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vhost/net: remove vhost_net_page_frag_refill()

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The page frag in vhost_net_page_frag_refill() uses the
'struct page_frag' from skb_page_frag_refill(), but it's
implementation is similar to page_frag_alloc_align() now.

This patch removes vhost_net_page_frag_refill() by using
'struct page_frag_cache' instead of 'struct page_frag',
and allocating frag using page_frag_alloc_align().

The added benefit is that not only unifying the page frag
implementation a little, but also having about 0.5% performance
boost testing by using the vhost_net_test introduced in the
last patch.

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Yunsheng Lin 2024-02-28 17:30:11 +08:00 committed by Paolo Abeni
parent a0727489ac
commit 4051bd8129
1 changed files with 27 additions and 64 deletions
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91
drivers/vhost/net.c
View File

@ -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 | __GFP_NOMEMALLOC,
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),
sock_hlen, from);
if (copied != sock_hlen)
return -EFAULT;
copied = copy_from_iter(buf + offsetof(struct tun_xdp_hdr, gso),
sock_hlen, from);
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;
}