[PATCH v4 07/10] perf: simplify and rename visit_groups_merge

[Ian Rogers]

To enable a future caching optimization, pass in whether
visit_groups_merge is operating on pinned or flexible groups. The
is_pinned argument makes the func argument redundant, rename the
function to ctx_groups_sched_in as it just schedules pinned or flexible
groups in. Compute the cpu and groups arguments locally to reduce the
argument list size. Remove sched_in_data as it repeats arguments already
passed in. Merge pinned_sched_in and flexible_sched_in and use the
pinned argument to determine the active list.

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 kernel/events/core.c | 149 ++++++++++++++-----------------------------
 1 file changed, 49 insertions(+), 100 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index f26871ef352a..948a66967eb5 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2118,7 +2118,6 @@ static void perf_group_detach(struct perf_event *event)
 
 		if (!RB_EMPTY_NODE(&event->group_node)) {
 			add_event_to_groups(sibling, event->ctx);
-
 			if (sibling->state == PERF_EVENT_STATE_ACTIVE) {
 				struct list_head *list = sibling->attr.pinned ?
 					&ctx->pinned_active : &ctx->flexible_active;
@@ -2441,6 +2440,8 @@ event_sched_in(struct perf_event *event,
 {
 	int ret = 0;
 
+	WARN_ON_ONCE(event->ctx != ctx);
+
 	lockdep_assert_held(&ctx->lock);
 
 	if (event->state <= PERF_EVENT_STATE_OFF)
@@ -3509,10 +3510,42 @@ static void __heap_add(struct min_max_heap *heap, struct perf_event *event)
 	}
 }
 
-static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
-				struct perf_event_groups *groups, int cpu,
-				int (*func)(struct perf_event *, void *),
-				void *data)
+static int merge_sched_in(struct perf_event_context *ctx,
+			struct perf_cpu_context *cpuctx,
+			struct perf_event *event,
+			bool is_pinned,
+			int *can_add_hw)
+{
+	WARN_ON_ONCE(event->ctx != ctx);
+
+	if (event->state <= PERF_EVENT_STATE_OFF)
+		return 0;
+
+	if (!event_filter_match(event))
+		return 0;
+
+	if (group_can_go_on(event, cpuctx, 1)) {
+		if (!group_sched_in(event, cpuctx, ctx)) {
+			list_add_tail(&event->active_list, is_pinned
+				? &ctx->pinned_active
+				: &ctx->flexible_active);
+		}
+	}
+
+	if (event->state == PERF_EVENT_STATE_INACTIVE) {
+		if (is_pinned)
+			perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
+
+		*can_add_hw = 0;
+		ctx->rotate_necessary = 1;
+	}
+
+	return 0;
+}
+
+static int ctx_groups_sched_in(struct perf_event_context *ctx,
+			struct perf_cpu_context *cpuctx,
+			bool is_pinned)
 {
 #ifdef CONFIG_CGROUP_PERF
 	struct cgroup_subsys_state *css = NULL;
@@ -3522,9 +3555,13 @@ static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
 	struct min_max_heap event_heap;
 	struct perf_event **evt;
 	struct perf_event *next;
-	int ret;
+	int ret, can_add_hw = 1;
+	int cpu = smp_processor_id();
+	struct perf_event_groups *groups = is_pinned
+		? &ctx->pinned_groups
+		: &ctx->flexible_groups;
 
-	if (cpuctx) {
+	if (ctx == &cpuctx->ctx) {
 		event_heap = (struct min_max_heap){
 			.data = cpuctx->itr_storage,
 			.size = 0,
@@ -3561,7 +3598,8 @@ static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
 	min_max_heapify_all(&event_heap, &perf_min_heap);
 
 	while (event_heap.size) {
-		ret = func(*evt, data);
+		ret = merge_sched_in(ctx, cpuctx, *evt, is_pinned, &can_add_hw);
+
 		if (ret)
 			return ret;
 
@@ -3576,96 +3614,6 @@ static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
 	return 0;
 }
 
-struct sched_in_data {
-	struct perf_event_context *ctx;
-	struct perf_cpu_context *cpuctx;
-	int can_add_hw;
-};
-
-static int pinned_sched_in(struct perf_event *event, void *data)
-{
-	struct sched_in_data *sid = data;
-
-	if (event->state <= PERF_EVENT_STATE_OFF)
-		return 0;
-
-	if (!event_filter_match(event))
-		return 0;
-
-	if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
-		if (!group_sched_in(event, sid->cpuctx, sid->ctx))
-			list_add_tail(&event->active_list, &sid->ctx->pinned_active);
-	}
-
-	/*
-	 * If this pinned group hasn't been scheduled,
-	 * put it in error state.
-	 */
-	if (event->state == PERF_EVENT_STATE_INACTIVE)
-		perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
-
-	return 0;
-}
-
-static int flexible_sched_in(struct perf_event *event, void *data)
-{
-	struct sched_in_data *sid = data;
-
-	if (event->state <= PERF_EVENT_STATE_OFF)
-		return 0;
-
-	if (!event_filter_match(event))
-		return 0;
-
-	if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
-		int ret = group_sched_in(event, sid->cpuctx, sid->ctx);
-		if (ret) {
-			sid->can_add_hw = 0;
-			sid->ctx->rotate_necessary = 1;
-			return 0;
-		}
-		list_add_tail(&event->active_list, &sid->ctx->flexible_active);
-	}
-
-	return 0;
-}
-
-static void
-ctx_pinned_sched_in(struct perf_event_context *ctx,
-		    struct perf_cpu_context *cpuctx)
-{
-	struct sched_in_data sid = {
-		.ctx = ctx,
-		.cpuctx = cpuctx,
-		.can_add_hw = 1,
-	};
-
-	if (ctx != &cpuctx->ctx)
-		cpuctx = NULL;
-
-	visit_groups_merge(cpuctx, &ctx->pinned_groups,
-			   smp_processor_id(),
-			   pinned_sched_in, &sid);
-}
-
-static void
-ctx_flexible_sched_in(struct perf_event_context *ctx,
-		      struct perf_cpu_context *cpuctx)
-{
-	struct sched_in_data sid = {
-		.ctx = ctx,
-		.cpuctx = cpuctx,
-		.can_add_hw = 1,
-	};
-
-	if (ctx != &cpuctx->ctx)
-		cpuctx = NULL;
-
-	visit_groups_merge(cpuctx, &ctx->flexible_groups,
-			   smp_processor_id(),
-			   flexible_sched_in, &sid);
-}
-
 static void
 ctx_sched_in(struct perf_event_context *ctx,
 	     struct perf_cpu_context *cpuctx,
@@ -3702,11 +3650,12 @@ ctx_sched_in(struct perf_event_context *ctx,
 	 * in order to give them the best chance of going on.
 	 */
 	if (is_active & EVENT_PINNED)
-		ctx_pinned_sched_in(ctx, cpuctx);
+		ctx_groups_sched_in(ctx, cpuctx, /*is_pinned=*/true);
+
 
 	/* Then walk through the lower prio flexible groups */
 	if (is_active & EVENT_FLEXIBLE)
-		ctx_flexible_sched_in(ctx, cpuctx);
+		ctx_groups_sched_in(ctx, cpuctx, /*is_pinned=*/false);
 }
 
 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
-- 
2.24.0.432.g9d3f5f5b63-goog