On Mon, Jun 26, 2017 at 04:13:33PM +0300, Andrey V. Elsukov wrote: > On 25.06.2017 18:32, Ryan Stone 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. > > I think it is not mlxen specific problem, we have the same symptoms with > ixgbe(4) driver too. To avoid the problem we have patches that are > disable using of 9k mbufs, and instead only use 4k mbufs.
I had the same issue on a lightly loaded HP DL20 machine (BCM5720 chipsets), 8GB of RAM, running 10.3. Problem usually happens within 30 days with 9k jumbo clusters allocation failure. > > -- > WBR, Andrey V. Elsukov > -- Julien Cigar Belgian Biodiversity Platform (http://www.biodiversity.be) PGP fingerprint: EEF9 F697 4B68 D275 7B11 6A25 B2BB 3710 A204 23C0 No trees were killed in the creation of this message. However, many electrons were terribly inconvenienced.
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