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Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 

* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: disable the hrtick for now
  sched: revert back to per-rq vruntime
  sched: fair scheduler should not resched rt tasks
  sched: optimize group load balancer
  sched: minor fast-path overhead reduction
  sched: fix the wrong mask_len, cleanup
  sched: kill unused scheduler decl.
  sched: fix the wrong mask_len
  sched: only update rq->clock while holding rq->lock
This commit is contained in:
Linus Torvalds 2008-10-23 09:37:16 -07:00
parent e82cff752f 0c4b83da58
commit 133e887f90
6 changed files with 79 additions and 50 deletions
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2
include/linux/sched.h
View File

@ -287,7 +287,6 @@ extern void trap_init(void);
extern void account_process_tick(struct task_struct *task, int user);
extern void update_process_times(int user);
extern void scheduler_tick(void);
extern void hrtick_resched(void);
extern void sched_show_task(struct task_struct *p);
@ -1665,6 +1664,7 @@ extern unsigned int sysctl_sched_features;
extern unsigned int sysctl_sched_migration_cost;
extern unsigned int sysctl_sched_nr_migrate;
extern unsigned int sysctl_sched_shares_ratelimit;
extern unsigned int sysctl_sched_shares_thresh;
int sched_nr_latency_handler(struct ctl_table *table, int write,
struct file *file, void __user *buffer, size_t *length,

51
kernel/sched.c
View File

@ -818,6 +818,13 @@ const_debug unsigned int sysctl_sched_nr_migrate = 32;
*/
unsigned int sysctl_sched_shares_ratelimit = 250000;
/*
* Inject some fuzzyness into changing the per-cpu group shares
* this avoids remote rq-locks at the expense of fairness.
* default: 4
*/
unsigned int sysctl_sched_shares_thresh = 4;
/*
* period over which we measure -rt task cpu usage in us.
* default: 1s
@ -1454,8 +1461,8 @@ static void __set_se_shares(struct sched_entity *se, unsigned long shares);
* Calculate and set the cpu's group shares.
*/
static void
__update_group_shares_cpu(struct task_group *tg, int cpu,
unsigned long sd_shares, unsigned long sd_rq_weight)
update_group_shares_cpu(struct task_group *tg, int cpu,
unsigned long sd_shares, unsigned long sd_rq_weight)
{
int boost = 0;
unsigned long shares;
@ -1486,19 +1493,23 @@ __update_group_shares_cpu(struct task_group *tg, int cpu,
*
*/
shares = (sd_shares * rq_weight) / (sd_rq_weight + 1);
shares = clamp_t(unsigned long, shares, MIN_SHARES, MAX_SHARES);
/*
* record the actual number of shares, not the boosted amount.
*/
tg->cfs_rq[cpu]->shares = boost ? 0 : shares;
tg->cfs_rq[cpu]->rq_weight = rq_weight;
if (abs(shares - tg->se[cpu]->load.weight) >
sysctl_sched_shares_thresh) {
struct rq *rq = cpu_rq(cpu);
unsigned long flags;
if (shares < MIN_SHARES)
shares = MIN_SHARES;
else if (shares > MAX_SHARES)
shares = MAX_SHARES;
spin_lock_irqsave(&rq->lock, flags);
/*
* record the actual number of shares, not the boosted amount.
*/
tg->cfs_rq[cpu]->shares = boost ? 0 : shares;
tg->cfs_rq[cpu]->rq_weight = rq_weight;
__set_se_shares(tg->se[cpu], shares);
__set_se_shares(tg->se[cpu], shares);
spin_unlock_irqrestore(&rq->lock, flags);
}
}
/*
@ -1527,14 +1538,8 @@ static int tg_shares_up(struct task_group *tg, void *data)
if (!rq_weight)
rq_weight = cpus_weight(sd->span) * NICE_0_LOAD;
for_each_cpu_mask(i, sd->span) {
struct rq *rq = cpu_rq(i);
unsigned long flags;
spin_lock_irqsave(&rq->lock, flags);
__update_group_shares_cpu(tg, i, shares, rq_weight);
spin_unlock_irqrestore(&rq->lock, flags);
}
for_each_cpu_mask(i, sd->span)
update_group_shares_cpu(tg, i, shares, rq_weight);
return 0;
}
@ -4443,12 +4448,8 @@ need_resched_nonpreemptible:
if (sched_feat(HRTICK))
hrtick_clear(rq);
/*
* Do the rq-clock update outside the rq lock:
*/
local_irq_disable();
spin_lock_irq(&rq->lock);
update_rq_clock(rq);
spin_lock(&rq->lock);
clear_tsk_need_resched(prev);
if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {

62
kernel/sched_fair.c
View File

@ -73,6 +73,8 @@ unsigned int sysctl_sched_wakeup_granularity = 5000000UL;
const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
static const struct sched_class fair_sched_class;
/**************************************************************
* CFS operations on generic schedulable entities:
*/
@ -334,7 +336,7 @@ int sched_nr_latency_handler(struct ctl_table *table, int write,
#endif
/*
* delta *= w / rw
* delta *= P[w / rw]
*/
static inline unsigned long
calc_delta_weight(unsigned long delta, struct sched_entity *se)
@ -348,15 +350,13 @@ calc_delta_weight(unsigned long delta, struct sched_entity *se)
}
/*
* delta *= rw / w
* delta /= w
*/
static inline unsigned long
calc_delta_fair(unsigned long delta, struct sched_entity *se)
{
for_each_sched_entity(se) {
delta = calc_delta_mine(delta,
cfs_rq_of(se)->load.weight, &se->load);
}
if (unlikely(se->load.weight != NICE_0_LOAD))
delta = calc_delta_mine(delta, NICE_0_LOAD, &se->load);
return delta;
}
@ -386,26 +386,26 @@ static u64 __sched_period(unsigned long nr_running)
* We calculate the wall-time slice from the period by taking a part
* proportional to the weight.
*
* s = p*w/rw
* s = p*P[w/rw]
*/
static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
return calc_delta_weight(__sched_period(cfs_rq->nr_running), se);
unsigned long nr_running = cfs_rq->nr_running;
if (unlikely(!se->on_rq))
nr_running++;
return calc_delta_weight(__sched_period(nr_running), se);
}
/*
* We calculate the vruntime slice of a to be inserted task
*
* vs = s*rw/w = p
* vs = s/w
*/
static u64 sched_vslice_add(struct cfs_rq *cfs_rq, struct sched_entity *se)
static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
unsigned long nr_running = cfs_rq->nr_running;
if (!se->on_rq)
nr_running++;
return __sched_period(nr_running);
return calc_delta_fair(sched_slice(cfs_rq, se), se);
}
/*
@ -628,7 +628,7 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
* stays open at the end.
*/
if (initial && sched_feat(START_DEBIT))
vruntime += sched_vslice_add(cfs_rq, se);
vruntime += sched_vslice(cfs_rq, se);
if (!initial) {
/* sleeps upto a single latency don't count. */
@ -748,7 +748,7 @@ pick_next(struct cfs_rq *cfs_rq, struct sched_entity *se)
struct rq *rq = rq_of(cfs_rq);
u64 pair_slice = rq->clock - cfs_rq->pair_start;
if (!cfs_rq->next || pair_slice > sched_slice(cfs_rq, cfs_rq->next)) {
if (!cfs_rq->next || pair_slice > sysctl_sched_min_granularity) {
cfs_rq->pair_start = rq->clock;
return se;
}
@ -849,11 +849,31 @@ static void hrtick_start_fair(struct rq *rq, struct task_struct *p)
hrtick_start(rq, delta);
}
}
/*
* called from enqueue/dequeue and updates the hrtick when the
* current task is from our class and nr_running is low enough
* to matter.
*/
static void hrtick_update(struct rq *rq)
{
struct task_struct *curr = rq->curr;
if (curr->sched_class != &fair_sched_class)
return;
if (cfs_rq_of(&curr->se)->nr_running < sched_nr_latency)
hrtick_start_fair(rq, curr);
}
#else /* !CONFIG_SCHED_HRTICK */
static inline void
hrtick_start_fair(struct rq *rq, struct task_struct *p)
{
}
static inline void hrtick_update(struct rq *rq)
{
}
#endif
/*
@ -874,7 +894,7 @@ static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup)
wakeup = 1;
}
hrtick_start_fair(rq, rq->curr);
hrtick_update(rq);
}
/*
@ -896,7 +916,7 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep)
sleep = 1;
}
hrtick_start_fair(rq, rq->curr);
hrtick_update(rq);
}
/*
@ -1002,8 +1022,6 @@ static inline int wake_idle(int cpu, struct task_struct *p)
#ifdef CONFIG_SMP
static const struct sched_class fair_sched_class;
#ifdef CONFIG_FAIR_GROUP_SCHED
/*
* effective_load() calculates the load change as seen from the root_task_group

2
kernel/sched_features.h
View File

@ -5,7 +5,7 @@ SCHED_FEAT(START_DEBIT, 1)
SCHED_FEAT(AFFINE_WAKEUPS, 1)
SCHED_FEAT(CACHE_HOT_BUDDY, 1)
SCHED_FEAT(SYNC_WAKEUPS, 1)
SCHED_FEAT(HRTICK, 1)
SCHED_FEAT(HRTICK, 0)
SCHED_FEAT(DOUBLE_TICK, 0)
SCHED_FEAT(ASYM_GRAN, 1)
SCHED_FEAT(LB_BIAS, 1)

2
kernel/sched_stats.h
View File

@ -9,7 +9,7 @@
static int show_schedstat(struct seq_file *seq, void *v)
{
int cpu;
int mask_len = NR_CPUS/32 * 9;
int mask_len = DIV_ROUND_UP(NR_CPUS, 32) * 9;
char *mask_str = kmalloc(mask_len, GFP_KERNEL);
if (mask_str == NULL)

10
kernel/sysctl.c
View File

@ -274,6 +274,16 @@ static struct ctl_table kern_table[] = {
.mode = 0644,
.proc_handler = &proc_dointvec,
},
{
.ctl_name = CTL_UNNUMBERED,
.procname = "sched_shares_thresh",
.data = &sysctl_sched_shares_thresh,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &zero,
},
{
.ctl_name = CTL_UNNUMBERED,
.procname = "sched_child_runs_first",