Re: [PATCH v5 02/13] hw/core/qdev: add trace events to help with resettable transition

[Damien Hedde]

On 11/1/19 12:23 AM, Philippe Mathieu-Daudé wrote:
> On 10/18/19 5:06 PM, Damien Hedde wrote:
>> Adds trace events to reset procedure and when updating the parent
>> bus of a device.
>>
>> Signed-off-by: Damien Hedde <address@hidden>
>> ---
>>   hw/core/qdev.c       | 27 ++++++++++++++++++++++++---
>>   hw/core/trace-events |  9 +++++++++
>>   2 files changed, 33 insertions(+), 3 deletions(-)
>>
>> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
>> index 60be2f2fef..f230063189 100644
>> --- a/hw/core/qdev.c
>> +++ b/hw/core/qdev.c
>> @@ -38,6 +38,7 @@
>>   #include "hw/boards.h"
>>   #include "hw/sysbus.h"
>>   #include "migration/vmstate.h"
>> +#include "trace.h"
>>     bool qdev_hotplug = false;
>>   static bool qdev_hot_added = false;
>> @@ -98,7 +99,9 @@ void qdev_set_parent_bus(DeviceState *dev, BusState
>> *bus)
>>       bool replugging = dev->parent_bus != NULL;
>>         if (replugging) {
>> -        /* Keep a reference to the device while it's not plugged into
>> +        trace_qdev_update_parent_bus(dev, dev->parent_bus, bus);
> 
> Nitpicking, if you respin, can you add object_get_typename(OBJECT(dev)))
> and object_get_typename(OBJECT(bus)))?

sure. I was wondering if having some kind of qom object support to trace
would be feasible. Because it's a bit tedious to add this each time. And
IMO it would be more useful to have the path, but we can't reasonably
compute it as a trace_..() arguments.

> 
> With/without it:
> Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
> 
>> +        /*
>> +         * Keep a reference to the device while it's not plugged into
>>            * any bus, to avoid it potentially evaporating when it is
>>            * dereffed in bus_remove_child().
>>            */
>> @@ -272,6 +275,18 @@ HotplugHandler
>> *qdev_get_hotplug_handler(DeviceState *dev)
>>       return hotplug_ctrl;
>>   }
>>   +static int qdev_prereset(DeviceState *dev, void *opaque)
>> +{
>> +    trace_qdev_reset_tree(dev, object_get_typename(OBJECT(dev)));
>> +    return 0;
>> +}
>> +
>> +static int qbus_prereset(BusState *bus, void *opaque)
>> +{
>> +    trace_qbus_reset_tree(bus, object_get_typename(OBJECT(bus)));
>> +    return 0;
>> +}
>> +
>>   static int qdev_reset_one(DeviceState *dev, void *opaque)
>>   {
>>       device_legacy_reset(dev);
>> @@ -282,6 +297,7 @@ static int qdev_reset_one(DeviceState *dev, void
>> *opaque)
>>   static int qbus_reset_one(BusState *bus, void *opaque)
>>   {
>>       BusClass *bc = BUS_GET_CLASS(bus);
>> +    trace_qbus_reset(bus, object_get_typename(OBJECT(bus)));
>>       if (bc->reset) {
>>           bc->reset(bus);
>>       }
>> @@ -290,7 +306,9 @@ static int qbus_reset_one(BusState *bus, void
>> *opaque)
>>     void qdev_reset_all(DeviceState *dev)
>>   {
>> -    qdev_walk_children(dev, NULL, NULL, qdev_reset_one,
>> qbus_reset_one, NULL);
>> +    trace_qdev_reset_all(dev, object_get_typename(OBJECT(dev)));
>> +    qdev_walk_children(dev, qdev_prereset, qbus_prereset,
>> +                       qdev_reset_one, qbus_reset_one, NULL);
>>   }
>>     void qdev_reset_all_fn(void *opaque)
>> @@ -300,7 +318,9 @@ void qdev_reset_all_fn(void *opaque)
>>     void qbus_reset_all(BusState *bus)
>>   {
>> -    qbus_walk_children(bus, NULL, NULL, qdev_reset_one,
>> qbus_reset_one, NULL);
>> +    trace_qbus_reset_all(bus, object_get_typename(OBJECT(bus)));
>> +    qbus_walk_children(bus, qdev_prereset, qbus_prereset,
>> +                       qdev_reset_one, qbus_reset_one, NULL);
>>   }
>>     void qbus_reset_all_fn(void *opaque)
>> @@ -1108,6 +1128,7 @@ void device_legacy_reset(DeviceState *dev)
>>   {
>>       DeviceClass *klass = DEVICE_GET_CLASS(dev);
>>   +    trace_qdev_reset(dev, object_get_typename(OBJECT(dev)));
>>       if (klass->reset) {
>>           klass->reset(dev);
>>       }
>> diff --git a/hw/core/trace-events b/hw/core/trace-events
>> index fe47a9c8cb..1a669be0ea 100644
>> --- a/hw/core/trace-events
>> +++ b/hw/core/trace-events
>> @@ -1,2 +1,11 @@
>>   # loader.c
>>   loader_write_rom(const char *name, uint64_t gpa, uint64_t size, bool
>> isrom) "%s: @0x%"PRIx64" size=0x%"PRIx64" ROM=%d"
>> +
>> +# qdev.c
>> +qdev_reset(void *obj, const char *objtype) "obj=%p(%s)"
>> +qdev_reset_all(void *obj, const char *objtype) "obj=%p(%s)"
>> +qdev_reset_tree(void *obj, const char *objtype) "obj=%p(%s)"
>> +qbus_reset(void *obj, const char *objtype) "obj=%p(%s)"
>> +qbus_reset_all(void *obj, const char *objtype) "obj=%p(%s)"
>> +qbus_reset_tree(void *obj, const char *objtype) "obj=%p(%s)"
>> +qdev_update_parent_bus(void *obj, void *oldp, void *newp) "obj=%p
>> old_parent=%p new_parent=%p"
>>