perf, x86: implement group scheduling transactional APIs

Convert to the transactional PMU API and remove the duplication of
group_sched_in().

Reviewed-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Miller <davem@davemloft.net>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1272002172.5707.61.camel@minggr.sh.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 27fa9ee..fd4db0d 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -110,6 +110,8 @@ struct cpu_hw_events {
        u64                     tags[X86_PMC_IDX_MAX];
        struct perf_event       *event_list[X86_PMC_IDX_MAX]; /* in enabled order */
 
+       unsigned int            group_flag;
+
        /*
         * Intel DebugStore bits
         */
@@ -961,6 +963,14 @@ static int x86_pmu_enable(struct perf_event *event)
        if (n < 0)
                return n;
 
+       /*
+        * If group events scheduling transaction was started,
+        * 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)
+               goto out;
+
        ret = x86_pmu.schedule_events(cpuc, n, assign);
        if (ret)
                return ret;
@@ -970,6 +980,7 @@ static int x86_pmu_enable(struct perf_event *event)
         */
        memcpy(cpuc->assign, assign, n*sizeof(int));
 
+out:
        cpuc->n_events = n;
        cpuc->n_added += n - n0;
 
@@ -1227,119 +1238,6 @@ x86_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event)
        return &unconstrained;
 }
 
-static int x86_event_sched_in(struct perf_event *event,
-                         struct perf_cpu_context *cpuctx)
-{
-       int ret = 0;
-
-       event->state = PERF_EVENT_STATE_ACTIVE;
-       event->oncpu = smp_processor_id();
-       event->tstamp_running += event->ctx->time - event->tstamp_stopped;
-
-       if (!is_x86_event(event))
-               ret = event->pmu->enable(event);
-
-       if (!ret && !is_software_event(event))
-               cpuctx->active_oncpu++;
-
-       if (!ret && event->attr.exclusive)
-               cpuctx->exclusive = 1;
-
-       return ret;
-}
-
-static void x86_event_sched_out(struct perf_event *event,
-                           struct perf_cpu_context *cpuctx)
-{
-       event->state = PERF_EVENT_STATE_INACTIVE;
-       event->oncpu = -1;
-
-       if (!is_x86_event(event))
-               event->pmu->disable(event);
-
-       event->tstamp_running -= event->ctx->time - event->tstamp_stopped;
-
-       if (!is_software_event(event))
-               cpuctx->active_oncpu--;
-
-       if (event->attr.exclusive || !cpuctx->active_oncpu)
-               cpuctx->exclusive = 0;
-}
-
-/*
- * Called to enable a whole group of events.
- * Returns 1 if the group was enabled, or -EAGAIN if it could not be.
- * Assumes the caller has disabled interrupts and has
- * frozen the PMU with hw_perf_save_disable.
- *
- * called with PMU disabled. If successful and return value 1,
- * then guaranteed to call perf_enable() and hw_perf_enable()
- */
-int hw_perf_group_sched_in(struct perf_event *leader,
-              struct perf_cpu_context *cpuctx,
-              struct perf_event_context *ctx)
-{
-       struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
-       struct perf_event *sub;
-       int assign[X86_PMC_IDX_MAX];
-       int n0, n1, ret;
-
-       if (!x86_pmu_initialized())
-               return 0;
-
-       /* n0 = total number of events */
-       n0 = collect_events(cpuc, leader, true);
-       if (n0 < 0)
-               return n0;
-
-       ret = x86_pmu.schedule_events(cpuc, n0, assign);
-       if (ret)
-               return ret;
-
-       ret = x86_event_sched_in(leader, cpuctx);
-       if (ret)
-               return ret;
-
-       n1 = 1;
-       list_for_each_entry(sub, &leader->sibling_list, group_entry) {
-               if (sub->state > PERF_EVENT_STATE_OFF) {
-                       ret = x86_event_sched_in(sub, cpuctx);
-                       if (ret)
-                               goto undo;
-                       ++n1;
-               }
-       }
-       /*
-        * copy new assignment, now we know it is possible
-        * will be used by hw_perf_enable()
-        */
-       memcpy(cpuc->assign, assign, n0*sizeof(int));
-
-       cpuc->n_events  = n0;
-       cpuc->n_added  += n1;
-       ctx->nr_active += n1;
-
-       /*
-        * 1 means successful and events are active
-        * This is not quite true because we defer
-        * actual activation until hw_perf_enable() but
-        * this way we* ensure caller won't try to enable
-        * individual events
-        */
-       return 1;
-undo:
-       x86_event_sched_out(leader, cpuctx);
-       n0  = 1;
-       list_for_each_entry(sub, &leader->sibling_list, group_entry) {
-               if (sub->state == PERF_EVENT_STATE_ACTIVE) {
-                       x86_event_sched_out(sub, cpuctx);
-                       if (++n0 == n1)
-                               break;
-               }
-       }
-       return ret;
-}
-
 #include "perf_event_amd.c"
 #include "perf_event_p6.c"
 #include "perf_event_p4.c"
@@ -1471,6 +1369,59 @@ static inline void x86_pmu_read(struct perf_event *event)
        x86_perf_event_update(event);
 }
 
+/*
+ * Start group events scheduling transaction
+ * 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(const struct pmu *pmu)
+{
+       struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+
+       cpuc->group_flag |= PERF_EVENT_TXN_STARTED;
+}
+
+/*
+ * Stop group events scheduling transaction
+ * Clear the flag and pmu::enable() will perform the
+ * schedulability test.
+ */
+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;
+}
+
+/*
+ * Commit group events scheduling transaction
+ * Perform the group schedulability test as a whole
+ * Return 0 if success
+ */
+static int x86_pmu_commit_txn(const struct pmu *pmu)
+{
+       struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+       int assign[X86_PMC_IDX_MAX];
+       int n, ret;
+
+       n = cpuc->n_events;
+
+       if (!x86_pmu_initialized())
+               return -EAGAIN;
+
+       ret = x86_pmu.schedule_events(cpuc, n, assign);
+       if (ret)
+               return ret;
+
+       /*
+        * copy new assignment, now we know it is possible
+        * will be used by hw_perf_enable()
+        */
+       memcpy(cpuc->assign, assign, n*sizeof(int));
+
+       return 0;
+}
+
 static const struct pmu pmu = {
        .enable         = x86_pmu_enable,
        .disable        = x86_pmu_disable,
@@ -1478,6 +1429,9 @@ static const struct pmu pmu = {
        .stop           = x86_pmu_stop,
        .read           = x86_pmu_read,
        .unthrottle     = x86_pmu_unthrottle,
+       .start_txn      = x86_pmu_start_txn,
+       .cancel_txn     = x86_pmu_cancel_txn,
+       .commit_txn     = x86_pmu_commit_txn,
 };
 
 /*