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authorYan, Zheng <zheng.z.yan@intel.com>2012-06-15 14:31:33 +0800
committerSimon Shields <keepcalm444@gmail.com>2016-12-13 00:14:52 +1100
commitab5cf14fb4432d2550896d37e77aa88c335ce9b8 (patch)
tree766ebdd36a300789219202229fabf597bc83c364 /kernel
parent55306f62c769cba0a97465b04790b8b9fbdce907 (diff)
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BACKPORT: perf: Introduce perf_pmu_migrate_context()
Originally from Peter Zijlstra. The helper migrates perf events from one cpu to another cpu. Conflicts (perf: Fix race in removing an event): kernel/events/core.c Change-Id: I7885fe36c9e2803b10477d556163197085be3d19 Signed-off-by: Zheng Yan <zheng.z.yan@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1339741902-8449-5-git-send-email-zheng.z.yan@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/core.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index b9ed867..9d57031 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1580,6 +1580,8 @@ perf_install_in_context(struct perf_event_context *ctx,
lockdep_assert_held(&ctx->mutex);
event->ctx = ctx;
+ if (event->cpu != -1)
+ event->cpu = cpu;
if (!task) {
/*
@@ -6651,6 +6653,7 @@ SYSCALL_DEFINE5(perf_event_open,
mutex_lock(&ctx->mutex);
if (move_group) {
+ synchronize_rcu();
perf_install_in_context(ctx, group_leader, event->cpu);
get_ctx(ctx);
list_for_each_entry(sibling, &group_leader->sibling_list,
@@ -6750,6 +6753,39 @@ err:
}
EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
+void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
+{
+ struct perf_event_context *src_ctx;
+ struct perf_event_context *dst_ctx;
+ struct perf_event *event, *tmp;
+ LIST_HEAD(events);
+
+ src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
+ dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
+
+ mutex_lock(&src_ctx->mutex);
+ list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
+ event_entry) {
+ perf_remove_from_context(event, true);
+ put_ctx(src_ctx);
+ list_add(&event->event_entry, &events);
+ }
+ mutex_unlock(&src_ctx->mutex);
+
+ synchronize_rcu();
+
+ mutex_lock(&dst_ctx->mutex);
+ list_for_each_entry_safe(event, tmp, &events, event_entry) {
+ list_del(&event->event_entry);
+ if (event->state >= PERF_EVENT_STATE_OFF)
+ event->state = PERF_EVENT_STATE_INACTIVE;
+ perf_install_in_context(dst_ctx, event, dst_cpu);
+ get_ctx(dst_ctx);
+ }
+ mutex_unlock(&dst_ctx->mutex);
+}
+EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
+
static void sync_child_event(struct perf_event *child_event,
struct task_struct *child)
{