XDP bulk APIs introduce a defer/flush mechanism to return
pages belonging to the same xdp_mem_allocator object
(identified via the mem.id field) in bulk to optimize
I-cache and D-cache since xdp_return_frame is usually run
inside the driver NAPI tx completion loop.
The bulk queue size is set to 16 to be aligned to how
XDP_REDIRECT bulking works. The bulk is flushed when
it is full or when mem.id changes.
xdp_frame_bulk is usually stored/allocated on the function
call-stack to avoid locking penalties.
Current implementation considers only page_pool memory model.
Suggested-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Co-developed-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Signed-off-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
---
include/net/xdp.h | 17 +++++++++++++-
net/core/xdp.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 75 insertions(+), 1 deletion(-)
diff --git a/include/net/xdp.h b/include/net/xdp.h
index 3814fb631d52..7d48b2ae217a 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -104,6 +104,18 @@ struct xdp_frame {
struct net_device *dev_rx; /* used by cpumap */
};
+#define XDP_BULK_QUEUE_SIZE 16
+struct xdp_frame_bulk {
+ int count;
+ void *xa;
+ void *q[XDP_BULK_QUEUE_SIZE];
+};
+
+static __always_inline void xdp_frame_bulk_init(struct xdp_frame_bulk *bq)
+{
+ /* bq->count will be zero'ed when bq->xa gets updated */
+ bq->xa = NULL;
+}
static inline struct skb_shared_info *
xdp_get_shared_info_from_frame(struct xdp_frame *frame)
@@ -194,6 +206,9 @@ struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp)
void xdp_return_frame(struct xdp_frame *xdpf);
void xdp_return_frame_rx_napi(struct xdp_frame *xdpf);
void xdp_return_buff(struct xdp_buff *xdp);
+void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq);
+void xdp_return_frame_bulk(struct xdp_frame *xdpf,
+ struct xdp_frame_bulk *bq);
/* When sending xdp_frame into the network stack, then there is no
* return point callback, which is needed to release e.g. DMA-mapping
@@ -245,6 +260,6 @@ bool xdp_attachment_flags_ok(struct xdp_attachment_info *info,
void xdp_attachment_setup(struct xdp_attachment_info *info,
struct netdev_bpf *bpf);
-#define DEV_MAP_BULK_SIZE 16
+#define DEV_MAP_BULK_SIZE XDP_BULK_QUEUE_SIZE
#endif /* __LINUX_NET_XDP_H__ */
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 48aba933a5a8..bbaee7fdd44f 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -380,6 +380,65 @@ void xdp_return_frame_rx_napi(struct xdp_frame *xdpf)
}
EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi);
+/* XDP bulk APIs introduce a defer/flush mechanism to return
+ * pages belonging to the same xdp_mem_allocator object
+ * (identified via the mem.id field) in bulk to optimize
+ * I-cache and D-cache.
+ * The bulk queue size is set to 16 to be aligned to how
+ * XDP_REDIRECT bulking works. The bulk is flushed when
+ * it is full or when mem.id changes.
+ * xdp_frame_bulk is usually stored/allocated on the function
+ * call-stack to avoid locking penalties.
+ */
+void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq)
+{
+ struct xdp_mem_allocator *xa = bq->xa;
+ int i;
+
+ if (unlikely(!xa))
+ return;
+
+ for (i = 0; i < bq->count; i++) {
+ struct page *page = virt_to_head_page(bq->q[i]);
+
+ page_pool_put_full_page(xa->page_pool, page, false);
+ }
+ /* bq->xa is not cleared to save lookup, if mem.id same in next bulk */
+ bq->count = 0;
+}
+EXPORT_SYMBOL_GPL(xdp_flush_frame_bulk);
+
+/* Must be called with rcu_read_lock held */
+void xdp_return_frame_bulk(struct xdp_frame *xdpf,
+ struct xdp_frame_bulk *bq)
+{
+ struct xdp_mem_info *mem = &xdpf->mem;
+ struct xdp_mem_allocator *xa;
+
+ if (mem->type != MEM_TYPE_PAGE_POOL) {
+ __xdp_return(xdpf->data, &xdpf->mem, false);
+ return;
+ }
+
+ xa = bq->xa;
+ if (unlikely(!xa)) {
+ xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
+ bq->count = 0;
+ bq->xa = xa;
+ }
+
+ if (bq->count == XDP_BULK_QUEUE_SIZE)
+ xdp_flush_frame_bulk(bq);
+
+ if (unlikely(mem->id != xa->mem.id)) {
+ xdp_flush_frame_bulk(bq);
+ bq->xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
+ }
+
+ bq->q[bq->count++] = xdpf->data;
+}
+EXPORT_SYMBOL_GPL(xdp_return_frame_bulk);
+
void xdp_return_buff(struct xdp_buff *xdp)
{
__xdp_return(xdp->data, &xdp->rxq->mem, true);
--
2.26.2
