[PATCH v2] bpf: Allocate bpf_event_entry with node info

Namhyung Kim
2024-05-29T06:53:12Z

It was reported that accessing perf_event map entry caused pretty high
LLC misses in get_map_perf_counter(). As reading perf_event is allowed
for the local CPU only, I think we can use the target CPU of the event
as hint for the allocation like in perf_event_alloc() so that the event
and the entry can be in the same node at least.

Reported-by: Aleksei Shchekotikhin <alekseis@google.com>
Reported-by: Nilay Vaish <nilayvaish@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
v2) fix build errors

kernel/bpf/arraymap.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index feabc0193852..067f7cf27042 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -1194,10 +1194,17 @@ static struct bpf_event_entry *bpf_event_entry_gen(struct file *perf_file,
struct file *map_file)
{
struct bpf_event_entry *ee;
+ struct perf_event *event = perf_file->private_data;
+ int node = -1;

- ee = kzalloc(sizeof(*ee), GFP_KERNEL);
+#ifdef CONFIG_PERF_EVENTS
+ if (event->cpu >= 0)
+ node = cpu_to_node(event->cpu);
+#endif
+
+ ee = kzalloc_node(sizeof(*ee), GFP_KERNEL, node);
if (ee) {
- ee->event = perf_file->private_data;
+ ee->event = event;
ee->perf_file = perf_file;
ee->map_file = map_file;
}
--
2.45.1.288.g0e0cd299f1-goog