[PATCH 1/4] perf: Add 'flags' parameter to pmu txn interfaces

@@ -1573,10 +1573,13 @@ static void power_pmu_stop(struct perf_event *event, int ef_flags)
  * Set the flag to make pmu::enable() not perform the
  * schedulability test, it will be performed at commit time
  */
-static void power_pmu_start_txn(struct pmu *pmu)
+static void power_pmu_start_txn(struct pmu *pmu, int flags)
 {
 	struct cpu_hw_events *cpuhw = this_cpu_ptr(&cpu_hw_events);
 
+	if (flags & ~PERF_PMU_TXN_ADD)
+		return;
+
 	perf_pmu_disable(pmu);
 	cpuhw->group_flag |= PERF_EVENT_TXN;
 	cpuhw->n_txn_start = cpuhw->n_events;

@@ -1587,10 +1590,13 @@ static void power_pmu_start_txn(struct pmu *pmu)
  * Clear the flag and pmu::enable() will perform the
  * schedulability test.
  */
-static void power_pmu_cancel_txn(struct pmu *pmu)
+static void power_pmu_cancel_txn(struct pmu *pmu, int flags)
 {
 	struct cpu_hw_events *cpuhw = this_cpu_ptr(&cpu_hw_events);
 
+	if (flags & ~PERF_PMU_TXN_ADD)
+		return;
+
 	cpuhw->group_flag &= ~PERF_EVENT_TXN;
 	perf_pmu_enable(pmu);
 }

@@ -1600,11 +1606,14 @@ static void power_pmu_cancel_txn(struct pmu *pmu)
  * Perform the group schedulability test as a whole
  * Return 0 if success
  */
-static int power_pmu_commit_txn(struct pmu *pmu)
+static int power_pmu_commit_txn(struct pmu *pmu, int flags)
 {
 	struct cpu_hw_events *cpuhw;
 	long i, n;
 
+	if (flags & ~PERF_PMU_TXN_ADD)
+		return -EINVAL;
+
 	if (!ppmu)
 		return -EAGAIN;
 	cpuhw = this_cpu_ptr(&cpu_hw_events);

@@ -1607,8 +1607,11 @@ static inline void x86_pmu_read(struct perf_event *event)
  * Set the flag to make pmu::enable() not perform the
  * schedulability test, it will be performed at commit time
  */
-static void x86_pmu_start_txn(struct pmu *pmu)
+static void x86_pmu_start_txn(struct pmu *pmu, int flags)
 {
+	if (flags & ~PERF_PMU_TXN_ADD)
+		return;
+
 	perf_pmu_disable(pmu);
 	__this_cpu_or(cpu_hw_events.group_flag, PERF_EVENT_TXN);
 	__this_cpu_write(cpu_hw_events.n_txn, 0);

@@ -1619,8 +1622,11 @@ static void x86_pmu_start_txn(struct pmu *pmu)
  * Clear the flag and pmu::enable() will perform the
  * schedulability test.
  */
-static void x86_pmu_cancel_txn(struct pmu *pmu)
+static void x86_pmu_cancel_txn(struct pmu *pmu, int flags)
 {
+	if (flags & ~PERF_PMU_TXN_ADD)
+		return;
+
 	__this_cpu_and(cpu_hw_events.group_flag, ~PERF_EVENT_TXN);
 	/*
 	 * Truncate collected array by the number of events added in this

@@ -1638,12 +1644,15 @@ static void x86_pmu_cancel_txn(struct pmu *pmu)
  *
  * Does not cancel the transaction on failure; expects the caller to do this.
  */
-static int x86_pmu_commit_txn(struct pmu *pmu)
+static int x86_pmu_commit_txn(struct pmu *pmu, int flags)
 {
 	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
 	int assign[X86_PMC_IDX_MAX];
 	int n, ret;
 
+	if (flags & ~PERF_PMU_TXN_ADD)
+		return -EINVAL;
+
 	n = cpuc->n_events;
 
 	if (!x86_pmu_initialized())

@@ -225,6 +225,8 @@ struct pmu {
 	 * should stop the counter when perf_event_overflow() returns
 	 * !0. ->start() will be used to continue.
 	 */
+#define	PERF_PMU_TXN_ADD	1
+#define	PERF_PMU_TXN_READ	2
 	void (*start)			(struct perf_event *event, int flags);
 	void (*stop)			(struct perf_event *event, int flags);
 

@@ -240,20 +242,26 @@ struct pmu {
 	 *
 	 * Start the transaction, after this ->add() doesn't need to
 	 * do schedulability tests.
+	 *
+	 * Optional.
 	 */
-	void (*start_txn)		(struct pmu *pmu); /* optional */
+	void (*start_txn)		(struct pmu *pmu, int flags);
 	/*
 	 * If ->start_txn() disabled the ->add() 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.
+	 *
+	 * Optional.
 	 */
-	int  (*commit_txn)		(struct pmu *pmu); /* optional */
+	int  (*commit_txn)		(struct pmu *pmu, int flags);
 	/*
 	 * Will cancel the transaction, assumes ->del() is called
 	 * for each successful ->add() during the transaction.
+	 *
+	 * Optional.
 	 */
-	void (*cancel_txn)		(struct pmu *pmu); /* optional */
+	void (*cancel_txn)		(struct pmu *pmu, int flags);
 
 	/*
 	 * Will return the value for perf_event_mmap_page::index for this event,

@@ -1924,10 +1924,10 @@ group_sched_in(struct perf_event *group_event,
 	if (group_event->state == PERF_EVENT_STATE_OFF)
 		return 0;
 
-	pmu->start_txn(pmu);
+	pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
 
 	if (event_sched_in(group_event, cpuctx, ctx)) {
-		pmu->cancel_txn(pmu);
+		pmu->cancel_txn(pmu, PERF_PMU_TXN_ADD);
 		perf_cpu_hrtimer_restart(cpuctx);
 		return -EAGAIN;
 	}

@@ -1942,7 +1942,7 @@ group_sched_in(struct perf_event *group_event,
 		}
 	}
 
-	if (!pmu->commit_txn(pmu))
+	if (!pmu->commit_txn(pmu, PERF_PMU_TXN_ADD))
 		return 0;
 
 group_error:

@@ -1973,7 +1973,7 @@ group_error:
 	}
 	event_sched_out(group_event, cpuctx, ctx);
 
-	pmu->cancel_txn(pmu);
+	pmu->cancel_txn(pmu, PERF_PMU_TXN_ADD);
 
 	perf_cpu_hrtimer_restart(cpuctx);
 

@@ -6718,23 +6718,27 @@ static void perf_pmu_nop_void(struct pmu *pmu)
 {
 }
 
-static int perf_pmu_nop_int(struct pmu *pmu)
+static void perf_pmu_nop_txn(struct pmu *pmu, int flags)
+{
+}
+
+static int perf_pmu_nop_txn_int(struct pmu *pmu, int flags)
 {
 	return 0;
 }
 
-static void perf_pmu_start_txn(struct pmu *pmu)
+static void perf_pmu_start_txn(struct pmu *pmu, int flags)
 {
 	perf_pmu_disable(pmu);
 }
 
-static int perf_pmu_commit_txn(struct pmu *pmu)
+static int perf_pmu_commit_txn(struct pmu *pmu, int flags)
 {
 	perf_pmu_enable(pmu);
 	return 0;
 }
 
-static void perf_pmu_cancel_txn(struct pmu *pmu)
+static void perf_pmu_cancel_txn(struct pmu *pmu, int flags)
 {
 	perf_pmu_enable(pmu);
 }

@@ -6968,9 +6972,9 @@ got_cpu_context:
 			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;
+			pmu->start_txn  = perf_pmu_nop_txn;
+			pmu->commit_txn = perf_pmu_nop_txn_int;
+			pmu->cancel_txn = perf_pmu_nop_txn;
 		}
 	}