diff --git a/kernel/events/core.c b/kernel/events/core.c
index 8c0b7334230b967f2e3ee0a07de7290c4108eedd..cbcee23d05f054285ae17c0a31aac5e20ae749a2 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -355,6 +355,8 @@ enum event_type_t {
EVENT_FLEXIBLE = 0x1,
EVENT_PINNED = 0x2,
EVENT_TIME = 0x4,
+ /* see ctx_resched() for details */
+ EVENT_CPU = 0x8,
EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
};
@@ -1442,6 +1444,20 @@ static void update_group_times(struct perf_event *leader)
update_event_times(event);
}
+static enum event_type_t get_event_type(struct perf_event *event)
+{
+ struct perf_event_context *ctx = event->ctx;
+ enum event_type_t event_type;
+
+ lockdep_assert_held(&ctx->lock);
+
+ event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
+ if (!ctx->task)
+ event_type |= EVENT_CPU;
+
+ return event_type;
+}
+
static struct list_head *
ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
{
@@ -2215,7 +2231,8 @@ ctx_sched_in(struct perf_event_context *ctx,
struct task_struct *task);
static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
- struct perf_event_context *ctx)
+ struct perf_event_context *ctx,
+ enum event_type_t event_type)
{
if (!cpuctx->task_ctx)
return;
@@ -2223,7 +2240,7 @@ static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
return;
- ctx_sched_out(ctx, cpuctx, EVENT_ALL);
+ ctx_sched_out(ctx, cpuctx, event_type);
}
static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
@@ -2238,13 +2255,51 @@ static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
}
+/*
+ * We want to maintain the following priority of scheduling:
+ * - CPU pinned (EVENT_CPU | EVENT_PINNED)
+ * - task pinned (EVENT_PINNED)
+ * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
+ * - task flexible (EVENT_FLEXIBLE).
+ *
+ * In order to avoid unscheduling and scheduling back in everything every
+ * time an event is added, only do it for the groups of equal priority and
+ * below.
+ *
+ * This can be called after a batch operation on task events, in which case
+ * event_type is a bit mask of the types of events involved. For CPU events,
+ * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
+ */
static void ctx_resched(struct perf_cpu_context *cpuctx,
- struct perf_event_context *task_ctx)
+ struct perf_event_context *task_ctx,
+ enum event_type_t event_type)
{
+ enum event_type_t ctx_event_type = event_type & EVENT_ALL;
+ bool cpu_event = !!(event_type & EVENT_CPU);
+
+ /*
+ * If pinned groups are involved, flexible groups also need to be
+ * scheduled out.
+ */
+ if (event_type & EVENT_PINNED)
+ event_type |= EVENT_FLEXIBLE;
+
perf_pmu_disable(cpuctx->ctx.pmu);
if (task_ctx)
- task_ctx_sched_out(cpuctx, task_ctx);
- cpu_ctx_sched_out(cpuctx, EVENT_ALL);
+ task_ctx_sched_out(cpuctx, task_ctx, event_type);
+
+ /*
+ * Decide which cpu ctx groups to schedule out based on the types
+ * of events that caused rescheduling:
+ * - EVENT_CPU: schedule out corresponding groups;
+ * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
+ * - otherwise, do nothing more.
+ */
+ if (cpu_event)
+ cpu_ctx_sched_out(cpuctx, ctx_event_type);
+ else if (ctx_event_type & EVENT_PINNED)
+ cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
+
perf_event_sched_in(cpuctx, task_ctx, current);
perf_pmu_enable(cpuctx->ctx.pmu);
}
@@ -2291,7 +2346,7 @@ static int __perf_install_in_context(void *info)
if (reprogram) {
ctx_sched_out(ctx, cpuctx, EVENT_TIME);
add_event_to_ctx(event, ctx);
- ctx_resched(cpuctx, task_ctx);
+ ctx_resched(cpuctx, task_ctx, get_event_type(event));
} else {
add_event_to_ctx(event, ctx);
}
@@ -2458,7 +2513,7 @@ static void __perf_event_enable(struct perf_event *event,
if (ctx->task)
WARN_ON_ONCE(task_ctx != ctx);
- ctx_resched(cpuctx, task_ctx);
+ ctx_resched(cpuctx, task_ctx, get_event_type(event));
}
/*
@@ -2885,7 +2940,7 @@ static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
if (do_switch) {
raw_spin_lock(&ctx->lock);
- task_ctx_sched_out(cpuctx, ctx);
+ task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
raw_spin_unlock(&ctx->lock);
}
}
@@ -3442,6 +3497,7 @@ static int event_enable_on_exec(struct perf_event *event,
static void perf_event_enable_on_exec(int ctxn)
{
struct perf_event_context *ctx, *clone_ctx = NULL;
+ enum event_type_t event_type = 0;
struct perf_cpu_context *cpuctx;
struct perf_event *event;
unsigned long flags;
@@ -3455,15 +3511,17 @@ static void perf_event_enable_on_exec(int ctxn)
cpuctx = __get_cpu_context(ctx);
perf_ctx_lock(cpuctx, ctx);
ctx_sched_out(ctx, cpuctx, EVENT_TIME);
- list_for_each_entry(event, &ctx->event_list, event_entry)
+ list_for_each_entry(event, &ctx->event_list, event_entry) {
enabled |= event_enable_on_exec(event, ctx);
+ event_type |= get_event_type(event);
+ }
/*
* Unclone and reschedule this context if we enabled any event.
*/
if (enabled) {
clone_ctx = unclone_ctx(ctx);
- ctx_resched(cpuctx, ctx);
+ ctx_resched(cpuctx, ctx, event_type);
}
perf_ctx_unlock(cpuctx, ctx);
@@ -10224,7 +10282,7 @@ static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
* in.
*/
raw_spin_lock_irq(&child_ctx->lock);
- task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
+ task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
/*
* Now that the context is inactive, destroy the task <-> ctx relation