On 5/22/2018 12:35 AM, Jakub Kicinski wrote: > On Mon, 21 May 2018 16:59:37 -0500, Tom Lendacky wrote: >> + rx = combined + channels->rx_count; >> + tx = combined + channels->tx_count; >> + netdev_notice(netdev, "final channel count assignment: combined=%u, >> rx-only=%u, tx-only=%u\n", >> + min(rx, tx), rx - min(rx, tx), tx - min(rx, tx)); > > If user requests combined 0 rx 8 tx 8 they will end up with combined 8 > rx 0 tx 0. Is that expected?
Yes, which is the reason that I issue the final channel count message. I debated on how to do all this and looked at other drivers as well as the ethtool man page and decided on this logic. > > The man page clearly sayeth: > > -L --set-channels > Changes the numbers of channels of the specified network device. > > rx N Changes the number of channels with only receive queues. > > tx N Changes the number of channels with only transmit queues. > > other N > Changes the number of channels used only for other purposes > e.g. link interrupts or SR-IOV co-ordination. > > combined N > Changes the number of multi-purpose channels. > > Note the use of word *only*. There are drivers in tree which adhere to > this interpretation and dutifully allocate separate IRQs if RX and TX > channels are requested separately. The amd-xgbe driver is not designed to allocate separate IRQs for Rx and Tx. In general, there is one IRQ for a channel of which Tx and Rx are shared. You can have more Tx channels than Rx channels or vice-versa, but the min() of those numbers will be a combined Tx/Rx with the excess being Tx or Rx only: e.g. combined 0 tx 8 rx 10 results in 8 combined channels plus two Rx only channels. I thought this was the most reasonable way to do this, please let me know if there's a strong objection to this. Thanks, Tom > > Which is not to claim that majority of existing drivers adhere to this > wording :) >
