Instead of sharing sd->defer_list & sd->defer_count with many cpus, add one pair for each NUMA node. Signed-off-by: Eric Dumazet --- include/linux/netdevice.h | 4 ---- include/net/hotdata.h | 7 +++++++ net/core/dev.c | 37 +++++++++++++++++++++++++------------ net/core/dev.h | 2 +- net/core/skbuff.c | 11 ++++++----- 5 files changed, 39 insertions(+), 22 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 5c9aa16933d197f70746d64e5f44cae052d9971c..d1a687444b275d45d105e336d2ede264fd310f1b 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3536,10 +3536,6 @@ struct softnet_data { struct numa_drop_counters drop_counters; - /* Another possibly contended cache line */ - struct llist_head defer_list ____cacheline_aligned_in_smp; - atomic_long_t defer_count; - int defer_ipi_scheduled ____cacheline_aligned_in_smp; call_single_data_t defer_csd; }; diff --git a/include/net/hotdata.h b/include/net/hotdata.h index fda94b2647ffa242c256c95ae929d9ef25e54f96..4acec191c54ab367ca12fff590d1f8c8aad64651 100644 --- a/include/net/hotdata.h +++ b/include/net/hotdata.h @@ -2,10 +2,16 @@ #ifndef _NET_HOTDATA_H #define _NET_HOTDATA_H +#include #include #include #include +struct skb_defer_node { + struct llist_head defer_list; + atomic_long_t defer_count; +} ____cacheline_aligned_in_smp; + /* Read mostly data used in network fast paths. */ struct net_hotdata { #if IS_ENABLED(CONFIG_INET) @@ -30,6 +36,7 @@ struct net_hotdata { struct rps_sock_flow_table __rcu *rps_sock_flow_table; u32 rps_cpu_mask; #endif + struct skb_defer_node __percpu *skb_defer_nodes; int gro_normal_batch; int netdev_budget; int netdev_budget_usecs; diff --git a/net/core/dev.c b/net/core/dev.c index fb67372774de10b0b112ca71c7c7a13819c2325b..afcf07352eaa3b9a563173106c84167ebe1ab387 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5180,8 +5180,9 @@ static void napi_schedule_rps(struct softnet_data *sd) __napi_schedule_irqoff(&mysd->backlog); } -void kick_defer_list_purge(struct softnet_data *sd, unsigned int cpu) +void kick_defer_list_purge(unsigned int cpu) { + struct softnet_data *sd = &per_cpu(softnet_data, cpu); unsigned long flags; if (use_backlog_threads()) { @@ -6715,18 +6716,26 @@ bool napi_complete_done(struct napi_struct *n, int work_done) } EXPORT_SYMBOL(napi_complete_done); -static void skb_defer_free_flush(struct softnet_data *sd) +struct skb_defer_node __percpu *skb_defer_nodes; + +static void skb_defer_free_flush(void) { struct llist_node *free_list; struct sk_buff *skb, *next; + struct skb_defer_node *sdn; + int node; - if (llist_empty(&sd->defer_list)) - return; - atomic_long_set(&sd->defer_count, 0); - free_list = llist_del_all(&sd->defer_list); + for_each_node(node) { + sdn = this_cpu_ptr(net_hotdata.skb_defer_nodes) + node; - llist_for_each_entry_safe(skb, next, free_list, ll_node) { - napi_consume_skb(skb, 1); + if (llist_empty(&sdn->defer_list)) + continue; + atomic_long_set(&sdn->defer_count, 0); + free_list = llist_del_all(&sdn->defer_list); + + llist_for_each_entry_safe(skb, next, free_list, ll_node) { + napi_consume_skb(skb, 1); + } } } @@ -6854,7 +6863,7 @@ static void __napi_busy_loop(unsigned int napi_id, if (work > 0) __NET_ADD_STATS(dev_net(napi->dev), LINUX_MIB_BUSYPOLLRXPACKETS, work); - skb_defer_free_flush(this_cpu_ptr(&softnet_data)); + skb_defer_free_flush(); bpf_net_ctx_clear(bpf_net_ctx); local_bh_enable(); @@ -7713,7 +7722,7 @@ static void napi_threaded_poll_loop(struct napi_struct *napi) local_irq_disable(); net_rps_action_and_irq_enable(sd); } - skb_defer_free_flush(sd); + skb_defer_free_flush(); bpf_net_ctx_clear(bpf_net_ctx); local_bh_enable(); @@ -7755,7 +7764,7 @@ static __latent_entropy void net_rx_action(void) for (;;) { struct napi_struct *n; - skb_defer_free_flush(sd); + skb_defer_free_flush(); if (list_empty(&list)) { if (list_empty(&repoll)) { @@ -12989,7 +12998,6 @@ static int __init net_dev_init(void) sd->cpu = i; #endif INIT_CSD(&sd->defer_csd, trigger_rx_softirq, sd); - init_llist_head(&sd->defer_list); gro_init(&sd->backlog.gro); sd->backlog.poll = process_backlog; @@ -12999,6 +13007,11 @@ static int __init net_dev_init(void) if (net_page_pool_create(i)) goto out; } + net_hotdata.skb_defer_nodes = + __alloc_percpu(sizeof(struct skb_defer_node) * nr_node_ids, + __alignof__(struct skb_defer_node)); + if (!net_hotdata.skb_defer_nodes) + goto out; if (use_backlog_threads()) smpboot_register_percpu_thread(&backlog_threads); diff --git a/net/core/dev.h b/net/core/dev.h index d6b08d435479b2ba476b1ddeeaae1dce6ac875a2..900880e8b5b4b9492eca23a4d9201045e6bf7f74 100644 --- a/net/core/dev.h +++ b/net/core/dev.h @@ -357,7 +357,7 @@ static inline void napi_assert_will_not_race(const struct napi_struct *napi) WARN_ON(READ_ONCE(napi->list_owner) != -1); } -void kick_defer_list_purge(struct softnet_data *sd, unsigned int cpu); +void kick_defer_list_purge(unsigned int cpu); #define XMIT_RECURSION_LIMIT 8 diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 22d9dba0e433cf67243a5b7dda77e61d146baf50..03ed51050efe81b582c2bad147afecce3a7115e1 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -7184,9 +7184,9 @@ static void kfree_skb_napi_cache(struct sk_buff *skb) */ void skb_attempt_defer_free(struct sk_buff *skb) { + struct skb_defer_node *sdn; unsigned long defer_count; int cpu = skb->alloc_cpu; - struct softnet_data *sd; unsigned int defer_max; bool kick; @@ -7200,14 +7200,15 @@ nodefer: kfree_skb_napi_cache(skb); DEBUG_NET_WARN_ON_ONCE(skb_dst(skb)); DEBUG_NET_WARN_ON_ONCE(skb->destructor); - sd = &per_cpu(softnet_data, cpu); + sdn = per_cpu_ptr(net_hotdata.skb_defer_nodes, cpu) + numa_node_id(); + defer_max = READ_ONCE(net_hotdata.sysctl_skb_defer_max); - defer_count = atomic_long_inc_return(&sd->defer_count); + defer_count = atomic_long_inc_return(&sdn->defer_count); if (defer_count >= defer_max) goto nodefer; - llist_add(&skb->ll_node, &sd->defer_list); + llist_add(&skb->ll_node, &sdn->defer_list); /* Send an IPI every time queue reaches half capacity. */ kick = (defer_count - 1) == (defer_max >> 1); @@ -7216,7 +7217,7 @@ nodefer: kfree_skb_napi_cache(skb); * if we are unlucky enough (this seems very unlikely). */ if (unlikely(kick)) - kick_defer_list_purge(sd, cpu); + kick_defer_list_purge(cpu); } static void skb_splice_csum_page(struct sk_buff *skb, struct page *page, -- 2.51.0.536.g15c5d4f767-goog