[RFC PATCH net-next-2.6 1/2] net: XPS: Allow driver to provide a default mapping of CPUs to TX queues
From: Ben Hutchings <hidden>
Date: 2011-02-18 16:15:05
Subsystem:
networking drivers, networking [general], the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
As with RFS acceleration, drivers may use the irq_cpu_rmap facility to provide a mapping from each CPU to the 'nearest' TX queue. Define CONFIG_PACKET_STEERING and CONFIG_NET_IRQ_CPU_RMAP so that drivers can make all cpu_rmap initialisation conditional on the latter. Signed-off-by: Ben Hutchings <redacted> --- include/linux/netdevice.h | 10 +++++++--- net/Kconfig | 17 ++++++++++++----- net/core/dev.c | 41 +++++++++++++++++++++++------------------ 3 files changed, 42 insertions(+), 26 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index c7d7074..c5cba16 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h@@ -1080,14 +1080,13 @@ struct net_device { /* Number of RX queues currently active in device */ unsigned int real_num_rx_queues; - -#ifdef CONFIG_RFS_ACCEL +#endif +#ifdef CONFIG_NET_IRQ_CPU_RMAP /* CPU reverse-mapping for RX completion interrupts, indexed * by RX queue number. Assigned by driver. This must only be * set if the ndo_rx_flow_steer operation is defined. */ struct cpu_rmap *rx_cpu_rmap; #endif -#endif rx_handler_func_t __rcu *rx_handler; void __rcu *rx_handler_data;
@@ -1114,6 +1113,11 @@ struct net_device { #ifdef CONFIG_XPS struct xps_dev_maps __rcu *xps_maps; #endif +#ifdef CONFIG_NET_IRQ_CPU_RMAP + /* CPU reverse-mapping for TX completion interrupts. Assigned + * by driver. */ + struct cpu_rmap *tx_cpu_rmap; +#endif /* These may be needed for future network-power-down code. */
diff --git a/net/Kconfig b/net/Kconfig
index 79cabf1..fa0a093 100644
--- a/net/Kconfig
+++ b/net/Kconfig@@ -216,21 +216,28 @@ source "net/dcb/Kconfig" source "net/dns_resolver/Kconfig" source "net/batman-adv/Kconfig" -config RPS +config PACKET_STEERING boolean depends on SMP && SYSFS && USE_GENERIC_SMP_HELPERS + select RPS + select XPS default y -config RFS_ACCEL +config NET_IRQ_CPU_RMAP boolean - depends on RPS && GENERIC_HARDIRQS + depends on PACKET_STEERING && GENERIC_HARDIRQS select CPU_RMAP + select RFS_ACCEL default y +config RPS + boolean + +config RFS_ACCEL + boolean + config XPS boolean - depends on SMP && SYSFS && USE_GENERIC_SMP_HELPERS - default y menu "Network testing"
diff --git a/net/core/dev.c b/net/core/dev.c
index 54aaca6..dd38b88 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -2257,27 +2257,32 @@ static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb) rcu_read_lock(); dev_maps = rcu_dereference(dev->xps_maps); - if (dev_maps) { + if (dev_maps) map = rcu_dereference( - dev_maps->cpu_map[raw_smp_processor_id()]); - if (map) { - if (map->len == 1) - queue_index = map->queues[0]; - else { - u32 hash; - if (skb->sk && skb->sk->sk_hash) - hash = skb->sk->sk_hash; - else - hash = (__force u16) skb->protocol ^ - skb->rxhash; - hash = jhash_1word(hash, hashrnd); - queue_index = map->queues[ - ((u64)hash * map->len) >> 32]; - } - if (unlikely(queue_index >= dev->real_num_tx_queues)) - queue_index = -1; + dev_maps->cpu_map[raw_smp_processor_id()]); + if (map) { + if (map->len == 1) + queue_index = map->queues[0]; + else { + u32 hash; + if (skb->sk && skb->sk->sk_hash) + hash = skb->sk->sk_hash; + else + hash = (__force u16) skb->protocol ^ + skb->rxhash; + hash = jhash_1word(hash, hashrnd); + queue_index = map->queues[ + ((u64)hash * map->len) >> 32]; } + if (unlikely(queue_index >= dev->real_num_tx_queues)) + queue_index = -1; + } +#ifdef CONFIG_PACKET_STEERING_CPU_RMAP + else if (dev->tx_cpu_rmap) { + queue_index = cpu_rmap_lookup_index(dev->tx_cpu_rmap, + raw_smp_processor_id()); } +#endif rcu_read_unlock(); return queue_index;
--
1.7.3.4
--
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.