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-rw-r--r--kernel/perf_counter.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 7af16d1c480f..4d8f97375f3a 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -1120,7 +1120,8 @@ void perf_counter_task_tick(struct task_struct *curr, int cpu)
__perf_counter_task_sched_out(ctx);
rotate_ctx(&cpuctx->ctx);
- rotate_ctx(ctx);
+ if (ctx->rr_allowed)
+ rotate_ctx(ctx);
perf_counter_cpu_sched_in(cpuctx, cpu);
perf_counter_task_sched_in(curr, cpu);
@@ -3108,6 +3109,7 @@ __perf_counter_init_context(struct perf_counter_context *ctx,
mutex_init(&ctx->mutex);
INIT_LIST_HEAD(&ctx->counter_list);
INIT_LIST_HEAD(&ctx->event_list);
+ ctx->rr_allowed = 1;
ctx->task = task;
}
@@ -3348,6 +3350,9 @@ void perf_counter_init_task(struct task_struct *child)
*/
mutex_lock(&parent_ctx->mutex);
+ parent_ctx->rr_allowed = 0;
+ barrier(); /* irqs */
+
/*
* We dont have to disable NMIs - we are only looking at
* the list, not manipulating it:
@@ -3361,6 +3366,9 @@ void perf_counter_init_task(struct task_struct *child)
break;
}
+ barrier(); /* irqs */
+ parent_ctx->rr_allowed = 1;
+
mutex_unlock(&parent_ctx->mutex);
}