Re: [RFC PATCH bpf-next 04/13] xsk: introduce AF_XDP buffer allocation API
flat view
From: Björn Töpel <hidden>
Date: 2020-05-06 11:43:58
Also in:
bpf
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, Jesper Dangaard Brouer, John Fastabend
On 2020-05-06 11:51, Maxim Mikityanskiy wrote:
On 2020-05-04 14:37, Björn Töpel wrote:
[]
quoted
@@ -389,6 +390,11 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct,xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); xa->zc_alloc->free(xa->zc_alloc, handle); rcu_read_unlock(); + break; + case MEM_TYPE_XSK_BUFF_POOL: + /* NB! Only valid from an xdp_buff! */ + xsk_buff_free(xdp); + break;I remember I asked about it, but not sure what we decided here. xdp_return_buff is the only way to get in this new case, and it's called only from XSK flows. Maybe it would make sense to kill this case and xdp_return_buff, and call xsk_buff_free directly? It'll save some time that we waste in switch-case, a function call and two parameters of __xdp_return - should make everything faster. Do you think it makes sense?
I forgot about this! Thanks for the reminder. Yeah, that makes sense. Wdyt about the patch below:
From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= <redacted>
Date: Wed, 6 May 2020 13:39:05 +0200
Subject: [PATCH] xdp: simplify xdp_return_{frame,frame_rx_napi,buff}
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The xdp_return_{frame,frame_rx_napi,buff} function are never used,
except in xdp_convert_zc_to_xdp_frame(), by the MEM_TYPE_XSK_BUFF_POOL
memory type.
To simplify and reduce code, change so that
xdp_convert_zc_to_xdp_frame() calls xsk_buff_free() directly since the
type is know, and remove MEM_TYPE_XSK_BUFF_POOL from the switch
statement in __xdp_return() function.
Suggested-by: Maxim Mikityanskiy <redacted>
Signed-off-by: Björn Töpel <redacted>
---
net/core/xdp.c | 21 +++++++++------------
1 file changed, 9 insertions(+), 12 deletions(-)
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 11273c976e19..7ab1f9014c5e 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c@@ -334,10 +334,11 @@ EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model); * scenarios (e.g. queue full), it is possible to return the xdp_frame * while still leveraging this protection. The @napi_direct boolean * is used for those calls sites. Thus, allowing for faster recycling - * of xdp_frames/pages in those cases. + * of xdp_frames/pages in those cases. This path is never used by the + * MEM_TYPE_XSK_BUFF_POOL memory type, so it's explicitly not part of + * the switch-statement. */ -static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, - struct xdp_buff *xdp) +static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct) { struct xdp_mem_allocator *xa; struct page *page;
@@ -359,33 +360,29 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, page = virt_to_page(data); /* Assumes order0 page*/ put_page(page); break; - case MEM_TYPE_XSK_BUFF_POOL: - /* NB! Only valid from an xdp_buff! */ - xsk_buff_free(xdp); - break; default: /* Not possible, checked in xdp_rxq_info_reg_mem_model() */ + WARN(1, "Incorrect XDP memory type (%d) usage", mem->type); break; } } void xdp_return_frame(struct xdp_frame *xdpf) { - __xdp_return(xdpf->data, &xdpf->mem, false, NULL); + __xdp_return(xdpf->data, &xdpf->mem, false); } EXPORT_SYMBOL_GPL(xdp_return_frame); void xdp_return_frame_rx_napi(struct xdp_frame *xdpf) { - __xdp_return(xdpf->data, &xdpf->mem, true, NULL); + __xdp_return(xdpf->data, &xdpf->mem, true); } EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi); void xdp_return_buff(struct xdp_buff *xdp) { - __xdp_return(xdp->data, &xdp->rxq->mem, true, xdp); + __xdp_return(xdp->data, &xdp->rxq->mem, true); } -EXPORT_SYMBOL_GPL(xdp_return_buff); /* Only called for MEM_TYPE_PAGE_POOL see xdp.h */ void __xdp_release_frame(void *data, struct xdp_mem_info *mem)
@@ -466,7 +463,7 @@ struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp) xdpf->metasize = metasize; xdpf->mem.type = MEM_TYPE_PAGE_ORDER0; - xdp_return_buff(xdp); + xsk_buff_free(xdp); return xdpf; } EXPORT_SYMBOL_GPL(xdp_convert_zc_to_xdp_frame);
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2.25.1