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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: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200214075133.181299-5-irogers@google.com
This commit is contained in:
Ian Rogers 2020-02-13 23:51:31 -08:00 committed by Ingo Molnar
parent 6eef8a7116
commit 836196beb3
2 changed files with 39 additions and 11 deletions
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7
include/linux/perf_event.h
View File

@ -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 {

43
kernel/events/core.c
View File

@ -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 = {
.data = itrs,
.nr = 0,
.size = ARRAY_SIZE(itrs),
};
struct perf_event **evt = event_heap.data;
struct min_heap event_heap;
struct perf_event **evt;
int ret;
__heap_add(&event_heap, perf_event_groups_first(groups, -1));
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),
};
/* 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 @@ int perf_pmu_register(struct pmu *pmu, const char *name, int 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: