[PATCH bpf-next v3 2/3] xdp: Use bulking for non-map XDP_REDIRECT and consolidate code paths
From: Toke Høiland-Jørgensen <hidden>
Date: 2020-01-16 15:22:50
Also in:
bpf
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking drivers, networking [general], the rest, tracing, tun/tap driver, virtio net driver, xdp (express data path) · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Steven Rostedt, Masami Hiramatsu, Willem de Bruijn, Jason Wang, "Michael S. Tsirkin", Jesper Dangaard Brouer, John Fastabend
From: Toke Høiland-Jørgensen <redacted> Since the bulk queue used by XDP_REDIRECT now lives in struct net_device, we can re-use the bulking for the non-map version of the bpf_redirect() helper. This is a simple matter of having xdp_do_redirect_slow() queue the frame on the bulk queue instead of sending it out with __bpf_tx_xdp(). Unfortunately we can't make the bpf_redirect() helper return an error if the ifindex doesn't exit (as bpf_redirect_map() does), because we don't have a reference to the network namespace of the ingress device at the time the helper is called. So we have to leave it as-is and keep the device lookup in xdp_do_redirect_slow(). Since this leaves less reason to have the non-map redirect code in a separate function, so we get rid of the xdp_do_redirect_slow() function entirely. This does lose us the tracepoint disambiguation, but fortunately the xdp_redirect and xdp_redirect_map tracepoints use the same tracepoint entry structures. This means both can contain a map index, so we can just amend the tracepoint definitions so we always emit the xdp_redirect(_err) tracepoints, but with the map ID only populated if a map is present. This means we retire the xdp_redirect_map(_err) tracepoints entirely, but keep the definitions around in case someone is still listening for them. With this change, the performance of the xdp_redirect sample program goes from 5Mpps to 8.4Mpps (a 68% increase). Since the flush functions are no longer map-specific, rename the flush() functions to drop _map from their names. One of the renamed functions is the xdp_do_flush_map() callback used in all the xdp-enabled drivers. To keep from having to update all drivers, use a #define to keep the old name working, and only update the virtual drivers in this patch. Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Toke Høiland-Jørgensen <redacted> --- drivers/net/tun.c | 4 +- drivers/net/veth.c | 2 - drivers/net/virtio_net.c | 2 - include/linux/bpf.h | 13 +++++- include/linux/filter.h | 10 +++- include/trace/events/xdp.h | 101 +++++++++++++++++++------------------------- kernel/bpf/devmap.c | 32 ++++++++++---- net/core/filter.c | 90 ++++++++------------------------------- 8 files changed, 108 insertions(+), 146 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 683d371e6e82..3a5a6c655dda 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c@@ -1718,7 +1718,7 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, if (err < 0) goto err_xdp; if (err == XDP_REDIRECT) - xdp_do_flush_map(); + xdp_do_flush(); if (err != XDP_PASS) goto out;
@@ -2549,7 +2549,7 @@ static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) } if (flush) - xdp_do_flush_map(); + xdp_do_flush(); rcu_read_unlock(); local_bh_enable();
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index a552df37a347..1c89017beebb 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c@@ -769,7 +769,7 @@ static int veth_poll(struct napi_struct *napi, int budget) if (xdp_xmit & VETH_XDP_TX) veth_xdp_flush(rq->dev, &bq); if (xdp_xmit & VETH_XDP_REDIR) - xdp_do_flush_map(); + xdp_do_flush(); xdp_clear_return_frame_no_direct(); return done;
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 4d7d5434cc5d..c458cd313281 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c@@ -1432,7 +1432,7 @@ static int virtnet_poll(struct napi_struct *napi, int budget) virtqueue_napi_complete(napi, rq->vq, received); if (xdp_xmit & VIRTIO_XDP_REDIR) - xdp_do_flush_map(); + xdp_do_flush(); if (xdp_xmit & VIRTIO_XDP_TX) { sq = virtnet_xdp_sq(vi);
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 3517e32149a4..8e3b8f4ad183 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h@@ -1056,7 +1056,9 @@ struct sk_buff; struct bpf_dtab_netdev *__dev_map_lookup_elem(struct bpf_map *map, u32 key); struct bpf_dtab_netdev *__dev_map_hash_lookup_elem(struct bpf_map *map, u32 key); -void __dev_map_flush(void); +void __dev_flush(void); +int dev_xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp, + struct net_device *dev_rx); int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp, struct net_device *dev_rx); int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb,
@@ -1169,13 +1171,20 @@ static inline struct net_device *__dev_map_hash_lookup_elem(struct bpf_map *map return NULL; } -static inline void __dev_map_flush(void) +static inline void __dev_flush(void) { } struct xdp_buff; struct bpf_dtab_netdev; +static inline +int dev_xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp, + struct net_device *dev_rx) +{ + return 0; +} + static inline int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp, struct net_device *dev_rx)
diff --git a/include/linux/filter.h b/include/linux/filter.h
index a366a0b64a57..f349e2c0884c 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h@@ -918,7 +918,7 @@ static inline int xdp_ok_fwd_dev(const struct net_device *fwd, return 0; } -/* The pair of xdp_do_redirect and xdp_do_flush_map MUST be called in the +/* The pair of xdp_do_redirect and xdp_do_flush MUST be called in the * same cpu context. Further for best results no more than a single map * for the do_redirect/do_flush pair should be used. This limitation is * because we only track one map and force a flush when the map changes.
@@ -929,7 +929,13 @@ int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb, int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp, struct bpf_prog *prog); -void xdp_do_flush_map(void); +void xdp_do_flush(void); + +/* The xdp_do_flush_map() helper has been renamed to drop the _map suffix, as + * it is no longer only flushing maps. Keep this define for compatibility + * until all drivers are updated - do not use xdp_do_flush_map() in new code! + */ +#define xdp_do_flush_map xdp_do_flush void bpf_warn_invalid_xdp_action(u32 act);
diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h
index 72bad13d4a3c..b680973687b4 100644
--- a/include/trace/events/xdp.h
+++ b/include/trace/events/xdp.h@@ -79,14 +79,26 @@ TRACE_EVENT(xdp_bulk_tx, __entry->sent, __entry->drops, __entry->err) ); +#ifndef __DEVMAP_OBJ_TYPE +#define __DEVMAP_OBJ_TYPE +struct _bpf_dtab_netdev { + struct net_device *dev; +}; +#endif /* __DEVMAP_OBJ_TYPE */ + +#define devmap_ifindex(tgt, map) \ + (((map->map_type == BPF_MAP_TYPE_DEVMAP || \ + map->map_type == BPF_MAP_TYPE_DEVMAP_HASH)) ? \ + ((struct _bpf_dtab_netdev *)tgt)->dev->ifindex : 0) + DECLARE_EVENT_CLASS(xdp_redirect_template, TP_PROTO(const struct net_device *dev, const struct bpf_prog *xdp, - int to_ifindex, int err, - const struct bpf_map *map, u32 map_index), + const void *tgt, int err, + const struct bpf_map *map, u32 index), - TP_ARGS(dev, xdp, to_ifindex, err, map, map_index), + TP_ARGS(dev, xdp, tgt, err, map, index), TP_STRUCT__entry( __field(int, prog_id)
@@ -103,90 +115,65 @@ DECLARE_EVENT_CLASS(xdp_redirect_template, __entry->act = XDP_REDIRECT; __entry->ifindex = dev->ifindex; __entry->err = err; - __entry->to_ifindex = to_ifindex; + __entry->to_ifindex = map ? devmap_ifindex(tgt, map) : + index; __entry->map_id = map ? map->id : 0; - __entry->map_index = map_index; + __entry->map_index = map ? index : 0; ), - TP_printk("prog_id=%d action=%s ifindex=%d to_ifindex=%d err=%d", + TP_printk("prog_id=%d action=%s ifindex=%d to_ifindex=%d err=%d" + " map_id=%d map_index=%d", __entry->prog_id, __print_symbolic(__entry->act, __XDP_ACT_SYM_TAB), __entry->ifindex, __entry->to_ifindex, - __entry->err) + __entry->err, __entry->map_id, __entry->map_index) ); DEFINE_EVENT(xdp_redirect_template, xdp_redirect, TP_PROTO(const struct net_device *dev, const struct bpf_prog *xdp, - int to_ifindex, int err, - const struct bpf_map *map, u32 map_index), - TP_ARGS(dev, xdp, to_ifindex, err, map, map_index) + const void *tgt, int err, + const struct bpf_map *map, u32 index), + TP_ARGS(dev, xdp, tgt, err, map, index) ); DEFINE_EVENT(xdp_redirect_template, xdp_redirect_err, TP_PROTO(const struct net_device *dev, const struct bpf_prog *xdp, - int to_ifindex, int err, - const struct bpf_map *map, u32 map_index), - TP_ARGS(dev, xdp, to_ifindex, err, map, map_index) + const void *tgt, int err, + const struct bpf_map *map, u32 index), + TP_ARGS(dev, xdp, tgt, err, map, index) ); #define _trace_xdp_redirect(dev, xdp, to) \ - trace_xdp_redirect(dev, xdp, to, 0, NULL, 0); + trace_xdp_redirect(dev, xdp, NULL, 0, NULL, to); #define _trace_xdp_redirect_err(dev, xdp, to, err) \ - trace_xdp_redirect_err(dev, xdp, to, err, NULL, 0); + trace_xdp_redirect_err(dev, xdp, NULL, err, NULL, to); + +#define _trace_xdp_redirect_map(dev, xdp, to, map, index) \ + trace_xdp_redirect(dev, xdp, to, 0, map, index); + +#define _trace_xdp_redirect_map_err(dev, xdp, to, map, index, err) \ + trace_xdp_redirect_err(dev, xdp, to, err, map, index); -DEFINE_EVENT_PRINT(xdp_redirect_template, xdp_redirect_map, +/* not used anymore, but kept around so as not to break old programs */ +DEFINE_EVENT(xdp_redirect_template, xdp_redirect_map, TP_PROTO(const struct net_device *dev, const struct bpf_prog *xdp, - int to_ifindex, int err, - const struct bpf_map *map, u32 map_index), - TP_ARGS(dev, xdp, to_ifindex, err, map, map_index), - TP_printk("prog_id=%d action=%s ifindex=%d to_ifindex=%d err=%d" - " map_id=%d map_index=%d", - __entry->prog_id, - __print_symbolic(__entry->act, __XDP_ACT_SYM_TAB), - __entry->ifindex, __entry->to_ifindex, - __entry->err, - __entry->map_id, __entry->map_index) + const void *tgt, int err, + const struct bpf_map *map, u32 index), + TP_ARGS(dev, xdp, tgt, err, map, index) ); -DEFINE_EVENT_PRINT(xdp_redirect_template, xdp_redirect_map_err, +DEFINE_EVENT(xdp_redirect_template, xdp_redirect_map_err, TP_PROTO(const struct net_device *dev, const struct bpf_prog *xdp, - int to_ifindex, int err, - const struct bpf_map *map, u32 map_index), - TP_ARGS(dev, xdp, to_ifindex, err, map, map_index), - TP_printk("prog_id=%d action=%s ifindex=%d to_ifindex=%d err=%d" - " map_id=%d map_index=%d", - __entry->prog_id, - __print_symbolic(__entry->act, __XDP_ACT_SYM_TAB), - __entry->ifindex, __entry->to_ifindex, - __entry->err, - __entry->map_id, __entry->map_index) + const void *tgt, int err, + const struct bpf_map *map, u32 index), + TP_ARGS(dev, xdp, tgt, err, map, index) ); -#ifndef __DEVMAP_OBJ_TYPE -#define __DEVMAP_OBJ_TYPE -struct _bpf_dtab_netdev { - struct net_device *dev; -}; -#endif /* __DEVMAP_OBJ_TYPE */ - -#define devmap_ifindex(fwd, map) \ - ((map->map_type == BPF_MAP_TYPE_DEVMAP || \ - map->map_type == BPF_MAP_TYPE_DEVMAP_HASH) ? \ - ((struct _bpf_dtab_netdev *)fwd)->dev->ifindex : 0) - -#define _trace_xdp_redirect_map(dev, xdp, fwd, map, idx) \ - trace_xdp_redirect_map(dev, xdp, devmap_ifindex(fwd, map), \ - 0, map, idx) - -#define _trace_xdp_redirect_map_err(dev, xdp, fwd, map, idx, err) \ - trace_xdp_redirect_map_err(dev, xdp, devmap_ifindex(fwd, map), \ - err, map, idx) - TRACE_EVENT(xdp_cpumap_kthread, TP_PROTO(int map_id, unsigned int processed, unsigned int drops,
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 030d125c3839..d5311009953f 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c@@ -81,7 +81,7 @@ struct bpf_dtab { u32 n_buckets; }; -static DEFINE_PER_CPU(struct list_head, dev_map_flush_list); +static DEFINE_PER_CPU(struct list_head, dev_flush_list); static DEFINE_SPINLOCK(dev_map_lock); static LIST_HEAD(dev_map_list);
@@ -357,16 +357,16 @@ static int bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags) goto out; } -/* __dev_map_flush is called from xdp_do_flush_map() which _must_ be signaled +/* __dev_flush is called from xdp_do_flush() which _must_ be signaled * from the driver before returning from its napi->poll() routine. The poll() * routine is called either from busy_poll context or net_rx_action signaled * from NET_RX_SOFTIRQ. Either way the poll routine must complete before the * net device can be torn down. On devmap tear down we ensure the flush list * is empty before completing to ensure all flush operations have completed. */ -void __dev_map_flush(void) +void __dev_flush(void) { - struct list_head *flush_list = this_cpu_ptr(&dev_map_flush_list); + struct list_head *flush_list = this_cpu_ptr(&dev_flush_list); struct xdp_dev_bulk_queue *bq, *tmp; rcu_read_lock();
@@ -396,9 +396,8 @@ struct bpf_dtab_netdev *__dev_map_lookup_elem(struct bpf_map *map, u32 key) */ static int bq_enqueue(struct net_device *dev, struct xdp_frame *xdpf, struct net_device *dev_rx) - { - struct list_head *flush_list = this_cpu_ptr(&dev_map_flush_list); + struct list_head *flush_list = this_cpu_ptr(&dev_flush_list); struct xdp_dev_bulk_queue *bq = this_cpu_ptr(dev->xdp_bulkq); if (unlikely(bq->count == DEV_MAP_BULK_SIZE))
@@ -419,10 +418,9 @@ static int bq_enqueue(struct net_device *dev, struct xdp_frame *xdpf, return 0; } -int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp, - struct net_device *dev_rx) +static inline int __xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp, + struct net_device *dev_rx) { - struct net_device *dev = dst->dev; struct xdp_frame *xdpf; int err;
@@ -440,6 +438,20 @@ int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp, return bq_enqueue(dev, xdpf, dev_rx); } +int dev_xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp, + struct net_device *dev_rx) +{ + return __xdp_enqueue(dev, xdp, dev_rx); +} + +int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp, + struct net_device *dev_rx) +{ + struct net_device *dev = dst->dev; + + return __xdp_enqueue(dev, xdp, dev_rx); +} + int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb, struct bpf_prog *xdp_prog) {
@@ -762,7 +774,7 @@ static int __init dev_map_init(void) register_netdevice_notifier(&dev_map_notifier); for_each_possible_cpu(cpu) - INIT_LIST_HEAD(&per_cpu(dev_map_flush_list, cpu)); + INIT_LIST_HEAD(&per_cpu(dev_flush_list, cpu)); return 0; }
diff --git a/net/core/filter.c b/net/core/filter.c
index d6f58dc4e1c4..17de6747d9e3 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -3458,58 +3458,6 @@ static const struct bpf_func_proto bpf_xdp_adjust_meta_proto = { .arg2_type = ARG_ANYTHING, }; -static int __bpf_tx_xdp(struct net_device *dev, - struct bpf_map *map, - struct xdp_buff *xdp, - u32 index) -{ - struct xdp_frame *xdpf; - int err, sent; - - if (!dev->netdev_ops->ndo_xdp_xmit) { - return -EOPNOTSUPP; - } - - err = xdp_ok_fwd_dev(dev, xdp->data_end - xdp->data); - if (unlikely(err)) - return err; - - xdpf = convert_to_xdp_frame(xdp); - if (unlikely(!xdpf)) - return -EOVERFLOW; - - sent = dev->netdev_ops->ndo_xdp_xmit(dev, 1, &xdpf, XDP_XMIT_FLUSH); - if (sent <= 0) - return sent; - return 0; -} - -static noinline int -xdp_do_redirect_slow(struct net_device *dev, struct xdp_buff *xdp, - struct bpf_prog *xdp_prog, struct bpf_redirect_info *ri) -{ - struct net_device *fwd; - u32 index = ri->tgt_index; - int err; - - fwd = dev_get_by_index_rcu(dev_net(dev), index); - ri->tgt_index = 0; - if (unlikely(!fwd)) { - err = -EINVAL; - goto err; - } - - err = __bpf_tx_xdp(fwd, NULL, xdp, 0); - if (unlikely(err)) - goto err; - - _trace_xdp_redirect(dev, xdp_prog, index); - return 0; -err: - _trace_xdp_redirect_err(dev, xdp_prog, index, err); - return err; -} - static int __bpf_tx_xdp_map(struct net_device *dev_rx, void *fwd, struct bpf_map *map, struct xdp_buff *xdp) {
@@ -3527,13 +3475,13 @@ static int __bpf_tx_xdp_map(struct net_device *dev_rx, void *fwd, return 0; } -void xdp_do_flush_map(void) +void xdp_do_flush(void) { - __dev_map_flush(); + __dev_flush(); __cpu_map_flush(); __xsk_map_flush(); } -EXPORT_SYMBOL_GPL(xdp_do_flush_map); +EXPORT_SYMBOL_GPL(xdp_do_flush); static inline void *__xdp_map_lookup_elem(struct bpf_map *map, u32 index) {
@@ -3568,10 +3516,11 @@ void bpf_clear_redirect_map(struct bpf_map *map) } } -static int xdp_do_redirect_map(struct net_device *dev, struct xdp_buff *xdp, - struct bpf_prog *xdp_prog, struct bpf_map *map, - struct bpf_redirect_info *ri) +int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp, + struct bpf_prog *xdp_prog) { + struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info); + struct bpf_map *map = READ_ONCE(ri->map); u32 index = ri->tgt_index; void *fwd = ri->tgt_value; int err;
@@ -3580,7 +3529,18 @@ static int xdp_do_redirect_map(struct net_device *dev, struct xdp_buff *xdp, ri->tgt_value = NULL; WRITE_ONCE(ri->map, NULL); - err = __bpf_tx_xdp_map(dev, fwd, map, xdp); + if (unlikely(!map)) { + fwd = dev_get_by_index_rcu(dev_net(dev), index); + if (unlikely(!fwd)) { + err = -EINVAL; + goto err; + } + + err = dev_xdp_enqueue(fwd, xdp, dev); + } else { + err = __bpf_tx_xdp_map(dev, fwd, map, xdp); + } + if (unlikely(err)) goto err;
@@ -3590,18 +3550,6 @@ static int xdp_do_redirect_map(struct net_device *dev, struct xdp_buff *xdp, _trace_xdp_redirect_map_err(dev, xdp_prog, fwd, map, index, err); return err; } - -int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp, - struct bpf_prog *xdp_prog) -{ - struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info); - struct bpf_map *map = READ_ONCE(ri->map); - - if (likely(map)) - return xdp_do_redirect_map(dev, xdp, xdp_prog, map, ri); - - return xdp_do_redirect_slow(dev, xdp, xdp_prog, ri); -} EXPORT_SYMBOL_GPL(xdp_do_redirect); static int xdp_do_generic_redirect_map(struct net_device *dev,