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perf/cgroup: Grow per perf_cpu_context heap storage

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Allow the per-CPU min heap storage to have sufficient space for per-cgroup
iterators.

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/20200214075133.181299-6-irogers@google.com
This commit is contained in:
Ian Rogers 2020-02-13 23:51:32 -08:00 committed by Ingo Molnar
parent 836196beb3
commit c2283c9368
1 changed files with 47 additions and 0 deletions
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47
kernel/events/core.c
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@ -892,6 +892,47 @@ static inline void perf_cgroup_sched_in(struct task_struct *prev,
rcu_read_unlock();
}
static int perf_cgroup_ensure_storage(struct perf_event *event,
struct cgroup_subsys_state *css)
{
struct perf_cpu_context *cpuctx;
struct perf_event **storage;
int cpu, heap_size, ret = 0;
/*
* Allow storage to have sufficent space for an iterator for each
* possibly nested cgroup plus an iterator for events with no cgroup.
*/
for (heap_size = 1; css; css = css->parent)
heap_size++;
for_each_possible_cpu(cpu) {
cpuctx = per_cpu_ptr(event->pmu->pmu_cpu_context, cpu);
if (heap_size <= cpuctx->heap_size)
continue;
storage = kmalloc_node(heap_size * sizeof(struct perf_event *),
GFP_KERNEL, cpu_to_node(cpu));
if (!storage) {
ret = -ENOMEM;
break;
}
raw_spin_lock_irq(&cpuctx->ctx.lock);
if (cpuctx->heap_size < heap_size) {
swap(cpuctx->heap, storage);
if (storage == cpuctx->heap_default)
storage = NULL;
cpuctx->heap_size = heap_size;
}
raw_spin_unlock_irq(&cpuctx->ctx.lock);
kfree(storage);
}
return ret;
}
static inline int perf_cgroup_connect(int fd, struct perf_event *event,
struct perf_event_attr *attr,
struct perf_event *group_leader)
@ -911,6 +952,10 @@ static inline int perf_cgroup_connect(int fd, struct perf_event *event,
goto out;
}
ret = perf_cgroup_ensure_storage(event, css);
if (ret)
goto out;
cgrp = container_of(css, struct perf_cgroup, css);
event->cgrp = cgrp;
@ -3440,6 +3485,8 @@ static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
.nr = 0,
.size = cpuctx->heap_size,
};
lockdep_assert_held(&cpuctx->ctx.lock);
} else {
event_heap = (struct min_heap){
.data = itrs,