perf/x86/intel: Allocate space for storing LBR stack

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.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Stephane Eranian <eranian@google.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: jolsa@redhat.com
Link: http://lkml.kernel.org/r/1415156173-10035-8-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 6b1fd26a37cf6f09e6e06627652bb06a91bdeaf3..8ffd71ec2173a3dfd4bb659cbacba585ba481fb0 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -432,6 +432,9 @@ int x86_pmu_hw_config(struct perf_event *event)
                }
        }
 
+       if (event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_CALL_STACK)
+               event->attach_state |= PERF_ATTACH_TASK_DATA;
+
        /*
         * Generate PMC IRQs:
         * (keep 'enabled' bit clear for now)
@@ -1950,6 +1953,7 @@ 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 *event,

diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index c9a62c5bca75a3ee41973ae6f39b55dcd250eb6a..69c26b396cf43fa5ec47f82b4867a0f8893e8955 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -516,6 +516,13 @@ 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,