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Commit ad5133b7 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf: Default PMU ops 



Provide default implementations for the pmu txn methods, this
allows us to remove some conditional code.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus <paulus@samba.org>
Cc: stephane eranian <eranian@googlemail.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Lin Ming <ming.m.lin@intel.com>
Cc: Yanmin <yanmin_zhang@linux.intel.com>
Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Cc: David Miller <davem@davemloft.net>
Cc: Michael Cree <mcree@orcon.net.nz>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 33696fc0

include/linux/perf_event.h

+5 −5
Original line number Diff line number Diff line
@@ -565,8 +565,8 @@ struct pmu { 


	int				*pmu_disable_count;



	void (*pmu_enable)		(struct pmu *pmu);

	void (*pmu_disable)		(struct pmu *pmu);

	void (*pmu_enable)		(struct pmu *pmu); /* optional */

	void (*pmu_disable)		(struct pmu *pmu); /* optional */



	/*

	 * Should return -ENOENT when the @event doesn't match this PMU.
@@ -590,19 +590,19 @@ struct pmu { 
	 * Start the transaction, after this ->enable() doesn't need to

	 * do schedulability tests.

	 */

	void (*start_txn)	(struct pmu *pmu);

	void (*start_txn)	(struct pmu *pmu); /* optional */

	/*

	 * If ->start_txn() disabled the ->enable() schedulability test

	 * then ->commit_txn() is required to perform one. On success

	 * the transaction is closed. On error the transaction is kept

	 * open until ->cancel_txn() is called.

	 */

	int  (*commit_txn)	(struct pmu *pmu);

	int  (*commit_txn)	(struct pmu *pmu); /* optional */

	/*

	 * Will cancel the transaction, assumes ->disable() is called

	 * for each successfull ->enable() during the transaction.

	 */

	void (*cancel_txn)	(struct pmu *pmu);

	void (*cancel_txn)	(struct pmu *pmu); /* optional */

};



/**

kernel/perf_event.c

+52 −12
Original line number Diff line number Diff line
@@ -674,20 +674,13 @@ group_sched_in(struct perf_event *group_event, 
{

	struct perf_event *event, *partial_group = NULL;

	struct pmu *pmu = group_event->pmu;

	bool txn = false;



	if (group_event->state == PERF_EVENT_STATE_OFF)

		return 0;



	/* Check if group transaction availabe */

	if (pmu->start_txn)

		txn = true;



	if (txn)

	pmu->start_txn(pmu);



	if (event_sched_in(group_event, cpuctx, ctx)) {

		if (txn)

		pmu->cancel_txn(pmu);

		return -EAGAIN;

	}
@@ -702,7 +695,7 @@ group_sched_in(struct perf_event *group_event, 
		}

	}



	if (!txn || !pmu->commit_txn(pmu))

	if (!pmu->commit_txn(pmu))

		return 0;



group_error:
@@ -717,7 +710,6 @@ group_sched_in(struct perf_event *group_event, 
	}

	event_sched_out(group_event, cpuctx, ctx);



	if (txn)

	pmu->cancel_txn(pmu);



	return -EAGAIN;
@@ -4965,6 +4957,31 @@ static LIST_HEAD(pmus); 
static DEFINE_MUTEX(pmus_lock);

static struct srcu_struct pmus_srcu;



static void perf_pmu_nop_void(struct pmu *pmu)

{

}



static int perf_pmu_nop_int(struct pmu *pmu)

{

	return 0;

}



static void perf_pmu_start_txn(struct pmu *pmu)

{

	perf_pmu_disable(pmu);

}



static int perf_pmu_commit_txn(struct pmu *pmu)

{

	perf_pmu_enable(pmu);

	return 0;

}



static void perf_pmu_cancel_txn(struct pmu *pmu)

{

	perf_pmu_enable(pmu);

}



int perf_pmu_register(struct pmu *pmu)

{

	int ret;
@@ -4974,6 +4991,29 @@ int perf_pmu_register(struct pmu *pmu) 
	pmu->pmu_disable_count = alloc_percpu(int);

	if (!pmu->pmu_disable_count)

		goto unlock;



	if (!pmu->start_txn) {

		if (pmu->pmu_enable) {

			/*

			 * If we have pmu_enable/pmu_disable calls, install

			 * transaction stubs that use that to try and batch

			 * hardware accesses.

			 */

			pmu->start_txn  = perf_pmu_start_txn;

			pmu->commit_txn = perf_pmu_commit_txn;

			pmu->cancel_txn = perf_pmu_cancel_txn;

		} else {

			pmu->start_txn  = perf_pmu_nop_void;

			pmu->commit_txn = perf_pmu_nop_int;

			pmu->cancel_txn = perf_pmu_nop_void;

		}

	}



	if (!pmu->pmu_enable) {

		pmu->pmu_enable  = perf_pmu_nop_void;

		pmu->pmu_disable = perf_pmu_nop_void;

	}



	list_add_rcu(&pmu->entry, &pmus);

	ret = 0;

unlock: