Commit 6702d60d authored by Paolo Abeni's avatar Paolo Abeni
Browse files

Merge branch 'remove-page-frag-implementation-in-vhost_net' 

Yunsheng Lin says:

====================
remove page frag implementation in vhost_net

Currently there are three implementations for page frag:

1. mm/page_alloc.c: net stack seems to be using it in the
   rx part with 'struct page_frag_cache' and the main API
   being page_frag_alloc_align().
2. net/core/sock.c: net stack seems to be using it in the
   tx part with 'struct page_frag' and the main API being
   skb_page_frag_refill().
3. drivers/vhost/net.c: vhost seems to be using it to build
   xdp frame, and it's implementation seems to be a mix of
   the above two.

This patchset tries to unfiy the page frag implementation a
little bit by unifying gfp bit for order 3 page allocation
and replacing page frag implementation in vhost.c with the
one in page_alloc.c.

After this patchset, we are not only able to unify the page
frag implementation a little, but also able to have about
0.5% performance boost testing by using the vhost_net_test
introduced in the last patch.

Before this patchset:
Performance counter stats for './vhost_net_test' (10 runs):

     305325.78 msec task-clock                       #    1.738 CPUs utilized               ( +-  0.12% )
       1048668      context-switches                 #    3.435 K/sec                       ( +-  0.00% )
            11      cpu-migrations                   #    0.036 /sec                        ( +- 17.64% )
            33      page-faults                      #    0.108 /sec                        ( +-  0.49% )
  244651819491      cycles                           #    0.801 GHz                         ( +-  0.43% )  (64)
   64714638024      stalled-cycles-frontend          #   26.45% frontend cycles idle        ( +-  2.19% )  (67)
   30774313491      stalled-cycles-backend           #   12.58% backend cycles idle         ( +-  7.68% )  (70)
  201749748680      instructions                     #    0.82  insn per cycle
                                              #    0.32  stalled cycles per insn     ( +-  0.41% )  (66.76%)
   65494787909      branches                         #  214.508 M/sec                       ( +-  0.35% )  (64)
    4284111313      branch-misses                    #    6.54% of all branches             ( +-  0.45% )  (66)

       175.699 +- 0.189 seconds time elapsed  ( +-  0.11% )

After this patchset:
Performance counter stats for './vhost_net_test' (10 runs):

     303974.38 msec task-clock                       #    1.739 CPUs utilized               ( +-  0.14% )
       1048807      context-switches                 #    3.450 K/sec                       ( +-  0.00% )
            14      cpu-migrations                   #    0.046 /sec                        ( +- 12.86% )
            33      page-faults                      #    0.109 /sec                        ( +-  0.46% )
  251289376347      cycles                           #    0.827 GHz                         ( +-  0.32% )  (60)
   67885175415      stalled-cycles-frontend          #   27.01% frontend cycles idle        ( +-  0.48% )  (63)
   27809282600      stalled-cycles-backend           #   11.07% backend cycles idle         ( +-  0.36% )  (71)
  195543234672      instructions                     #    0.78  insn per cycle
                                              #    0.35  stalled cycles per insn     ( +-  0.29% )  (69.04%)
   62423183552      branches                         #  205.357 M/sec                       ( +-  0.48% )  (67)
    4135666632      branch-misses                    #    6.63% of all branches             ( +-  0.63% )  (67)

       174.764 +- 0.214 seconds time elapsed  ( +-  0.12% )

Changelog:
V6: Add timeout for poll() and simplify some logic as suggested
    by Jason.

V5: Address the comment from jason in vhost_net_test.c and the
    comment about leaving out the gfp change for page frag in
    sock.c as suggested by Paolo.

V4: Resend based on latest net-next branch.

V3:
1. Add __page_frag_alloc_align() which is passed with the align mask
   the original function expected as suggested by Alexander.
2. Drop patch 3 in v2 suggested by Alexander.
3. Reorder patch 4 & 5 in v2 suggested by Alexander.

Note that placing this gfp flags handing for order 3 page in an inline
function is not considered, as we may be able to unify the page_frag
and page_frag_cache handling.

V2: Change 'xor'd' to 'masked off', add vhost tx testing for
    vhost_net_test.

V1: Fix some typo, drop RFC tag and rebase on latest net-next.
====================

Link: https://lore.kernel.org/r/20240228093013.8263-1-linyunsheng@huawei.com


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parents 0e71862a c5d3705c

drivers/net/ethernet/google/gve/gve_main.c

+2 −9
Original line number Diff line number Diff line
@@ -1276,17 +1276,10 @@ static void gve_unreg_xdp_info(struct gve_priv *priv) 


static void gve_drain_page_cache(struct gve_priv *priv)

{

	struct page_frag_cache *nc;

	int i;



	for (i = 0; i < priv->rx_cfg.num_queues; i++) {

		nc = &priv->rx[i].page_cache;

		if (nc->va) {

			__page_frag_cache_drain(virt_to_page(nc->va),

						nc->pagecnt_bias);

			nc->va = NULL;

		}

	}

	for (i = 0; i < priv->rx_cfg.num_queues; i++)

		page_frag_cache_drain(&priv->rx[i].page_cache);

}



static void gve_qpls_get_curr_alloc_cfg(struct gve_priv *priv,

drivers/net/ethernet/mediatek/mtk_wed_wo.c

+2 −15
Original line number Diff line number Diff line
@@ -286,7 +286,6 @@ mtk_wed_wo_queue_free(struct mtk_wed_wo *wo, struct mtk_wed_wo_queue *q) 
static void

mtk_wed_wo_queue_tx_clean(struct mtk_wed_wo *wo, struct mtk_wed_wo_queue *q)

{

	struct page *page;

	int i;



	for (i = 0; i < q->n_desc; i++) {
@@ -301,19 +300,12 @@ mtk_wed_wo_queue_tx_clean(struct mtk_wed_wo *wo, struct mtk_wed_wo_queue *q) 
		entry->buf = NULL;

	}



	if (!q->cache.va)

		return;



	page = virt_to_page(q->cache.va);

	__page_frag_cache_drain(page, q->cache.pagecnt_bias);

	memset(&q->cache, 0, sizeof(q->cache));

	page_frag_cache_drain(&q->cache);

}



static void

mtk_wed_wo_queue_rx_clean(struct mtk_wed_wo *wo, struct mtk_wed_wo_queue *q)

{

	struct page *page;



	for (;;) {

		void *buf = mtk_wed_wo_dequeue(wo, q, NULL, true);
@@ -323,12 +315,7 @@ mtk_wed_wo_queue_rx_clean(struct mtk_wed_wo *wo, struct mtk_wed_wo_queue *q) 
		skb_free_frag(buf);

	}



	if (!q->cache.va)

		return;



	page = virt_to_page(q->cache.va);

	__page_frag_cache_drain(page, q->cache.pagecnt_bias);

	memset(&q->cache, 0, sizeof(q->cache));

	page_frag_cache_drain(&q->cache);

}



static void

drivers/nvme/host/tcp.c

+1 −6
Original line number Diff line number Diff line
@@ -1344,7 +1344,6 @@ static int nvme_tcp_alloc_async_req(struct nvme_tcp_ctrl *ctrl) 


static void nvme_tcp_free_queue(struct nvme_ctrl *nctrl, int qid)

{

	struct page *page;

	struct nvme_tcp_ctrl *ctrl = to_tcp_ctrl(nctrl);

	struct nvme_tcp_queue *queue = &ctrl->queues[qid];

	unsigned int noreclaim_flag;
@@ -1355,11 +1354,7 @@ static void nvme_tcp_free_queue(struct nvme_ctrl *nctrl, int qid) 
	if (queue->hdr_digest || queue->data_digest)

		nvme_tcp_free_crypto(queue);



	if (queue->pf_cache.va) {

		page = virt_to_head_page(queue->pf_cache.va);

		__page_frag_cache_drain(page, queue->pf_cache.pagecnt_bias);

		queue->pf_cache.va = NULL;

	}

	page_frag_cache_drain(&queue->pf_cache);



	noreclaim_flag = memalloc_noreclaim_save();

	/* ->sock will be released by fput() */

drivers/nvme/target/tcp.c

+1 −3
Original line number Diff line number Diff line
@@ -1591,7 +1591,6 @@ static void nvmet_tcp_free_cmd_data_in_buffers(struct nvmet_tcp_queue *queue) 


static void nvmet_tcp_release_queue_work(struct work_struct *w)

{

	struct page *page;

	struct nvmet_tcp_queue *queue =

		container_of(w, struct nvmet_tcp_queue, release_work);
@@ -1615,8 +1614,7 @@ static void nvmet_tcp_release_queue_work(struct work_struct *w) 
	if (queue->hdr_digest || queue->data_digest)

		nvmet_tcp_free_crypto(queue);

	ida_free(&nvmet_tcp_queue_ida, queue->idx);

	page = virt_to_head_page(queue->pf_cache.va);

	__page_frag_cache_drain(page, queue->pf_cache.pagecnt_bias);

	page_frag_cache_drain(&queue->pf_cache);

	kfree(queue);

}

drivers/vhost/net.c

+27 −64
Original line number Diff line number Diff line
@@ -141,10 +141,8 @@ struct vhost_net { 
	unsigned tx_zcopy_err;

	/* Flush in progress. Protected by tx vq lock. */

	bool tx_flush;

	/* Private page frag */

	struct page_frag page_frag;

	/* Refcount bias of page frag */

	int refcnt_bias;

	/* Private page frag cache */

	struct page_frag_cache pf_cache;

};



static unsigned vhost_net_zcopy_mask __read_mostly;
@@ -655,41 +653,6 @@ static bool tx_can_batch(struct vhost_virtqueue *vq, size_t total_len) 
	       !vhost_vq_avail_empty(vq->dev, vq);

}



static bool vhost_net_page_frag_refill(struct vhost_net *net, unsigned int sz,

				       struct page_frag *pfrag, gfp_t gfp)

{

	if (pfrag->page) {

		if (pfrag->offset + sz <= pfrag->size)

			return true;

		__page_frag_cache_drain(pfrag->page, net->refcnt_bias);

	}



	pfrag->offset = 0;

	net->refcnt_bias = 0;

	if (SKB_FRAG_PAGE_ORDER) {

		/* Avoid direct reclaim but allow kswapd to wake */

		pfrag->page = alloc_pages((gfp & ~__GFP_DIRECT_RECLAIM) |

					  __GFP_COMP | __GFP_NOWARN |

					  __GFP_NORETRY,

					  SKB_FRAG_PAGE_ORDER);

		if (likely(pfrag->page)) {

			pfrag->size = PAGE_SIZE << SKB_FRAG_PAGE_ORDER;

			goto done;

		}

	}

	pfrag->page = alloc_page(gfp);

	if (likely(pfrag->page)) {

		pfrag->size = PAGE_SIZE;

		goto done;

	}

	return false;



done:

	net->refcnt_bias = USHRT_MAX;

	page_ref_add(pfrag->page, USHRT_MAX - 1);

	return true;

}



#define VHOST_NET_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)



static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq,
@@ -699,7 +662,6 @@ static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq, 
	struct vhost_net *net = container_of(vq->dev, struct vhost_net,

					     dev);

	struct socket *sock = vhost_vq_get_backend(vq);

	struct page_frag *alloc_frag = &net->page_frag;

	struct virtio_net_hdr *gso;

	struct xdp_buff *xdp = &nvq->xdp[nvq->batched_xdp];

	struct tun_xdp_hdr *hdr;
@@ -710,6 +672,7 @@ static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq, 
	int sock_hlen = nvq->sock_hlen;

	void *buf;

	int copied;

	int ret;



	if (unlikely(len < nvq->sock_hlen))

		return -EFAULT;
@@ -719,18 +682,17 @@ static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq, 
		return -ENOSPC;



	buflen += SKB_DATA_ALIGN(len + pad);

	alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);

	if (unlikely(!vhost_net_page_frag_refill(net, buflen,

						 alloc_frag, GFP_KERNEL)))

	buf = page_frag_alloc_align(&net->pf_cache, buflen, GFP_KERNEL,

				    SMP_CACHE_BYTES);

	if (unlikely(!buf))

		return -ENOMEM;



	buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;

	copied = copy_page_from_iter(alloc_frag->page,

				     alloc_frag->offset +

				     offsetof(struct tun_xdp_hdr, gso),

	copied = copy_from_iter(buf + offsetof(struct tun_xdp_hdr, gso),

				sock_hlen, from);

	if (copied != sock_hlen)

		return -EFAULT;

	if (copied != sock_hlen) {

		ret = -EFAULT;

		goto err;

	}



	hdr = buf;

	gso = &hdr->gso;
@@ -743,27 +705,30 @@ static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq, 
			       vhost16_to_cpu(vq, gso->csum_start) +

			       vhost16_to_cpu(vq, gso->csum_offset) + 2);



		if (vhost16_to_cpu(vq, gso->hdr_len) > len)

			return -EINVAL;

		if (vhost16_to_cpu(vq, gso->hdr_len) > len) {

			ret = -EINVAL;

			goto err;

		}

	}



	len -= sock_hlen;

	copied = copy_page_from_iter(alloc_frag->page,

				     alloc_frag->offset + pad,

				     len, from);

	if (copied != len)

		return -EFAULT;

	copied = copy_from_iter(buf + pad, len, from);

	if (copied != len) {

		ret = -EFAULT;

		goto err;

	}



	xdp_init_buff(xdp, buflen, NULL);

	xdp_prepare_buff(xdp, buf, pad, len, true);

	hdr->buflen = buflen;



	--net->refcnt_bias;

	alloc_frag->offset += buflen;



	++nvq->batched_xdp;



	return 0;



err:

	page_frag_free(buf);

	return ret;

}



static void handle_tx_copy(struct vhost_net *net, struct socket *sock)
@@ -1353,8 +1318,7 @@ static int vhost_net_open(struct inode *inode, struct file *f) 
			vqs[VHOST_NET_VQ_RX]);



	f->private_data = n;

	n->page_frag.page = NULL;

	n->refcnt_bias = 0;

	n->pf_cache.va = NULL;



	return 0;

}
@@ -1422,8 +1386,7 @@ static int vhost_net_release(struct inode *inode, struct file *f) 
	kfree(n->vqs[VHOST_NET_VQ_RX].rxq.queue);

	kfree(n->vqs[VHOST_NET_VQ_TX].xdp);

	kfree(n->dev.vqs);

	if (n->page_frag.page)

		__page_frag_cache_drain(n->page_frag.page, n->refcnt_bias);

	page_frag_cache_drain(&n->pf_cache);

	kvfree(n);

	return 0;

}