[PATCH 06/11] perf: Move cgroup init before PMU ->event_init()

From: Matt Fleming
Date: Wed Oct 01 2014 - 10:36:55 EST


From: Matt Fleming <matt.fleming@xxxxxxxxx>

The Intel QoS PMU needs to know whether an event is part of a cgroup
during ->event_init(), because tasks in the same cgroup share a
monitoring ID.

Move the cgroup initialisation before calling into the PMU driver.

Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Matt Fleming <matt.fleming@xxxxxxxxx>
---
kernel/events/core.c | 28 ++++++++++++++++------------
1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 2d5cde7af58f..b61ca7db3197 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6872,7 +6872,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
struct perf_event *group_leader,
struct perf_event *parent_event,
perf_overflow_handler_t overflow_handler,
- void *context)
+ void *context, bool cgroup, pid_t pid)
{
struct pmu *pmu;
struct perf_event *event;
@@ -6965,6 +6965,12 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
goto err_ns;

+ if (cgroup) {
+ err = perf_cgroup_connect(pid, event, attr, group_leader);
+ if (err)
+ goto err_ns;
+ }
+
pmu = perf_init_event(event);
if (!pmu)
goto err_ns;
@@ -6988,6 +6994,8 @@ err_pmu:
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);
kfree(event);
@@ -7191,6 +7199,7 @@ SYSCALL_DEFINE5(perf_event_open,
struct fd group = {NULL, 0};
struct task_struct *task = NULL;
struct pmu *pmu;
+ bool cgroup = false;
int event_fd;
int move_group = 0;
int err;
@@ -7260,21 +7269,16 @@ SYSCALL_DEFINE5(perf_event_open,

get_online_cpus();

+ if (flags & PERF_FLAG_PID_CGROUP)
+ cgroup = true;
+
event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
- NULL, NULL);
+ NULL, NULL, cgroup, pid);
if (IS_ERR(event)) {
err = PTR_ERR(event);
goto err_cpus;
}

- if (flags & PERF_FLAG_PID_CGROUP) {
- err = perf_cgroup_connect(pid, event, &attr, group_leader);
- if (err) {
- __free_event(event);
- goto err_cpus;
- }
- }
-
if (is_sampling_event(event)) {
if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
err = -ENOTSUPP;
@@ -7474,7 +7478,7 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
*/

event = perf_event_alloc(attr, cpu, task, NULL, NULL,
- overflow_handler, context);
+ overflow_handler, context, false, -1);
if (IS_ERR(event)) {
err = PTR_ERR(event);
goto err;
@@ -7812,7 +7816,7 @@ inherit_event(struct perf_event *parent_event,
parent_event->cpu,
child,
group_leader, parent_event,
- NULL, NULL);
+ NULL, NULL, false, -1);
if (IS_ERR(child_event))
return child_event;

--
1.9.3

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