On 11/8/2018 5:35 PM, Matan Azrad wrote:
From: Jeff Guo
On 11/8/2018 3:28 PM, Matan Azrad wrote:
From: Ananyev, Konstantin
-----Original Message-----
From: Guo, Jia
Sent: Wednesday, November 7, 2018 7:30 AM
To: Matan Azrad <ma...@mellanox.com>; Ananyev, Konstantin
<konstantin.anan...@intel.com>; Burakov, Anatoly
<anatoly.bura...@intel.com>; Thomas Monjalon
<tho...@monjalon.net>;
Iremonger, Bernard <bernard.iremon...@intel.com>; Wu, Jingjing
<jingjing...@intel.com>; Lu, Wenzhuo <wenzhuo...@intel.com>
Cc: Yigit, Ferruh <ferruh.yi...@intel.com>; dev@dpdk.org; Zhang,
Helin <helin.zh...@intel.com>; He, Shaopeng
<shaopeng...@intel.com>
Subject: Re: [PATCH 3/3] app/testpmd: fix callback issue for
hot-unplug
matan
On 11/6/2018 2:36 PM, Matan Azrad wrote:
Hi Jeff
From: Jeff Guo <jia....@intel.com>
Before detach device when device be hot-unplugged, the failure
process in user space and kernel space both need to be finished,
such as eal interrupt callback need to be inactive before the
callback be unregistered when device is being cleaned. This patch
add rte alarm for device detaching, with that it could finish
interrupt callback soon and give time to let the failure process
done
before detaching.
Fixes: 2049c5113fe8 ("app/testpmd: use hotplug failure handler")
Signed-off-by: Jeff Guo <jia....@intel.com>
---
app/test-pmd/testpmd.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c index
9c0edca..9c673cf 100644
--- a/app/test-pmd/testpmd.c
+++ b/app/test-pmd/testpmd.c
@@ -2620,7 +2620,18 @@ eth_dev_event_callback(const char
*device_name, enum rte_dev_event_type type,
device_name);
return;
}
- rmv_event_callback((void *)(intptr_t)port_id);
+ /*
+ * Before detach device, the hot-unplug failure
process in
+ * user space and kernel space both need to be
finished,
+ * such as eal interrupt callback need to be inactive
before
+ * the callback be unregistered when device is being
cleaned.
+ * So finished interrupt callback soon here and give
time to
+ * let the work done before detaching.
+ */
+ if (rte_eal_alarm_set(100000,
+ rmv_event_callback, (void
*)(intptr_t)port_id))
+ RTE_LOG(ERR, EAL,
+ "Could not set up deferred device
It looks me strange to use callback and alarm to remove a device:
Why not to use callback and that is it?
I think that it's better to let the EAL to detach the device after
all the
callbacks were done and not to do it by the user callback.
So the application\callback owners just need to clean its resources
with understanding that after the callback the device(and the
callback
itself) will be detached by the EAL.
Firstly, at the currently framework and solution, such as callback
for RTE_ETH_EVENT_INTR_RMV, still need to use the deferred device
removal,
we tend to give the control of detaching device to the application,
and the whole process is located on the user's callback. Notify app
to detach device by callback but make it deferred, i think it is fine.
But the device must be detached in remove event, why not to do it in EAL?
I think it because of before detached the device, application should be stop
the forwarding at first, then stop the device, then close
the device, finally call eal unplug API to detach device. If eal directly detach
device at the first step, there will be mountain user space error need to
handle, so that is one reason why need to provider the remove notification
to app, and let app to process it.
This is why the EAL need to detach the device only after all the user callbacks
were done.
If i correctly got your meaning, you suppose to let eal to mandatory
detach device but not app, app just need to stop/close port, right?
If so, it will need to modify rmv_event_callback by not invoke the
detaching func and add some detaching logic to hotplug framework in eal.
It is hardly say better or worse but this new propose need to discuss
more in public. And it might be better to use another specific patch to
handler it. What do you or other guys think so?
It is also unclear to me my we need an alarm here.
First (probably wrong) impression we just try to hide some
synchronization Problem by introducing delay.
Looks like, the issue is that the callback function memory will be removed
from the function itself (by the detach call), no?
Answer here for both Konstantin and Matan.
Yes, i think matan is right, the interrupt callback will be destroy in the app
callback itself, the sequence is that as below
hot-unplug interrupt -> interrupt callback -> app callback(return to finish
interrupt callback, delay detaching) -> detach device(unregister interrupt
callback)
Konstantin
Secondly, the vfio is different with igb_uio for hot-unplug, it
register/unregister hotplug interrupt callback for each device, so
need to make the callback done before unregister the callback.
So I think it should be considerate as an workaround here, before we
find a better way.
removal\n");
break;
case RTE_DEV_EVENT_ADD:
RTE_LOG(ERR, EAL, "The device: %s has been
added!\n",
--
2.7.4
