On Fri, Jan 3, 2014 at 6:48 AM, Yan, Zheng <zheng.z....@intel.com> wrote:
> Later patches will use pmu specific data to save LBR stack.
>
I think the changelog could be more descriptive here.
Explain what you add.
Reviewed-by: Stephane Eranian <eran...@google.com>
> Signed-off-by: Yan, Zheng <zheng.z....@intel.com>
> ---
> include/linux/perf_event.h | 5 +++++
> kernel/events/core.c | 19 ++++++++++++++++++-
> 2 files changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> index 96cb88b..147f9d3 100644
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -252,6 +252,10 @@ struct pmu {
> */
> void (*sched_task) (struct perf_event_context *ctx,
> bool sched_in);
> + /*
> + * PMU specific data size
> + */
> + size_t task_ctx_size;
> };
>
> /**
> @@ -496,6 +500,7 @@ struct perf_event_context {
> int pin_count;
> int nr_cgroups; /* cgroup evts */
> int nr_branch_stack; /* branch_stack evt
> */
> + void *task_ctx_data; /* pmu specific data
> */
> struct rcu_head rcu_head;
> };
>
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index aba4d6d..b6650ab 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -883,6 +883,15 @@ static void get_ctx(struct perf_event_context *ctx)
> WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
> }
>
> +static void free_ctx(struct rcu_head *head)
> +{
> + struct perf_event_context *ctx;
> +
> + ctx = container_of(head, struct perf_event_context, rcu_head);
> + kfree(ctx->task_ctx_data);
> + kfree(ctx);
> +}
> +
> static void put_ctx(struct perf_event_context *ctx)
> {
> if (atomic_dec_and_test(&ctx->refcount)) {
> @@ -890,7 +899,7 @@ static void put_ctx(struct perf_event_context *ctx)
> put_ctx(ctx->parent_ctx);
> if (ctx->task)
> put_task_struct(ctx->task);
> - kfree_rcu(ctx, rcu_head);
> + call_rcu(&ctx->rcu_head, free_ctx);
> }
> }
>
> @@ -3020,6 +3029,14 @@ alloc_perf_context(struct pmu *pmu, struct task_struct
> *task)
> if (!ctx)
> return NULL;
>
> + if (task && pmu->task_ctx_size > 0) {
> + ctx->task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
> + if (!ctx->task_ctx_data) {
> + kfree(ctx);
> + return NULL;
> + }
> + }
> +
> __perf_event_init_context(ctx);
> if (task) {
> ctx->task = task;
> --
> 1.8.4.2
>
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