Messages in this thread |  | | | Subject | Re: [net-next RFC PATCH 4/7] tuntap: multiqueue support | | From | Eric Dumazet <> | | Date | Fri, 12 Aug 2011 16:29:36 +0200 |
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Le vendredi 12 août 2011 à 09:55 +0800, Jason Wang a écrit :
>+ rxq = skb_get_rxhash(skb); >+ if (rxq) { >+ tfile = rcu_dereference(tun->tfiles[rxq % numqueues]); >+ if (tfile) >+ goto out; >+ }
You can avoid an expensive divide with following trick :
u32 idx = ((u64)rxq * numqueues) >> 32;
> -static struct tun_struct *tun_get(struct file *file) > +static void tun_detach_all(struct net_device *dev) > { > - return __tun_get(file->private_data); > + struct tun_struct *tun = netdev_priv(dev); > + struct tun_file *tfile, *tfile_list[MAX_TAP_QUEUES]; > + int i, j = 0; > + > + spin_lock(&tun_lock); > + > + for (i = 0; i < MAX_TAP_QUEUES && tun->numqueues; i++) { > + tfile = rcu_dereference_protected(tun->tfiles[i], > + lockdep_is_held(&tun_lock)); > + if (tfile) { > + wake_up_all(&tfile->wq.wait); > + tfile_list[i++] = tfile;
typo here, you want tfile_list[j++] = tfile;
> + rcu_assign_pointer(tun->tfiles[i], NULL); > + rcu_assign_pointer(tfile->tun, NULL); > + --tun->numqueues; > + } > + } > + BUG_ON(tun->numqueues != 0); > + spin_unlock(&tun_lock); > + > + synchronize_rcu(); > + for(--j; j >= 0; j--) > + sock_put(&tfile_list[j]->sk); > } >
Could you take a look at net/packet/af_packet.c, to check how David did the whole fanout thing ?
__fanout_unlink()
Trick is to not leave NULL entries in the tun->tfiles[] array.
It makes things easier in hot path.
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