rps: shortcut net_rps_action()
net_rps_action() is a bit expensive on NR_CPUS=64..4096 kernels, even if
RPS is not active.
Tom Herbert used two bitmasks to hold information needed to send IPI,
but a single LIFO list seems more appropriate.
Move all RPS logic into net_rps_action() to cleanup net_rx_action() code
(remove two ifdefs)
Move rps_remote_softirq_cpus into softnet_data to share its first cache
line, filling an existing hole.
In a future patch, we could call net_rps_action() from process_backlog()
to make sure we send IPI before handling this cpu backlog.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 649a025..83ab3da 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1381,17 +1381,20 @@
}
/*
- * Incoming packets are placed on per-cpu queues so that
- * no locking is needed.
+ * Incoming packets are placed on per-cpu queues
*/
struct softnet_data {
struct Qdisc *output_queue;
struct list_head poll_list;
struct sk_buff *completion_queue;
- /* Elements below can be accessed between CPUs for RPS */
#ifdef CONFIG_RPS
+ struct softnet_data *rps_ipi_list;
+
+ /* Elements below can be accessed between CPUs for RPS */
struct call_single_data csd ____cacheline_aligned_in_smp;
+ struct softnet_data *rps_ipi_next;
+ unsigned int cpu;
unsigned int input_queue_head;
#endif
struct sk_buff_head input_pkt_queue;