Don't forget that, generally, as I understand it, the network stack suffers from the same problem for 9k buffers.
On Sun, Jun 25, 2017 at 12:56 PM, Ben RUBSON <ben.rub...@gmail.com> wrote: > > On 25 Jun 2017, at 17:32, Ryan Stone <ryst...@gmail.com> wrote: > > > > Having looking at the original email more closely, I see that you showed > an mlxen interface with a 9020 MTU. Seeing allocation failures of 9k mbuf > clusters increase while you are far below the zone's limit means that > you're definitely running into the bug I'm describing, and this bug could > plausibly cause the iSCSI errors that you describe. > > > > The issue is that the newer version of the driver tries to allocate a > single buffer to accommodate an MTU-sized packet. Over time, however, > memory will become fragmented and eventually it can become impossible to > allocate a 9k physically contiguous buffer. When this happens the driver > is unable to allocate buffers to receive packets and is forced to drop > them. Presumably, if iSCSI suffers too many packet drops it will terminate > the connection. The older version of the driver limited itself to > page-sized buffers, so it was immune to issues with memory fragmentation. > > Thank you for your explanation Ryan. > You say "over time", and you're right, I have to wait several days (here > 88) before the problem occurs. > Strange however that in 2500MB free memory system is unable to find 9k > physically contiguous. But we never know :) > > Let's then wait for your patch ! > (and reboot for now) > > Many thx ! > > Ben > _______________________________________________ > freebsd-net@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org" > _______________________________________________ freebsd-net@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"