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-rw-r--r--kernel/fork.c11
-rw-r--r--kernel/latencytop.c83
-rw-r--r--kernel/rcuclassic.c4
-rw-r--r--kernel/rcupdate.c12
-rw-r--r--kernel/rcupreempt.c3
-rw-r--r--kernel/rcutree.c4
-rw-r--r--kernel/sched.c215
-rw-r--r--kernel/sched_debug.c1
-rw-r--r--kernel/sched_fair.c59
-rw-r--r--kernel/sched_features.h3
-rw-r--r--kernel/sched_rt.c537
-rw-r--r--kernel/seccomp.c7
-rw-r--r--kernel/softirq.c1
-rw-r--r--kernel/sys.c31
-rw-r--r--kernel/tsacct.c6
-rw-r--r--kernel/user.c32
-rw-r--r--kernel/user_namespace.c21
17 files changed, 778 insertions, 252 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index a66fbde..4854c2c 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1179,10 +1179,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
#endif
clear_all_latency_tracing(p);
- /* Our parent execution domain becomes current domain
- These must match for thread signalling to apply */
- p->parent_exec_id = p->self_exec_id;
-
/* ok, now we should be set up.. */
p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL);
p->pdeath_signal = 0;
@@ -1220,10 +1216,13 @@ static struct task_struct *copy_process(unsigned long clone_flags,
set_task_cpu(p, smp_processor_id());
/* CLONE_PARENT re-uses the old parent */
- if (clone_flags & (CLONE_PARENT|CLONE_THREAD))
+ if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) {
p->real_parent = current->real_parent;
- else
+ p->parent_exec_id = current->parent_exec_id;
+ } else {
p->real_parent = current;
+ p->parent_exec_id = current->self_exec_id;
+ }
spin_lock(&current->sighand->siglock);
diff --git a/kernel/latencytop.c b/kernel/latencytop.c
index 449db46..ca07c5c 100644
--- a/kernel/latencytop.c
+++ b/kernel/latencytop.c
@@ -9,6 +9,44 @@
* as published by the Free Software Foundation; version 2
* of the License.
*/
+
+/*
+ * CONFIG_LATENCYTOP enables a kernel latency tracking infrastructure that is
+ * used by the "latencytop" userspace tool. The latency that is tracked is not
+ * the 'traditional' interrupt latency (which is primarily caused by something
+ * else consuming CPU), but instead, it is the latency an application encounters
+ * because the kernel sleeps on its behalf for various reasons.
+ *
+ * This code tracks 2 levels of statistics:
+ * 1) System level latency
+ * 2) Per process latency
+ *
+ * The latency is stored in fixed sized data structures in an accumulated form;
+ * if the "same" latency cause is hit twice, this will be tracked as one entry
+ * in the data structure. Both the count, total accumulated latency and maximum
+ * latency are tracked in this data structure. When the fixed size structure is
+ * full, no new causes are tracked until the buffer is flushed by writing to
+ * the /proc file; the userspace tool does this on a regular basis.
+ *
+ * A latency cause is identified by a stringified backtrace at the point that
+ * the scheduler gets invoked. The userland tool will use this string to
+ * identify the cause of the latency in human readable form.
+ *
+ * The information is exported via /proc/latency_stats and /proc/<pid>/latency.
+ * These files look like this:
+ *
+ * Latency Top version : v0.1
+ * 70 59433 4897 i915_irq_wait drm_ioctl vfs_ioctl do_vfs_ioctl sys_ioctl
+ * | | | |
+ * | | | +----> the stringified backtrace
+ * | | +---------> The maximum latency for this entry in microseconds
+ * | +--------------> The accumulated latency for this entry (microseconds)
+ * +-------------------> The number of times this entry is hit
+ *
+ * (note: the average latency is the accumulated latency divided by the number
+ * of times)
+ */
+
#include <linux/latencytop.h>
#include <linux/kallsyms.h>
#include <linux/seq_file.h>
@@ -72,7 +110,7 @@ account_global_scheduler_latency(struct task_struct *tsk, struct latency_record
firstnonnull = i;
continue;
}
- for (q = 0 ; q < LT_BACKTRACEDEPTH ; q++) {
+ for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
unsigned long record = lat->backtrace[q];
if (latency_record[i].backtrace[q] != record) {
@@ -101,31 +139,52 @@ account_global_scheduler_latency(struct task_struct *tsk, struct latency_record
memcpy(&latency_record[i], lat, sizeof(struct latency_record));
}
-static inline void store_stacktrace(struct task_struct *tsk, struct latency_record *lat)
+/*
+ * Iterator to store a backtrace into a latency record entry
+ */
+static inline void store_stacktrace(struct task_struct *tsk,
+ struct latency_record *lat)
{
struct stack_trace trace;
memset(&trace, 0, sizeof(trace));
trace.max_entries = LT_BACKTRACEDEPTH;
trace.entries = &lat->backtrace[0];
- trace.skip = 0;
save_stack_trace_tsk(tsk, &trace);
}
+/**
+ * __account_scheduler_latency - record an occured latency
+ * @tsk - the task struct of the task hitting the latency
+ * @usecs - the duration of the latency in microseconds
+ * @inter - 1 if the sleep was interruptible, 0 if uninterruptible
+ *
+ * This function is the main entry point for recording latency entries
+ * as called by the scheduler.
+ *
+ * This function has a few special cases to deal with normal 'non-latency'
+ * sleeps: specifically, interruptible sleep longer than 5 msec is skipped
+ * since this usually is caused by waiting for events via select() and co.
+ *
+ * Negative latencies (caused by time going backwards) are also explicitly
+ * skipped.
+ */
void __sched
-account_scheduler_latency(struct task_struct *tsk, int usecs, int inter)
+__account_scheduler_latency(struct task_struct *tsk, int usecs, int inter)
{
unsigned long flags;
int i, q;
struct latency_record lat;
- if (!latencytop_enabled)
- return;
-
/* Long interruptible waits are generally user requested... */
if (inter && usecs > 5000)
return;
+ /* Negative sleeps are time going backwards */
+ /* Zero-time sleeps are non-interesting */
+ if (usecs <= 0)
+ return;
+
memset(&lat, 0, sizeof(lat));
lat.count = 1;
lat.time = usecs;
@@ -143,12 +202,12 @@ account_scheduler_latency(struct task_struct *tsk, int usecs, int inter)
if (tsk->latency_record_count >= LT_SAVECOUNT)
goto out_unlock;
- for (i = 0; i < LT_SAVECOUNT ; i++) {
+ for (i = 0; i < LT_SAVECOUNT; i++) {
struct latency_record *mylat;
int same = 1;
mylat = &tsk->latency_record[i];
- for (q = 0 ; q < LT_BACKTRACEDEPTH ; q++) {
+ for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
unsigned long record = lat.backtrace[q];
if (mylat->backtrace[q] != record) {
@@ -186,7 +245,7 @@ static int lstats_show(struct seq_file *m, void *v)
for (i = 0; i < MAXLR; i++) {
if (latency_record[i].backtrace[0]) {
int q;
- seq_printf(m, "%i %li %li ",
+ seq_printf(m, "%i %lu %lu ",
latency_record[i].count,
latency_record[i].time,
latency_record[i].max);
@@ -223,7 +282,7 @@ static int lstats_open(struct inode *inode, struct file *filp)
return single_open(filp, lstats_show, NULL);
}
-static struct file_operations lstats_fops = {
+static const struct file_operations lstats_fops = {
.open = lstats_open,
.read = seq_read,
.write = lstats_write,
@@ -236,4 +295,4 @@ static int __init init_lstats_procfs(void)
proc_create("latency_stats", 0644, NULL, &lstats_fops);
return 0;
}
-__initcall(init_lstats_procfs);
+device_initcall(init_lstats_procfs);
diff --git a/kernel/rcuclassic.c b/kernel/rcuclassic.c
index bd5a900..654c640 100644
--- a/kernel/rcuclassic.c
+++ b/kernel/rcuclassic.c
@@ -679,8 +679,8 @@ int rcu_needs_cpu(int cpu)
void rcu_check_callbacks(int cpu, int user)
{
if (user ||
- (idle_cpu(cpu) && !in_softirq() &&
- hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
+ (idle_cpu(cpu) && rcu_scheduler_active &&
+ !in_softirq() && hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
/*
* Get here if this CPU took its interrupt from user
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index d92a76a..cae8a05 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -44,6 +44,7 @@
#include <linux/cpu.h>
#include <linux/mutex.h>
#include <linux/module.h>
+#include <linux/kernel_stat.h>
enum rcu_barrier {
RCU_BARRIER_STD,
@@ -55,6 +56,7 @@ static DEFINE_PER_CPU(struct rcu_head, rcu_barrier_head) = {NULL};
static atomic_t rcu_barrier_cpu_count;
static DEFINE_MUTEX(rcu_barrier_mutex);
static struct completion rcu_barrier_completion;
+int rcu_scheduler_active __read_mostly;
/*
* Awaken the corresponding synchronize_rcu() instance now that a
@@ -80,6 +82,10 @@ void wakeme_after_rcu(struct rcu_head *head)
void synchronize_rcu(void)
{
struct rcu_synchronize rcu;
+
+ if (rcu_blocking_is_gp())
+ return;
+
init_completion(&rcu.completion);
/* Will wake me after RCU finished. */
call_rcu(&rcu.head, wakeme_after_rcu);
@@ -175,3 +181,9 @@ void __init rcu_init(void)
__rcu_init();
}
+void rcu_scheduler_starting(void)
+{
+ WARN_ON(num_online_cpus() != 1);
+ WARN_ON(nr_context_switches() > 0);
+ rcu_scheduler_active = 1;
+}
diff --git a/kernel/rcupreempt.c b/kernel/rcupreempt.c
index 33cfc50..5d59e85 100644
--- a/kernel/rcupreempt.c
+++ b/kernel/rcupreempt.c
@@ -1181,6 +1181,9 @@ void __synchronize_sched(void)
{
struct rcu_synchronize rcu;
+ if (num_online_cpus() == 1)
+ return; /* blocking is gp if only one CPU! */
+
init_completion(&rcu.completion);
/* Will wake me after RCU finished. */
call_rcu_sched(&rcu.head, wakeme_after_rcu);
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index b2fd602..97ce315 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -948,8 +948,8 @@ static void rcu_do_batch(struct rcu_data *rdp)
void rcu_check_callbacks(int cpu, int user)
{
if (user ||
- (idle_cpu(cpu) && !in_softirq() &&
- hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
+ (idle_cpu(cpu) && rcu_scheduler_active &&
+ !in_softirq() && hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
/*
* Get here if this CPU took its interrupt from user
diff --git a/kernel/sched.c b/kernel/sched.c
index 410eec4..2f28351 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -223,7 +223,7 @@ static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
{
ktime_t now;
- if (rt_bandwidth_enabled() && 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))
@@ -331,6 +331,13 @@ static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp;
*/
static DEFINE_SPINLOCK(task_group_lock);
+#ifdef CONFIG_SMP
+static int root_task_group_empty(void)
+{
+ return list_empty(&root_task_group.children);
+}
+#endif
+
#ifdef CONFIG_FAIR_GROUP_SCHED
#ifdef CONFIG_USER_SCHED
# define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
@@ -391,6 +398,13 @@ static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
#else
+#ifdef CONFIG_SMP
+static int root_task_group_empty(void)
+{
+ return 1;
+}
+#endif
+
static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
static inline struct task_group *task_group(struct task_struct *p)
{
@@ -467,11 +481,17 @@ struct rt_rq {
struct rt_prio_array active;
unsigned long rt_nr_running;
#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
- int highest_prio; /* highest queued rt task prio */
+ struct {
+ int curr; /* highest queued rt task prio */
+#ifdef CONFIG_SMP
+ int next; /* next highest */
+#endif
+ } highest_prio;
#endif
#ifdef CONFIG_SMP
unsigned long rt_nr_migratory;
int overloaded;
+ struct plist_head pushable_tasks;
#endif
int rt_throttled;
u64 rt_time;
@@ -549,7 +569,6 @@ struct rq {
unsigned long nr_running;
#define CPU_LOAD_IDX_MAX 5
unsigned long cpu_load[CPU_LOAD_IDX_MAX];
- unsigned char idle_at_tick;
#ifdef CONFIG_NO_HZ
unsigned long last_tick_seen;
unsigned char in_nohz_recently;
@@ -590,6 +609,7 @@ struct rq {
struct root_domain *rd;
struct sched_domain *sd;
+ unsigned char idle_at_tick;
/* For active balancing */
int active_balance;
int push_cpu;
@@ -1183,10 +1203,10 @@ static void resched_task(struct task_struct *p)
assert_spin_locked(&task_rq(p)->lock);
- if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED)))
+ if (test_tsk_need_resched(p))
return;
- set_tsk_thread_flag(p, TIF_NEED_RESCHED);
+ set_tsk_need_resched(p);
cpu = task_cpu(p);
if (cpu == smp_processor_id())
@@ -1242,7 +1262,7 @@ void wake_up_idle_cpu(int cpu)
* lockless. The worst case is that the other CPU runs the
* idle task through an additional NOOP schedule()
*/
- set_tsk_thread_flag(rq->idle, TIF_NEED_RESCHED);
+ set_tsk_need_resched(rq->idle);
/* NEED_RESCHED must be visible before we test polling */
smp_mb();
@@ -1610,21 +1630,42 @@ static inline void update_shares_locked(struct rq *rq, struct sched_domain *sd)
#endif
+#ifdef CONFIG_PREEMPT
+
/*
- * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
+ * fair double_lock_balance: Safely acquires both rq->locks in a fair
+ * way at the expense of forcing extra atomic operations in all
+ * invocations. This assures that the double_lock is acquired using the
+ * same underlying policy as the spinlock_t on this architecture, which
+ * reduces latency compared to the unfair variant below. However, it
+ * also adds more overhead and therefore may reduce throughput.
*/
-static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
+static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
+ __releases(this_rq->lock)
+ __acquires(busiest->lock)
+ __acquires(this_rq->lock)
+{
+ spin_unlock(&this_rq->lock);
+ double_rq_lock(this_rq, busiest);
+
+ return 1;
+}
+
+#else
+/*
+ * Unfair double_lock_balance: Optimizes throughput at the expense of
+ * latency by eliminating extra atomic operations when the locks are
+ * already in proper order on entry. This favors lower cpu-ids and will
+ * grant the double lock to lower cpus over higher ids under contention,
+ * regardless of entry order into the function.
+ */
+static int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
__releases(this_rq->lock)
__acquires(busiest->lock)
__acquires(this_rq->lock)
{
int ret = 0;
- if (unlikely(!irqs_disabled())) {
- /* printk() doesn't work good under rq->lock */
- spin_unlock(&this_rq->lock);
- BUG_ON(1);
- }
if (unlikely(!spin_trylock(&busiest->lock))) {
if (busiest < this_rq) {
spin_unlock(&this_rq->lock);
@@ -1637,6 +1678,22 @@ static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
return ret;
}
+#endif /* CONFIG_PREEMPT */
+
+/*
+ * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
+ */
+static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
+{
+ if (unlikely(!irqs_disabled())) {
+ /* printk() doesn't work good under rq->lock */
+ spin_unlock(&this_rq->lock);
+ BUG_ON(1);
+ }
+
+ return _double_lock_balance(this_rq, busiest);
+}
+
static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
__releases(busiest->lock)
{
@@ -1705,6 +1762,9 @@ static void update_avg(u64 *avg, u64 sample)
static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup)
{
+ if (wakeup)
+ p->se.start_runtime = p->se.sum_exec_runtime;
+
sched_info_queued(p);
p->sched_class->enqueue_task(rq, p, wakeup);
p->se.on_rq = 1;
@@ -1712,10 +1772,15 @@ static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup)
static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
{
- if (sleep && p->se.last_wakeup) {
- update_avg(&p->se.avg_overlap,
- p->se.sum_exec_runtime - p->se.last_wakeup);
- p->se.last_wakeup = 0;
+ if (sleep) {
+ if (p->se.last_wakeup) {
+ update_avg(&p->se.avg_overlap,
+ p->se.sum_exec_runtime - p->se.last_wakeup);
+ p->se.last_wakeup = 0;
+ } else {
+ update_avg(&p->se.avg_wakeup,
+ sysctl_sched_wakeup_granularity);
+ }
}
sched_info_dequeued(p);
@@ -2267,7 +2332,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
sync = 0;
#ifdef CONFIG_SMP
- if (sched_feat(LB_WAKEUP_UPDATE)) {
+ if (sched_feat(LB_WAKEUP_UPDATE) && !root_task_group_empty()) {
struct sched_domain *sd;
this_cpu = raw_smp_processor_id();
@@ -2345,6 +2410,22 @@ out_activate:
activate_task(rq, p, 1);
success = 1;
+ /*
+ * Only attribute actual wakeups done by this task.
+ */
+ if (!in_interrupt()) {
+ struct sched_entity *se = &current->se;
+ u64 sample = se->sum_exec_runtime;
+
+ if (se->last_wakeup)
+ sample -= se->last_wakeup;
+ else
+ sample -= se->start_runtime;
+ update_avg(&se->avg_wakeup, sample);
+
+ se->last_wakeup = se->sum_exec_runtime;
+ }
+
out_running:
trace_sched_wakeup(rq, p, success);
check_preempt_curr(rq, p, sync);
@@ -2355,8 +2436,6 @@ out_running:
p->sched_class->task_wake_up(rq, p);
#endif
out:
- current->se.last_wakeup = current->se.sum_exec_runtime;
-
task_rq_unlock(rq, &flags);
return success;
@@ -2386,6 +2465,8 @@ static void __sched_fork(struct task_struct *p)
p->se.prev_sum_exec_runtime = 0;
p->se.last_wakeup = 0;
p->se.avg_overlap = 0;
+ p->se.start_runtime = 0;
+ p->se.avg_wakeup = sysctl_sched_wakeup_granularity;
#ifdef CONFIG_SCHEDSTATS
p->se.wait_start = 0;
@@ -2448,6 +2529,8 @@ void sched_fork(struct task_struct *p, int clone_flags)
/* Want to start with kernel preemption disabled. */
task_thread_info(p)->preempt_count = 1;
#endif
+ plist_node_init(&p->pushable_tasks, MAX_PRIO);
+
put_cpu();
}
@@ -2588,6 +2671,12 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
{
struct mm_struct *mm = rq->prev_mm;
long prev_state;
+#ifdef CONFIG_SMP
+ int post_schedule = 0;
+
+ if (current->sched_class->needs_post_schedule)
+ post_schedule = current->sched_class->needs_post_schedule(rq);
+#endif
rq->prev_mm = NULL;
@@ -2606,7 +2695,7 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
finish_arch_switch(prev);
finish_lock_switch(rq, prev);
#ifdef CONFIG_SMP
- if (current->sched_class->post_schedule)
+ if (post_schedule)
current->sched_class->post_schedule(rq);
#endif
@@ -2987,6 +3076,16 @@ next:
pulled++;
rem_load_move -= p->se.load.weight;
+#ifdef CONFIG_PREEMPT
+ /*
+ * NEWIDLE balancing is a source of latency, so preemptible kernels
+ * will stop after the first task is pulled to minimize the critical
+ * section.
+ */
+ if (idle == CPU_NEWLY_IDLE)
+ goto out;
+#endif
+
/*
* We only want to steal up to the prescribed amount of weighted load.
*/
@@ -3033,9 +3132,15 @@ static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
sd, idle, all_pinned, &this_best_prio);
class = class->next;
+#ifdef CONFIG_PREEMPT
+ /*
+ * NEWIDLE balancing is a source of latency, so preemptible
+ * kernels will stop after the first task is pulled to minimize
+ * the critical section.
+ */
if (idle == CPU_NEWLY_IDLE && this_rq->nr_running)
break;
-
+#endif
} while (class && max_load_move > total_load_moved);
return total_load_moved > 0;
@@ -4057,6 +4162,11 @@ static void run_rebalance_domains(struct softirq_action *h)
#endif
}
+static inline int on_null_domain(int cpu)
+{
+ return !rcu_dereference(cpu_rq(cpu)->sd);
+}
+
/*
* Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
*
@@ -4114,7 +4224,9 @@ static inline void trigger_load_balance(struct rq *rq, int cpu)
cpumask_test_cpu(cpu, nohz.cpu_mask))
return;
#endif
- if (time_after_eq(jiffies, rq->next_balance))
+ /* Don't need to rebalance while attached to NULL domain */
+ if (time_after_eq(jiffies, rq->next_balance) &&
+ likely(!on_null_domain(cpu)))
raise_softirq(SCHED_SOFTIRQ);
}
@@ -4508,11 +4620,33 @@ static inline void schedule_debug(struct task_struct *prev)
#endif
}
+static void put_prev_task(struct rq *rq, struct task_struct *prev)
+{
+ if (prev->state == TASK_RUNNING) {
+ u64 runtime = prev->se.sum_exec_runtime;
+
+ runtime -= prev->se.prev_sum_exec_runtime;
+ runtime = min_t(u64, runtime, 2*sysctl_sched_migration_cost);
+
+ /*
+ * In order to avoid avg_overlap growing stale when we are
+ * indeed overlapping and hence not getting put to sleep, grow
+ * the avg_overlap on preemption.
+ *
+ * We use the average preemption runtime because that
+ * correlates to the amount of cache footprint a task can
+ * build up.
+ */
+ update_avg(&prev->se.avg_overlap, runtime);
+ }
+ prev->sched_class->put_prev_task(rq, prev);
+}
+
/*
* Pick up the highest-prio task:
*/
static inline struct task_struct *
-pick_next_task(struct rq *rq, struct task_struct *prev)
+pick_next_task(struct rq *rq)
{
const struct sched_class *class;
struct task_struct *p;
@@ -4586,8 +4720,8 @@ need_resched_nonpreemptible:
if (unlikely(!rq->nr_running))
idle_balance(cpu, rq);
- prev->sched_class->put_prev_task(rq, prev);
- next = pick_next_task(rq, prev);
+ put_prev_task(rq, prev);
+ next = pick_next_task(rq);
if (likely(prev != next)) {
sched_info_switch(prev, next);
@@ -4642,7 +4776,7 @@ asmlinkage void __sched preempt_schedule(void)
* between schedule and now.
*/
barrier();
- } while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
+ } while (need_resched());
}
EXPORT_SYMBOL(preempt_schedule);
@@ -4671,7 +4805,7 @@ asmlinkage void __sched preempt_schedule_irq(void)
* between schedule and now.
*/
barrier();
- } while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
+ } while (need_resched());
}
#endif /* CONFIG_PREEMPT */
@@ -5145,7 +5279,7 @@ SYSCALL_DEFINE1(nice, int, increment)
if (increment > 40)
increment = 40;
- nice = PRIO_TO_NICE(current->static_prio) + increment;
+ nice = TASK_NICE(current) + increment;
if (nice < -20)
nice = -20;
if (nice > 19)
@@ -6423,7 +6557,7 @@ static void migrate_dead_tasks(unsigned int dead_cpu)
if (!rq->nr_running)
break;
update_rq_clock(rq);
- next = pick_next_task(rq, rq->curr);
+ next = pick_next_task(rq);
if (!next)
break;
next->sched_class->put_prev_task(rq, next);
@@ -8218,11 +8352,15 @@ static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
__set_bit(MAX_RT_PRIO, array->bitmap);
#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
- rt_rq->highest_prio = MAX_RT_PRIO;
+ rt_rq->highest_prio.curr = MAX_RT_PRIO;
+#ifdef CONFIG_SMP
+ rt_rq->highest_prio.next = MAX_RT_PRIO;
+#endif
#endif
#ifdef CONFIG_SMP
rt_rq->rt_nr_migratory = 0;
rt_rq->overloaded = 0;
+ plist_head_init(&rq->rt.pushable_tasks, &rq->lock);
#endif
rt_rq->rt_time = 0;
@@ -9224,6 +9362,16 @@ static int sched_rt_global_constraints(void)
return ret;
}
+
+int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
+{
+ /* Don't accept realtime tasks when there is no way for them to run */
+ if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
+ return 0;
+
+ return 1;
+}
+
#else /* !CONFIG_RT_GROUP_SCHED */
static int sched_rt_global_constraints(void)
{
@@ -9317,8 +9465,7 @@ cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct task_struct *tsk)
{
#ifdef CONFIG_RT_GROUP_SCHED
- /* Don't accept realtime tasks when there is no way for them to run */
- if (rt_task(tsk) && cgroup_tg(cgrp)->rt_bandwidth.rt_runtime == 0)
+ if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk))
return -EINVAL;
#else
/* We don't support RT-tasks being in separate groups */
@@ -9589,7 +9736,7 @@ static void cpuacct_charge(struct task_struct *tsk, u64 cputime)
struct cpuacct *ca;
int cpu;
- if (!cpuacct_subsys.active)
+ if (unlikely(!cpuacct_subsys.active))
return;
cpu = task_cpu(tsk);
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index 16eeba4e..2b1260f 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -397,6 +397,7 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
PN(se.vruntime);
PN(se.sum_exec_runtime);
PN(se.avg_overlap);
+ PN(se.avg_wakeup);
nr_switches = p->nvcsw + p->nivcsw;
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 0566f2a..3816f21 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1314,16 +1314,63 @@ out:
}
#endif /* CONFIG_SMP */
-static unsigned long wakeup_gran(struct sched_entity *se)
+/*
+ * Adaptive granularity
+ *
+ * se->avg_wakeup gives the average time a task runs until it does a wakeup,
+ * with the limit of wakeup_gran -- when it never does a wakeup.
+ *
+ * So the smaller avg_wakeup is the faster we want this task to preempt,
+ * but we don't want to treat the preemptee unfairly and therefore allow it
+ * to run for at least the amount of time we'd like to run.
+ *
+ * NOTE: we use 2*avg_wakeup to increase the probability of actually doing one
+ *
+ * NOTE: we use *nr_running to scale with load, this nicely matches the
+ * degrading latency on load.
+ */
+static unsigned long
+adaptive_gran(struct sched_entity *curr, struct sched_entity *se)
+{
+ u64 this_run = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
+ u64 expected_wakeup = 2*se->avg_wakeup * cfs_rq_of(se)->nr_running;
+ u64 gran = 0;
+
+ if (this_run < expected_wakeup)
+ gran = expected_wakeup - this_run;
+
+ return min_t(s64, gran, sysctl_sched_wakeup_granularity);
+}
+
+static unsigned long
+wakeup_gran(struct sched_entity *curr, struct sched_entity *se)
{
unsigned long gran = sysctl_sched_wakeup_granularity;
+ if (cfs_rq_of(curr)->curr && sched_feat(ADAPTIVE_GRAN))
+ gran = adaptive_gran(curr, se);
+
/*
- * More easily preempt - nice tasks, while not making it harder for
- * + nice tasks.
+ * Since its curr running now, convert the gran from real-time
+ * to virtual-time in his units.
*/
- if (!sched_feat(ASYM_GRAN) || se->load.weight > NICE_0_LOAD)
- gran = calc_delta_fair(sysctl_sched_wakeup_granularity, se);
+ if (sched_feat(ASYM_GRAN)) {
+ /*
+ * By using 'se' instead of 'curr' we penalize light tasks, so
+ * they get preempted easier. That is, if 'se' < 'curr' then
+ * the resulting gran will be larger, therefore penalizing the
+ * lighter, if otoh 'se' > 'curr' then the resulting gran will
+ * be smaller, again penalizing the lighter task.
+ *
+ * This is especially important for buddies when the leftmost
+ * task is higher priority than the buddy.
+ */
+ if (unlikely(se->load.weight != NICE_0_LOAD))
+ gran = calc_delta_fair(gran, se);
+ } else {
+ if (unlikely(curr->load.weight != NICE_0_LOAD))
+ gran = calc_delta_fair(gran, curr);
+ }
return gran;
}
@@ -1350,7 +1397,7 @@ wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
if (vdiff <= 0)
return -1;
- gran = wakeup_gran(curr);
+ gran = wakeup_gran(curr, se);
if (vdiff > gran)
return 1;
diff --git a/kernel/sched_features.h b/kernel/sched_features.h
index da5d93b..76f6175 100644
--- a/kernel/sched_features.h
+++ b/kernel/sched_features.h
@@ -1,5 +1,6 @@
SCHED_FEAT(NEW_FAIR_SLEEPERS, 1)
-SCHED_FEAT(NORMALIZED_SLEEPER, 1)
+SCHED_FEAT(NORMALIZED_SLEEPER, 0)
+SCHED_FEAT(ADAPTIVE_GRAN, 1)
SCHED_FEAT(WAKEUP_PREEMPT, 1)
SCHED_FEAT(START_DEBIT, 1)
SCHED_FEAT(AFFINE_WAKEUPS, 1)
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index bac1061..c79dc78 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -3,6 +3,40 @@
* policies)
*/
+static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
+{
+ return container_of(rt_se, struct task_struct, rt);
+}
+
+#ifdef CONFIG_RT_GROUP_SCHED
+
+static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
+{
+ return rt_rq->rq;
+}
+
+static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
+{
+ return rt_se->rt_rq;
+}
+
+#else /* CONFIG_RT_GROUP_SCHED */
+
+static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
+{
+ return container_of(rt_rq, struct rq, rt);
+}
+
+static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
+{
+ struct task_struct *p = rt_task_of(rt_se);
+ struct rq *rq = task_rq(p);
+
+ return &rq->rt;
+}
+
+#endif /* CONFIG_RT_GROUP_SCHED */
+
#ifdef CONFIG_SMP
static inline int rt_overloaded(struct rq *rq)
@@ -37,25 +71,69 @@ static inline void rt_clear_overload(struct rq *rq)
cpumask_clear_cpu(rq->cpu, rq->rd->rto_mask);
}
-static void update_rt_migration(struct rq *rq)
+static void update_rt_migration(struct rt_rq *rt_rq)
{
- if (rq->rt.rt_nr_migratory && (rq->rt.rt_nr_running > 1)) {
- if (!rq->rt.overloaded) {
- rt_set_overload(rq);
- rq->rt.overloaded = 1;
+ if (rt_rq->rt_nr_migratory && (rt_rq->rt_nr_running > 1)) {
+ if (!rt_rq->overloaded) {
+ rt_set_overload(rq_of_rt_rq(rt_rq));
+ rt_rq->overloaded = 1;
}
- } else if (rq->rt.overloaded) {
- rt_clear_overload(rq);
- rq->rt.overloaded = 0;
+ } else if (rt_rq->overloaded) {
+ rt_clear_overload(rq_of_rt_rq(rt_rq));
+ rt_rq->overloaded = 0;
}
}
-#endif /* CONFIG_SMP */
-static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
+static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+ if (rt_se->nr_cpus_allowed > 1)
+ rt_rq->rt_nr_migratory++;
+
+ update_rt_migration(rt_rq);
+}
+
+static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+ if (rt_se->nr_cpus_allowed > 1)
+ rt_rq->rt_nr_migratory--;
+
+ update_rt_migration(rt_rq);
+}
+
+static void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
+{
+ plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
+ plist_node_init(&p->pushable_tasks, p->prio);
+ plist_add(&p->pushable_tasks, &rq->rt.pushable_tasks);
+}
+
+static void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
+{
+ plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
+}
+
+#else
+
+static inline void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
{
- return container_of(rt_se, struct task_struct, rt);
}
+static inline void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline
+void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+}
+
+static inline
+void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+}
+
+#endif /* CONFIG_SMP */
+
static inline int on_rt_rq(struct sched_rt_entity *rt_se)
{
return !list_empty(&rt_se->run_list);
@@ -79,16 +157,6 @@ static inline u64 sched_rt_period(struct rt_rq *rt_rq)
#define for_each_leaf_rt_rq(rt_rq, rq) \
list_for_each_entry_rcu(rt_rq, &rq->leaf_rt_rq_list, leaf_rt_rq_list)
-static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
-{
- return rt_rq->rq;
-}
-
-static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
-{
- return rt_se->rt_rq;
-}
-
#define for_each_sched_rt_entity(rt_se) \
for (; rt_se; rt_se = rt_se->parent)
@@ -108,7 +176,7 @@ static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
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)
+ if (rt_rq->highest_prio.curr < curr->prio)
resched_task(curr);
}
}
@@ -176,19 +244,6 @@ static inline u64 sched_rt_period(struct rt_rq *rt_rq)
#define for_each_leaf_rt_rq(rt_rq, rq) \
for (rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
-static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
-{
- return container_of(rt_rq, struct rq, rt);
-}
-
-static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
-{
- struct task_struct *p = rt_task_of(rt_se);
- struct rq *rq = task_rq(p);
-
- return &rq->rt;
-}
-
#define for_each_sched_rt_entity(rt_se) \
for (; rt_se; rt_se = NULL)
@@ -473,7 +528,7 @@ static inline int rt_se_prio(struct sched_rt_entity *rt_se)
struct rt_rq *rt_rq = group_rt_rq(rt_se);
if (rt_rq)
- return rt_rq->highest_prio;
+ return rt_rq->highest_prio.curr;
#endif
return rt_task_of(rt_se)->prio;
@@ -547,91 +602,174 @@ static void update_curr_rt(struct rq *rq)
}
}
-static inline
-void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+#if defined CONFIG_SMP
+
+static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu);
+
+static inline int next_prio(struct rq *rq)
{
- WARN_ON(!rt_prio(rt_se_prio(rt_se)));
- 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
+ struct task_struct *next = pick_next_highest_task_rt(rq, rq->cpu);
+
+ if (next && rt_prio(next->prio))
+ return next->prio;
+ else
+ return MAX_RT_PRIO;
+}
+
+static void
+inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
+{
+ struct rq *rq = rq_of_rt_rq(rt_rq);
+
+ if (prio < prev_prio) {
+
+ /*
+ * If the new task is higher in priority than anything on the
+ * run-queue, we know that the previous high becomes our
+ * next-highest.
+ */
+ rt_rq->highest_prio.next = prev_prio;
- rt_rq->highest_prio = rt_se_prio(rt_se);
-#ifdef CONFIG_SMP
if (rq->online)
- cpupri_set(&rq->rd->cpupri, rq->cpu,
- rt_se_prio(rt_se));
-#endif
- }
-#endif
-#ifdef CONFIG_SMP
- if (rt_se->nr_cpus_allowed > 1) {
- struct rq *rq = rq_of_rt_rq(rt_rq);
+ cpupri_set(&rq->rd->cpupri, rq->cpu, prio);
- rq->rt.rt_nr_migratory++;
- }
+ } else if (prio == rt_rq->highest_prio.curr)
+ /*
+ * If the next task is equal in priority to the highest on
+ * the run-queue, then we implicitly know that the next highest
+ * task cannot be any lower than current
+ */
+ rt_rq->highest_prio.next = prio;
+ else if (prio < rt_rq->highest_prio.next)
+ /*
+ * Otherwise, we need to recompute next-highest
+ */
+ rt_rq->highest_prio.next = next_prio(rq);
+}
- update_rt_migration(rq_of_rt_rq(rt_rq));
-#endif
-#ifdef CONFIG_RT_GROUP_SCHED
- if (rt_se_boosted(rt_se))
- rt_rq->rt_nr_boosted++;
+static void
+dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
+{
+ struct rq *rq = rq_of_rt_rq(rt_rq);
- if (rt_rq->tg)
- start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
-#else
- start_rt_bandwidth(&def_rt_bandwidth);
-#endif
+ if (rt_rq->rt_nr_running && (prio <= rt_rq->highest_prio.next))
+ rt_rq->highest_prio.next = next_prio(rq);
+
+ if (rq->online && rt_rq->highest_prio.curr != prev_prio)
+ cpupri_set(&rq->rd->cpupri, rq->cpu, rt_rq->highest_prio.curr);
}
+#else /* CONFIG_SMP */
+
static inline
-void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
-{
-#ifdef CONFIG_SMP
- int highest_prio = rt_rq->highest_prio;
-#endif
+void inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
+static inline
+void dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
+
+#endif /* CONFIG_SMP */
- WARN_ON(!rt_prio(rt_se_prio(rt_se)));
- WARN_ON(!rt_rq->rt_nr_running);
- rt_rq->rt_nr_running--;
#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
+static void
+inc_rt_prio(struct rt_rq *rt_rq, int prio)
+{
+ int prev_prio = rt_rq->highest_prio.curr;
+
+ if (prio < prev_prio)
+ rt_rq->highest_prio.curr = prio;
+
+ inc_rt_prio_smp(rt_rq, prio, prev_prio);
+}
+
+static void
+dec_rt_prio(struct rt_rq *rt_rq, int prio)
+{
+ int prev_prio = rt_rq->highest_prio.curr;
+
if (rt_rq->rt_nr_running) {
- struct rt_prio_array *array;
- WARN_ON(rt_se_prio(rt_se) < rt_rq->highest_prio);
- if (rt_se_prio(rt_se) == rt_rq->highest_prio) {
- /* recalculate */
- array = &rt_rq->active;
- rt_rq->highest_prio =
+ WARN_ON(prio < prev_prio);
+
+ /*
+ * This may have been our highest task, and therefore
+ * we may have some recomputation to do
+ */
+ if (prio == prev_prio) {
+ struct rt_prio_array *array = &rt_rq->active;
+
+ rt_rq->highest_prio.curr =
sched_find_first_bit(array->bitmap);
- } /* otherwise leave rq->highest prio alone */
+ }
+
} else
- rt_rq->highest_prio = MAX_RT_PRIO;
-#endif
-#ifdef CONFIG_SMP
- if (rt_se->nr_cpus_allowed > 1) {
- struct rq *rq = rq_of_rt_rq(rt_rq);
- rq->rt.rt_nr_migratory--;
- }
+ rt_rq->highest_prio.curr = MAX_RT_PRIO;
- if (rt_rq->highest_prio != highest_prio) {
- struct rq *rq = rq_of_rt_rq(rt_rq);
+ dec_rt_prio_smp(rt_rq, prio, prev_prio);
+}
- if (rq->online)
- cpupri_set(&rq->rd->cpupri, rq->cpu,
- rt_rq->highest_prio);
- }
+#else
+
+static inline void inc_rt_prio(struct rt_rq *rt_rq, int prio) {}
+static inline void dec_rt_prio(struct rt_rq *rt_rq, int prio) {}
+
+#endif /* CONFIG_SMP || CONFIG_RT_GROUP_SCHED */
- update_rt_migration(rq_of_rt_rq(rt_rq));
-#endif /* CONFIG_SMP */
#ifdef CONFIG_RT_GROUP_SCHED
+
+static void
+inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+ if (rt_se_boosted(rt_se))
+ rt_rq->rt_nr_boosted++;
+
+ if (rt_rq->tg)
+ start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
+}
+
+static void
+dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
if (rt_se_boosted(rt_se))
rt_rq->rt_nr_boosted--;
WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted);
-#endif
+}
+
+#else /* CONFIG_RT_GROUP_SCHED */
+
+static void
+inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+ start_rt_bandwidth(&def_rt_bandwidth);
+}
+
+static inline
+void dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) {}
+
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+static inline
+void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+ int prio = rt_se_prio(rt_se);
+
+ WARN_ON(!rt_prio(prio));
+ rt_rq->rt_nr_running++;
+
+ inc_rt_prio(rt_rq, prio);
+ inc_rt_migration(rt_se, rt_rq);
+ inc_rt_group(rt_se, rt_rq);
+}
+
+static inline
+void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+ WARN_ON(!rt_prio(rt_se_prio(rt_se)));
+ WARN_ON(!rt_rq->rt_nr_running);
+ rt_rq->rt_nr_running--;
+
+ dec_rt_prio(rt_rq, rt_se_prio(rt_se));
+ dec_rt_migration(rt_se, rt_rq);
+ dec_rt_group(rt_se, rt_rq);
}
static void __enqueue_rt_entity(struct sched_rt_entity *rt_se)
@@ -718,6 +856,9 @@ static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup)
enqueue_rt_entity(rt_se);
+ if (!task_current(rq, p) && p->rt.nr_cpus_allowed > 1)
+ enqueue_pushable_task(rq, p);
+
inc_cpu_load(rq, p->se.load.weight);
}
@@ -728,6 +869,8 @@ static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep)
update_curr_rt(rq);
dequeue_rt_entity(rt_se);
+ dequeue_pushable_task(rq, p);
+
dec_cpu_load(rq, p->se.load.weight);
}
@@ -878,7 +1021,7 @@ static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
return next;
}
-static struct task_struct *pick_next_task_rt(struct rq *rq)
+static struct task_struct *_pick_next_task_rt(struct rq *rq)
{
struct sched_rt_entity *rt_se;
struct task_struct *p;
@@ -900,6 +1043,18 @@ static struct task_struct *pick_next_task_rt(struct rq *rq)
p = rt_task_of(rt_se);
p->se.exec_start = rq->clock;
+
+ return p;
+}
+
+static struct task_struct *pick_next_task_rt(struct rq *rq)
+{
+ struct task_struct *p = _pick_next_task_rt(rq);
+
+ /* The running task is never eligible for pushing */
+ if (p)
+ dequeue_pushable_task(rq, p);
+
return p;
}
@@ -907,6 +1062,13 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
{
update_curr_rt(rq);
p->se.exec_start = 0;
+
+ /*
+ * The previous task needs to be made eligible for pushing
+ * if it is still active
+ */
+ if (p->se.on_rq && p->rt.nr_cpus_allowed > 1)
+ enqueue_pushable_task(rq, p);
}
#ifdef CONFIG_SMP
@@ -1072,7 +1234,7 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
}
/* If this rq is still suitable use it. */
- if (lowest_rq->rt.highest_prio > task->prio)
+ if (lowest_rq->rt.highest_prio.curr > task->prio)
break;
/* try again */
@@ -1083,6 +1245,31 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
return lowest_rq;
}
+static inline int has_pushable_tasks(struct rq *rq)
+{
+ return !plist_head_empty(&rq->rt.pushable_tasks);
+}
+
+static struct task_struct *pick_next_pushable_task(struct rq *rq)
+{
+ struct task_struct *p;
+
+ if (!has_pushable_tasks(rq))
+ return NULL;
+
+ p = plist_first_entry(&rq->rt.pushable_tasks,
+ struct task_struct, pushable_tasks);
+
+ BUG_ON(rq->cpu != task_cpu(p));
+ BUG_ON(task_current(rq, p));
+ BUG_ON(p->rt.nr_cpus_allowed <= 1);
+
+ BUG_ON(!p->se.on_rq);
+ BUG_ON(!rt_task(p));
+
+ return p;
+}
+
/*
* If the current CPU has more than one RT task, see if the non
* running task can migrate over to a CPU that is running a task
@@ -1092,13 +1279,11 @@ static int push_rt_task(struct rq *rq)
{
struct task_struct *next_task;
struct rq *lowest_rq;
- int ret = 0;
- int paranoid = RT_MAX_TRIES;
if (!rq->rt.overloaded)
return 0;
- next_task = pick_next_highest_task_rt(rq, -1);
+ next_task = pick_next_pushable_task(rq);
if (!next_task)
return 0;
@@ -1127,16 +1312,34 @@ static int push_rt_task(struct rq *rq)
struct task_struct *task;
/*
* find lock_lowest_rq releases rq->lock
- * so it is possible that next_task has changed.
- * If it has, then try again.
+ * so it is possible that next_task has migrated.
+ *
+ * We need to make sure that the task is still on the same
+ * run-queue and is also still the next task eligible for
+ * pushing.
*/
- task = pick_next_highest_task_rt(rq, -1);
- if (unlikely(task != next_task) && task && paranoid--) {
- put_task_struct(next_task);
- next_task = task;
- goto retry;
+ task = pick_next_pushable_task(rq);
+ if (task_cpu(next_task) == rq->cpu && task == next_task) {
+ /*
+ * If we get here, the task hasnt moved at all, but
+ * it has failed to push. We will not try again,
+ * since the other cpus will pull from us when they
+ * are ready.
+ */
+ dequeue_pushable_task(rq, next_task);
+ goto out;
}
- goto out;
+
+ if (!task)
+ /* No more tasks, just exit */
+ goto out;
+
+ /*
+ * Something has shifted, try again.
+ */
+ put_task_struct(next_task);
+ next_task = task;
+ goto retry;
}
deactivate_task(rq, next_task, 0);
@@ -1147,23 +1350,12 @@ static int push_rt_task(struct rq *rq)
double_unlock_balance(rq, lowest_rq);
- ret = 1;
out:
put_task_struct(next_task);
- return ret;
+ return 1;
}
-/*
- * TODO: Currently we just use the second highest prio task on
- * the queue, and stop when it can't migrate (or there's
- * no more RT tasks). There may be a case where a lower
- * priority RT task has a different affinity than the
- * higher RT task. In this case the lower RT task could
- * possibly be able to migrate where as the higher priority
- * RT task could not. We currently ignore this issue.
- * Enhancements are welcome!
- */
static void push_rt_tasks(struct rq *rq)
{
/* push_rt_task will return true if it moved an RT */
@@ -1174,33 +1366,35 @@ static void push_rt_tasks(struct rq *rq)
static int pull_rt_task(struct rq *this_rq)
{
int this_cpu = this_rq->cpu, ret = 0, cpu;
- struct task_struct *p, *next;
+ struct task_struct *p;
struct rq *src_rq;
if (likely(!rt_overloaded(this_rq)))
return 0;
- next = pick_next_task_rt(this_rq);
-
for_each_cpu(cpu, this_rq->rd->rto_mask) {
if (this_cpu == cpu)
continue;
src_rq = cpu_rq(cpu);
+
+ /*
+ * Don't bother taking the src_rq->lock if the next highest
+ * task is known to be lower-priority than our current task.
+ * This may look racy, but if this value is about to go
+ * logically higher, the src_rq will push this task away.
+ * And if its going logically lower, we do not care
+ */
+ if (src_rq->rt.highest_prio.next >=
+ this_rq->rt.highest_prio.curr)
+ continue;
+
/*
* We can potentially drop this_rq's lock in
* double_lock_balance, and another CPU could
- * steal our next task - hence we must cause
- * the caller to recalculate the next task
- * in that case:
+ * alter this_rq
*/
- if (double_lock_balance(this_rq, src_rq)) {
- struct task_struct *old_next = next;
-
- next = pick_next_task_rt(this_rq);
- if (next != old_next)
- ret = 1;
- }
+ double_lock_balance(this_rq, src_rq);
/*
* Are there still pullable RT tasks?
@@ -1214,7 +1408,7 @@ static int pull_rt_task(struct rq *this_rq)
* Do we have an RT task that preempts
* the to-be-scheduled task?
*/
- if (p && (!next || (p->prio < next->prio))) {
+ if (p && (p->prio < this_rq->rt.highest_prio.curr)) {
WARN_ON(p == src_rq->curr);
WARN_ON(!p->se.on_rq);
@@ -1224,12 +1418,9 @@ static int pull_rt_task(struct rq *this_rq)
* This is just that p is wakeing up and hasn't
* had a chance to schedule. We only pull
* p if it is lower in priority than the
- * current task on the run queue or
- * this_rq next task is lower in prio than
- * the current task on that rq.
+ * current task on the run queue
*/
- if (p->prio < src_rq->curr->prio ||
- (next && next->prio < src_rq->curr->prio))
+ if (p->prio < src_rq->curr->prio)
goto skip;
ret = 1;
@@ -1242,13 +1433,7 @@ static int pull_rt_task(struct rq *this_rq)
* case there's an even higher prio task
* in another runqueue. (low likelyhood
* but possible)
- *
- * Update next so that we won't pick a task
- * on another cpu with a priority lower (or equal)
- * than the one we just picked.
*/
- next = p;
-
}
skip:
double_unlock_balance(this_rq, src_rq);
@@ -1260,24 +1445,27 @@ static int pull_rt_task(struct rq *this_rq)
static void pre_schedule_rt(struct rq *rq, struct task_struct *prev)
{
/* Try to pull RT tasks here if we lower this rq's prio */
- if (unlikely(rt_task(prev)) && rq->rt.highest_prio > prev->prio)
+ if (unlikely(rt_task(prev)) && rq->rt.highest_prio.curr > prev->prio)
pull_rt_task(rq);
}
+/*
+ * assumes rq->lock is held
+ */
+static int needs_post_schedule_rt(struct rq *rq)
+{
+ return has_pushable_tasks(rq);
+}
+
static void post_schedule_rt(struct rq *rq)
{
/*
- * If we have more than one rt_task queued, then
- * see if we can push the other rt_tasks off to other CPUS.
- * Note we may release the rq lock, and since
- * the lock was owned by prev, we need to release it
- * first via finish_lock_switch and then reaquire it here.
+ * This is only called if needs_post_schedule_rt() indicates that
+ * we need to push tasks away
*/
- if (unlikely(rq->rt.overloaded)) {
- spin_lock_irq(&rq->lock);
- push_rt_tasks(rq);
- spin_unlock_irq(&rq->lock);
- }
+ spin_lock_irq(&rq->lock);
+ push_rt_tasks(rq);
+ spin_unlock_irq(&rq->lock);
}
/*
@@ -1288,7 +1476,8 @@ static void task_wake_up_rt(struct rq *rq, struct task_struct *p)
{
if (!task_running(rq, p) &&
!test_tsk_need_resched(rq->curr) &&
- rq->rt.overloaded)
+ has_pushable_tasks(rq) &&
+ p->rt.nr_cpus_allowed > 1)
push_rt_tasks(rq);
}
@@ -1324,6 +1513,24 @@ static void set_cpus_allowed_rt(struct task_struct *p,
if (p->se.on_rq && (weight != p->rt.nr_cpus_allowed)) {
struct rq *rq = task_rq(p);
+ if (!task_current(rq, p)) {
+ /*
+ * Make sure we dequeue this task from the pushable list
+ * before going further. It will either remain off of
+ * the list because we are no longer pushable, or it
+ * will be requeued.
+ */
+ if (p->rt.nr_cpus_allowed > 1)
+ dequeue_pushable_task(rq, p);
+
+ /*
+ * Requeue if our weight is changing and still > 1
+ */
+ if (weight > 1)
+ enqueue_pushable_task(rq, p);
+
+ }
+
if ((p->rt.nr_cpus_allowed <= 1) && (weight > 1)) {
rq->rt.rt_nr_migratory++;
} else if ((p->rt.nr_cpus_allowed > 1) && (weight <= 1)) {
@@ -1331,7 +1538,7 @@ static void set_cpus_allowed_rt(struct task_struct *p,
rq->rt.rt_nr_migratory--;
}
- update_rt_migration(rq);
+ update_rt_migration(&rq->rt);
}
cpumask_copy(&p->cpus_allowed, new_mask);
@@ -1346,7 +1553,7 @@ static void rq_online_rt(struct rq *rq)
__enable_runtime(rq);
- cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio);
+ cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr);
}
/* Assumes rq->lock is held */
@@ -1438,7 +1645,7 @@ static void prio_changed_rt(struct rq *rq, struct task_struct *p,
* can release the rq lock and p could migrate.
* Only reschedule if p is still on the same runqueue.
*/
- if (p->prio > rq->rt.highest_prio && rq->curr == p)
+ if (p->prio > rq->rt.highest_prio.curr && rq->curr == p)
resched_task(p);
#else
/* For UP simply resched on drop of prio */
@@ -1509,6 +1716,9 @@ static void set_curr_task_rt(struct rq *rq)
struct task_struct *p = rq->curr;
p->se.exec_start = rq->clock;
+
+ /* The running task is never eligible for pushing */
+ dequeue_pushable_task(rq, p);
}
static const struct sched_class rt_sched_class = {
@@ -1531,6 +1741,7 @@ static const struct sched_class rt_sched_class = {
.rq_online = rq_online_rt,
.rq_offline = rq_offline_rt,
.pre_schedule = pre_schedule_rt,
+ .needs_post_schedule = needs_post_schedule_rt,
.post_schedule = post_schedule_rt,
.task_wake_up = task_wake_up_rt,
.switched_from = switched_from_rt,
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index ad64fcb..57d4b13 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -8,6 +8,7 @@
#include <linux/seccomp.h>
#include <linux/sched.h>
+#include <linux/compat.h>
/* #define SECCOMP_DEBUG 1 */
#define NR_SECCOMP_MODES 1
@@ -22,7 +23,7 @@ static int mode1_syscalls[] = {
0, /* null terminated */
};
-#ifdef TIF_32BIT
+#ifdef CONFIG_COMPAT
static int mode1_syscalls_32[] = {
__NR_seccomp_read_32, __NR_seccomp_write_32, __NR_seccomp_exit_32, __NR_seccomp_sigreturn_32,
0, /* null terminated */
@@ -37,8 +38,8 @@ void __secure_computing(int this_syscall)
switch (mode) {
case 1:
syscall = mode1_syscalls;
-#ifdef TIF_32BIT
- if (test_thread_flag(TIF_32BIT))
+#ifdef CONFIG_COMPAT
+ if (is_compat_task())
syscall = mode1_syscalls_32;
#endif
do {
diff --git a/kernel/softirq.c b/kernel/softirq.c
index bdbe9de..9041ea7 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -626,6 +626,7 @@ static int ksoftirqd(void * __bind_cpu)
preempt_enable_no_resched();
cond_resched();
preempt_disable();
+ rcu_qsctr_inc((long)__bind_cpu);
}
preempt_enable();
set_current_state(TASK_INTERRUPTIBLE);
diff --git a/kernel/sys.c b/kernel/sys.c
index f145c41..37f458e 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -559,7 +559,7 @@ error:
abort_creds(new);
return retval;
}
-
+
/*
* change the user struct in a credentials set to match the new UID
*/
@@ -571,6 +571,11 @@ static int set_user(struct cred *new)
if (!new_user)
return -EAGAIN;
+ if (!task_can_switch_user(new_user, current)) {
+ free_uid(new_user);
+ return -EINVAL;
+ }
+
if (atomic_read(&new_user->processes) >=
current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
new_user != INIT_USER) {
@@ -631,10 +636,11 @@ SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
goto error;
}
- retval = -EAGAIN;
- if (new->uid != old->uid && set_user(new) < 0)
- goto error;
-
+ if (new->uid != old->uid) {
+ retval = set_user(new);
+ if (retval < 0)
+ goto error;
+ }
if (ruid != (uid_t) -1 ||
(euid != (uid_t) -1 && euid != old->uid))
new->suid = new->euid;
@@ -680,9 +686,10 @@ SYSCALL_DEFINE1(setuid, uid_t, uid)
retval = -EPERM;
if (capable(CAP_SETUID)) {
new->suid = new->uid = uid;
- if (uid != old->uid && set_user(new) < 0) {
- retval = -EAGAIN;
- goto error;
+ if (uid != old->uid) {
+ retval = set_user(new);
+ if (retval < 0)
+ goto error;
}
} else if (uid != old->uid && uid != new->suid) {
goto error;
@@ -734,11 +741,13 @@ SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
goto error;
}
- retval = -EAGAIN;
if (ruid != (uid_t) -1) {
new->uid = ruid;
- if (ruid != old->uid && set_user(new) < 0)
- goto error;
+ if (ruid != old->uid) {
+ retval = set_user(new);
+ if (retval < 0)
+ goto error;
+ }
}
if (euid != (uid_t) -1)
new->euid = euid;
diff --git a/kernel/tsacct.c b/kernel/tsacct.c
index 43f891b..00d59d0 100644
--- a/kernel/tsacct.c
+++ b/kernel/tsacct.c
@@ -122,8 +122,10 @@ void acct_update_integrals(struct task_struct *tsk)
if (likely(tsk->mm)) {
cputime_t time, dtime;
struct timeval value;
+ unsigned long flags;
u64 delta;
+ local_irq_save(flags);
time = tsk->stime + tsk->utime;
dtime = cputime_sub(time, tsk->acct_timexpd);
jiffies_to_timeval(cputime_to_jiffies(dtime), &value);
@@ -131,10 +133,12 @@ void acct_update_integrals(struct task_struct *tsk)
delta = delta * USEC_PER_SEC + value.tv_usec;
if (delta == 0)
- return;
+ goto out;
tsk->acct_timexpd = time;
tsk->acct_rss_mem1 += delta * get_mm_rss(tsk->mm);
tsk->acct_vm_mem1 += delta * tsk->mm->total_vm;
+ out:
+ local_irq_restore(flags);
}
}
diff --git a/kernel/user.c b/kernel/user.c
index 3551ac7..fbb300e 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -286,14 +286,12 @@ int __init uids_sysfs_init(void)
/* work function to remove sysfs directory for a user and free up
* corresponding structures.
*/
-static void remove_user_sysfs_dir(struct work_struct *w)
+static void cleanup_user_struct(struct work_struct *w)
{
struct user_struct *up = container_of(w, struct user_struct, work);
unsigned long flags;
int remove_user = 0;
- if (up->user_ns != &init_user_ns)
- return;
/* Make uid_hash_remove() + sysfs_remove_file() + kobject_del()
* atomic.
*/
@@ -312,9 +310,11 @@ static void remove_user_sysfs_dir(struct work_struct *w)
if (!remove_user)
goto done;
- kobject_uevent(&up->kobj, KOBJ_REMOVE);
- kobject_del(&up->kobj);
- kobject_put(&up->kobj);
+ if (up->user_ns == &init_user_ns) {
+ kobject_uevent(&up->kobj, KOBJ_REMOVE);
+ kobject_del(&up->kobj);
+ kobject_put(&up->kobj);
+ }
sched_destroy_user(up);
key_put(up->uid_keyring);
@@ -335,7 +335,7 @@ static void free_user(struct user_struct *up, unsigned long flags)
atomic_inc(&up->__count);
spin_unlock_irqrestore(&uidhash_lock, flags);
- INIT_WORK(&up->work, remove_user_sysfs_dir);
+ INIT_WORK(&up->work, cleanup_user_struct);
schedule_work(&up->work);
}
@@ -362,6 +362,24 @@ static void free_user(struct user_struct *up, unsigned long flags)
#endif
+#if defined(CONFIG_RT_GROUP_SCHED) && defined(CONFIG_USER_SCHED)
+/*
+ * We need to check if a setuid can take place. This function should be called
+ * before successfully completing the setuid.
+ */
+int task_can_switch_user(struct user_struct *up, struct task_struct *tsk)
+{
+
+ return sched_rt_can_attach(up->tg, tsk);
+
+}
+#else
+int task_can_switch_user(struct user_struct *up, struct task_struct *tsk)
+{
+ return 1;
+}
+#endif
+
/*
* Locate the user_struct for the passed UID. If found, take a ref on it. The
* caller must undo that ref with free_uid().
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 7908431..076c7c8 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -60,12 +60,25 @@ int create_user_ns(struct cred *new)
return 0;
}
-void free_user_ns(struct kref *kref)
+/*
+ * Deferred destructor for a user namespace. This is required because
+ * free_user_ns() may be called with uidhash_lock held, but we need to call
+ * back to free_uid() which will want to take the lock again.
+ */
+static void free_user_ns_work(struct work_struct *work)
{
- struct user_namespace *ns;
-
- ns = container_of(kref, struct user_namespace, kref);
+ struct user_namespace *ns =
+ container_of(work, struct user_namespace, destroyer);
free_uid(ns->creator);
kfree(ns);
}
+
+void free_user_ns(struct kref *kref)
+{
+ struct user_namespace *ns =
+ container_of(kref, struct user_namespace, kref);
+
+ INIT_WORK(&ns->destroyer, free_user_ns_work);
+ schedule_work(&ns->destroyer);
+}
EXPORT_SYMBOL(free_user_ns);
generated by cgit v0.10.2 at 2024-07-19 15:04:44 (GMT)