perf core: Allocate perf_event in the target node memory

For cpu events, it'd better allocating them in the corresponding node
memory as they would be mostly accessed by the target cpu.  Although
perf tools sets the cpu affinity before calling perf_event_open, there
are places it doesn't (notably perf record) and we should consider
other external users too.
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210311115413.444407-2-namhyung@kernel.org

kernel/events/core.c

@@ -11288,13 +11288,16 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
 	struct perf_event *event;
 	struct hw_perf_event *hwc;
 	long err = -EINVAL;
+	int node;
 
 	if ((unsigned)cpu >= nr_cpu_ids) {
 		if (!task || cpu != -1)
 			return ERR_PTR(-EINVAL);
 	}
 
-	event = kmem_cache_zalloc(perf_event_cache, GFP_KERNEL);
+	node = (cpu >= 0) ? cpu_to_node(cpu) : -1;
+	event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,
+				      node);
 	if (!event)
 		return ERR_PTR(-ENOMEM);