On Mon, Jun 30, 2014 at 04:50:42PM +0800, Yan, Zheng wrote:

> @@ -3068,6 +3077,14 @@ alloc_perf_context(struct pmu *pmu, struct task_struct *task)
>  	if (!ctx)
>  		return NULL;
>  
> +	if (task && pmu->task_ctx_size > 0) {
> +		ctx->task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
> +		if (!ctx->task_ctx_data) {
> +			kfree(ctx);
> +			return NULL;
> +		}
> +	}

Can we delay this allocation until such time as that its actually
needed? Otherwise we're wasting all this memory..