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sched/numa: Decide whether to favour task or group weights based on swap candidate relationships

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This patch separately considers task and group affinities when searching
for swap candidates during task NUMA placement. If tasks are not part of
a group or the same group then the task weights are considered.
Otherwise the group weights are compared.

Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1381141781-10992-54-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Rik van Riel 2013-10-07 11:29:31 +01:00 committed by Ingo Molnar
parent b32e86b430
commit 887c290e82
1 changed files with 36 additions and 23 deletions
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59
kernel/sched/fair.c
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@ -1039,13 +1039,15 @@ static void task_numa_assign(struct task_numa_env *env,
* into account that it might be best if task running on the dst_cpu should
* be exchanged with the source task
*/
static void task_numa_compare(struct task_numa_env *env, long imp)
static void task_numa_compare(struct task_numa_env *env,
long taskimp, long groupimp)
{
struct rq *src_rq = cpu_rq(env->src_cpu);
struct rq *dst_rq = cpu_rq(env->dst_cpu);
struct task_struct *cur;
long dst_load, src_load;
long load;
long imp = (groupimp > 0) ? groupimp : taskimp;
rcu_read_lock();
cur = ACCESS_ONCE(dst_rq->curr);
@ -1064,10 +1066,19 @@ static void task_numa_compare(struct task_numa_env *env, long imp)
if (!cpumask_test_cpu(env->src_cpu, tsk_cpus_allowed(cur)))
goto unlock;
imp += task_weight(cur, env->src_nid) +
group_weight(cur, env->src_nid) -
task_weight(cur, env->dst_nid) -
group_weight(cur, env->dst_nid);
/*
* If dst and source tasks are in the same NUMA group, or not
* in any group then look only at task weights otherwise give
* priority to the group weights.
*/
if (!cur->numa_group || !env->p->numa_group ||
cur->numa_group == env->p->numa_group) {
imp = taskimp + task_weight(cur, env->src_nid) -
task_weight(cur, env->dst_nid);
} else {
imp = groupimp + group_weight(cur, env->src_nid) -
group_weight(cur, env->dst_nid);
}
}
if (imp < env->best_imp)
@ -1117,7 +1128,8 @@ unlock:
rcu_read_unlock();
}
static void task_numa_find_cpu(struct task_numa_env *env, long imp)
static void task_numa_find_cpu(struct task_numa_env *env,
long taskimp, long groupimp)
{
int cpu;
@ -1127,7 +1139,7 @@ static void task_numa_find_cpu(struct task_numa_env *env, long imp)
continue;
env->dst_cpu = cpu;
task_numa_compare(env, imp);
task_numa_compare(env, taskimp, groupimp);
}
}
@ -1146,9 +1158,9 @@ static int task_numa_migrate(struct task_struct *p)
.best_cpu = -1
};
struct sched_domain *sd;
unsigned long weight;
unsigned long taskweight, groupweight;
int nid, ret;
long imp;
long taskimp, groupimp;
/*
* Pick the lowest SD_NUMA domain, as that would have the smallest
@ -1163,15 +1175,17 @@ static int task_numa_migrate(struct task_struct *p)
env.imbalance_pct = 100 + (sd->imbalance_pct - 100) / 2;
rcu_read_unlock();
weight = task_weight(p, env.src_nid) + group_weight(p, env.src_nid);
taskweight = task_weight(p, env.src_nid);
groupweight = group_weight(p, env.src_nid);
update_numa_stats(&env.src_stats, env.src_nid);
env.dst_nid = p->numa_preferred_nid;
imp = task_weight(p, env.dst_nid) + group_weight(p, env.dst_nid) - weight;
taskimp = task_weight(p, env.dst_nid) - taskweight;
groupimp = group_weight(p, env.dst_nid) - groupweight;
update_numa_stats(&env.dst_stats, env.dst_nid);
/* If the preferred nid has capacity, try to use it. */
if (env.dst_stats.has_capacity)
task_numa_find_cpu(&env, imp);
task_numa_find_cpu(&env, taskimp, groupimp);
/* No space available on the preferred nid. Look elsewhere. */
if (env.best_cpu == -1) {
@ -1180,13 +1194,14 @@ static int task_numa_migrate(struct task_struct *p)
continue;
/* Only consider nodes where both task and groups benefit */
imp = task_weight(p, nid) + group_weight(p, nid) - weight;
if (imp < 0)
taskimp = task_weight(p, nid) - taskweight;
groupimp = group_weight(p, nid) - groupweight;
if (taskimp < 0 && groupimp < 0)
continue;
env.dst_nid = nid;
update_numa_stats(&env.dst_stats, env.dst_nid);
task_numa_find_cpu(&env, imp);
task_numa_find_cpu(&env, taskimp, groupimp);
}
}
@ -4679,10 +4694,9 @@ static bool migrate_improves_locality(struct task_struct *p, struct lb_env *env)
if (dst_nid == p->numa_preferred_nid)
return true;
/* After the task has settled, check if the new node is better. */
if (p->numa_migrate_seq >= sysctl_numa_balancing_settle_count &&
task_weight(p, dst_nid) + group_weight(p, dst_nid) >
task_weight(p, src_nid) + group_weight(p, src_nid))
/* If both task and group weight improve, this move is a winner. */
if (task_weight(p, dst_nid) > task_weight(p, src_nid) &&
group_weight(p, dst_nid) > group_weight(p, src_nid))
return true;
return false;
@ -4709,10 +4723,9 @@ static bool migrate_degrades_locality(struct task_struct *p, struct lb_env *env)
if (src_nid == p->numa_preferred_nid)
return true;
/* After the task has settled, check if the new node is worse. */
if (p->numa_migrate_seq >= sysctl_numa_balancing_settle_count &&
task_weight(p, dst_nid) + group_weight(p, dst_nid) <
task_weight(p, src_nid) + group_weight(p, src_nid))
/* If either task or group weight get worse, don't do it. */
if (task_weight(p, dst_nid) < task_weight(p, src_nid) ||
group_weight(p, dst_nid) < group_weight(p, src_nid))
return true;
return false;