[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] netfront/netback multiqueue exhausting grants
On 2016/1/20 7:23, Ian Campbell wrote: There have been a few reports recently[0] which relate to a failure of netfront to allocate sufficient grant refs for all the queues: [ 0.533589] xen_netfront: can't alloc rx grant refs [ 0.533612] net eth0: only created 31 queues Which can be worked around by increasing the number of grants on the hypervisor command line or by limiting the number of queues permitted by either back or front using a module param (which was broken but is now fixed on both sides, but I'm not sure it has been backported everywhere such that it is a reliable thing to always tell users as a workaround). Following are the patches to fix module param, they exist since v4.3. xen-netfront: respect user provided max_queues https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=32a844056fd43dda647e1c3c6b9983bdfa04d17d xen-netback: respect user provided max_queues https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=4c82ac3c37363e8c4ded6a5fe1ec5fa756b34df3 We run into similar issue recently, and guess it is better to suggest user to set netback module parameter with the default value as 8? see this link, http://wiki.xenproject.org/wiki/Xen-netback_and_xen-netfront_multi-queue_performance_testingIs there any plan to do anything about the default/out of the box experience? Either limiting the number of queues or making both ends cope more gracefully with failure to create some queues (or both) might be sufficient? Probably more test are needed to get the default number of best experience. I think the crash after the above in the first link at [0] is fixed? I think that was the purpose of ca88ea1247df "xen-netfront: update num_queues to real created" which was in 4.3. Correct. Thanks Annie Ian. [0] http://lists.xen.org/archives/html/xen-users/2016-01/msg00100.html http://lists.xen.org/archives/html/xen-users/2016-01/msg00072.html some before hte xmas break too IIRC _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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