On 2020-05-06 11:51, Maxim Mikityanskiy wrote:
On 2020-05-04 14:37, Björn Töpel wrote:
[]
@@ -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?= <bjorn.topel@xxxxxxxxx>
Date: Wed, 6 May 2020 13:39:05 +0200
Subject: [PATCH] xdp: simplify xdp_return_{frame,frame_rx_napi,buff}
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
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 <maximmi@xxxxxxxxxxxx>
Signed-off-by: Björn Töpel <bjorn.topel@xxxxxxxxx>
---
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);
--
2.25.1
