On Tue, Jun 19, 2018 at 8:39 PM, Todd Poynor <toddpoynor@xxxxxxxxx> wrote:
> From: Todd Poynor <toddpoynor@xxxxxxxxxx>
>
> Add initcall_debug logs for each driver device probe call, for example:
>
> probe of a3800000.ramoops returned after 3007 usecs
>
> This replaces the previous code added to report times for deferred
> probes. It also reports OF platform bus device creates that were
> formerly lumped together in a single entry for function
> of_platform_default_populate_init, as well as helping to annotate other
> initcalls that involve device probing.
>
> Signed-off-by: Todd Poynor <toddpoynor@xxxxxxxxxx>
> ---
> drivers/base/dd.c | 50 +++++++++++++++++++++++------------------------
> 1 file changed, 24 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index 1435d7281c66..56db446a467a 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -62,26 +62,6 @@ static bool initcalls_done;
> */
> static bool defer_all_probes;
>
> -/*
> - * For initcall_debug, show the deferred probes executed in late_initcall
> - * processing.
> - */
> -static void deferred_probe_debug(struct device *dev)
> -{
> - ktime_t calltime, delta, rettime;
> - unsigned long long duration;
> -
> - printk(KERN_DEBUG "deferred probe %s @ %i\n", dev_name(dev),
> - task_pid_nr(current));
> - calltime = ktime_get();
> - bus_probe_device(dev);
> - rettime = ktime_get();
> - delta = ktime_sub(rettime, calltime);
> - duration = (unsigned long long) ktime_to_ns(delta) >> 10;
> - printk(KERN_DEBUG "deferred probe %s returned after %lld usecs\n",
> - dev_name(dev), duration);
> -}
> -
> /*
> * deferred_probe_work_func() - Retry probing devices in the active list.
> */
> @@ -125,11 +105,7 @@ static void deferred_probe_work_func(struct work_struct *work)
> device_pm_move_to_tail(dev);
>
> dev_dbg(dev, "Retrying from deferred list\n");
> - if (initcall_debug && !initcalls_done)
> - deferred_probe_debug(dev);
> - else
> - bus_probe_device(dev);
> -
> + bus_probe_device(dev);
> mutex_lock(&deferred_probe_mutex);
>
> put_device(dev);
> @@ -527,6 +503,25 @@ static int really_probe(struct device *dev, struct device_driver *drv)
> return ret;
> }
>
> +/*
> + * For initcall_debug, show the driver probe time.
> + */
> +static int really_probe_debug(struct device *dev, struct device_driver *drv)
> +{
> + ktime_t calltime, delta, rettime;
> + unsigned long long duration;
Probably should be s64.
> + int ret;
> +
> + calltime = ktime_get();
> + ret = really_probe(dev, drv);
> + rettime = ktime_get();
> + delta = ktime_sub(rettime, calltime);
> + duration = (unsigned long long) ktime_to_ns(delta) >> 10;
Is avoiding a divide really worth optimizing here compared to the
flood of messages typically on the serial port? Just use ktime_to_us.
Perhaps just get rid of duration and do the conversion in the printk
arg.
> + printk(KERN_DEBUG "probe of %s returned after %lld usecs\n",
> + dev_name(dev), duration);
Including the return code here too would be good.
> + return ret;
> +}
> +
> /**
> * driver_probe_done
> * Determine if the probe sequence is finished or not.
> @@ -585,7 +580,10 @@ int driver_probe_device(struct device_driver *drv, struct device *dev)
> pm_runtime_get_sync(dev->parent);
>
> pm_runtime_barrier(dev);
> - ret = really_probe(dev, drv);
> + if (initcall_debug && !initcalls_done)
> + ret = really_probe_debug(dev, drv);
> + else
> + ret = really_probe(dev, drv);
> pm_request_idle(dev);
>
> if (dev->parent)
> --
> 2.18.0.rc1.244.gcf134e6275-goog
>
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