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perf: Disable sampled events if no PMU interrupt

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Add common code to generate -ENOTSUPP at event creation time if an
architecture attempts to create a sampled event and
PERF_PMU_NO_INTERRUPT is set.

This adds a new pmu->capabilities flag.  Initially we only support
PERF_PMU_NO_INTERRUPT (to indicate a PMU has no support for generating
hardware interrupts) but there are other capabilities that can be
added later.

Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Acked-by: Will Deacon <will.deacon@arm.com>
[peterz: rename to PERF_PMU_CAP_* and moved the pmu::capabilities word into a hole]
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1405161708060.11099@vincent-weaver-1.umelst.maine.edu
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Vince Weaver 2014-05-16 17:12:12 -04:00 committed by Ingo Molnar
parent ebf905fc7a
commit 53b25335dd
2 changed files with 17 additions and 0 deletions
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10
include/linux/perf_event.h
View File

@ -166,6 +166,11 @@ struct perf_event;
*/
#define PERF_EVENT_TXN 0x1
/**
* pmu::capabilities flags
*/
#define PERF_PMU_CAP_NO_INTERRUPT 0x01
/**
* struct pmu - generic performance monitoring unit
*/
@ -178,6 +183,11 @@ struct pmu {
const char *name;
int type;
/*
* various common per-pmu feature flags
*/
int capabilities;
int * __percpu pmu_disable_count;
struct perf_cpu_context * __percpu pmu_cpu_context;
int task_ctx_nr;

7
kernel/events/core.c
View File

@ -7120,6 +7120,13 @@ SYSCALL_DEFINE5(perf_event_open,
}
}
if (is_sampling_event(event)) {
if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
err = -ENOTSUPP;
goto err_alloc;
}
}
account_event(event);
/*