Re: [PATCH v3 01/10] perf/cgroup: Reorder perf_cgroup_connect()

[Peter Zijlstra]

Hurm, you didn't fix my missing Changelog.. 

On Wed, Nov 13, 2019 at 04:30:33PM -0800, Ian Rogers wrote:
> 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 cfd89b4a02d8..0dce28b0aae0 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -10597,12 +10597,6 @@ 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);
> @@ -10615,6 +10609,12 @@ 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;
> @@ -10675,12 +10675,12 @@ 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)
> -- 
> 2.24.0.432.g9d3f5f5b63-goog
>