From f5bd91388e26557f64ca999e0006038c7a919308 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Fri, 7 Sep 2018 10:18:46 +0200 Subject: [PATCH] net: xsk: add a simple buffer reuse queue XSK UMEM is strongly single producer single consumer so reuse of frames is challenging. Add a simple "stash" of FILL packets to reuse for drivers to optionally make use of. This is useful when driver has to free (ndo_stop) or resize a ring with an active AF_XDP ZC socket. Signed-off-by: Jakub Kicinski Tested-by: Andrew Bowers Signed-off-by: Jeff Kirsher --- include/net/xdp_sock.h | 69 ++++++++++++++++++++++++++++++++++++++++++ net/xdp/xdp_umem.c | 2 ++ net/xdp/xsk_queue.c | 55 +++++++++++++++++++++++++++++++++ net/xdp/xsk_queue.h | 3 ++ 4 files changed, 129 insertions(+) diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h index 932ca0dad6f3..70a115bea4f4 100644 --- a/include/net/xdp_sock.h +++ b/include/net/xdp_sock.h @@ -21,6 +21,12 @@ struct xdp_umem_page { dma_addr_t dma; }; +struct xdp_umem_fq_reuse { + u32 nentries; + u32 length; + u64 handles[]; +}; + struct xdp_umem { struct xsk_queue *fq; struct xsk_queue *cq; @@ -37,6 +43,7 @@ struct xdp_umem { struct page **pgs; u32 npgs; struct net_device *dev; + struct xdp_umem_fq_reuse *fq_reuse; u16 queue_id; bool zc; spinlock_t xsk_list_lock; @@ -75,6 +82,10 @@ void xsk_umem_discard_addr(struct xdp_umem *umem); void xsk_umem_complete_tx(struct xdp_umem *umem, u32 nb_entries); bool xsk_umem_consume_tx(struct xdp_umem *umem, dma_addr_t *dma, u32 *len); void xsk_umem_consume_tx_done(struct xdp_umem *umem); +struct xdp_umem_fq_reuse *xsk_reuseq_prepare(u32 nentries); +struct xdp_umem_fq_reuse *xsk_reuseq_swap(struct xdp_umem *umem, + struct xdp_umem_fq_reuse *newq); +void xsk_reuseq_free(struct xdp_umem_fq_reuse *rq); static inline char *xdp_umem_get_data(struct xdp_umem *umem, u64 addr) { @@ -85,6 +96,35 @@ static inline dma_addr_t xdp_umem_get_dma(struct xdp_umem *umem, u64 addr) { return umem->pages[addr >> PAGE_SHIFT].dma + (addr & (PAGE_SIZE - 1)); } + +/* Reuse-queue aware version of FILL queue helpers */ +static inline u64 *xsk_umem_peek_addr_rq(struct xdp_umem *umem, u64 *addr) +{ + struct xdp_umem_fq_reuse *rq = umem->fq_reuse; + + if (!rq->length) + return xsk_umem_peek_addr(umem, addr); + + *addr = rq->handles[rq->length - 1]; + return addr; +} + +static inline void xsk_umem_discard_addr_rq(struct xdp_umem *umem) +{ + struct xdp_umem_fq_reuse *rq = umem->fq_reuse; + + if (!rq->length) + xsk_umem_discard_addr(umem); + else + rq->length--; +} + +static inline void xsk_umem_fq_reuse(struct xdp_umem *umem, u64 addr) +{ + struct xdp_umem_fq_reuse *rq = umem->fq_reuse; + + rq->handles[rq->length++] = addr; +} #else static inline int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp) { @@ -128,6 +168,21 @@ static inline void xsk_umem_consume_tx_done(struct xdp_umem *umem) { } +static inline struct xdp_umem_fq_reuse *xsk_reuseq_prepare(u32 nentries) +{ + return NULL; +} + +static inline struct xdp_umem_fq_reuse *xsk_reuseq_swap( + struct xdp_umem *umem, + struct xdp_umem_fq_reuse *newq) +{ + return NULL; +} +static inline void xsk_reuseq_free(struct xdp_umem_fq_reuse *rq) +{ +} + static inline char *xdp_umem_get_data(struct xdp_umem *umem, u64 addr) { return NULL; @@ -137,6 +192,20 @@ static inline dma_addr_t xdp_umem_get_dma(struct xdp_umem *umem, u64 addr) { return 0; } + +static inline u64 *xsk_umem_peek_addr_rq(struct xdp_umem *umem, u64 *addr) +{ + return NULL; +} + +static inline void xsk_umem_discard_addr_rq(struct xdp_umem *umem) +{ +} + +static inline void xsk_umem_fq_reuse(struct xdp_umem *umem, u64 addr) +{ +} + #endif /* CONFIG_XDP_SOCKETS */ #endif /* _LINUX_XDP_SOCK_H */ diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c index b3b632c5aeae..555427b3e0fe 100644 --- a/net/xdp/xdp_umem.c +++ b/net/xdp/xdp_umem.c @@ -165,6 +165,8 @@ static void xdp_umem_release(struct xdp_umem *umem) umem->cq = NULL; } + xsk_reuseq_destroy(umem); + xdp_umem_unpin_pages(umem); task = get_pid_task(umem->pid, PIDTYPE_PID); diff --git a/net/xdp/xsk_queue.c b/net/xdp/xsk_queue.c index 2dc1384d9f27..b66504592d9b 100644 --- a/net/xdp/xsk_queue.c +++ b/net/xdp/xsk_queue.c @@ -3,7 +3,9 @@ * Copyright(c) 2018 Intel Corporation. */ +#include #include +#include #include "xsk_queue.h" @@ -62,3 +64,56 @@ void xskq_destroy(struct xsk_queue *q) page_frag_free(q->ring); kfree(q); } + +struct xdp_umem_fq_reuse *xsk_reuseq_prepare(u32 nentries) +{ + struct xdp_umem_fq_reuse *newq; + + /* Check for overflow */ + if (nentries > (u32)roundup_pow_of_two(nentries)) + return NULL; + nentries = roundup_pow_of_two(nentries); + + newq = kvmalloc(struct_size(newq, handles, nentries), GFP_KERNEL); + if (!newq) + return NULL; + memset(newq, 0, offsetof(typeof(*newq), handles)); + + newq->nentries = nentries; + return newq; +} +EXPORT_SYMBOL_GPL(xsk_reuseq_prepare); + +struct xdp_umem_fq_reuse *xsk_reuseq_swap(struct xdp_umem *umem, + struct xdp_umem_fq_reuse *newq) +{ + struct xdp_umem_fq_reuse *oldq = umem->fq_reuse; + + if (!oldq) { + umem->fq_reuse = newq; + return NULL; + } + + if (newq->nentries < oldq->length) + return newq; + + memcpy(newq->handles, oldq->handles, + array_size(oldq->length, sizeof(u64))); + newq->length = oldq->length; + + umem->fq_reuse = newq; + return oldq; +} +EXPORT_SYMBOL_GPL(xsk_reuseq_swap); + +void xsk_reuseq_free(struct xdp_umem_fq_reuse *rq) +{ + kvfree(rq); +} +EXPORT_SYMBOL_GPL(xsk_reuseq_free); + +void xsk_reuseq_destroy(struct xdp_umem *umem) +{ + xsk_reuseq_free(umem->fq_reuse); + umem->fq_reuse = NULL; +} diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h index 82252cccb4e0..bcb5cbb40419 100644 --- a/net/xdp/xsk_queue.h +++ b/net/xdp/xsk_queue.h @@ -258,4 +258,7 @@ void xskq_set_umem(struct xsk_queue *q, u64 size, u64 chunk_mask); struct xsk_queue *xskq_create(u32 nentries, bool umem_queue); void xskq_destroy(struct xsk_queue *q_ops); +/* Executed by the core when the entire UMEM gets freed */ +void xsk_reuseq_destroy(struct xdp_umem *umem); + #endif /* _LINUX_XSK_QUEUE_H */