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: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240306160031.874438-19-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/net/hotdata.h b/include/net/hotdata.h
index b0b847585f7e62245cee81a56b5a252051e07834..003667a1efd6b63fc0f0d7cadd2c8472281331b0 100644 (file)
--- a/include/net/hotdata.h
+++ b/include/net/hotdata.h
@@ -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;

diff --git a/include/net/rps.h b/include/net/rps.h
index 6081d817d2458b7b34036d87fbdef3fa6dc914ea..7660243e905b92651a41292e04caf72c5f12f26e 100644 (file)
--- a/include/net/rps.h
+++ b/include/net/rps.h
@@ -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();

diff --git a/net/core/dev.c b/net/core/dev.c
index bcf49b0393d2fc2e837563bef48deaab52626a91..0766a245816bdf70f6609dc7b6d694ae81e7a9e5 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -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

diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 4b93e27404e83a5b3afaa23ebd18cf55b1fdc6e8..6973dda3abda63e0924efa4b6b7026786e8bfb4f 100644 (file)
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -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);