linux-kernel - [PATCH AUTOSEL 4.9 16/74] perf/x86/intel: Allow PEBS multi-entry in watermark mode

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Date:   Sat,  1 Jun 2019 09:24:03 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Stephane Eranian <eranian@...gle.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>, jolsa@...hat.com,
        kan.liang@...el.com, vincent.weaver@...ne.edu,
        Ingo Molnar <mingo@...nel.org>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 4.9 16/74] perf/x86/intel: Allow PEBS multi-entry in watermark mode

From: Stephane Eranian <eranian@...gle.com>

[ Upstream commit c7a286577d7592720c2f179aadfb325a1ff48c95 ]

This patch fixes a restriction/bug introduced by:

   583feb08e7f7 ("perf/x86/intel: Fix handling of wakeup_events for multi-entry PEBS")

The original patch prevented using multi-entry PEBS when wakeup_events != 0.
However given that wakeup_events is part of a union with wakeup_watermark, it
means that in watermark mode, PEBS multi-entry is also disabled which is not the
intent. This patch fixes this by checking is watermark mode is enabled.

Signed-off-by: Stephane Eranian <eranian@...gle.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: jolsa@...hat.com
Cc: kan.liang@...el.com
Cc: vincent.weaver@...ne.edu
Fixes: 583feb08e7f7 ("perf/x86/intel: Fix handling of wakeup_events for multi-entry PEBS")
Link: http://lkml.kernel.org/r/20190514003400.224340-1-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/x86/events/intel/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index cb8178a2783a8..e98e238d37750 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -2867,7 +2867,7 @@ static int intel_pmu_hw_config(struct perf_event *event)
 		return ret;
 
 	if (event->attr.precise_ip) {
-		if (!(event->attr.freq || event->attr.wakeup_events)) {
+		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_free_running_flags(event)))
-- 
2.20.1