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sched: Make tg_shares_up() walk on-demand 

Make tg_shares_up() use the active cgroup list, this means we cannot
do a strict bottom-up walk of the hierarchy, but assuming its a very
wide tree with a small number of active groups it should be a win.

Signed-off-by: Paul Turner <pjt@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20101115234937.754159484@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2010-11-15 15:47:02 -08:00 committed by Ingo Molnar
parent 3d4b47b4b0
commit 9e3081ca61
2 changed files with 58 additions and 67 deletions
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67
kernel/sched.c
View File

@ -279,13 +279,6 @@ static DEFINE_SPINLOCK(task_group_lock);
#ifdef CONFIG_FAIR_GROUP_SCHED
#ifdef CONFIG_SMP
static int root_task_group_empty(void)
{
return list_empty(&root_task_group.children);
}
#endif
# define INIT_TASK_GROUP_LOAD NICE_0_LOAD
/*
@ -1546,48 +1539,6 @@ static unsigned long cpu_avg_load_per_task(int cpu)
#ifdef CONFIG_FAIR_GROUP_SCHED
static void update_cfs_load(struct cfs_rq *cfs_rq, int lb);
static void update_cfs_shares(struct cfs_rq *cfs_rq);
/*
* update tg->load_weight by folding this cpu's load_avg
*/
static int tg_shares_up(struct task_group *tg, void *data)
{
long load_avg;
struct cfs_rq *cfs_rq;
unsigned long flags;
int cpu = (long)data;
struct rq *rq;
if (!tg->se[cpu])
return 0;
rq = cpu_rq(cpu);
cfs_rq = tg->cfs_rq[cpu];
raw_spin_lock_irqsave(&rq->lock, flags);
update_rq_clock(rq);
update_cfs_load(cfs_rq, 1);
load_avg = div64_u64(cfs_rq->load_avg, cfs_rq->load_period+1);
load_avg -= cfs_rq->load_contribution;
atomic_add(load_avg, &tg->load_weight);
cfs_rq->load_contribution += load_avg;
/*
* We need to update shares after updating tg->load_weight in
* order to adjust the weight of groups with long running tasks.
*/
update_cfs_shares(cfs_rq);
raw_spin_unlock_irqrestore(&rq->lock, flags);
return 0;
}
/*
* Compute the cpu's hierarchical load factor for each task group.
* This needs to be done in a top-down fashion because the load of a child
@ -1611,29 +1562,11 @@ static int tg_load_down(struct task_group *tg, void *data)
return 0;
}
static void update_shares(long cpu)
{
if (root_task_group_empty())
return;
/*
* XXX: replace with an on-demand list
*/
walk_tg_tree(tg_nop, tg_shares_up, (void *)cpu);
}
static void update_h_load(long cpu)
{
walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
}
#else
static inline void update_shares(int cpu)
{
}
#endif
#ifdef CONFIG_PREEMPT

58
kernel/sched_fair.c
View File

@ -2004,6 +2004,60 @@ out:
}
#ifdef CONFIG_FAIR_GROUP_SCHED
/*
* update tg->load_weight by folding this cpu's load_avg
*/
static int tg_shares_up(struct task_group *tg, int cpu)
{
struct cfs_rq *cfs_rq;
unsigned long flags;
struct rq *rq;
long load_avg;
if (!tg->se[cpu])
return 0;
rq = cpu_rq(cpu);
cfs_rq = tg->cfs_rq[cpu];
raw_spin_lock_irqsave(&rq->lock, flags);
update_rq_clock(rq);
update_cfs_load(cfs_rq, 1);
load_avg = div64_u64(cfs_rq->load_avg, cfs_rq->load_period+1);
load_avg -= cfs_rq->load_contribution;
atomic_add(load_avg, &tg->load_weight);
cfs_rq->load_contribution += load_avg;
/*
* We need to update shares after updating tg->load_weight in
* order to adjust the weight of groups with long running tasks.
*/
update_cfs_shares(cfs_rq);
raw_spin_unlock_irqrestore(&rq->lock, flags);
return 0;
}
static void update_shares(int cpu)
{
struct cfs_rq *cfs_rq;
struct rq *rq = cpu_rq(cpu);
rcu_read_lock();
for_each_leaf_cfs_rq(rq, cfs_rq) {
struct task_group *tg = cfs_rq->tg;
do {
tg_shares_up(tg, cpu);
tg = tg->parent;
} while (tg);
}
rcu_read_unlock();
}
static unsigned long
load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
unsigned long max_load_move,
@ -2051,6 +2105,10 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
return max_load_move - rem_load_move;
}
#else
static inline void update_shares(int cpu)
{
}
static unsigned long
load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
unsigned long max_load_move,