| Message ID | 20220707130842.49408-1-maciej.fijalkowski@intel.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | ca2e1a627035002cd33d9667431e80bad90c25fa |
| Delegated to: | BPF |
| Headers | show |
| Series | [v2,bpf-next] xsk: mark napi_id on sendmsg() | expand |
On Thu, Jul 7, 2022 at 3:20 PM Maciej Fijalkowski <maciej.fijalkowski@intel.com> wrote: > > When application runs in busy poll mode and does not receive a single > packet but only sends them, it is currently > impossible to get into napi_busy_loop() as napi_id is only marked on Rx > side in xsk_rcv_check(). In there, napi_id is being taken from > xdp_rxq_info carried by xdp_buff. From Tx perspective, we do not have > access to it. What we have handy is the xsk pool. > > Xsk pool works on a pool of internal xdp_buff wrappers called > xdp_buff_xsk. AF_XDP ZC enabled drivers call xp_set_rxq_info() so each > of xdp_buff_xsk has a valid pointer to xdp_rxq_info of underlying queue. > Therefore, on Tx side, napi_id can be pulled from > xs->pool->heads[0].xdp.rxq->napi_id. Hide this pointer chase under > helper function, xsk_pool_get_napi_id(). > > Do this only for sockets working in ZC mode as otherwise rxq pointers > would not be initialized. Thanks Maciej. Acked-by: Magnus Karlsson <magnus.karlsson@intel.com> > Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> > --- > > v2: > * target bpf-next instead of bpf and don't treat it as fix (Bjorn) > * hide pointer chasing under helper function (Bjorn) > > include/net/xdp_sock_drv.h | 14 ++++++++++++++ > net/xdp/xsk.c | 5 ++++- > 2 files changed, 18 insertions(+), 1 deletion(-) > > diff --git a/include/net/xdp_sock_drv.h b/include/net/xdp_sock_drv.h > index 4aa031849668..4277b0dcee05 100644 > --- a/include/net/xdp_sock_drv.h > +++ b/include/net/xdp_sock_drv.h > @@ -44,6 +44,15 @@ static inline void xsk_pool_set_rxq_info(struct xsk_buff_pool *pool, > xp_set_rxq_info(pool, rxq); > } > > +static inline unsigned int xsk_pool_get_napi_id(struct xsk_buff_pool *pool) > +{ > +#ifdef CONFIG_NET_RX_BUSY_POLL > + return pool->heads[0].xdp.rxq->napi_id; > +#else > + return 0; > +#endif > +} > + > static inline void xsk_pool_dma_unmap(struct xsk_buff_pool *pool, > unsigned long attrs) > { > @@ -198,6 +207,11 @@ static inline void xsk_pool_set_rxq_info(struct xsk_buff_pool *pool, > { > } > > +static inline unsigned int xsk_pool_get_napi_id(struct xsk_buff_pool *pool) > +{ > + return 0; > +} > + > static inline void xsk_pool_dma_unmap(struct xsk_buff_pool *pool, > unsigned long attrs) > { > diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c > index 19ac872a6624..86a97da7e50b 100644 > --- a/net/xdp/xsk.c > +++ b/net/xdp/xsk.c > @@ -637,8 +637,11 @@ static int __xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len > if (unlikely(need_wait)) > return -EOPNOTSUPP; > > - if (sk_can_busy_loop(sk)) > + if (sk_can_busy_loop(sk)) { > + if (xs->zc) > + __sk_mark_napi_id_once(sk, xsk_pool_get_napi_id(xs->pool)); > sk_busy_loop(sk, 1); /* only support non-blocking sockets */ > + } > > if (xs->zc && xsk_no_wakeup(sk)) > return 0; > -- > 2.27.0 >
Hello: This patch was applied to bpf/bpf-next.git (master) by Daniel Borkmann <daniel@iogearbox.net>: On Thu, 7 Jul 2022 15:08:42 +0200 you wrote: > When application runs in busy poll mode and does not receive a single > packet but only sends them, it is currently > impossible to get into napi_busy_loop() as napi_id is only marked on Rx > side in xsk_rcv_check(). In there, napi_id is being taken from > xdp_rxq_info carried by xdp_buff. From Tx perspective, we do not have > access to it. What we have handy is the xsk pool. > > [...] Here is the summary with links: - [v2,bpf-next] xsk: mark napi_id on sendmsg() https://git.kernel.org/bpf/bpf-next/c/ca2e1a627035 You are awesome, thank you!
diff --git a/include/net/xdp_sock_drv.h b/include/net/xdp_sock_drv.h index 4aa031849668..4277b0dcee05 100644 --- a/include/net/xdp_sock_drv.h +++ b/include/net/xdp_sock_drv.h @@ -44,6 +44,15 @@ static inline void xsk_pool_set_rxq_info(struct xsk_buff_pool *pool, xp_set_rxq_info(pool, rxq); } +static inline unsigned int xsk_pool_get_napi_id(struct xsk_buff_pool *pool) +{ +#ifdef CONFIG_NET_RX_BUSY_POLL + return pool->heads[0].xdp.rxq->napi_id; +#else + return 0; +#endif +} + static inline void xsk_pool_dma_unmap(struct xsk_buff_pool *pool, unsigned long attrs) { @@ -198,6 +207,11 @@ static inline void xsk_pool_set_rxq_info(struct xsk_buff_pool *pool, { } +static inline unsigned int xsk_pool_get_napi_id(struct xsk_buff_pool *pool) +{ + return 0; +} + static inline void xsk_pool_dma_unmap(struct xsk_buff_pool *pool, unsigned long attrs) { diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 19ac872a6624..86a97da7e50b 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -637,8 +637,11 @@ static int __xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len if (unlikely(need_wait)) return -EOPNOTSUPP; - if (sk_can_busy_loop(sk)) + if (sk_can_busy_loop(sk)) { + if (xs->zc) + __sk_mark_napi_id_once(sk, xsk_pool_get_napi_id(xs->pool)); sk_busy_loop(sk, 1); /* only support non-blocking sockets */ + } if (xs->zc && xsk_no_wakeup(sk)) return 0;
When application runs in busy poll mode and does not receive a single packet but only sends them, it is currently impossible to get into napi_busy_loop() as napi_id is only marked on Rx side in xsk_rcv_check(). In there, napi_id is being taken from xdp_rxq_info carried by xdp_buff. From Tx perspective, we do not have access to it. What we have handy is the xsk pool. Xsk pool works on a pool of internal xdp_buff wrappers called xdp_buff_xsk. AF_XDP ZC enabled drivers call xp_set_rxq_info() so each of xdp_buff_xsk has a valid pointer to xdp_rxq_info of underlying queue. Therefore, on Tx side, napi_id can be pulled from xs->pool->heads[0].xdp.rxq->napi_id. Hide this pointer chase under helper function, xsk_pool_get_napi_id(). Do this only for sockets working in ZC mode as otherwise rxq pointers would not be initialized. Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> --- v2: * target bpf-next instead of bpf and don't treat it as fix (Bjorn) * hide pointer chasing under helper function (Bjorn) include/net/xdp_sock_drv.h | 14 ++++++++++++++ net/xdp/xsk.c | 5 ++++- 2 files changed, 18 insertions(+), 1 deletion(-)