Commit 836196be authored by Ian Rogers's avatar Ian Rogers Committed by Ingo Molnar
Browse files

perf/core: Add per perf_cpu_context min_heap storage 



The storage required for visit_groups_merge's min heap needs to vary in
order to support more iterators, such as when multiple nested cgroups'
events are being visited. This change allows for 2 iterators and doesn't
support growth.

Based-on-work-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIan Rogers <irogers@google.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200214075133.181299-5-irogers@google.com
parent 6eef8a71

include/linux/perf_event.h

+7 −0
Original line number Diff line number Diff line
@@ -862,6 +862,13 @@ struct perf_cpu_context { 
	int				sched_cb_usage;



	int				online;

	/*

	 * Per-CPU storage for iterators used in visit_groups_merge. The default

	 * storage is of size 2 to hold the CPU and any CPU event iterators.

	 */

	int				heap_size;

	struct perf_event		**heap;

	struct perf_event		*heap_default[2];

};



struct perf_output_handle {

kernel/events/core.c

+32 −11
Original line number Diff line number Diff line
@@ -3423,22 +3423,34 @@ static void __heap_add(struct min_heap *heap, struct perf_event *event) 
	}

}



static noinline int visit_groups_merge(struct perf_event_groups *groups,

				int cpu,

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)

{

	/* Space for per CPU and/or any CPU event iterators. */

	struct perf_event *itrs[2];

	struct min_heap event_heap = {

	struct min_heap event_heap;

	struct perf_event **evt;

	int ret;



	if (cpuctx) {

		event_heap = (struct min_heap){

			.data = cpuctx->heap,

			.nr = 0,

			.size = cpuctx->heap_size,

		};

	} else {

		event_heap = (struct min_heap){

			.data = itrs,

			.nr = 0,

			.size = ARRAY_SIZE(itrs),

		};

	struct perf_event **evt = event_heap.data;

	int ret;



		/* Events not within a CPU context may be on any CPU. */

		__heap_add(&event_heap, perf_event_groups_first(groups, -1));

	}

	evt = event_heap.data;



	__heap_add(&event_heap, perf_event_groups_first(groups, cpu));



	min_heapify_all(&event_heap, &perf_min_heap);
@@ -3492,7 +3504,10 @@ ctx_pinned_sched_in(struct perf_event_context *ctx, 
{

	int can_add_hw = 1;



	visit_groups_merge(&ctx->pinned_groups,

	if (ctx != &cpuctx->ctx)

		cpuctx = NULL;



	visit_groups_merge(cpuctx, &ctx->pinned_groups,

			   smp_processor_id(),

			   merge_sched_in, &can_add_hw);

}
@@ -3503,7 +3518,10 @@ ctx_flexible_sched_in(struct perf_event_context *ctx, 
{

	int can_add_hw = 1;



	visit_groups_merge(&ctx->flexible_groups,

	if (ctx != &cpuctx->ctx)

		cpuctx = NULL;



	visit_groups_merge(cpuctx, &ctx->flexible_groups,

			   smp_processor_id(),

			   merge_sched_in, &can_add_hw);

}
@@ -10364,6 +10382,9 @@ skip_type: 
		cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);



		__perf_mux_hrtimer_init(cpuctx, cpu);



		cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);

		cpuctx->heap = cpuctx->heap_default;

	}



got_cpu_context:

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