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author | 2021-07-29 12:18:51 +0100 | |
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committer | 2021-07-29 12:18:51 +0100 | |
commit | 8cb79af5c63ff2dbcab048085302256dd7e8208d (patch) | |
tree | 3fd1eae06a0bb5286063d8aed35c11a51db5c531 | |
parent | Documentation: networking: add ioam6-sysctl into index (diff) | |
parent | veth: use skb_prepare_for_gro() (diff) | |
download | linux-dev-8cb79af5c63ff2dbcab048085302256dd7e8208d.tar.xz linux-dev-8cb79af5c63ff2dbcab048085302256dd7e8208d.zip |
Merge branch 'skb-gro-optimize'
Paolo Abeni says:
====================
sk_buff: optimize GRO for the common case
This is a trimmed down revision of "sk_buff: optimize layout for GRO",
specifically dropping the changes to the sk_buff layout[1].
This series tries to accomplish 2 goals:
- optimize the GRO stage for the most common scenario, avoiding a bunch
of conditional and some more code
- let owned skbs entering the GRO engine, allowing backpressure in the
veth GRO forward path.
A new sk_buff flag (!!!) is introduced and maintained for GRO's sake.
Such field uses an existing hole, so there is no change to the sk_buff
size.
[1] two main reasons:
- move skb->inner_ field requires some extra care, as some in kernel
users access and the fields regardless of skb->encapsulation.
- extending secmark size clash with ct and nft uAPIs
address the all above is possible, I think, but for sure not in a single
series.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r-- | drivers/net/veth.c | 2 | ||||
-rw-r--r-- | include/linux/skbuff.h | 6 | ||||
-rw-r--r-- | include/net/dst.h | 2 | ||||
-rw-r--r-- | include/net/sock.h | 9 | ||||
-rw-r--r-- | net/core/dev.c | 32 | ||||
-rw-r--r-- | net/core/skbuff.c | 27 |
6 files changed, 62 insertions, 16 deletions
diff --git a/drivers/net/veth.c b/drivers/net/veth.c index 381670c08ba7..50eb43e5bf45 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -713,7 +713,7 @@ static struct sk_buff *veth_xdp_rcv_skb(struct veth_rq *rq, int mac_len, delta, off; struct xdp_buff xdp; - skb_orphan_partial(skb); + skb_prepare_for_gro(skb); rcu_read_lock(); xdp_prog = rcu_dereference(rq->xdp_prog); diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index f19190820e63..b1e5bbfcc926 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -689,6 +689,7 @@ typedef unsigned char *sk_buff_data_t; * CHECKSUM_UNNECESSARY (max 3) * @dst_pending_confirm: need to confirm neighbour * @decrypted: Decrypted SKB + * @slow_gro: state present at GRO time, slower prepare step required * @napi_id: id of the NAPI struct this skb came from * @sender_cpu: (aka @napi_id) source CPU in XPS * @secmark: security marking @@ -870,6 +871,7 @@ struct sk_buff { #ifdef CONFIG_TLS_DEVICE __u8 decrypted:1; #endif + __u8 slow_gro:1; #ifdef CONFIG_NET_SCHED __u16 tc_index; /* traffic control index */ @@ -990,6 +992,7 @@ static inline struct dst_entry *skb_dst(const struct sk_buff *skb) */ static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst) { + skb->slow_gro |= !!dst; skb->_skb_refdst = (unsigned long)dst; } @@ -1006,6 +1009,7 @@ static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst) static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst) { WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held()); + skb->slow_gro = !!dst; skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF; } @@ -4216,6 +4220,7 @@ static inline unsigned long skb_get_nfct(const struct sk_buff *skb) static inline void skb_set_nfct(struct sk_buff *skb, unsigned long nfct) { #if IS_ENABLED(CONFIG_NF_CONNTRACK) + skb->slow_gro |= !!nfct; skb->_nfct = nfct; #endif } @@ -4375,6 +4380,7 @@ static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src) #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) nf_conntrack_put(skb_nfct(dst)); #endif + dst->slow_gro = src->slow_gro; __nf_copy(dst, src, true); } diff --git a/include/net/dst.h b/include/net/dst.h index 75b1e734e9c2..a057319aabef 100644 --- a/include/net/dst.h +++ b/include/net/dst.h @@ -277,6 +277,7 @@ static inline void skb_dst_drop(struct sk_buff *skb) static inline void __skb_dst_copy(struct sk_buff *nskb, unsigned long refdst) { + nskb->slow_gro |= !!refdst; nskb->_skb_refdst = refdst; if (!(nskb->_skb_refdst & SKB_DST_NOREF)) dst_clone(skb_dst(nskb)); @@ -316,6 +317,7 @@ static inline bool skb_dst_force(struct sk_buff *skb) dst = NULL; skb->_skb_refdst = (unsigned long)dst; + skb->slow_gro |= !!dst; } return skb->_skb_refdst != 0UL; diff --git a/include/net/sock.h b/include/net/sock.h index f23cb259b0e2..ff1be7e7e90b 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -2249,6 +2249,15 @@ static inline __must_check bool skb_set_owner_sk_safe(struct sk_buff *skb, struc return false; } +static inline void skb_prepare_for_gro(struct sk_buff *skb) +{ + if (skb->destructor != sock_wfree) { + skb_orphan(skb); + return; + } + skb->slow_gro = 1; +} + void sk_reset_timer(struct sock *sk, struct timer_list *timer, unsigned long expires); diff --git a/net/core/dev.c b/net/core/dev.c index fb5d12a3d52d..dcc87fcd64ba 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6014,7 +6014,6 @@ static void gro_list_prepare(const struct list_head *head, diffs |= skb_vlan_tag_present(p) ^ skb_vlan_tag_present(skb); if (skb_vlan_tag_present(p)) diffs |= skb_vlan_tag_get(p) ^ skb_vlan_tag_get(skb); - diffs |= skb_metadata_dst_cmp(p, skb); diffs |= skb_metadata_differs(p, skb); if (maclen == ETH_HLEN) diffs |= compare_ether_header(skb_mac_header(p), @@ -6024,17 +6023,30 @@ static void gro_list_prepare(const struct list_head *head, skb_mac_header(skb), maclen); - diffs |= skb_get_nfct(p) ^ skb_get_nfct(skb); + /* in most common scenarions _state is 0 + * otherwise we are already on some slower paths + * either skip all the infrequent tests altogether or + * avoid trying too hard to skip each of them individually + */ + if (!diffs && unlikely(skb->slow_gro | p->slow_gro)) { +#if IS_ENABLED(CONFIG_SKB_EXTENSIONS) && IS_ENABLED(CONFIG_NET_TC_SKB_EXT) + struct tc_skb_ext *skb_ext; + struct tc_skb_ext *p_ext; +#endif + + diffs |= p->sk != skb->sk; + diffs |= skb_metadata_dst_cmp(p, skb); + diffs |= skb_get_nfct(p) ^ skb_get_nfct(skb); + #if IS_ENABLED(CONFIG_SKB_EXTENSIONS) && IS_ENABLED(CONFIG_NET_TC_SKB_EXT) - if (!diffs) { - struct tc_skb_ext *skb_ext = skb_ext_find(skb, TC_SKB_EXT); - struct tc_skb_ext *p_ext = skb_ext_find(p, TC_SKB_EXT); + skb_ext = skb_ext_find(skb, TC_SKB_EXT); + p_ext = skb_ext_find(p, TC_SKB_EXT); diffs |= (!!p_ext) ^ (!!skb_ext); if (!diffs && unlikely(skb_ext)) diffs |= p_ext->chain ^ skb_ext->chain; - } #endif + } NAPI_GRO_CB(p)->same_flow = !diffs; } @@ -6299,8 +6311,12 @@ static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb) skb->encapsulation = 0; skb_shinfo(skb)->gso_type = 0; skb->truesize = SKB_TRUESIZE(skb_end_offset(skb)); - skb_ext_reset(skb); - nf_reset_ct(skb); + if (unlikely(skb->slow_gro)) { + skb_orphan(skb); + skb_ext_reset(skb); + nf_reset_ct(skb); + skb->slow_gro = 0; + } napi->skb = skb; } diff --git a/net/core/skbuff.c b/net/core/skbuff.c index fc7942c0dddc..fcbd977186b0 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -954,9 +954,13 @@ void __kfree_skb_defer(struct sk_buff *skb) void napi_skb_free_stolen_head(struct sk_buff *skb) { - nf_reset_ct(skb); - skb_dst_drop(skb); - skb_ext_put(skb); + if (unlikely(skb->slow_gro)) { + nf_reset_ct(skb); + skb_dst_drop(skb); + skb_ext_put(skb); + skb_orphan(skb); + skb->slow_gro = 0; + } napi_skb_cache_put(skb); } @@ -3889,6 +3893,9 @@ int skb_gro_receive_list(struct sk_buff *p, struct sk_buff *skb) NAPI_GRO_CB(p)->last = skb; NAPI_GRO_CB(p)->count++; p->data_len += skb->len; + + /* sk owenrship - if any - completely transferred to the aggregated packet */ + skb->destructor = NULL; p->truesize += skb->truesize; p->len += skb->len; @@ -4256,6 +4263,7 @@ int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb) unsigned int headlen = skb_headlen(skb); unsigned int len = skb_gro_len(skb); unsigned int delta_truesize; + unsigned int new_truesize; struct sk_buff *lp; if (unlikely(p->len + len >= 65536 || NAPI_GRO_CB(skb)->flush)) @@ -4287,10 +4295,10 @@ int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb) skb_frag_size_sub(frag, offset); /* all fragments truesize : remove (head size + sk_buff) */ - delta_truesize = skb->truesize - - SKB_TRUESIZE(skb_end_offset(skb)); + new_truesize = SKB_TRUESIZE(skb_end_offset(skb)); + delta_truesize = skb->truesize - new_truesize; - skb->truesize -= skb->data_len; + skb->truesize = new_truesize; skb->len -= skb->data_len; skb->data_len = 0; @@ -4319,12 +4327,16 @@ int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb) memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags); /* We dont need to clear skbinfo->nr_frags here */ - delta_truesize = skb->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff)); + new_truesize = SKB_TRUESIZE(sizeof(struct sk_buff)); + delta_truesize = skb->truesize - new_truesize; + skb->truesize = new_truesize; NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD; goto done; } merge: + /* sk owenrship - if any - completely transferred to the aggregated packet */ + skb->destructor = NULL; delta_truesize = skb->truesize; if (offset > headlen) { unsigned int eat = offset - headlen; @@ -6449,6 +6461,7 @@ void *skb_ext_add(struct sk_buff *skb, enum skb_ext_id id) new->chunks = newlen; new->offset[id] = newoff; set_active: + skb->slow_gro = 1; skb->extensions = new; skb->active_extensions |= 1 << id; return skb_ext_get_ptr(new, id); |