sched/numa: Use unsigned longs for numa group fault stats
As Peter says "If you're going to hold locks you can also do away with all
that atomic_long_*() nonsense". Lock aquisition moved slightly to protect
the updates.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1381141781-10992-63-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index e7884dc..5b2208e 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -916,8 +916,8 @@
struct list_head task_list;
struct rcu_head rcu;
- atomic_long_t total_faults;
- atomic_long_t faults[0];
+ unsigned long total_faults;
+ unsigned long faults[0];
};
pid_t task_numa_group_id(struct task_struct *p)
@@ -944,8 +944,7 @@
if (!p->numa_group)
return 0;
- return atomic_long_read(&p->numa_group->faults[2*nid]) +
- atomic_long_read(&p->numa_group->faults[2*nid+1]);
+ return p->numa_group->faults[2*nid] + p->numa_group->faults[2*nid+1];
}
/*
@@ -971,17 +970,10 @@
static inline unsigned long group_weight(struct task_struct *p, int nid)
{
- unsigned long total_faults;
-
- if (!p->numa_group)
+ if (!p->numa_group || !p->numa_group->total_faults)
return 0;
- total_faults = atomic_long_read(&p->numa_group->total_faults);
-
- if (!total_faults)
- return 0;
-
- return 1000 * group_faults(p, nid) / total_faults;
+ return 1000 * group_faults(p, nid) / p->numa_group->total_faults;
}
static unsigned long weighted_cpuload(const int cpu);
@@ -1397,9 +1389,9 @@
p->total_numa_faults += diff;
if (p->numa_group) {
/* safe because we can only change our own group */
- atomic_long_add(diff, &p->numa_group->faults[i]);
- atomic_long_add(diff, &p->numa_group->total_faults);
- group_faults += atomic_long_read(&p->numa_group->faults[i]);
+ p->numa_group->faults[i] += diff;
+ p->numa_group->total_faults += diff;
+ group_faults += p->numa_group->faults[i];
}
}
@@ -1475,7 +1467,7 @@
if (unlikely(!p->numa_group)) {
unsigned int size = sizeof(struct numa_group) +
- 2*nr_node_ids*sizeof(atomic_long_t);
+ 2*nr_node_ids*sizeof(unsigned long);
grp = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
if (!grp)
@@ -1487,9 +1479,9 @@
grp->gid = p->pid;
for (i = 0; i < 2*nr_node_ids; i++)
- atomic_long_set(&grp->faults[i], p->numa_faults[i]);
+ grp->faults[i] = p->numa_faults[i];
- atomic_long_set(&grp->total_faults, p->total_numa_faults);
+ grp->total_faults = p->total_numa_faults;
list_add(&p->numa_entry, &grp->task_list);
grp->nr_tasks++;
@@ -1543,15 +1535,15 @@
if (!join)
return;
- for (i = 0; i < 2*nr_node_ids; i++) {
- atomic_long_sub(p->numa_faults[i], &my_grp->faults[i]);
- atomic_long_add(p->numa_faults[i], &grp->faults[i]);
- }
- atomic_long_sub(p->total_numa_faults, &my_grp->total_faults);
- atomic_long_add(p->total_numa_faults, &grp->total_faults);
-
double_lock(&my_grp->lock, &grp->lock);
+ for (i = 0; i < 2*nr_node_ids; i++) {
+ my_grp->faults[i] -= p->numa_faults[i];
+ grp->faults[i] += p->numa_faults[i];
+ }
+ my_grp->total_faults -= p->total_numa_faults;
+ grp->total_faults += p->total_numa_faults;
+
list_move(&p->numa_entry, &grp->task_list);
my_grp->nr_tasks--;
grp->nr_tasks++;
@@ -1571,12 +1563,11 @@
void *numa_faults = p->numa_faults;
if (grp) {
- for (i = 0; i < 2*nr_node_ids; i++)
- atomic_long_sub(p->numa_faults[i], &grp->faults[i]);
-
- atomic_long_sub(p->total_numa_faults, &grp->total_faults);
-
spin_lock(&grp->lock);
+ for (i = 0; i < 2*nr_node_ids; i++)
+ grp->faults[i] -= p->numa_faults[i];
+ grp->total_faults -= p->total_numa_faults;
+
list_del(&p->numa_entry);
grp->nr_tasks--;
spin_unlock(&grp->lock);