From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
We do two things, both of which are purely to simplify and clarify the
implementation:
1.
Simplify the CPU online callback so it is more obvious that the purpose
there is to set a single CPU mask bit for the first CPU which comes
online. Using cpumask_weight for this reads more obvious than the trick
with cpumask_and_any.
2.
Modify the event init so that events can be created only on a single CPU.
This removes looking at the requested CPU thread siblings, and only allows
creating on the current active CPU.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Dmitry Rogozhkin <dmitry.v.rogozhkin@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_pmu.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index d7acdaf7d9f8..d83653c83d6e 100644
--- a/drivers/gpu/drm/i915/i915_pmu.c
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -326,7 +326,7 @@ static int i915_pmu_event_init(struct perf_event *event)
{
struct drm_i915_private *i915 =
container_of(event->pmu, typeof(*i915), pmu.base);
- int cpu, ret;
+ int ret;
if (event->attr.type != event->pmu->type)
return -ENOENT;
@@ -341,9 +341,8 @@ static int i915_pmu_event_init(struct perf_event *event)
if (event->cpu < 0)
return -EINVAL;
- cpu = cpumask_any_and(&i915_pmu_cpumask,
- topology_sibling_cpumask(event->cpu));
- if (cpu >= nr_cpu_ids)
+ /* only allow running on one cpu at a time */
+ if (!cpumask_test_cpu(event->cpu, &i915_pmu_cpumask))
return -ENODEV;
if (is_engine_event(event)) {
@@ -378,7 +377,6 @@ static int i915_pmu_event_init(struct perf_event *event)
if (ret)
return ret;
- event->cpu = cpu;
if (!event->parent)
event->destroy = i915_pmu_event_destroy;
@@ -745,13 +743,11 @@ static const struct attribute_group *i915_pmu_attr_groups[] = {
static int i915_pmu_cpu_online(unsigned int cpu, struct hlist_node *node)
{
struct i915_pmu *pmu = hlist_entry_safe(node, typeof(*pmu), node);
- unsigned int target;
GEM_BUG_ON(!pmu->base.event_init);
- target = cpumask_any_and(&i915_pmu_cpumask, &i915_pmu_cpumask);
/* Select the first online CPU as a designated reader. */
- if (target >= nr_cpu_ids)
+ if (!cpumask_weight(&i915_pmu_cpumask))
cpumask_set_cpu(cpu, &i915_pmu_cpumask);
return 0;
--
2.14.1
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