[tip:perf/core] perf/core: Let userspace know if the PMU supports address filters

tip-bot for Alexander Shishkin
2016-05-05T09:48:49Z

Commit-ID: 6e855cd4f4b5258016cf707f94f96bfa51c32f32
Gitweb: http://git.kernel.org/tip/6e855cd4f4b5258016cf707f94f96bfa51c32f32
Author: Alexander Shishkin <alexander.shishkin@linux.intel.com>
AuthorDate: Wed, 27 Apr 2016 18:44:48 +0300
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 5 May 2016 10:13:58 +0200

perf/core: Let userspace know if the PMU supports address filters

Export an additional common attribute for PMUs that support address range
filtering to let the perf userspace identify such PMUs in a uniform way.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: vince@deater.net
Link: http://lkml.kernel.org/r/1461771888-10409-8-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/events/core.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index ffdc096..63be654 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8273,6 +8273,20 @@ static void free_pmu_context(struct pmu *pmu)
out:
mutex_unlock(&pmus_lock);
}
+
+/*
+ * Let userspace know that this PMU supports address range filtering:
+ */
+static ssize_t nr_addr_filters_show(struct device *dev,
+ struct device_attribute *attr,
+ char *page)
+{
+ struct pmu *pmu = dev_get_drvdata(dev);
+
+ return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
+}
+DEVICE_ATTR_RO(nr_addr_filters);
+
static struct idr pmu_idr;

static ssize_t
@@ -8374,9 +8388,19 @@ static int pmu_dev_alloc(struct pmu *pmu)
if (ret)
goto free_dev;

+ /* For PMUs with address filters, throw in an extra attribute: */
+ if (pmu->nr_addr_filters)
+ ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
+
+ if (ret)
+ goto del_dev;
+
out:
return ret;

+del_dev:
+ device_del(pmu->dev);
+
free_dev:
put_device(pmu->dev);
goto out;
@@ -8512,6 +8536,8 @@ void perf_pmu_unregister(struct pmu *pmu)
free_percpu(pmu->pmu_disable_count);
if (pmu->type >= PERF_TYPE_MAX)
idr_remove(&pmu_idr, pmu->type);
+ if (pmu->nr_addr_filters)
+ device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
device_del(pmu->dev);
put_device(pmu->dev);
free_pmu_context(pmu);