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authorLorenzo Bianconi <lorenzo@kernel.org>2020-11-13 12:48:28 +0100
committerDaniel Borkmann <daniel@iogearbox.net>2020-11-14 02:28:59 +0100
commit8965398713d831f6b893805880c249e62e9059ae (patch)
tree2ad1b15917d4d49c22c4a4e8ab01052b590b976f /net
parent6f100640ca5b2a2ff67b001c9fd3de21f7b12cf2 (diff)
downloadlinux-8965398713d831f6b893805880c249e62e9059ae.tar.gz
net: xdp: Introduce bulking for xdp tx return path
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@redhat.com> Co-developed-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Link: https://lore.kernel.org/bpf/e190c03eac71b20c8407ae0fc2c399eda7835f49.1605267335.git.lorenzo@kernel.org
Diffstat (limited to 'net')
-rw-r--r--net/core/xdp.c59
1 files changed, 59 insertions, 0 deletions
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);