On Wed, Sep 10, 2014 at 10:08:59AM -0400, [email protected] wrote:
> From: Kan Liang <[email protected]>
>
> The callback is invoked when process is scheduled in or out.
> It provides mechanism for later patches to save/store the LBR
> stack. For the schedule in case, the callback is invoked at
> the same place that flush branch stack callback is invoked.
> So it also can replace the flush branch stack callback. To
> avoid unnecessary overhead, the callback is enabled only when
> there are events use the LBR stack.
>
> Signed-off-by: Yan, Zheng <[email protected]>
Same broken attribution and SoB chain.
> +void perf_sched_cb_disable(struct pmu *pmu)
> +{
> + this_cpu_dec(perf_sched_cb_usages);
> +}
> +
> +void perf_sched_cb_enable(struct pmu *pmu)
> +{
> + this_cpu_inc(perf_sched_cb_usages);
> +}
lkml.kernel.org/r/[email protected]
> +/*
> + * This function provides the context switch callback to the lower code
> + * layer. It is invoked ONLY when the context switch callback is enabled.
> + */
> +static void perf_pmu_sched_task(struct task_struct *prev,
> + struct task_struct *next,
> + bool sched_in)
> +{
> + struct perf_cpu_context *cpuctx;
> + struct pmu *pmu;
> + unsigned long flags;
> +
> + if (prev == next)
> + return;
> +
> + local_irq_save(flags);
> +
> + rcu_read_lock();
> +
> + list_for_each_entry_rcu(pmu, &pmus, entry) {
> + if (pmu->sched_task) {
> + cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
> +
> + perf_ctx_lock(cpuctx, cpuctx->task_ctx);
> +
> + perf_pmu_disable(pmu);
> +
> + pmu->sched_task(cpuctx->task_ctx, sched_in);
> +
> + perf_pmu_enable(pmu);
> +
> + perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
> + /* only CPU PMU has context switch callback */
> + break;
> + }
> + }
> +
> + rcu_read_unlock();
> +
> + local_irq_restore(flags);
> +}
lkml.kernel.org/r/[email protected]
Maybe you should have read back the previous postings before taking over
this series :-)
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