[RESEND PATCH v4 3/5] MIPS/Perf-events: Fix event check in validate_event()

From: Deng-Cheng Zhu
Date: Mon Jan 24 2011 - 02:36:09 EST

Ignore events that are in off/error state or belong to a different PMU.

This patch originates from the following commit for ARM by Will Deacon:

- 65b4711ff513767341aa1915c822de6ec0de65cb
ARM: 6352/1: perf: fix event validation

The validate_event function in the ARM perf events backend has the
following problems:

1.) Events that are disabled count towards the cost.
2.) Events associated with other PMUs [for example, software events or
breakpoints] do not count towards the cost, but do fail validation,
causing the group to fail.

This patch changes validate_event so that it ignores events in the
PERF_EVENT_STATE_OFF state or that are scheduled for other PMUs.

Acked-by: Will Deacon <will.deacon@xxxxxxx>
Acked-by: David Daney <ddaney@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@xxxxxxxxx>
v4 - v3:
o None
v3 - v2:
o Keep all mentioned commits in the form of number + title + original
summary + (MIPS specific info when needed).
v2 - v1:
o Corrected the return value of the event check in validate_event().

arch/mips/kernel/perf_event.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/mips/kernel/perf_event.c b/arch/mips/kernel/perf_event.c
index 1ee44a3..3d55761 100644
--- a/arch/mips/kernel/perf_event.c
+++ b/arch/mips/kernel/perf_event.c
@@ -486,8 +486,9 @@ static int validate_event(struct cpu_hw_events *cpuc,
struct hw_perf_event fake_hwc = event->hw;

- if (event->pmu && event->pmu != &pmu)
- return 0;
+ /* Allow mixed event group. So return 1 to pass validation. */
+ if (event->pmu != &pmu || event->state <= PERF_EVENT_STATE_OFF)
+ return 1;

return mipspmu->alloc_counter(cpuc, &fake_hwc) >= 0;

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