Re: [Xen-devel] compound skb frag pages appearing in start_xmit
flat view
From: Sander Eikelenboom <hidden>
Date: 2012-10-10 13:31:24
Wednesday, October 10, 2012, 2:29:09 PM, you wrote:
On Wed, 2012-10-10 at 13:24 +0100, Sander Eikelenboom wrote:quoted
Wednesday, October 10, 2012, 12:13:04 PM, you wrote:quoted
On Tue, 2012-10-09 at 15:40 +0100, Ian Campbell wrote:quoted
On Tue, 2012-10-09 at 15:27 +0100, Eric Dumazet wrote:quoted
On Tue, 2012-10-09 at 15:17 +0100, Ian Campbell wrote:quoted
Does the higher order pages effectively reduce the number of frags which are in use? e.g if MAX_SKB_FRAGS is 16, then for order-0 pages you could have 64K worth of frag data. If we switch to order-3 pages everywhere then can the skb contain 512K of data, or does the effective maximum number of frags in an skb reduce to 2?effective number of frags reduce to 2 or 3 (We still limit GSO packets to ~63536 bytes)Great! Then I think the fix is more/less trivial...quoted
The following seems to work for me.But it doesn't seem to work for me ... dmesg attached.
quoted
[ 191.777994] ------------[ cut here ]------------ [ 191.784245] kernel BUG at drivers/net/xen-netback/netback.c:481!
Looks like that BUG_ON is a little aggressive. It'll trigger if the data happens to end on a frame boundary. Hopefully this will fix it for you:
Yes it does ! Thanks .. will recompile and test the netfront case as well -- Sander
quoted hunk ↗ jump to hunk
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index d747e30..f2d6b78 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c@@ -477,7 +477,7 @@ static void netbk_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb, size -= bytes; /* Next frame */ - if (offset == PAGE_SIZE) { + if (offset == PAGE_SIZE && size) { BUG_ON(!PageCompound(page)); page++; offset = 0;