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-rw-r--r--kernel/sched.c73
1 files changed, 47 insertions, 26 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 3f6bd11..4fb3532 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -52,7 +52,6 @@
#include <linux/cpu.h>
#include <linux/cpuset.h>
#include <linux/percpu.h>
-#include <linux/cpu_acct.h>
#include <linux/kthread.h>
#include <linux/seq_file.h>
#include <linux/sysctl.h>
@@ -75,7 +74,7 @@
*/
unsigned long long __attribute__((weak)) sched_clock(void)
{
- return (unsigned long long)jiffies * (1000000000 / HZ);
+ return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ);
}
/*
@@ -99,8 +98,8 @@ unsigned long long __attribute__((weak)) sched_clock(void)
/*
* Some helpers for converting nanosecond timing to jiffy resolution
*/
-#define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (1000000000 / HZ))
-#define JIFFIES_TO_NS(TIME) ((TIME) * (1000000000 / HZ))
+#define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
+#define JIFFIES_TO_NS(TIME) ((TIME) * (NSEC_PER_SEC / HZ))
#define NICE_0_LOAD SCHED_LOAD_SCALE
#define NICE_0_SHIFT SCHED_LOAD_SHIFT
@@ -460,7 +459,6 @@ enum {
SCHED_FEAT_TREE_AVG = 4,
SCHED_FEAT_APPROX_AVG = 8,
SCHED_FEAT_WAKEUP_PREEMPT = 16,
- SCHED_FEAT_PREEMPT_RESTRICT = 32,
};
const_debug unsigned int sysctl_sched_features =
@@ -468,12 +466,17 @@ const_debug unsigned int sysctl_sched_features =
SCHED_FEAT_START_DEBIT * 1 |
SCHED_FEAT_TREE_AVG * 0 |
SCHED_FEAT_APPROX_AVG * 0 |
- SCHED_FEAT_WAKEUP_PREEMPT * 1 |
- SCHED_FEAT_PREEMPT_RESTRICT * 1;
+ SCHED_FEAT_WAKEUP_PREEMPT * 1;
#define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x)
/*
+ * Number of tasks to iterate in a single balance run.
+ * Limited because this is done with IRQs disabled.
+ */
+const_debug unsigned int sysctl_sched_nr_migrate = 32;
+
+/*
* For kernel-internal use: high-speed (but slightly incorrect) per-cpu
* clock constructed from sched_clock():
*/
@@ -2237,7 +2240,7 @@ balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
enum cpu_idle_type idle, int *all_pinned,
int *this_best_prio, struct rq_iterator *iterator)
{
- int pulled = 0, pinned = 0, skip_for_load;
+ int loops = 0, pulled = 0, pinned = 0, skip_for_load;
struct task_struct *p;
long rem_load_move = max_load_move;
@@ -2251,10 +2254,10 @@ balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
*/
p = iterator->start(iterator->arg);
next:
- if (!p)
+ if (!p || loops++ > sysctl_sched_nr_migrate)
goto out;
/*
- * To help distribute high priority tasks accross CPUs we don't
+ * To help distribute high priority tasks across CPUs we don't
* skip a task if it will be the highest priority task (i.e. smallest
* prio value) on its new queue regardless of its load weight
*/
@@ -2271,8 +2274,7 @@ next:
rem_load_move -= p->se.load.weight;
/*
- * We only want to steal up to the prescribed number of tasks
- * and the prescribed amount of weighted load.
+ * We only want to steal up to the prescribed amount of weighted load.
*/
if (rem_load_move > 0) {
if (p->prio < *this_best_prio)
@@ -3335,13 +3337,9 @@ void account_user_time(struct task_struct *p, cputime_t cputime)
{
struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
cputime64_t tmp;
- struct rq *rq = this_rq();
p->utime = cputime_add(p->utime, cputime);
- if (p != rq->idle)
- cpuacct_charge(p, cputime);
-
/* Add user time to cpustat. */
tmp = cputime_to_cputime64(cputime);
if (TASK_NICE(p) > 0)
@@ -3405,10 +3403,9 @@ void account_system_time(struct task_struct *p, int hardirq_offset,
cpustat->irq = cputime64_add(cpustat->irq, tmp);
else if (softirq_count())
cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
- else if (p != rq->idle) {
+ else if (p != rq->idle)
cpustat->system = cputime64_add(cpustat->system, tmp);
- cpuacct_charge(p, cputime);
- } else if (atomic_read(&rq->nr_iowait) > 0)
+ else if (atomic_read(&rq->nr_iowait) > 0)
cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
else
cpustat->idle = cputime64_add(cpustat->idle, tmp);
@@ -3444,10 +3441,8 @@ void account_steal_time(struct task_struct *p, cputime_t steal)
cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
else
cpustat->idle = cputime64_add(cpustat->idle, tmp);
- } else {
+ } else
cpustat->steal = cputime64_add(cpustat->steal, tmp);
- cpuacct_charge(p, -tmp);
- }
}
/*
@@ -4992,6 +4987,32 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu)
*/
cpumask_t nohz_cpu_mask = CPU_MASK_NONE;
+/*
+ * Increase the granularity value when there are more CPUs,
+ * because with more CPUs the 'effective latency' as visible
+ * to users decreases. But the relationship is not linear,
+ * so pick a second-best guess by going with the log2 of the
+ * number of CPUs.
+ *
+ * This idea comes from the SD scheduler of Con Kolivas:
+ */
+static inline void sched_init_granularity(void)
+{
+ unsigned int factor = 1 + ilog2(num_online_cpus());
+ const unsigned long limit = 200000000;
+
+ sysctl_sched_min_granularity *= factor;
+ if (sysctl_sched_min_granularity > limit)
+ sysctl_sched_min_granularity = limit;
+
+ sysctl_sched_latency *= factor;
+ if (sysctl_sched_latency > limit)
+ sysctl_sched_latency = limit;
+
+ sysctl_sched_wakeup_granularity *= factor;
+ sysctl_sched_batch_wakeup_granularity *= factor;
+}
+
#ifdef CONFIG_SMP
/*
* This is how migration works:
@@ -5621,7 +5642,7 @@ static struct notifier_block __cpuinitdata migration_notifier = {
.priority = 10
};
-int __init migration_init(void)
+void __init migration_init(void)
{
void *cpu = (void *)(long)smp_processor_id();
int err;
@@ -5631,8 +5652,6 @@ int __init migration_init(void)
BUG_ON(err == NOTIFY_BAD);
migration_call(&migration_notifier, CPU_ONLINE, cpu);
register_cpu_notifier(&migration_notifier);
-
- return 0;
}
#endif
@@ -6688,10 +6707,12 @@ void __init sched_init_smp(void)
/* Move init over to a non-isolated CPU */
if (set_cpus_allowed(current, non_isolated_cpus) < 0)
BUG();
+ sched_init_granularity();
}
#else
void __init sched_init_smp(void)
{
+ sched_init_granularity();
}
#endif /* CONFIG_SMP */
@@ -7228,7 +7249,7 @@ static u64 cpu_usage_read(struct cgroup *cgrp, struct cftype *cft)
spin_unlock_irqrestore(&cpu_rq(i)->lock, flags);
}
/* Convert from ns to ms */
- do_div(res, 1000000);
+ do_div(res, NSEC_PER_MSEC);
return res;
}
generated by cgit v1.1 at 2025-05-28 19:34:18 +0000