Change in vdsm[master]: network: wait for udev after configuring SRIOV

ibarkan at redhat.com ibarkan at redhat.com
Mon May 4 13:02:48 UTC 2015


Ido Barkan has posted comments on this change.

Change subject: network: wait for udev after configuring SRIOV
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Patch Set 6: Verified+1

after some inspection of kernel code it seems like every driver is free to implement a synchronous/asynchronous approach of creating devices.
when running a script like so with igbvf (intel driver):

P="/sys/bus/pci/devices/0000:02:00.0/sriov_numvfs"
echo "0" > $P &&logger "write 0 eneded" && sleep 10 && logger "before writing 7" && echo "7" > $P && logger "write 7 ended"

and inspecting 'journalcrl -o short-precise' the line "write 7 ended" only apeard at _after_ all the events from the kernel have been processed. one udev rename event happened a few milliseconds after the write returned. This implies that the driver itself is adding pci devices in a synchronous manner, but again, the kernel calls the drivers and those are free to implement the update as they like.

So, IMHO, there is no much value to invest more in it (e.g. counting devices) until we fix it properly by listening to the expected events before creating them.

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Gerrit-MessageType: comment
Gerrit-Change-Id: I04d63ca35aab585051c3d0a5f2652dbf2f91b080
Gerrit-PatchSet: 6
Gerrit-Project: vdsm
Gerrit-Branch: master
Gerrit-Owner: Ido Barkan <ibarkan at redhat.com>
Gerrit-Reviewer: Dan Kenigsberg <danken at redhat.com>
Gerrit-Reviewer: Ido Barkan <ibarkan at redhat.com>
Gerrit-Reviewer: Jenkins CI
Gerrit-Reviewer: Martin Polednik <mpolednik at redhat.com>
Gerrit-Reviewer: Nir Soffer <nsoffer at redhat.com>
Gerrit-Reviewer: automation at ovirt.org
Gerrit-HasComments: No


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