On Fri, Jan 3, 2014 at 6:48 AM, Yan, Zheng <zheng.z....@intel.com> wrote:
> When the LBR call stack is enabled, it is necessary to save/restore
> the LBR stack on context switch. We can use pmu specific data to
> store LBR stack when task is scheduled out. This patch adds code
> that allocates the pmu specific data.
>
Reviewed-by: Stephane Eranian <eran...@google.com>
> Signed-off-by: Yan, Zheng <zheng.z....@intel.com>
> ---
> arch/x86/kernel/cpu/perf_event.c | 1 +
> arch/x86/kernel/cpu/perf_event.h | 7 +++++++
> 2 files changed, 8 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/perf_event.c
> b/arch/x86/kernel/cpu/perf_event.c
> index 69e2095..2e43f1b 100644
> --- a/arch/x86/kernel/cpu/perf_event.c
> +++ b/arch/x86/kernel/cpu/perf_event.c
> @@ -1879,6 +1879,7 @@ static struct pmu pmu = {
>
> .event_idx = x86_pmu_event_idx,
> .sched_task = x86_pmu_sched_task,
> + .task_ctx_size = sizeof(struct x86_perf_task_context),
> };
>
> void arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now)
> diff --git a/arch/x86/kernel/cpu/perf_event.h
> b/arch/x86/kernel/cpu/perf_event.h
> index 3ef4b79..3ed9629 100644
> --- a/arch/x86/kernel/cpu/perf_event.h
> +++ b/arch/x86/kernel/cpu/perf_event.h
> @@ -459,6 +459,13 @@ struct x86_pmu {
> struct perf_guest_switch_msr *(*guest_get_msrs)(int *nr);
> };
>
> +struct x86_perf_task_context {
> + u64 lbr_from[MAX_LBR_ENTRIES];
> + u64 lbr_to[MAX_LBR_ENTRIES];
> + int lbr_callstack_users;
> + int lbr_stack_state;
> +};
> +
> enum {
> PERF_SAMPLE_BRANCH_CALL_STACK_SHIFT = PERF_SAMPLE_BRANCH_MAX_SHIFT,
> PERF_SAMPLE_BRANCH_SELECT_MAP_SIZE,
> --
> 1.8.4.2
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
