Re: [PATCH v2 1/4] perf: Allow using AUX data in perf samples

[Peter Zijlstra]

On Tue, Oct 22, 2019 at 12:58:09PM +0300, Alexander Shishkin wrote:

> @@ -964,6 +979,7 @@ struct perf_sample_data {
>  		u32	reserved;
>  	}				cpu_entry;
>  	struct perf_callchain_entry	*callchain;
> +	u64				aux_size;
>  
>  	/*
>  	 * regs_user may point to task_pt_regs or to regs_user_copy, depending
> @@ -996,6 +1012,7 @@ static inline void perf_sample_data_init(struct perf_sample_data *data,
>  	data->weight = 0;
>  	data->data_src.val = PERF_MEM_NA;
>  	data->txn = 0;
> +	data->aux_size = 0;
>  }
>  

That is really sad; so far we've managed to only touch a single
cacheline there, you just wrecked that.