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.
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
