Commit c464c76e authored by Yan, Zheng's avatar Yan, Zheng Committed by Ingo Molnar
Browse files

perf: Allow building PMU drivers as modules 



This patch adds support for building PMU driver as module. It exports
the functions perf_pmu_{register,unregister}() and adds reference tracking
for the PMU driver module.

When the PMU driver is built as a module, each active event of the PMU
holds a reference to the driver module.

Signed-off-by: default avatarYan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1395133004-23205-1-git-send-email-zheng.z.yan@intel.com


Cc: eranian@google.com
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 1111b680

include/linux/perf_event.h

+1 −0
Original line number Diff line number Diff line
@@ -172,6 +172,7 @@ struct perf_event; 
struct pmu {

	struct list_head		entry;



	struct module			*module;

	struct device			*dev;

	const struct attribute_group	**attr_groups;

	const char			*name;

kernel/events/core.c

+15 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ 
#include <linux/hw_breakpoint.h>

#include <linux/mm_types.h>

#include <linux/cgroup.h>

#include <linux/module.h>



#include "internal.h"
@@ -3229,6 +3230,9 @@ static void __free_event(struct perf_event *event) 
	if (event->ctx)

		put_ctx(event->ctx);



	if (event->pmu)

		module_put(event->pmu->module);



	call_rcu(&event->rcu_head, free_event_rcu);

}

static void free_event(struct perf_event *event)
@@ -6551,6 +6555,7 @@ free_pdc: 
	free_percpu(pmu->pmu_disable_count);

	goto unlock;

}

EXPORT_SYMBOL_GPL(perf_pmu_register);



void perf_pmu_unregister(struct pmu *pmu)

{
@@ -6572,6 +6577,7 @@ void perf_pmu_unregister(struct pmu *pmu) 
	put_device(pmu->dev);

	free_pmu_context(pmu);

}

EXPORT_SYMBOL_GPL(perf_pmu_unregister);



struct pmu *perf_init_event(struct perf_event *event)

{
@@ -6585,6 +6591,10 @@ struct pmu *perf_init_event(struct perf_event *event) 
	pmu = idr_find(&pmu_idr, event->attr.type);

	rcu_read_unlock();

	if (pmu) {

		if (!try_module_get(pmu->module)) {

			pmu = ERR_PTR(-ENODEV);

			goto unlock;

		}

		event->pmu = pmu;

		ret = pmu->event_init(event);

		if (ret)
@@ -6593,6 +6603,10 @@ struct pmu *perf_init_event(struct perf_event *event) 
	}



	list_for_each_entry_rcu(pmu, &pmus, entry) {

		if (!try_module_get(pmu->module)) {

			pmu = ERR_PTR(-ENODEV);

			goto unlock;

		}

		event->pmu = pmu;

		ret = pmu->event_init(event);

		if (!ret)
@@ -6771,6 +6785,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, 
err_pmu:

	if (event->destroy)

		event->destroy(event);

	module_put(pmu->module);

err_ns:

	if (event->ns)

		put_pid_ns(event->ns);

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