perf: Cleanup {start,commit,cancel}_txn details

Clarify some of the transactional group scheduling API details
and change it so that a successfull ->commit_txn also closes
the transaction.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1274803086.5882.1752.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

3 files changed, 13 insertions, 15 deletions

diff --git a/arch/powerpc/kernel/perf_event.c b/arch/powerpc/kernel/perf_event.c
index 43b83c3..ac2a8c2 100644
--- a/arch/powerpc/kernel/perf_event.c
+++ b/arch/powerpc/kernel/perf_event.c
@@ -754,7 +754,7 @@ static int power_pmu_enable(struct perf_event *event)
 	 * skip the schedulability test here, it will be peformed
 	 * at commit time(->commit_txn) as a whole
 	 */
-	if (cpuhw->group_flag & PERF_EVENT_TXN_STARTED)
+	if (cpuhw->group_flag & PERF_EVENT_TXN)
 		goto nocheck;
 
 	if (check_excludes(cpuhw->event, cpuhw->flags, n0, 1))
@@ -858,7 +858,7 @@ void power_pmu_start_txn(const struct pmu *pmu)
 {
 	struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
 
-	cpuhw->group_flag |= PERF_EVENT_TXN_STARTED;
+	cpuhw->group_flag |= PERF_EVENT_TXN;
 	cpuhw->n_txn_start = cpuhw->n_events;
 }
 
@@ -871,7 +871,7 @@ void power_pmu_cancel_txn(const struct pmu *pmu)
 {
 	struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
 
-	cpuhw->group_flag &= ~PERF_EVENT_TXN_STARTED;
+	cpuhw->group_flag &= ~PERF_EVENT_TXN;
 }
 
 /*
@@ -897,6 +897,7 @@ int power_pmu_commit_txn(const struct pmu *pmu)
 	for (i = cpuhw->n_txn_start; i < n; ++i)
 		cpuhw->event[i]->hw.config = cpuhw->events[i];
 
+	cpuhw->group_flag &= ~PERF_EVENT_TXN;
 	return 0;
 }
 
diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
index 0ec92c8..beeb92f 100644
--- a/arch/sparc/kernel/perf_event.c
+++ b/arch/sparc/kernel/perf_event.c
@@ -1005,7 +1005,7 @@ static int sparc_pmu_enable(struct perf_event *event)
 	 * skip the schedulability test here, it will be peformed
 	 * at commit time(->commit_txn) as a whole
 	 */
-	if (cpuc->group_flag & PERF_EVENT_TXN_STARTED)
+	if (cpuc->group_flag & PERF_EVENT_TXN)
 		goto nocheck;
 
 	if (check_excludes(cpuc->event, n0, 1))
@@ -1102,7 +1102,7 @@ static void sparc_pmu_start_txn(const struct pmu *pmu)
 {
 	struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
 
-	cpuhw->group_flag |= PERF_EVENT_TXN_STARTED;
+	cpuhw->group_flag |= PERF_EVENT_TXN;
 }
 
 /*
@@ -1114,7 +1114,7 @@ static void sparc_pmu_cancel_txn(const struct pmu *pmu)
 {
 	struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
 
-	cpuhw->group_flag &= ~PERF_EVENT_TXN_STARTED;
+	cpuhw->group_flag &= ~PERF_EVENT_TXN;
 }
 
 /*
@@ -1137,6 +1137,7 @@ static int sparc_pmu_commit_txn(const struct pmu *pmu)
 	if (sparc_check_constraints(cpuc->event, cpuc->events, n))
 		return -EAGAIN;
 
+	cpuc->group_flag &= ~PERF_EVENT_TXN;
 	return 0;
 }
 
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 5db5b7d..af04c6fa 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -969,7 +969,7 @@ static int x86_pmu_enable(struct perf_event *event)
 	 * skip the schedulability test here, it will be peformed
 	 * at commit time(->commit_txn) as a whole
 	 */
-	if (cpuc->group_flag & PERF_EVENT_TXN_STARTED)
+	if (cpuc->group_flag & PERF_EVENT_TXN)
 		goto out;
 
 	ret = x86_pmu.schedule_events(cpuc, n, assign);
@@ -1096,7 +1096,7 @@ static void x86_pmu_disable(struct perf_event *event)
 	 * The events never got scheduled and ->cancel_txn will truncate
 	 * the event_list.
 	 */
-	if (cpuc->group_flag & PERF_EVENT_TXN_STARTED)
+	if (cpuc->group_flag & PERF_EVENT_TXN)
 		return;
 
 	x86_pmu_stop(event);
@@ -1388,7 +1388,7 @@ static void x86_pmu_start_txn(const struct pmu *pmu)
 {
 	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
 
-	cpuc->group_flag |= PERF_EVENT_TXN_STARTED;
+	cpuc->group_flag |= PERF_EVENT_TXN;
 	cpuc->n_txn = 0;
 }
 
@@ -1401,7 +1401,7 @@ static void x86_pmu_cancel_txn(const struct pmu *pmu)
 {
 	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
 
-	cpuc->group_flag &= ~PERF_EVENT_TXN_STARTED;
+	cpuc->group_flag &= ~PERF_EVENT_TXN;
 	/*
 	 * Truncate the collected events.
 	 */
@@ -1435,11 +1435,7 @@ static int x86_pmu_commit_txn(const struct pmu *pmu)
 	 */
 	memcpy(cpuc->assign, assign, n*sizeof(int));
 
-	/*
-	 * Clear out the txn count so that ->cancel_txn() which gets
-	 * run after ->commit_txn() doesn't undo things.
-	 */
-	cpuc->n_txn = 0;
+	cpuc->group_flag &= ~PERF_EVENT_TXN;
 
 	return 0;
 }