On 04/13/2014 09:40 PM, David Miller wrote: > From: Steven Galgano <sgalg...@adjacentlink.com> > Date: Sun, 13 Apr 2014 21:30:27 -0400 > >> Added optional per queue flow control support using IFF_FLOW_CONTROL. When >> the IFF_FLOW_CONTROL TUNSETIFF flag is specified it will set a per queue >> flag to indicate that the queue should be stopped using >> netif_tx_stop_queue(), rather than discarding frames once full. After >> reading a frame from the respective stopped queue, a netif_tx_wake_queue() >> is issued to signal resource availability. >> >> The per queue TUN_FLOW_CONTROL flag is stored in struct tun_file. This >> provides the flexibility to enable flow control on all, none or some queues >> when using IFF_MULTI_QUEUE. When not using IFF_MULTI_QUEUE, IFF_FLOW_CONTROL >> will apply to the single queue. No changes were made to the default drop >> frame policy. >> >> This change adds support for back pressure use cases. >> >> Reported-by: Brian Adamson <brian.adam...@nrl.navy.mil> >> Tested-by: Joseph Giovatto <jgiova...@djacentlink.com> >> Signed-off-by: Steven Galgano <sgalg...@adjacentlink.com> > > Please format your commit messages to ~80 columns of text. > > It won't be automatically formatted by GIT and in fact it looks ugly > with all the wrapping in text based tools. > Added optional per queue flow control support using IFF_FLOW_CONTROL. When the IFF_FLOW_CONTROL TUNSETIFF flag is specified it will set a per queue flag to indicate that the queue should be stopped using netif_tx_stop_queue(), rather than discarding frames once full. After reading a frame from the respective stopped queue, a netif_tx_wake_queue() is issued to signal resource availability.
The per queue TUN_FLOW_CONTROL flag is stored in struct tun_file. This provides the flexibility to enable flow control on all, none or some queues when using IFF_MULTI_QUEUE. When not using IFF_MULTI_QUEUE, IFF_FLOW_CONTROL will apply to the single queue. No changes were made to the default drop frame policy. This change adds support for back pressure use cases. Reported-by: Brian Adamson <brian.adam...@nrl.navy.mil> Tested-by: Joseph Giovatto <jgiova...@djacentlink.com> Signed-off-by: Steven Galgano <sgalg...@adjacentlink.com> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
