[PATCH 5.10 254/290] perf/x86/intel: Set PERF_ATTACH_SCHED_CB for large PEBS and LBR

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>

[ Upstream commit afbef30149587ad46f4780b1e0cc5e219745ce90 ]

To supply a PID/TID for large PEBS, it requires flushing the PEBS buffer
in a context switch.

For normal LBRs, a context switch can flip the address space and LBR
entries are not tagged with an identifier, we need to wipe the LBR, even
for per-cpu events.

For LBR callstack, save/restore the stack is required during a context
switch.

Set PERF_ATTACH_SCHED_CB for the event with large PEBS & LBR.

Fixes: 9c964efa4330 ("perf/x86/intel: Drain the PEBS buffer during context switches")
Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20201130193842.10569-2-kan.liang@xxxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 arch/x86/events/intel/core.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index aaa7bffdb20f..4b05c876f9f6 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3565,8 +3565,10 @@ static int intel_pmu_hw_config(struct perf_event *event)
 		if (!(event->attr.freq || (event->attr.wakeup_events && !event->attr.watermark))) {
 			event->hw.flags |= PERF_X86_EVENT_AUTO_RELOAD;
 			if (!(event->attr.sample_type &
-			      ~intel_pmu_large_pebs_flags(event)))
+			      ~intel_pmu_large_pebs_flags(event))) {
 				event->hw.flags |= PERF_X86_EVENT_LARGE_PEBS;
+				event->attach_state |= PERF_ATTACH_SCHED_CB;
+			}
 		}
 		if (x86_pmu.pebs_aliases)
 			x86_pmu.pebs_aliases(event);
@@ -3579,6 +3581,7 @@ static int intel_pmu_hw_config(struct perf_event *event)
 		ret = intel_pmu_setup_lbr_filter(event);
 		if (ret)
 			return ret;
+		event->attach_state |= PERF_ATTACH_SCHED_CB;
 
 		/*
 		 * BTS is set up earlier in this path, so don't account twice
-- 
2.30.1






[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux