net: add low latency socket poll

Adds an ndo_ll_poll method and the code that supports it.
This method can be used by low latency applications to busy-poll
Ethernet device queues directly from the socket code.
sysctl_net_ll_poll controls how many microseconds to poll.
Default is zero (disabled).
Individual protocol support will be added by subsequent patches.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Eliezer Tamir <eliezer.tamir@linux.intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Tested-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 0 deletions

diff --git a/net/Kconfig b/net/Kconfig
index 523e43e6da1b..d6a9ce6e1800 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -243,6 +243,18 @@ config NETPRIO_CGROUP
           Cgroup subsystem for use in assigning processes to network priorities on
           a per-interface basis
 
+config NET_LL_RX_POLL
+        bool "Low Latency Receive Poll"
+        depends on X86_TSC
+        default n
+        ---help---
+          Support Low Latency Receive Queue Poll.
+          (For network card drivers which support this option.)
+          When waiting for data in read or poll call directly into the the device driver
+          to flush packets which may be pending on the device queues into the stack.
+
+          If unsure, say N.
+
 config BQL
         boolean
         depends on SYSFS