net: move sysctl_max_skb_frags to net_hotdata

sysctl_max_skb_frags is used in TCP and MPTCP fast paths,
move it to net_hodata for better cache locality.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240429134025.1233626-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index adf75d69770c80c6efce0a59671e737983df6fb6..36b133f04d30f1c0114ec932054e7213e5a466e5 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -353,8 +353,6 @@ struct sk_buff;
 
 #define MAX_SKB_FRAGS CONFIG_MAX_SKB_FRAGS
 
-extern int sysctl_max_skb_frags;
-
 /* Set skb_shinfo(skb)->gso_size to this in case you want skb_segment to
  * segment using its current segmentation instead.
  */

diff --git a/include/net/hotdata.h b/include/net/hotdata.h
index 003667a1efd6b63fc0f0d7cadd2c8472281331b0..a6cff65904267f338fbd258d23be79d46a062f9e 100644 (file)
--- a/include/net/hotdata.h
+++ b/include/net/hotdata.h
@@ -38,6 +38,7 @@ struct net_hotdata {
        int                     max_backlog;
        int                     dev_tx_weight;
        int                     dev_rx_weight;
+       int                     sysctl_max_skb_frags;
 };
 
 #define inet_ehash_secret      net_hotdata.tcp_protocol.secret

diff --git a/net/core/hotdata.c b/net/core/hotdata.c
index c8a7a451c18a383d091e413a510d84d163473f2f..f17cbb4807b99937b272be12953f790c66cc2cd1 100644 (file)
--- a/net/core/hotdata.c
+++ b/net/core/hotdata.c
@@ -18,5 +18,6 @@ struct net_hotdata net_hotdata __cacheline_aligned = {
        .max_backlog = 1000,
        .dev_tx_weight = 64,
        .dev_rx_weight = 64,
+       .sysctl_max_skb_frags = MAX_SKB_FRAGS,
 };
 EXPORT_SYMBOL(net_hotdata);

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 0c8b82750000f63b097cb4b7b990c647c81019df..65779b8f0b126a1c039cf24a47474c0cb80ff6ae 100644 (file)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -109,9 +109,6 @@ static struct kmem_cache *skbuff_ext_cache __ro_after_init;
 #define SKB_SMALL_HEAD_HEADROOM                                                \
        SKB_WITH_OVERHEAD(SKB_SMALL_HEAD_CACHE_SIZE)
 
-int sysctl_max_skb_frags __read_mostly = MAX_SKB_FRAGS;
-EXPORT_SYMBOL(sysctl_max_skb_frags);
-
 /* kcm_write_msgs() relies on casting paged frags to bio_vec to use
  * iov_iter_bvec(). These static asserts ensure the cast is valid is long as the
  * netmem is a page.
@@ -7040,7 +7037,7 @@ static void skb_splice_csum_page(struct sk_buff *skb, struct page *page,
 ssize_t skb_splice_from_iter(struct sk_buff *skb, struct iov_iter *iter,
                             ssize_t maxsize, gfp_t gfp)
 {
-       size_t frag_limit = READ_ONCE(sysctl_max_skb_frags);
+       size_t frag_limit = READ_ONCE(net_hotdata.sysctl_max_skb_frags);
        struct page *pages[8], **ppages = pages;
        ssize_t spliced = 0, ret = 0;
        unsigned int i;

diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 903ab4a51c178a4705b7eb610958c81c5ebcfdf5..e75375d54b9e50673af28f6d6b3bb83fc74cb1f8 100644 (file)
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -595,7 +595,7 @@ static struct ctl_table net_core_table[] = {
        },
        {
                .procname       = "max_skb_frags",
-               .data           = &sysctl_max_skb_frags,
+               .data           = &net_hotdata.sysctl_max_skb_frags,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 4ec0f4feee003d91fa5ae37ed4dd50e09c4c874a..388f6e115bf168e6f70b762096a984a2cacfa5c9 100644 (file)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -280,6 +280,7 @@
 #include <linux/uaccess.h>
 #include <asm/ioctls.h>
 #include <net/busy_poll.h>
+#include <net/hotdata.h>
 #include <net/rps.h>
 
 /* Track pending CMSGs. */
@@ -1188,7 +1189,7 @@ new_segment:
 
                        if (!skb_can_coalesce(skb, i, pfrag->page,
                                              pfrag->offset)) {
-                               if (i >= READ_ONCE(sysctl_max_skb_frags)) {
+                               if (i >= READ_ONCE(net_hotdata.sysctl_max_skb_frags)) {
                                        tcp_mark_push(tp, skb);
                                        goto new_segment;
                                }

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 4b13ca362efa395a2ef7a92e553a8c49feebec79..aff17597e6a71ecc4b9aef4d02f039318fa1fe7f 100644 (file)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -20,6 +20,7 @@
 #include <net/transp_v6.h>
 #endif
 #include <net/mptcp.h>
+#include <net/hotdata.h>
 #include <net/xfrm.h>
 #include <asm/ioctls.h>
 #include "protocol.h"
@@ -1272,7 +1273,7 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
 
                i = skb_shinfo(skb)->nr_frags;
                can_coalesce = skb_can_coalesce(skb, i, dfrag->page, offset);
-               if (!can_coalesce && i >= READ_ONCE(sysctl_max_skb_frags)) {
+               if (!can_coalesce && i >= READ_ONCE(net_hotdata.sysctl_max_skb_frags)) {
                        tcp_mark_push(tcp_sk(ssk), skb);
                        goto alloc_skb;
                }