[net-next PATCH RFC 4/8] net: core: add recycle capabilities on skbs via page_pool API
From: Jesper Dangaard Brouer <hidden>
Date: 2018-12-06 23:25:55
Subsystem:
networking [general], the rest, xdp (express data path) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Alexei Starovoitov, Daniel Borkmann, David S. Miller, Jesper Dangaard Brouer, John Fastabend
From: Ilias Apalodimas <ilias.apalodimas@linaro.org> This patch is changing struct sk_buff, and is thus per-definition controversial. Place a new member 'mem_info' of type struct xdp_mem_info, just after members (flags) head_frag and pfmemalloc, And not in between headers_start/end to ensure skb_copy() and pskb_copy() work as-is. Copying mem_info during skb_clone() is required. This makes sure that pages are correctly freed or recycled during the altered skb_free_head() invocation. The 'mem_info' name is chosen as this is not strictly tied to XDP, although the XDP return infrastructure is used. As a future plan, we could introduce a __u8 flags member to xdp_mem_info and move flags head_frag and pfmemalloc into this area. Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Signed-off-by: Jesper Dangaard Brouer <redacted> --- include/linux/skbuff.h | 6 +++++- include/net/xdp.h | 1 + net/core/skbuff.c | 7 +++++++ net/core/xdp.c | 6 ++++++ 4 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 7dcfb5591dc3..95dac0ba6947 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h@@ -40,6 +40,7 @@ #include <linux/in6.h> #include <linux/if_packet.h> #include <net/flow.h> +#include <net/xdp.h> /* The interface for checksum offload between the stack and networking drivers * is as follows...
@@ -744,6 +745,10 @@ struct sk_buff { head_frag:1, xmit_more:1, pfmemalloc:1; + /* TODO: Future idea, extend mem_info with __u8 flags, and + * move bits head_frag and pfmemalloc there. + */ + struct xdp_mem_info mem_info; /* fields enclosed in headers_start/headers_end are copied * using a single memcpy() in __copy_skb_header()
@@ -827,7 +832,6 @@ struct sk_buff { #ifdef CONFIG_NETWORK_SECMARK __u32 secmark; #endif - union { __u32 mark; __u32 reserved_tailroom;
diff --git a/include/net/xdp.h b/include/net/xdp.h
index 5c33b9e0efab..4a0ca7a3d5e5 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h@@ -128,6 +128,7 @@ struct xdp_frame *convert_to_xdp_frame(struct xdp_buff *xdp) void xdp_return_frame(struct xdp_frame *xdpf); void xdp_return_frame_rx_napi(struct xdp_frame *xdpf); void xdp_return_buff(struct xdp_buff *xdp); +void xdp_return_skb_page(void *data, struct xdp_mem_info *mem_info); int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq, struct net_device *dev, u32 queue_index);
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index b4ee5c8b928f..71aca186e44c 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c@@ -70,6 +70,7 @@ #include <net/checksum.h> #include <net/ip6_checksum.h> #include <net/xfrm.h> +#include <net/page_pool.h> #include <linux/uaccess.h> #include <trace/events/skb.h>
@@ -544,6 +545,11 @@ static void skb_free_head(struct sk_buff *skb) { unsigned char *head = skb->head; + if (skb->mem_info.type == MEM_TYPE_PAGE_POOL) { + xdp_return_skb_page(head, &skb->mem_info); + return; + } + if (skb->head_frag) skb_free_frag(head); else
@@ -859,6 +865,7 @@ static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb) n->nohdr = 0; n->peeked = 0; C(pfmemalloc); + C(mem_info); n->destructor = NULL; C(tail); C(end);
diff --git a/net/core/xdp.c b/net/core/xdp.c
index e79526314864..1703be4c2611 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c@@ -379,6 +379,12 @@ void xdp_return_buff(struct xdp_buff *xdp) } EXPORT_SYMBOL_GPL(xdp_return_buff); +void xdp_return_skb_page(void *data, struct xdp_mem_info *mem_info) +{ + __xdp_return(data, mem_info, false, 0); +} +EXPORT_SYMBOL(xdp_return_skb_page); + int xdp_attachment_query(struct xdp_attachment_info *info, struct netdev_bpf *bpf) {