Commit ce7f49ab authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

net: move rps_sock_flow_table to net_hotdata 



rps_sock_flow_table and rps_cpu_mask are used in fast path.

Move them to net_hotdata for better cache locality.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240306160031.874438-19-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 490a79fa

include/net/hotdata.h

+4 −0
Original line number Diff line number Diff line
@@ -27,6 +27,10 @@ struct net_hotdata { 
	struct kmem_cache	*skbuff_cache;

	struct kmem_cache	*skbuff_fclone_cache;

	struct kmem_cache	*skb_small_head_cache;

#ifdef CONFIG_RPS

	struct rps_sock_flow_table __rcu *rps_sock_flow_table;

	u32			rps_cpu_mask;

#endif

	int			gro_normal_batch;

	int			netdev_budget;

	int			netdev_budget_usecs;

include/net/rps.h

+3 −5
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
#include <linux/types.h>

#include <linux/static_key.h>

#include <net/sock.h>

#include <net/hotdata.h>



#ifdef CONFIG_RPS
@@ -64,14 +65,11 @@ struct rps_sock_flow_table { 


#define RPS_NO_CPU 0xffff



extern u32 rps_cpu_mask;

extern struct rps_sock_flow_table __rcu *rps_sock_flow_table;



static inline void rps_record_sock_flow(struct rps_sock_flow_table *table,

					u32 hash)

{

	unsigned int index = hash & table->mask;

	u32 val = hash & ~rps_cpu_mask;

	u32 val = hash & ~net_hotdata.rps_cpu_mask;



	/* We only give a hint, preemption can change CPU under us */

	val |= raw_smp_processor_id();
@@ -93,7 +91,7 @@ static inline void sock_rps_record_flow_hash(__u32 hash) 
	if (!hash)

		return;

	rcu_read_lock();

	sock_flow_table = rcu_dereference(rps_sock_flow_table);

	sock_flow_table = rcu_dereference(net_hotdata.rps_sock_flow_table);

	if (sock_flow_table)

		rps_record_sock_flow(sock_flow_table, hash);

	rcu_read_unlock();

net/core/dev.c

+3 −9
Original line number Diff line number Diff line
@@ -4450,12 +4450,6 @@ static inline void ____napi_schedule(struct softnet_data *sd, 


#ifdef CONFIG_RPS



/* One global table that all flow-based protocols share. */

struct rps_sock_flow_table __rcu *rps_sock_flow_table __read_mostly;

EXPORT_SYMBOL(rps_sock_flow_table);

u32 rps_cpu_mask __read_mostly;

EXPORT_SYMBOL(rps_cpu_mask);



struct static_key_false rps_needed __read_mostly;

EXPORT_SYMBOL(rps_needed);

struct static_key_false rfs_needed __read_mostly;
@@ -4547,7 +4541,7 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb, 
	if (!hash)

		goto done;



	sock_flow_table = rcu_dereference(rps_sock_flow_table);

	sock_flow_table = rcu_dereference(net_hotdata.rps_sock_flow_table);

	if (flow_table && sock_flow_table) {

		struct rps_dev_flow *rflow;

		u32 next_cpu;
@@ -4557,10 +4551,10 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb, 
		 * This READ_ONCE() pairs with WRITE_ONCE() from rps_record_sock_flow().

		 */

		ident = READ_ONCE(sock_flow_table->ents[hash & sock_flow_table->mask]);

		if ((ident ^ hash) & ~rps_cpu_mask)

		if ((ident ^ hash) & ~net_hotdata.rps_cpu_mask)

			goto try_rps;



		next_cpu = ident & rps_cpu_mask;

		next_cpu = ident & net_hotdata.rps_cpu_mask;



		/* OK, now we know there is a match,

		 * we can look at the local (per receive queue) flow table

net/core/sysctl_net_core.c

+6 −3
Original line number Diff line number Diff line
@@ -140,7 +140,8 @@ static int rps_sock_flow_sysctl(struct ctl_table *table, int write, 


	mutex_lock(&sock_flow_mutex);



	orig_sock_table = rcu_dereference_protected(rps_sock_flow_table,

	orig_sock_table = rcu_dereference_protected(

					net_hotdata.rps_sock_flow_table,

					lockdep_is_held(&sock_flow_mutex));

	size = orig_size = orig_sock_table ? orig_sock_table->mask + 1 : 0;
@@ -161,7 +162,8 @@ static int rps_sock_flow_sysctl(struct ctl_table *table, int write, 
					mutex_unlock(&sock_flow_mutex);

					return -ENOMEM;

				}

				rps_cpu_mask = roundup_pow_of_two(nr_cpu_ids) - 1;

				net_hotdata.rps_cpu_mask =

					roundup_pow_of_two(nr_cpu_ids) - 1;

				sock_table->mask = size - 1;

			} else

				sock_table = orig_sock_table;
@@ -172,7 +174,8 @@ static int rps_sock_flow_sysctl(struct ctl_table *table, int write, 
			sock_table = NULL;



		if (sock_table != orig_sock_table) {

			rcu_assign_pointer(rps_sock_flow_table, sock_table);

			rcu_assign_pointer(net_hotdata.rps_sock_flow_table,

					   sock_table);

			if (sock_table) {

				static_branch_inc(&rps_needed);

				static_branch_inc(&rfs_needed);