data *this_rdp, struct rcu_head *list,
- struct rcu_head **tail)
+ struct rcu_head **tail, long batch)
{
- local_irq_disable();
- *this_rdp->nxttail = list;
- if (list)
- this_rdp->nxttail = tail;
- local_irq_enable();
+ unsigned long flags;
+
+ if (list) {
+ local_irq_save(flags);
+ this_rdp->batch = batch;
+ *this_rdp->nxttail[2] = list;
+ this_rdp->nxttail[2] = tail;
+ local_irq_restore(flags);
+ }
}
static void __rcu_offline_cpu(struct rcu_data *this_rdp,
struct rcu_ctrlblk *rcp, struct rcu_data *rdp)
{
- /* if the cpu going offline owns the grace period
+ unsigned long flags;
+
+ /*
+ * if the cpu going offline owns the grace period
* we can block indefinitely waiting for it, so flush
* it here
*/
- spin_lock_bh(&rcp->lock);
+ spin_lock_irqsave(&rcp->lock, flags);
if (rcp->cur != rcp->completed)
cpu_quiet(rdp->cpu, rcp);
- spin_unlock_bh(&rcp->lock);
- rcu_move_batch(this_rdp, rdp->donelist, rdp->donetail);
- rcu_move_batch(this_rdp, rdp->curlist, rdp->curtail);
- rcu_move_batch(this_rdp, rdp->nxtlist, rdp->nxttail);
+ rcu_move_batch(this_rdp, rdp->donelist, rdp->donetail, rcp->cur + 1);
+ rcu_move_batch(this_rdp, rdp->nxtlist, rdp->nxttail[2], rcp->cur + 1);
+ spin_unlock(&rcp->lock);
- local_irq_disable();
this_rdp->qlen += rdp->qlen;
- local_irq_enable();
+ local_irq_restore(flags);
}
static void rcu_offline_cpu(int cpu)
@@ -420,38 +527,52 @@ static void rcu_offline_cpu(int cpu)
static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp,
struct rcu_data *rdp)
{
- if (rdp->curlist && !rcu_batch_before(rcp->completed, rdp->batch)) {
- *rdp->donetail = rdp->curlist;
- rdp->donetail = rdp->curtail;
- rdp->curlist = NULL;
- rdp->curtail = &rdp->curlist;
- }
+ unsigned long flags;
+ long completed_snap;
- if (rdp->nxtlist && !rdp->curlist) {
- local_irq_disable();
- rdp->curlist = rdp->nxtlist;
- rdp->curtail = rdp->nxttail;
- rdp->nxtlist = NULL;
- rdp->nxttail = &rdp->nxtlist;
- local_irq_enable();
+ if (rdp->nxtlist) {
+ local_irq_save(flags);
+ completed_snap = ACCESS_ONCE(rcp->completed);
/*
- * start the next batch of callbacks
+ * move the other grace-period-completed entries to
+ * [rdp->nxtlist, *rdp->nxttail[0]) temporarily
*/
+ if (!rcu_batch_before(completed_snap, rdp->batch))
+ rdp->nxttail[0] = rdp->nxttail[1] = rdp->nxttail[2];
+ else if (!rcu_batch_before(completed_snap, rdp->batch - 1))
+ rdp->nxttail[0] = rdp->nxttail[1];
- /* determine batch number */
- rdp->batch = rcp->cur + 1;
- /* see the comment and corresponding wmb() in
- * the rcu_start_batch()
+ /*
+ * the grace period for entries in
+ * [rdp->nxtlist, *rdp->nxttail[0]) has completed and
+ * move these entries to donelist
*/
- smp_rmb();
+ if (rdp->nxttail[0] != &rdp->nxtlist) {
+ *rdp->donetail = rdp->nxtlist;
+ rdp->donetail = rdp->nxttail[0];
+ rdp->nxtlist = *rdp->nxttail[0];
+ *rdp->donetail = NULL;
+
+ if (rdp->nxttail[1] == rdp->nxttail[0])
+ rdp->nxttail[1] = &rdp->nxtlist;
+ if (rdp->nxttail[2] == rdp->nxttail[0])
+ rdp->nxttail[2] = &rdp->nxtlist;
+ rdp->nxttail[0] = &rdp->nxtlist;
+ }
+
+ local_irq_restore(flags);
+
+ if (rcu_batch_after(rdp->batch, rcp->pending)) {
+ unsigned long flags2;
- if (!rcp->next_pending) {
/* and start it/schedule start if it's a new batch */
- spin_lock(&rcp->lock);
- rcp->next_pending = 1;
- rcu_start_batch(rcp);
- spin_unlock(&rcp->lock);
+ spin_lock_irqsave(&rcp->lock, flags2);
+ if (rcu_batch_after(rdp->batch, rcp->pending)) {
+ rcp->pending = rdp->batch;
+ rcu_start_batch(rcp);
+ }
+ spin_unlock_irqrestore(&rcp->lock, flags2);
}
}
@@ -462,21 +583,53 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp,
static void rcu_process_callbacks(struct softirq_action *unused)
{
+ /*
+ * Memory references from any prior RCU read-side critical sections
+ * executed by the interrupted code must be see before any RCU
+ * grace-period manupulations below.
+ */
+
+ smp_mb(); /* See above block comment. */
+
__rcu_process_callbacks(&rcu_ctrlblk, &__get_cpu_var(rcu_data));
__rcu_process_callbacks(&rcu_bh_ctrlblk, &__get_cpu_var(rcu_bh_data));
+
+ /*
+ * Memory references from any later RCU read-side critical sections
+ * executed by the interrupted code must be see after any RCU
+ * grace-period manupulations above.
+ */
+
+ smp_mb(); /* See above block comment. */
}
static int __rcu_pending(struct rcu_ctrlblk *rcp, struct rcu_data *rdp)
{
- /* This cpu has pending rcu entries and the grace period
- * for them has completed.
- */
- if (rdp->curlist && !rcu_batch_before(rcp->completed, rdp->batch))
- return 1;
+ /* Check for CPU stalls, if enabled. */
+ check_cpu_stall(rcp);
- /* This cpu has no pending entries, but there are new entries */
- if (!rdp->curlist && rdp->nxtlist)
- return 1;
+ if (rdp->nxtlist) {
+ long completed_snap = ACCESS_ONCE(rcp->completed);
+
+ /*
+ * This cpu has pending rcu entries and the grace period
+ * for them has completed.
+ */
+ if (!rcu_batch_before(completed_snap, rdp->batch))
+ return 1;
+ if (!rcu_batch_before(completed_snap, rdp->batch - 1) &&
+ rdp->nxttail[0] != rdp->nxttail[1])
+ return 1;
+ if (rdp->nxttail[0] != &rdp->nxtlist)
+ return 1;
+
+ /*
+ * This cpu has pending rcu entries and the new batch
+ * for then hasn't been started nor scheduled start
+ */
+ if (rcu_batch_after(rdp->batch, rcp->pending))
+ return 1;
+ }
/* This cpu has finished callbacks to invoke */
if (rdp->donelist)
@@ -512,9 +665,15 @@ int rcu_needs_cpu(int cpu)
struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
struct rcu_data *rdp_bh = &per_cpu(rcu_bh_data, cpu);
- return (!!rdp->curlist || !!rdp_bh->curlist || rcu_pending(cpu));
+ return !!rdp->nxtlist || !!rdp_bh->nxtlist || rcu_pending(cpu);
}
+/*
+ * Top-level function driving RCU grace-period detection, normally
+ * invoked from the scheduler-clock interrupt. This function simply
+ * increments counters that are read only from softirq by this same
+ * CPU, so there are no memory barriers required.
+ */
void rcu_check_callbacks(int cpu, int user)
{
if (user ||
@@ -558,14 +717,17 @@ void rcu_check_callbacks(int cpu, int user)
static void rcu_init_percpu_data(int cpu, struct rcu_ctrlblk *rcp,
struct rcu_data *rdp)
{
+ unsigned long flags;
+
+ spin_lock_irqsave(&rcp->lock, flags);
memset(rdp, 0, sizeof(*rdp));
- rdp->curtail = &rdp->curlist;
- rdp->nxttail = &rdp->nxtlist;
+ rdp->nxttail[0] = rdp->nxttail[1] = rdp->nxttail[2] = &rdp->nxtlist;
rdp->donetail = &rdp->donelist;
rdp->quiescbatch = rcp->completed;
rdp->qs_pending = 0;
rdp->cpu = cpu;
rdp->blimit = blimit;
+ spin_unlock_irqrestore(&rcp->lock, flags);
}
static void __cpuinit rcu_online_cpu(int cpu)
@@ -610,6 +772,9 @@ static struct notifier_block __cpuinitdata rcu_nb = {
*/
void __init __rcu_init(void)
{
+#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
+ printk(KERN_INFO "RCU-based detection of stalled CPUs is enabled.\n");
+#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
rcu_cpu_notify(&rcu_nb, CPU_UP_PREPARE,
(void *)(long)smp_processor_id());
/* Register notifier for non-boot CPUs */
diff --git a/kernel/rcupreempt.c b/kernel/rcupreempt.c
index 2782793..ca4bbbe 100644
--- a/kernel/rcupreempt.c
+++ b/kernel/rcupreempt.c
@@ -59,14 +59,6 @@
#include <linux/rcupreempt_trace.h>
/*
- * Macro that prevents the compiler from reordering accesses, but does
- * absolutely -nothing- to prevent CPUs from reordering. This is used
- * only to mediate communication between mainline code and hardware
- * interrupt and NMI handlers.
- */
-#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
-
-/*
* PREEMPT_RCU data structures.
*/
diff --git a/kernel/rcupreempt_trace.c b/kernel/rcupreempt_trace.c
index 5edf82c..35c2d33 100644
--- a/kernel/rcupreempt_trace.c
+++ b/kernel/rcupreempt_trace.c
@@ -308,11 +308,16 @@ out:
static int __init rcupreempt_trace_init(void)
{
+ int ret;
+
mutex_init(&rcupreempt_trace_mutex);
rcupreempt_trace_buf = kmalloc(RCUPREEMPT_TRACE_BUF_SIZE, GFP_KERNEL);
if (!rcupreempt_trace_buf)
return 1;
- return rcupreempt_debugfs_init();
+ ret = rcupreempt_debugfs_init();
+ if (ret)
+ kfree(rcupreempt_trace_buf);
+ return ret;
}
static void __exit rcupreempt_trace_cleanup(void)
diff --git a/kernel/sched.c b/kernel/sched.c
index ad1962d..6f23059 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -204,11 +204,16 @@ void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
rt_b->rt_period_timer.cb_mode = HRTIMER_CB_IRQSAFE_UNLOCKED;
}
+static inline int rt_bandwidth_enabled(void)
+{
+ return sysctl_sched_rt_runtime >= 0;
+}
+
static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
{
ktime_t now;
- if (rt_b->rt_runtime == RUNTIME_INF)
+ if (rt_bandwidth_enabled() && rt_b->rt_runtime == RUNTIME_INF)
return;
if (hrtimer_active(&rt_b->rt_period_timer))
@@ -298,9 +303,9 @@ static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp;
static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity);
static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp;
#endif /* CONFIG_RT_GROUP_SCHED */
-#else /* !CONFIG_FAIR_GROUP_SCHED */
+#else /* !CONFIG_USER_SCHED */
#define root_task_group init_task_group
-#endif /* CONFIG_FAIR_GROUP_SCHED */
+#endif /* CONFIG_USER_SCHED */
/* task_group_lock serializes add/remove of task groups and also changes to
* a task group's cpu shares.
@@ -604,9 +609,9 @@ struct rq {
static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
-static inline void check_preempt_curr(struct rq *rq, struct task_struct *p)
+static inline void check_preempt_curr(struct rq *rq, struct task_struct *p, int sync)
{
- rq->curr->sched_class->check_preempt_curr(rq, p);
+ rq->curr->sched_class->check_preempt_curr(rq, p, sync);
}
static inline int cpu_of(struct rq *rq)
@@ -1102,7 +1107,7 @@ 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)
+static inline void init_hrtick(void)
{
}
#endif /* CONFIG_SMP */
@@ -1121,7 +1126,7 @@ static void init_rq_hrtick(struct rq *rq)
rq->hrtick_timer.function = hrtick;
rq->hrtick_timer.cb_mode = HRTIMER_CB_IRQSAFE_PERCPU;
}
-#else
+#else /* CONFIG_SCHED_HRTICK */
static inline void hrtick_clear(struct rq *rq)
{
}
@@ -1133,7 +1138,7 @@ static inline void init_rq_hrtick(struct rq *rq)
static inline void init_hrtick(void)
{
}
-#endif
+#endif /* CONFIG_SCHED_HRTICK */
/*
* resched_task - mark a task 'to be rescheduled now'.
@@ -1380,38 +1385,24 @@ static inline void dec_cpu_load(struct rq *rq, unsigned long load)
update_load_sub(&rq->load, load);
}
-#ifdef CONFIG_SMP
-static unsigned long source_load(int cpu, int type);
-static unsigned long target_load(int cpu, int type);
-static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
-
-static unsigned long cpu_avg_load_per_task(int cpu)
-{
- struct rq *rq = cpu_rq(cpu);
-
- if (rq->nr_running)
- rq->avg_load_per_task = rq->load.weight / rq->nr_running;
-
- return rq->avg_load_per_task;
-}
-
-#ifdef CONFIG_FAIR_GROUP_SCHED
-
-typedef void (*tg_visitor)(struct task_group *, int, struct sched_domain *);
+#if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
+typedef int (*tg_visitor)(struct task_group *, void *);
/*
* Iterate the full tree, calling @down when first entering a node and @up when
* leaving it for the final time.
*/
-static void
-walk_tg_tree(tg_visitor down, tg_visitor up, int cpu, struct sched_domain *sd)
+static int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
{
struct task_group *parent, *child;
+ int ret;
rcu_read_lock();
parent = &root_task_group;
down:
- (*down)(parent, cpu, sd);
+ ret = (*down)(parent, data);
+ if (ret)
+ goto out_unlock;
list_for_each_entry_rcu(child, &parent->children, siblings) {
parent = child;
goto down;
@@ -1419,15 +1410,43 @@ down:
up:
continue;
}
- (*up)(parent, cpu, sd);
+ ret = (*up)(parent, data);
+ if (ret)
+ goto out_unlock;
child = parent;
parent = parent->parent;
if (parent)
goto up;
+out_unlock:
rcu_read_unlock();
+
+ return ret;
}
+static int tg_nop(struct task_group *tg, void *data)
+{
+ return 0;
+}
+#endif
+
+#ifdef CONFIG_SMP
+static unsigned long source_load(int cpu, int type);
+static unsigned long target_load(int cpu, int type);
+static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
+
+static unsigned long cpu_avg_load_per_task(int cpu)
+{
+ struct rq *rq = cpu_rq(cpu);
+
+ if (rq->nr_running)
+ rq->avg_load_per_task = rq->load.weight / rq->nr_running;
+
+ return rq->avg_load_per_task;
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
static void __set_se_shares(struct sched_entity *se, unsigned long shares);
/*
@@ -1486,11 +1505,11 @@ __update_group_shares_cpu(struct task_group *tg, int cpu,
* This needs to be done in a bottom-up fashion because the rq weight of a
* parent group depends on the shares of its child groups.
*/
-static void
-tg_shares_up(struct task_group *tg, int cpu, struct sched_domain *sd)
+static int tg_shares_up(struct task_group *tg, void *data)
{
unsigned long rq_weight = 0;
unsigned long shares = 0;
+ struct sched_domain *sd = data;
int i;
for_each_cpu_mask(i, sd->span) {
@@ -1515,6 +1534,8 @@ tg_shares_up(struct task_group *tg, int cpu, struct sched_domain *sd)
__update_group_shares_cpu(tg, i, shares, rq_weight);
spin_unlock_irqrestore(&rq->lock, flags);
}
+
+ return 0;
}
/*
@@ -1522,10 +1543,10 @@ tg_shares_up(struct task_group *tg, int cpu, struct sched_domain *sd)
* This needs to be done in a top-down fashion because the load of a child
* group is a fraction of its parents load.
*/
-static void
-tg_load_down(struct task_group *tg, int cpu, struct sched_domain *sd)
+static int tg_load_down(struct task_group *tg, void *data)
{
unsigned long load;
+ long cpu = (long)data;
if (!tg->parent) {
load = cpu_rq(cpu)->load.weight;
@@ -1536,11 +1557,8 @@ tg_load_down(struct task_group *tg, int cpu, struct sched_domain *sd)
}
tg->cfs_rq[cpu]->h_load = load;
-}
-static void
-tg_nop(struct task_group *tg, int cpu, struct sched_domain *sd)
-{
+ return 0;
}
static void update_shares(struct sched_domain *sd)
@@ -1550,7 +1568,7 @@ static void update_shares(struct sched_domain *sd)
if (elapsed >= (s64)(u64)sysctl_sched_shares_ratelimit) {
sd->last_update = now;
- walk_tg_tree(tg_nop, tg_shares_up, 0, sd);
+ walk_tg_tree(tg_nop, tg_shares_up, sd);
}
}
@@ -1561,9 +1579,9 @@ static void update_shares_locked(struct rq *rq, struct sched_domain *sd)
spin_lock(&rq->lock);
}
-static void update_h_load(int cpu)
+static void update_h_load(long cpu)
{
- walk_tg_tree(tg_load_down, tg_nop, cpu, NULL);
+ walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
}
#else
@@ -1921,11 +1939,8 @@ unsigned long wait_task_inactive(struct task_struct *p, long match_state)
running = task_running(rq, p);
on_rq = p->se.on_rq;
ncsw = 0;
- if (!match_state || p->state == match_state) {
- ncsw = p->nivcsw + p->nvcsw;
- if (unlikely(!ncsw))
- ncsw = 1;
- }
+ if (!match_state || p->state == match_state)
+ ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
task_rq_unlock(rq, &flags);
/*
@@ -2285,7 +2300,7 @@ out_running:
trace_mark(kernel_sched_wakeup,
"pid %d state %ld ## rq %p task %p rq->curr %p",
p->pid, p->state, rq, p, rq->curr);
- check_preempt_curr(rq, p);
+ check_preempt_curr(rq, p, sync);
p->state = TASK_RUNNING;
#ifdef CONFIG_SMP
@@ -2420,7 +2435,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
trace_mark(kernel_sched_wakeup_new,
"pid %d state %ld ## rq %p task %p rq->curr %p",
p->pid, p->state, rq, p, rq->curr);
- check_preempt_curr(rq, p);
+ check_preempt_curr(rq, p, 0);
#ifdef CONFIG_SMP
if (p->sched_class->task_wake_up)
p->sched_class->task_wake_up(rq, p);
@@ -2880,7 +2895,7 @@ static void pull_task(struct rq *src_rq, struct task_struct *p,
* Note that idle threads have a prio of MAX_PRIO, for this test
* to be always true for them.
*/
- check_preempt_curr(this_rq, p);
+ check_preempt_curr(this_rq, p, 0);
}
/*
@@ -4627,6 +4642,15 @@ __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
}
EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
+/**
+ * complete: - signals a single thread waiting on this completion
+ * @x: holds the state of this particular completion
+ *
+ * This will wake up a single thread waiting on this completion. Threads will be
+ * awakened in the same order in which they were queued.
+ *
+ * See also complete_all(), wait_for_completion() and related routines.
+ */
void complete(struct completion *x)
{
unsigned long flags;
@@ -4638,6 +4662,12 @@ void complete(struct completion *x)
}
EXPORT_SYMBOL(complete);
+/**
+ * complete_all: - signals all threads waiting on this completion
+ * @x: holds the state of this particular completion
+ *
+ * This will wake up all threads waiting on this particular completion event.
+ */
void complete_all(struct completion *x)
{
unsigned long flags;
@@ -4658,10 +4688,7 @@ do_wait_for_common(struct completion *x, long timeout, int state)
wait.flags |= WQ_FLAG_EXCLUSIVE;
__add_wait_queue_tail(&x->wait, &wait);
do {
- if ((state == TASK_INTERRUPTIBLE &&
- signal_pending(current)) ||
- (state == TASK_KILLABLE &&
- fatal_signal_pending(current))) {
+ if (signal_pending_state(state, current)) {
timeout = -ERESTARTSYS;
break;
}
@@ -4689,12 +4716,31 @@ wait_for_common(struct completion *x, long timeout, int state)
return timeout;
}
+/**
+ * wait_for_completion: - waits for completion of a task
+ * @x: holds the state of this particular completion
+ *
+ * This waits to be signaled for completion of a specific task. It is NOT
+ * interruptible and there is no timeout.
+ *
+ * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
+ * and interrupt capability. Also see complete().
+ */
void __sched wait_for_completion(struct completion *x)
{
wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL(wait_for_completion);
+/**
+ * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
+ * @x: holds the state of this particular completion
+ * @timeout: timeout value in jiffies
+ *
+ * This waits for either a completion of a specific task to be signaled or for a
+ * specified timeout to expire. The timeout is in jiffies. It is not
+ * interruptible.
+ */
unsigned long __sched
wait_for_completion_timeout(struct completion *x, unsigned long timeout)
{
@@ -4702,6 +4748,13 @@ wait_for_completion_timeout(struct completion *x, unsigned long timeout)
}
EXPORT_SYMBOL(wait_for_completion_timeout);
+/**
+ * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
+ * @x: holds the state of this particular completion
+ *
+ * This waits for completion of a specific task to be signaled. It is
+ * interruptible.
+ */
int __sched wait_for_completion_interruptible(struct completion *x)
{
long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
@@ -4711,6 +4764,14 @@ int __sched wait_for_completion_interruptible(struct completion *x)
}
EXPORT_SYMBOL(wait_for_completion_interruptible);
+/**
+ * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
+ * @x: holds the state of this particular completion
+ * @timeout: timeout value in jiffies
+ *
+ * This waits for either a completion of a specific task to be signaled or for a
+ * specified timeout to expire. It is interruptible. The timeout is in jiffies.
+ */
unsigned long __sched
wait_for_completion_interruptible_timeout(struct completion *x,
unsigned long timeout)
@@ -4719,6 +4780,13 @@ wait_for_completion_interruptible_timeout(struct completion *x,
}
EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
+/**
+ * wait_for_completion_killable: - waits for completion of a task (killable)
+ * @x: holds the state of this particular completion
+ *
+ * This waits to be signaled for completion of a specific task. It can be
+ * interrupted by a kill signal.
+ */
int __sched wait_for_completion_killable(struct completion *x)
{
long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
@@ -5121,7 +5189,8 @@ recheck:
* Do not allow realtime tasks into groups that have no runtime
* assigned.
*/
- if (rt_policy(policy) && task_group(p)->rt_bandwidth.rt_runtime == 0)
+ if (rt_bandwidth_enabled() && rt_policy(policy) &&
+ task_group(p)->rt_bandwidth.rt_runtime == 0)
return -EPERM;
#endif
@@ -5957,7 +6026,7 @@ static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
set_task_cpu(p, dest_cpu);
if (on_rq) {
activate_task(rq_dest, p, 0);
- check_preempt_curr(rq_dest, p);
+ check_preempt_curr(rq_dest, p, 0);
}
done:
ret = 1;
@@ -6282,7 +6351,7 @@ set_table_entry(struct ctl_table *entry,
static struct ctl_table *
sd_alloc_ctl_domain_table(struct sched_domain *sd)
{
- struct ctl_table *table = sd_alloc_ctl_entry(12);
+ struct ctl_table *table = sd_alloc_ctl_entry(13);
if (table == NULL)
return NULL;
@@ -6310,7 +6379,9 @@ sd_alloc_ctl_domain_table(struct sched_domain *sd)
sizeof(int), 0644, proc_dointvec_minmax);
set_table_entry(&table[10], "flags", &sd->flags,
sizeof(int), 0644, proc_dointvec_minmax);
- /* &table[11] is terminator */
+ set_table_entry(&table[11], "name", sd->name,
+ CORENAME_MAX_SIZE, 0444, proc_dostring);
+ /* &table[12] is terminator */
return table;
}
@@ -7194,13 +7265,21 @@ static void init_sched_groups_power(int cpu, struct sched_domain *sd)
* Non-inlined to reduce accumulated stack pressure in build_sched_domains()
*/
+#ifdef CONFIG_SCHED_DEBUG
+# define SD_INIT_NAME(sd, type) sd->name = #type
+#else
+# define SD_INIT_NAME(sd, type) do { } while (0)
+#endif
+
#define SD_INIT(sd, type) sd_init_##type(sd)
+
#define SD_INIT_FUNC(type) \
static noinline void sd_init_##type(struct sched_domain *sd) \
{ \
memset(sd, 0, sizeof(*sd)); \
*sd = SD_##type##_INIT; \
sd->level = SD_LV_##type; \
+ SD_INIT_NAME(sd, type); \
}
SD_INIT_FUNC(CPU)
@@ -8242,20 +8321,25 @@ void __might_sleep(char *file, int line)
#ifdef in_atomic
static unsigned long prev_jiffy; /* ratelimiting */
- if ((in_atomic() || irqs_disabled()) &&
- system_state == SYSTEM_RUNNING && !oops_in_progress) {
- if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
- return;
- prev_jiffy = jiffies;
- printk(KERN_ERR "BUG: sleeping function called from invalid"
- " context at %s:%d\n", file, line);
- printk("in_atomic():%d, irqs_disabled():%d\n",
- in_atomic(), irqs_disabled());
- debug_show_held_locks(current);
- if (irqs_disabled())
- print_irqtrace_events(current);
- dump_stack();
- }
+ if ((!in_atomic() && !irqs_disabled()) ||
+ system_state != SYSTEM_RUNNING || oops_in_progress)
+ return;
+ if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
+ return;
+ prev_jiffy = jiffies;
+
+ printk(KERN_ERR
+ "BUG: sleeping function called from invalid context at %s:%d\n",
+ file, line);
+ printk(KERN_ERR
+ "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
+ in_atomic(), irqs_disabled(),
+ current->pid, current->comm);
+
+ debug_show_held_locks(current);
+ if (irqs_disabled())
+ print_irqtrace_events(current);
+ dump_stack();
#endif
}
EXPORT_SYMBOL(__might_sleep);
@@ -8753,73 +8837,95 @@ static DEFINE_MUTEX(rt_constraints_mutex);
static unsigned long to_ratio(u64 period, u64 runtime)
{
if (runtime == RUNTIME_INF)
- return 1ULL << 16;
+ return 1ULL << 20;
- return div64_u64(runtime << 16, period);
+ return div64_u64(runtime << 20, period);
}
-#ifdef CONFIG_CGROUP_SCHED
-static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
+/* Must be called with tasklist_lock held */
+static inline int tg_has_rt_tasks(struct task_group *tg)
{
- struct task_group *tgi, *parent = tg->parent;
- unsigned long total = 0;
+ struct task_struct *g, *p;
- if (!parent) {
- if (global_rt_period() < period)
- return 0;
+ do_each_thread(g, p) {
+ if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg)
+ return 1;
+ } while_each_thread(g, p);
- return to_ratio(period, runtime) <
- to_ratio(global_rt_period(), global_rt_runtime());
- }
+ return 0;
+}
- if (ktime_to_ns(parent->rt_bandwidth.rt_period) < period)
- return 0;
+struct rt_schedulable_data {
+ struct task_group *tg;
+ u64 rt_period;
+ u64 rt_runtime;
+};
- rcu_read_lock();
- list_for_each_entry_rcu(tgi, &parent->children, siblings) {
- if (tgi == tg)
- continue;
+static int tg_schedulable(struct task_group *tg, void *data)
+{
+ struct rt_schedulable_data *d = data;
+ struct task_group *child;
+ unsigned long total, sum = 0;
+ u64 period, runtime;
- total += to_ratio(ktime_to_ns(tgi->rt_bandwidth.rt_period),
- tgi->rt_bandwidth.rt_runtime);
+ period = ktime_to_ns(tg->rt_bandwidth.rt_period);
+ runtime = tg->rt_bandwidth.rt_runtime;
+
+ if (tg == d->tg) {
+ period = d->rt_period;
+ runtime = d->rt_runtime;
}
- rcu_read_unlock();
- return total + to_ratio(period, runtime) <=
- to_ratio(ktime_to_ns(parent->rt_bandwidth.rt_period),
- parent->rt_bandwidth.rt_runtime);
-}
-#elif defined CONFIG_USER_SCHED
-static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
-{
- struct task_group *tgi;
- unsigned long total = 0;
- unsigned long global_ratio =
- to_ratio(global_rt_period(), global_rt_runtime());
+ /*
+ * Cannot have more runtime than the period.
+ */
+ if (runtime > period && runtime != RUNTIME_INF)
+ return -EINVAL;
- rcu_read_lock();
- list_for_each_entry_rcu(tgi, &task_groups, list) {
- if (tgi == tg)
- continue;
+ /*
+ * Ensure we don't starve existing RT tasks.
+ */
+ if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
+ return -EBUSY;
+
+ total = to_ratio(period, runtime);
+
+ /*
+ * Nobody can have more than the global setting allows.
+ */
+ if (total > to_ratio(global_rt_period(), global_rt_runtime()))
+ return -EINVAL;
+
+ /*
+ * The sum of our children's runtime should not exceed our own.
+ */
+ list_for_each_entry_rcu(child, &tg->children, siblings) {
+ period = ktime_to_ns(child->rt_bandwidth.rt_period);
+ runtime = child->rt_bandwidth.rt_runtime;
+
+ if (child == d->tg) {
+ period = d->rt_period;
+ runtime = d->rt_runtime;
+ }
- total += to_ratio(ktime_to_ns(tgi->rt_bandwidth.rt_period),
- tgi->rt_bandwidth.rt_runtime);
+ sum += to_ratio(period, runtime);
}
- rcu_read_unlock();
- return total + to_ratio(period, runtime) < global_ratio;
+ if (sum > total)
+ return -EINVAL;
+
+ return 0;
}
-#endif
-/* Must be called with tasklist_lock held */
-static inline int tg_has_rt_tasks(struct task_group *tg)
+static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
{
- struct task_struct *g, *p;
- do_each_thread(g, p) {
- if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg)
- return 1;
- } while_each_thread(g, p);
- return 0;
+ struct rt_schedulable_data data = {
+ .tg = tg,
+ .rt_period = period,
+ .rt_runtime = runtime,
+ };
+
+ return walk_tg_tree(tg_schedulable, tg_nop, &data);
}
static int tg_set_bandwidth(struct task_group *tg,
@@ -8829,14 +8935,9 @@ static int tg_set_bandwidth(struct task_group *tg,
mutex_lock(&rt_constraints_mutex);
read_lock(&tasklist_lock);
- if (rt_runtime == 0 && tg_has_rt_tasks(tg)) {
- err = -EBUSY;
+ err = __rt_schedulable(tg, rt_period, rt_runtime);
+ if (err)
goto unlock;
- }
- if (!__rt_schedulable(tg, rt_period, rt_runtime)) {
- err = -EINVAL;
- goto unlock;
- }
spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
@@ -8905,19 +9006,25 @@ long sched_group_rt_period(struct task_group *tg)
static int sched_rt_global_constraints(void)
{
- struct task_group *tg = &root_task_group;
- u64 rt_runtime, rt_period;
+ u64 runtime, period;
int ret = 0;
if (sysctl_sched_rt_period <= 0)
return -EINVAL;
- rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
- rt_runtime = tg->rt_bandwidth.rt_runtime;
+ runtime = global_rt_runtime();
+ period = global_rt_period();
+
+ /*
+ * Sanity check on the sysctl variables.
+ */
+ if (runtime > period && runtime != RUNTIME_INF)
+ return -EINVAL;
mutex_lock(&rt_constraints_mutex);
- if (!__rt_schedulable(tg, rt_period, rt_runtime))
- ret = -EINVAL;
+ read_lock(&tasklist_lock);
+ ret = __rt_schedulable(NULL, 0, 0);
+ read_unlock(&tasklist_lock);
mutex_unlock(&rt_constraints_mutex);
return ret;
@@ -8991,7 +9098,6 @@ cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
if (!cgrp->parent) {
/* This is early initialization for the top cgroup */
- init_task_group.css.cgroup = cgrp;
return &init_task_group.css;
}
@@ -9000,9 +9106,6 @@ cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
if (IS_ERR(tg))
return ERR_PTR(-ENOMEM);
- /* Bind the cgroup to task_group object we just created */
- tg->css.cgroup = cgrp;
-
return &tg->css;
}
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index fb8994c..18fd171 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -409,64 +409,6 @@ static u64 sched_vslice_add(struct cfs_rq *cfs_rq, struct sched_entity *se)
}
/*
- * The goal of calc_delta_asym() is to be asymmetrically around NICE_0_LOAD, in
- * that it favours >=0 over <0.
- *
- * -20 |
- * |
- * 0 --------+-------
- * .'
- * 19 .'
- *
- */
-static unsigned long
-calc_delta_asym(unsigned long delta, struct sched_entity *se)
-{
- struct load_weight lw = {
- .weight = NICE_0_LOAD,
- .inv_weight = 1UL << (WMULT_SHIFT-NICE_0_SHIFT)
- };
-
- for_each_sched_entity(se) {
- struct load_weight *se_lw = &se->load;
- unsigned long rw = cfs_rq_of(se)->load.weight;
-
-#ifdef CONFIG_FAIR_SCHED_GROUP
- struct cfs_rq *cfs_rq = se->my_q;
- struct task_group *tg = NULL
-
- if (cfs_rq)
- tg = cfs_rq->tg;
-
- if (tg && tg->shares < NICE_0_LOAD) {
- /*
- * scale shares to what it would have been had
- * tg->weight been NICE_0_LOAD:
- *
- * weight = 1024 * shares / tg->weight
- */
- lw.weight *= se->load.weight;
- lw.weight /= tg->shares;
-
- lw.inv_weight = 0;
-
- se_lw = &lw;
- rw += lw.weight - se->load.weight;
- } else
-#endif
-
- if (se->load.weight < NICE_0_LOAD) {
- se_lw = &lw;
- rw += NICE_0_LOAD - se->load.weight;
- }
-
- delta = calc_delta_mine(delta, rw, se_lw);
- }
-
- return delta;
-}
-
-/*
* Update the current task's runtime statistics. Skip current tasks that
* are not in our scheduling class.
*/
@@ -586,11 +528,12 @@ account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
update_load_add(&cfs_rq->load, se->load.weight);
if (!parent_entity(se))
inc_cpu_load(rq_of(cfs_rq), se->load.weight);
- if (entity_is_task(se))
+ if (entity_is_task(se)) {
add_cfs_task_weight(cfs_rq, se->load.weight);
+ list_add(&se->group_node, &cfs_rq->tasks);
+ }
cfs_rq->nr_running++;
se->on_rq = 1;
- list_add(&se->group_node, &cfs_rq->tasks);
}
static void
@@ -599,11 +542,12 @@ account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
update_load_sub(&cfs_rq->load, se->load.weight);
if (!parent_entity(se))
dec_cpu_load(rq_of(cfs_rq), se->load.weight);
- if (entity_is_task(se))
+ if (entity_is_task(se)) {
add_cfs_task_weight(cfs_rq, -se->load.weight);
+ list_del_init(&se->group_node);
+ }
cfs_rq->nr_running--;
se->on_rq = 0;
- list_del_init(&se->group_node);
}
static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
@@ -1085,7 +1029,6 @@ static long effective_load(struct task_group *tg, int cpu,
long wl, long wg)
{
struct sched_entity *se = tg->se[cpu];
- long more_w;
if (!tg->parent)
return wl;
@@ -1097,18 +1040,17 @@ static long effective_load(struct task_group *tg, int cpu,
if (!wl && sched_feat(ASYM_EFF_LOAD))
return wl;
- /*
- * Instead of using this increment, also add the difference
- * between when the shares were last updated and now.
- */
- more_w = se->my_q->load.weight - se->my_q->rq_weight;
- wl += more_w;
- wg += more_w;
-
for_each_sched_entity(se) {
-#define D(n) (likely(n) ? (n) : 1)
-
long S, rw, s, a, b;
+ long more_w;
+
+ /*
+ * Instead of using this increment, also add the difference
+ * between when the shares were last updated and now.
+ */
+ more_w = se->my_q->load.weight - se->my_q->rq_weight;
+ wl += more_w;
+ wg += more_w;
S = se->my_q->tg->shares;
s = se->my_q->shares;
@@ -1117,7 +1059,11 @@ static long effective_load(struct task_group *tg, int cpu,
a = S*(rw + wl);
b = S*rw + s*wg;
- wl = s*(a-b)/D(b);
+ wl = s*(a-b);
+
+ if (likely(b))
+ wl /= b;
+
/*
* Assume the group is already running and will
* thus already be accounted for in the weight.
@@ -1126,7 +1072,6 @@ static long effective_load(struct task_group *tg, int cpu,
* alter the group weight.
*/
wg = 0;
-#undef D
}
return wl;
@@ -1143,7 +1088,7 @@ static inline unsigned long effective_load(struct task_group *tg, int cpu,
#endif
static int
-wake_affine(struct rq *rq, struct sched_domain *this_sd, struct rq *this_rq,
+wake_affine(struct sched_domain *this_sd, struct rq *this_rq,
struct task_struct *p, int prev_cpu, int this_cpu, int sync,
int idx, unsigned long load, unsigned long this_load,
unsigned int imbalance)
@@ -1158,6 +1103,11 @@ wake_affine(struct rq *rq, struct sched_domain *this_sd, struct rq *this_rq,
if (!(this_sd->flags & SD_WAKE_AFFINE) || !sched_feat(AFFINE_WAKEUPS))
return 0;
+ if (!sync && sched_feat(SYNC_WAKEUPS) &&
+ curr->se.avg_overlap < sysctl_sched_migration_cost &&
+ p->se.avg_overlap < sysctl_sched_migration_cost)
+ sync = 1;
+
/*
* If sync wakeup then subtract the (maximum possible)
* effect of the currently running task from the load
@@ -1182,17 +1132,14 @@ wake_affine(struct rq *rq, struct sched_domain *this_sd, struct rq *this_rq,
* a reasonable amount of time then attract this newly
* woken task:
*/
- if (sync && balanced) {
- if (curr->se.avg_overlap < sysctl_sched_migration_cost &&
- p->se.avg_overlap < sysctl_sched_migration_cost)
- return 1;
- }
+ if (sync && balanced)
+ return 1;
schedstat_inc(p, se.nr_wakeups_affine_attempts);
tl_per_task = cpu_avg_load_per_task(this_cpu);
- if ((tl <= load && tl + target_load(prev_cpu, idx) <= tl_per_task) ||
- balanced) {
+ if (balanced || (tl <= load && tl + target_load(prev_cpu, idx) <=
+ tl_per_task)) {
/*
* This domain has SD_WAKE_AFFINE and
* p is cache cold in this domain, and
@@ -1211,16 +1158,17 @@ static int select_task_rq_fair(struct task_struct *p, int sync)
struct sched_domain *sd, *this_sd = NULL;
int prev_cpu, this_cpu, new_cpu;
unsigned long load, this_load;
- struct rq *rq, *this_rq;
+ struct rq *this_rq;
unsigned int imbalance;
int idx;
prev_cpu = task_cpu(p);
- rq = task_rq(p);
this_cpu = smp_processor_id();
this_rq = cpu_rq(this_cpu);
new_cpu = prev_cpu;
+ if (prev_cpu == this_cpu)
+ goto out;
/*
* 'this_sd' is the first domain that both
* this_cpu and prev_cpu are present in:
@@ -1248,13 +1196,10 @@ static int select_task_rq_fair(struct task_struct *p, int sync)
load = source_load(prev_cpu, idx);
this_load = target_load(this_cpu, idx);
- if (wake_affine(rq, this_sd, this_rq, p, prev_cpu, this_cpu, sync, idx,
+ if (wake_affine(this_sd, this_rq, p, prev_cpu, this_cpu, sync, idx,
load, this_load, imbalance))
return this_cpu;
- if (prev_cpu == this_cpu)
- goto out;
-
/*
* Start passive balancing when half the imbalance_pct
* limit is reached.
@@ -1281,62 +1226,20 @@ static unsigned long wakeup_gran(struct sched_entity *se)
* + nice tasks.
*/
if (sched_feat(ASYM_GRAN))
- gran = calc_delta_asym(sysctl_sched_wakeup_granularity, se);
- else
- gran = calc_delta_fair(sysctl_sched_wakeup_granularity, se);
+ gran = calc_delta_mine(gran, NICE_0_LOAD, &se->load);
return gran;
}
/*
- * Should 'se' preempt 'curr'.
- *
- * |s1
- * |s2
- * |s3
- * g
- * |<--->|c
- *
- * w(c, s1) = -1
- * w(c, s2) = 0
- * w(c, s3) = 1
- *
- */
-static int
-wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
-{
- s64 gran, vdiff = curr->vruntime - se->vruntime;
-
- if (vdiff < 0)
- return -1;
-
- gran = wakeup_gran(curr);
- if (vdiff > gran)
- return 1;
-
- return 0;
-}
-
-/* return depth at which a sched entity is present in the hierarchy */
-static inline int depth_se(struct sched_entity *se)
-{
- int depth = 0;
-
- for_each_sched_entity(se)
- depth++;
-
- return depth;
-}
-
-/*
* Preempt the current task with a newly woken task if needed:
*/
-static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
+static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync)
{
struct task_struct *curr = rq->curr;
struct cfs_rq *cfs_rq = task_cfs_rq(curr);
struct sched_entity *se = &curr->se, *pse = &p->se;
- int se_depth, pse_depth;
+ s64 delta_exec;
if (unlikely(rt_prio(p->prio))) {
update_rq_clock(rq);
@@ -1351,6 +1254,13 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
cfs_rq_of(pse)->next = pse;
/*
+ * We can come here with TIF_NEED_RESCHED already set from new task
+ * wake up path.
+ */
+ if (test_tsk_need_resched(curr))
+ return;
+
+ /*
* Batch tasks do not preempt (their preemption is driven by
* the tick):
*/
@@ -1360,33 +1270,15 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
if (!sched_feat(WAKEUP_PREEMPT))
return;
- /*
- * preemption test can be made between sibling entities who are in the
- * same cfs_rq i.e who have a common parent. Walk up the hierarchy of
- * both tasks until we find their ancestors who are siblings of common
- * parent.
- */
-
- /* First walk up until both entities are at same depth */
- se_depth = depth_se(se);
- pse_depth = depth_se(pse);
-
- while (se_depth > pse_depth) {
- se_depth--;
- se = parent_entity(se);
- }
-
- while (pse_depth > se_depth) {
- pse_depth--;
- pse = parent_entity(pse);
- }
-
- while (!is_same_group(se, pse)) {
- se = parent_entity(se);
- pse = parent_entity(pse);
+ if (sched_feat(WAKEUP_OVERLAP) && (sync ||
+ (se->avg_overlap < sysctl_sched_migration_cost &&
+ pse->avg_overlap < sysctl_sched_migration_cost))) {
+ resched_task(curr);
+ return;
}
- if (wakeup_preempt_entity(se, pse) == 1)
+ delta_exec = se->sum_exec_runtime - se->prev_sum_exec_runtime;
+ if (delta_exec > wakeup_gran(pse))
resched_task(curr);
}
@@ -1445,19 +1337,9 @@ __load_balance_iterator(struct cfs_rq *cfs_rq, struct list_head *next)
if (next == &cfs_rq->tasks)
return NULL;
- /* Skip over entities that are not tasks */
- do {
- se = list_entry(next, struct sched_entity, group_node);
- next = next->next;
- } while (next != &cfs_rq->tasks && !entity_is_task(se));
-
- if (next == &cfs_rq->tasks)
- return NULL;
-
- cfs_rq->balance_iterator = next;
-
- if (entity_is_task(se))
- p = task_of(se);
+ se = list_entry(next, struct sched_entity, group_node);
+ p = task_of(se);
+ cfs_rq->balance_iterator = next->next;
return p;
}
@@ -1507,7 +1389,7 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
rcu_read_lock();
update_h_load(busiest_cpu);
- list_for_each_entry(tg, &task_groups, list) {
+ list_for_each_entry_rcu(tg, &task_groups, list) {
struct cfs_rq *busiest_cfs_rq = tg->cfs_rq[busiest_cpu];
unsigned long busiest_h_load = busiest_cfs_rq->h_load;
unsigned long busiest_weight = busiest_cfs_rq->load.weight;
@@ -1620,10 +1502,10 @@ static void task_new_fair(struct rq *rq, struct task_struct *p)
* 'current' within the tree based on its new key value.
*/
swap(curr->vruntime, se->vruntime);
+ resched_task(rq->curr);
}
enqueue_task_fair(rq, p, 0);
- resched_task(rq->curr);
}
/*
@@ -1642,7 +1524,7 @@ static void prio_changed_fair(struct rq *rq, struct task_struct *p,
if (p->prio > oldprio)
resched_task(rq->curr);
} else
- check_preempt_curr(rq, p);
+ check_preempt_curr(rq, p, 0);
}
/*
@@ -1659,7 +1541,7 @@ static void switched_to_fair(struct rq *rq, struct task_struct *p,
if (running)
resched_task(rq->curr);
else
- check_preempt_curr(rq, p);
+ check_preempt_curr(rq, p, 0);
}
/* Account for a task changing its policy or group.
diff --git a/kernel/sched_features.h b/kernel/sched_features.h
index 9353ca7..7c9e8f4 100644
--- a/kernel/sched_features.h
+++ b/kernel/sched_features.h
@@ -11,3 +11,4 @@ SCHED_FEAT(ASYM_GRAN, 1)
SCHED_FEAT(LB_BIAS, 1)
SCHED_FEAT(LB_WAKEUP_UPDATE, 1)
SCHED_FEAT(ASYM_EFF_LOAD, 1)
+SCHED_FEAT(WAKEUP_OVERLAP, 0)
diff --git a/kernel/sched_idletask.c b/kernel/sched_idletask.c
index 3a4f92d..dec4cca 100644
--- a/kernel/sched_idletask.c
+++ b/kernel/sched_idletask.c
@@ -14,7 +14,7 @@ static int select_task_rq_idle(struct task_struct *p, int sync)
/*
* Idle tasks are unconditionally rescheduled:
*/
-static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p)
+static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p, int sync)
{
resched_task(rq->idle);
}
@@ -76,7 +76,7 @@ static void switched_to_idle(struct rq *rq, struct task_struct *p,
if (running)
resched_task(rq->curr);
else
- check_preempt_curr(rq, p);
+ check_preempt_curr(rq, p, 0);
}
static void prio_changed_idle(struct rq *rq, struct task_struct *p,
@@ -93,7 +93,7 @@ static void prio_changed_idle(struct rq *rq, struct task_struct *p,
if (p->prio > oldprio)
resched_task(rq->curr);
} else
- check_preempt_curr(rq, p);
+ check_preempt_curr(rq, p, 0);
}
/*
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 1113157..cdf5740 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -102,12 +102,12 @@ static void dequeue_rt_entity(struct sched_rt_entity *rt_se);
static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
{
+ struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr;
struct sched_rt_entity *rt_se = rt_rq->rt_se;
- if (rt_se && !on_rt_rq(rt_se) && rt_rq->rt_nr_running) {
- struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr;
-
- enqueue_rt_entity(rt_se);
+ if (rt_rq->rt_nr_running) {
+ if (rt_se && !on_rt_rq(rt_se))
+ enqueue_rt_entity(rt_se);
if (rt_rq->highest_prio < curr->prio)
resched_task(curr);
}
@@ -231,6 +231,9 @@ static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
#endif /* CONFIG_RT_GROUP_SCHED */
#ifdef CONFIG_SMP
+/*
+ * We ran out of runtime, see if we can borrow some from our neighbours.
+ */
static int do_balance_runtime(struct rt_rq *rt_rq)
{
struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
@@ -250,9 +253,18 @@ static int do_balance_runtime(struct rt_rq *rt_rq)
continue;
spin_lock(&iter->rt_runtime_lock);
+ /*
+ * Either all rqs have inf runtime and there's nothing to steal
+ * or __disable_runtime() below sets a specific rq to inf to
+ * indicate its been disabled and disalow stealing.
+ */
if (iter->rt_runtime == RUNTIME_INF)
goto next;
+ /*
+ * From runqueues with spare time, take 1/n part of their
+ * spare time, but no more than our period.
+ */
diff = iter->rt_runtime - iter->rt_time;
if (diff > 0) {
diff = div_u64((u64)diff, weight);
@@ -274,6 +286,9 @@ next:
return more;
}
+/*
+ * Ensure this RQ takes back all the runtime it lend to its neighbours.
+ */
static void __disable_runtime(struct rq *rq)
{
struct root_domain *rd = rq->rd;
@@ -289,17 +304,33 @@ static void __disable_runtime(struct rq *rq)
spin_lock(&rt_b->rt_runtime_lock);
spin_lock(&rt_rq->rt_runtime_lock);
+ /*
+ * Either we're all inf and nobody needs to borrow, or we're
+ * already disabled and thus have nothing to do, or we have
+ * exactly the right amount of runtime to take out.
+ */
if (rt_rq->rt_runtime == RUNTIME_INF ||
rt_rq->rt_runtime == rt_b->rt_runtime)
goto balanced;
spin_unlock(&rt_rq->rt_runtime_lock);
+ /*
+ * Calculate the difference between what we started out with
+ * and what we current have, that's the amount of runtime
+ * we lend and now have to reclaim.
+ */
want = rt_b->rt_runtime - rt_rq->rt_runtime;
+ /*
+ * Greedy reclaim, take back as much as we can.
+ */
for_each_cpu_mask(i, rd->span) {
struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
s64 diff;
+ /*
+ * Can't reclaim from ourselves or disabled runqueues.
+ */
if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF)
continue;
@@ -319,8 +350,16 @@ static void __disable_runtime(struct rq *rq)
}
spin_lock(&rt_rq->rt_runtime_lock);
+ /*
+ * We cannot be left wanting - that would mean some runtime
+ * leaked out of the system.
+ */
BUG_ON(want);
balanced:
+ /*
+ * Disable all the borrow logic by pretending we have inf
+ * runtime - in which case borrowing doesn't make sense.
+ */
rt_rq->rt_runtime = RUNTIME_INF;
spin_unlock(&rt_rq->rt_runtime_lock);
spin_unlock(&rt_b->rt_runtime_lock);
@@ -343,6 +382,9 @@ static void __enable_runtime(struct rq *rq)
if (unlikely(!scheduler_running))
return;
+ /*
+ * Reset each runqueue's bandwidth settings
+ */
for_each_leaf_rt_rq(rt_rq, rq) {
struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
@@ -389,7 +431,7 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
int i, idle = 1;
cpumask_t span;
- if (rt_b->rt_runtime == RUNTIME_INF)
+ if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
return 1;
span = sched_rt_period_mask();
@@ -487,6 +529,9 @@ static void update_curr_rt(struct rq *rq)
curr->se.exec_start = rq->clock;
cpuacct_charge(curr, delta_exec);
+ if (!rt_bandwidth_enabled())
+ return;
+
for_each_sched_rt_entity(rt_se) {
rt_rq = rt_rq_of_se(rt_se);
@@ -784,7 +829,7 @@ static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
/*
* Preempt the current task with a newly woken task if needed:
*/
-static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p)
+static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int sync)
{
if (p->prio < rq->curr->prio) {
resched_task(rq->curr);
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index cb02324..a4d2193 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -20,6 +20,7 @@
#include <linux/profile.h>
#include <linux/sched.h>
#include <linux/tick.h>
+#include <linux/module.h>
#include <asm/irq_regs.h>
@@ -190,9 +191,17 @@ u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
{
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
- *last_update_time = ktime_to_us(ts->idle_lastupdate);
+ if (!tick_nohz_enabled)
+ return -1;
+
+ if (ts->idle_active)
+ *last_update_time = ktime_to_us(ts->idle_lastupdate);
+ else
+ *last_update_time = ktime_to_us(ktime_get());
+
return ktime_to_us(ts->idle_sleeptime);
}
+EXPORT_SYMBOL_GPL(get_cpu_idle_time_us);
/**
* tick_nohz_stop_sched_tick - stop the idle tick from the idle task
diff --git a/kernel/user.c b/kernel/user.c
index 865ecf57..39d6159 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -169,7 +169,7 @@ static ssize_t cpu_rt_runtime_show(struct kobject *kobj,
{
struct user_struct *up = container_of(kobj, struct user_struct, kobj);
- return sprintf(buf, "%lu\n", sched_group_rt_runtime(up->tg));
+ return sprintf(buf, "%ld\n", sched_group_rt_runtime(up->tg));
}
static ssize_t cpu_rt_runtime_store(struct kobject *kobj,
@@ -180,7 +180,7 @@ static ssize_t cpu_rt_runtime_store(struct kobject *kobj,
unsigned long rt_runtime;
int rc;
- sscanf(buf, "%lu", &rt_runtime);
+ sscanf(buf, "%ld", &rt_runtime);
rc = sched_group_set_rt_runtime(up->tg, rt_runtime);
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