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authorAmritha Nambiar <amritha.nambiar@intel.com>2018-06-29 21:26:46 -0700
committerDavid S. Miller <davem@davemloft.net>2018-07-02 09:06:24 +0900
commit04157469b7b848f4a9978b63b1ea2ce62ad3a0a3 (patch)
tree93bc64865c13a412a70ab8d3412025828a6f732c
parent80d19669ecd34423e85ca04f2210b0e42a47cb16 (diff)
net: Use static_key for XPS maps
Use static_key for XPS maps to reduce the cost of extra map checks, similar to how it is used for RPS and RFS. This includes static_key 'xps_needed' for XPS and another for 'xps_rxqs_needed' for XPS using Rx queues map. Signed-off-by: Amritha Nambiar <amritha.nambiar@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/core/dev.c31
1 files changed, 25 insertions, 6 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 71059558dc39..43b5575e40c5 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2081,6 +2081,10 @@ int netdev_txq_to_tc(struct net_device *dev, unsigned int txq)
EXPORT_SYMBOL(netdev_txq_to_tc);
#ifdef CONFIG_XPS
+struct static_key xps_needed __read_mostly;
+EXPORT_SYMBOL(xps_needed);
+struct static_key xps_rxqs_needed __read_mostly;
+EXPORT_SYMBOL(xps_rxqs_needed);
static DEFINE_MUTEX(xps_map_mutex);
#define xmap_dereference(P) \
rcu_dereference_protected((P), lockdep_is_held(&xps_map_mutex))
@@ -2168,14 +2172,18 @@ static void netif_reset_xps_queues(struct net_device *dev, u16 offset,
struct xps_dev_maps *dev_maps;
unsigned int nr_ids;
- mutex_lock(&xps_map_mutex);
+ if (!static_key_false(&xps_needed))
+ return;
- dev_maps = xmap_dereference(dev->xps_rxqs_map);
- if (dev_maps) {
- nr_ids = dev->num_rx_queues;
- clean_xps_maps(dev, possible_mask, dev_maps, nr_ids, offset,
- count, true);
+ mutex_lock(&xps_map_mutex);
+ if (static_key_false(&xps_rxqs_needed)) {
+ dev_maps = xmap_dereference(dev->xps_rxqs_map);
+ if (dev_maps) {
+ nr_ids = dev->num_rx_queues;
+ clean_xps_maps(dev, possible_mask, dev_maps, nr_ids,
+ offset, count, true);
+ }
}
dev_maps = xmap_dereference(dev->xps_cpus_map);
@@ -2189,6 +2197,10 @@ static void netif_reset_xps_queues(struct net_device *dev, u16 offset,
false);
out_no_maps:
+ if (static_key_enabled(&xps_rxqs_needed))
+ static_key_slow_dec(&xps_rxqs_needed);
+
+ static_key_slow_dec(&xps_needed);
mutex_unlock(&xps_map_mutex);
}
@@ -2297,6 +2309,10 @@ int __netif_set_xps_queue(struct net_device *dev, const unsigned long *mask,
if (!new_dev_maps)
goto out_no_new_maps;
+ static_key_slow_inc(&xps_needed);
+ if (is_rxqs_map)
+ static_key_slow_inc(&xps_rxqs_needed);
+
for (j = -1; j = netif_attrmask_next(j, possible_mask, nr_ids),
j < nr_ids;) {
/* copy maps belonging to foreign traffic classes */
@@ -3450,6 +3466,9 @@ static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb)
struct xps_map *map;
int queue_index = -1;
+ if (!static_key_false(&xps_needed))
+ return -1;
+
rcu_read_lock();
dev_maps = rcu_dereference(dev->xps_cpus_map);
if (dev_maps) {