The following commit has been merged into the perf/core branch of tip: Commit-ID: 836196beb377e59e54ec9e04f7402076ef7a8bd8 Gitweb: https://git.kernel.org/tip/836196beb377e59e54ec9e04f7402076ef7a8bd8 Author: Ian Rogers <irogers@xxxxxxxxxx> AuthorDate: Thu, 13 Feb 2020 23:51:31 -08:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Fri, 06 Mar 2020 11:57:00 +01:00 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@xxxxxxxxxxxxx> Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Link: https://lkml.kernel.org/r/20200214075133.181299-5-irogers@xxxxxxxxxx --- include/linux/perf_event.h | 7 ++++++- kernel/events/core.c | 43 +++++++++++++++++++++++++++---------- 2 files changed, 39 insertions(+), 11 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 68e21e8..8768a39 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -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 { diff --git a/kernel/events/core.c b/kernel/events/core.c index ddfb06c..7529e76 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -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 @@ 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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