On Sat, Oct 08, 2022 at 11:54:24AM +0530, Ravi Bangoria wrote:
> +static void perf_event_swap_task_ctx_data(struct perf_event_context *prev_ctx,
> + struct perf_event_context *next_ctx)
> +{
> + struct perf_event_pmu_context *prev_epc, *next_epc;
> +
> + if (!prev_ctx->nr_task_data)
> + return;
> +
> + prev_epc = list_first_entry(&prev_ctx->pmu_ctx_list,
> + struct perf_event_pmu_context,
> + pmu_ctx_entry);
> + next_epc = list_first_entry(&next_ctx->pmu_ctx_list,
> + struct perf_event_pmu_context,
> + pmu_ctx_entry);
> +
> + while (&prev_epc->pmu_ctx_entry != &prev_ctx->pmu_ctx_list &&
> + &next_epc->pmu_ctx_entry != &next_ctx->pmu_ctx_list) {
> +
> + WARN_ON_ONCE(prev_epc->pmu != next_epc->pmu);
> +
> + /*
> + * PMU specific parts of task perf context can require
> + * additional synchronization. As an example of such
> + * synchronization see implementation details of Intel
> + * LBR call stack data profiling;
> + */
> + if (prev_epc->pmu->swap_task_ctx)
> + prev_epc->pmu->swap_task_ctx(prev_epc, next_epc);
> + else
> + swap(prev_epc->task_ctx_data, next_epc->task_ctx_data);
Did I forget to advance the iterators here?
> + }
> +}
