Ben Hutchings <b...@decadent.org.uk> writes: > On Sun, 2016-04-10 at 11:15 -0700, Vagrant Cascadian wrote: >> It works for the most part, but floods syslog with messages: >> >> [501966.870273] net_ratelimit: 35702 callbacks suppressed >> [501966.875438] smsc95xx 1-1.1:1.0 eth0: kevent 2 may have been dropped >> >> It seems to function ok, though I'm not sure if there's degraded >> network performance... > [...] > > I understand network performance on all RPi models is poor due to lack > of a built-in Ethernet MAC and the poor design of the USB interface. > Also that message is a generic error message from the usbnet core and > is not specific to the smsc95xx driver.
Yes, kevent 2 is "EVENT_RX_MEMORY", and this error affects any usbnet based device under memory pressure. The usbnet framework just doesn't handle the case where GFP_KERNEL allocations fail. How could it? The only viable "fix" I can see is by preallocating and recycling all buffers instead of the repeated allocations done by usbnet now. But that's a major refactoring of usbnet. The log message spam could of course be fixed, but the rate-limiting is "good enough". Bjørn
