On 07/03/2013 06:06 AM, Thomas Zeitlhofer wrote: > On Tue, Jul 02, 2013 at 06:01:12PM -0300, Fabio Estevam wrote: >> On Tue, Jul 2, 2013 at 4:59 PM, Thomas Zeitlhofer >> <thomas.zeitlho...@nt.tuwien.ac.at> wrote: >>> Commit "tuntap: set SOCK_ZEROCOPY flag during open" introduces a >>> regression which is observed with live migration of qemu/kvm based >>> virtual machines that are connected to an openvswitch bridge. >>> >>> Reverting this commit (b26c93c46a3dec25ed236d4ba6107eb4ed5d9401 in >>> v3.9.8 and accordingly 19a6afb23e5d323e1245baa4e62755492b2f1200 in >>> v3.10) fixes the following problem: >> Should the sock_set_flag stay in tun_set_iff as it was prior to 54f968d6efd? >> >> --- a/drivers/net/tun.c >> +++ b/drivers/net/tun.c >> @@ -1652,6 +1652,7 @@ static int tun_set_iff(struct net *net, struct >> file *file, struct ifreq *ifr) >> tun->txflt.count = 0; >> tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); >> >> + sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); >> tun->filter_attached = false; >> tun->sndbuf = tfile->socket.sk->sk_sndbuf; >> >> @@ -2159,8 +2160,6 @@ static int tun_chr_open(struct inode *inode, >> struct file * file) >> set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); >> INIT_LIST_HEAD(&tfile->next); >> >> - sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); >> - >> return 0; >> } > I guess no, as this also leads to a kernel panic (tested against v3.10).
Yes, commit "tuntap: set SOCK_ZEROCOPY flag during open" just re-enable the zerocopy capability of tuntap. I believe it just uncover other zerocopy bugs. Which regression did you see? Thanks -- 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/
