From: Jason Wang Date: Wed, 2 May 2012 11:41:44 +0800 Subject: [2/5] macvtap: zerocopy: fix truesize underestimation commit 4ef67ebedffa44ed9939b34708ac2fee06d2f65f upstream. As the skb fragment were pinned/built from user pages, we should account the page instead of length for truesize. Signed-off-by: Jason Wang Signed-off-by: Michael S. Tsirkin --- drivers/net/macvtap.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index bd4a70d..7cb2684 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -519,6 +519,7 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, struct page *page[MAX_SKB_FRAGS]; int num_pages; unsigned long base; + unsigned long truesize; len = from->iov_len - offset; if (!len) { @@ -533,10 +534,11 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, (num_pages > MAX_SKB_FRAGS - skb_shinfo(skb)->nr_frags)) /* put_page is in skb free */ return -EFAULT; + truesize = size * PAGE_SIZE; skb->data_len += len; skb->len += len; - skb->truesize += len; - atomic_add(len, &skb->sk->sk_wmem_alloc); + skb->truesize += truesize; + atomic_add(truesize, &skb->sk->sk_wmem_alloc); while (len) { int off = base & ~PAGE_MASK; int size = min_t(int, len, PAGE_SIZE - off);