On Thu, 2014-04-03 at 09:07 +0100, Paul Durrant wrote: > > -----Original Message----- > > From: Zoltan Kiss > > Sent: 02 April 2014 18:05 > > To: Ian Campbell; Wei Liu; xen-de...@lists.xenproject.org > > Cc: Paul Durrant; net...@vger.kernel.org; linux-kernel@vger.kernel.org; > > Jonathan Davies; Zoltan Kiss > > Subject: [PATCH net-next v3 2/2] xen-netback: Grant copy the header > > instead of map and memcpy > > > > An old inefficiency of the TX path that we are grant mapping the first slot, > > and then copy the header part to the linear area. Instead, doing a grant > > copy > > for that header straight on is more reasonable. Especially because there are > > ongoing efforts to make Xen avoiding TLB flush after unmap when the page > > were > > not touched in Dom0. In the original way the memcpy ruined that. > > The key changes: > > - the vif has a tx_copy_ops array again > > - xenvif_tx_build_gops sets up the grant copy operations > > - we don't have to figure out whether the header and first frag are on the > > same > > grant mapped page or not > > Note, we only grant copy PKT_PROT_LEN bytes from the first slot, the rest > > (if > > any) will be on the first frag, which is grant mapped. If the first slot is > > smaller than PKT_PROT_LEN, then we grant copy that, and later > > __pskb_pull_tail > > will pull more from the frags (if any) > > > > Signed-off-by: Zoltan Kiss <zoltan.k...@citrix.com> > > Looks good to me. > > Reviewed-by: Paul Durrant <paul.durr...@citrix.com>
Me too: Acked-by: Ian Campbell <ian.campb...@citrix.com> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
