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Commit 04157469 authored by Amritha Nambiar's avatar Amritha Nambiar Committed by David S. Miller
Browse files

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: default avatarAmritha Nambiar <amritha.nambiar@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 80d19669

net/core/dev.c

+25 −6
Original line number Diff line number Diff line
@@ -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;



	if (!static_key_false(&xps_needed))

		return;



	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);



			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) {