From 1f5000bd8afab0ceed58c67f673250b864e5a9c9 Mon Sep 17 00:00:00 2001 From: Todd Poynor Date: Tue, 25 Jul 2017 16:31:59 -0700 Subject: initcall_debug: add deferred probe times initcall_debug attributes all deferred device probe retries for the late_initcall level to function deferred_probe_initcall. Add logs of the individual device probe routines called, to identify which drivers are executing for how long during the initcall path. Deferred probes that occur after initcall processing are not shown. Example log messages added: [ 0.505119] deferred probe my-sound-device @ 6 [ 0.517656] deferred probe my-sound-device returned after 1227 usecs Signed-off-by: Todd Poynor Signed-off-by: Greg Kroah-Hartman --- drivers/base/dd.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) (limited to 'drivers/base/dd.c') diff --git a/drivers/base/dd.c b/drivers/base/dd.c index c17fefc77345..ad44b40fe284 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -53,6 +54,7 @@ static DEFINE_MUTEX(deferred_probe_mutex); static LIST_HEAD(deferred_probe_pending_list); static LIST_HEAD(deferred_probe_active_list); static atomic_t deferred_trigger_count = ATOMIC_INIT(0); +static bool initcalls_done; /* * In some cases, like suspend to RAM or hibernation, It might be reasonable @@ -61,6 +63,26 @@ static atomic_t deferred_trigger_count = ATOMIC_INIT(0); */ 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. */ @@ -106,7 +128,10 @@ static void deferred_probe_work_func(struct work_struct *work) device_pm_unlock(); dev_dbg(dev, "Retrying from deferred list\n"); - bus_probe_device(dev); + if (initcall_debug && !initcalls_done) + deferred_probe_debug(dev); + else + bus_probe_device(dev); mutex_lock(&deferred_probe_mutex); @@ -215,6 +240,7 @@ static int deferred_probe_initcall(void) driver_deferred_probe_trigger(); /* Sort as many dependencies as possible before exiting initcalls */ flush_work(&deferred_probe_work); + initcalls_done = true; return 0; } late_initcall(deferred_probe_initcall); -- cgit v1.2.3