[PATCH v6 1/6] perf/cgroup: Reorder perf_cgroup_connect()

From: Ian Rogers
Date: Fri Feb 14 2020 - 02:51:49 EST


From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>

Move perf_cgroup_connect() after perf_event_alloc(), such that we can
find/use the PMU's cpu context.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
kernel/events/core.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 3f1f77de7247..9bd2af954c54 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10804,12 +10804,6 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
if (!has_branch_stack(event))
event->attr.branch_sample_type = 0;

- if (cgroup_fd != -1) {
- err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
- if (err)
- goto err_ns;
- }
-
pmu = perf_init_event(event);
if (IS_ERR(pmu)) {
err = PTR_ERR(pmu);
@@ -10831,6 +10825,12 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
goto err_pmu;
}

+ if (cgroup_fd != -1) {
+ err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
+ if (err)
+ goto err_pmu;
+ }
+
err = exclusive_event_init(event);
if (err)
goto err_pmu;
@@ -10891,12 +10891,12 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
exclusive_event_destroy(event);

err_pmu:
+ if (is_cgroup_event(event))
+ perf_detach_cgroup(event);
if (event->destroy)
event->destroy(event);
module_put(pmu->module);
err_ns:
- if (is_cgroup_event(event))
- perf_detach_cgroup(event);
if (event->ns)
put_pid_ns(event->ns);
if (event->hw.target)
--
2.25.0.265.gbab2e86ba0-goog