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Commit e18bf526 authored by Yan, Zheng's avatar Yan, Zheng Committed by Ingo Molnar
Browse files

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: default avatarYan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: default avatarKan Liang <kan.liang@intel.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarStephane 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: default avatarIngo Molnar <mingo@kernel.org>
parent 5a158c3c

arch/x86/kernel/cpu/perf_event.c

+4 −0
Original line number Diff line number Diff line
@@ -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,

arch/x86/kernel/cpu/perf_event.h

+7 −0
Original line number Diff line number Diff line
@@ -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,