Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754701AbaKXSpv (ORCPT ); Mon, 24 Nov 2014 13:45:51 -0500 Received: from mx3-phx2.redhat.com ([209.132.183.24]:43162 "EHLO mx3-phx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753956AbaKXSpt (ORCPT ); Mon, 24 Nov 2014 13:45:49 -0500 Date: Mon, 24 Nov 2014 13:45:33 -0500 (EST) From: Pankaj Gupta To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org Cc: davem@davemloft.net, jasowang@redhat.com, dgibson@redhat.com, vfalico@gmail.com, edumazet@google.com, vyasevic@redhat.com, hkchu@google.com, xemul@parallels.com, therbert@google.com, bhutchings@solarflare.com, xii@google.com, stephen@networkplumber.org, jiri@resnulli.us, sergei shtylyov Message-ID: <6511577.3326070.1416854733107.JavaMail.zimbra@redhat.com> In-Reply-To: <1416854044-10124-1-git-send-email-pagupta@redhat.com> References: <1416854044-10124-1-git-send-email-pagupta@redhat.com> Subject: Re: [PATCH v2 net-next 2/3] tuntap: reduce the size of tun_struct by using flex array. MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [10.5.82.11] X-Mailer: Zimbra 8.0.6_GA_5922 (ZimbraWebClient - FF23 (Linux)/8.0.6_GA_5922) Thread-Topic: tuntap: reduce the size of tun_struct by using flex array. Thread-Index: 6b4W//WG2T8p5+z83OTvdLDLUwFZ6w== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sorry! forgot to cc Michael, doing now. > > This patch switches to flex array to implement the flow caches, it brings > several advantages: > > - Reduce the size of the tun_struct structure, which allows us to increase > the > upper limit of queues in future. > - Avoid higher order memory allocation. It will be useful when switching to > pure hashing in flow cache which may demand a larger size array in future. > > After this patch, the size of tun_struct on x86_64 reduced from 8512 to > 328 > > Signed-off-by: Jason Wang > Signed-off-by: Pankaj Gupta > Reviewed-by: David Gibson > --- > drivers/net/tun.c | 49 +++++++++++++++++++++++++++++++++++++------------ > 1 file changed, 37 insertions(+), 12 deletions(-) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index e3fa65a..bd07a6d 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -65,6 +65,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -188,7 +189,7 @@ struct tun_struct { > int debug; > #endif > spinlock_t lock; > - struct hlist_head flows[TUN_NUM_FLOW_ENTRIES]; > + struct flex_array *flows; > struct timer_list flow_gc_timer; > unsigned long ageing_time; > unsigned int numdisabled; > @@ -249,10 +250,11 @@ static void tun_flow_flush(struct tun_struct *tun) > > spin_lock_bh(&tun->lock); > for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { > + struct hlist_head *h = flex_array_get(tun->flows, i); > struct tun_flow_entry *e; > struct hlist_node *n; > > - hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) > + hlist_for_each_entry_safe(e, n, h, hash_link) > tun_flow_delete(tun, e); > } > spin_unlock_bh(&tun->lock); > @@ -264,10 +266,11 @@ static void tun_flow_delete_by_queue(struct tun_struct > *tun, u16 queue_index) > > spin_lock_bh(&tun->lock); > for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { > + struct hlist_head *h = flex_array_get(tun->flows, i); > struct tun_flow_entry *e; > struct hlist_node *n; > > - hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { > + hlist_for_each_entry_safe(e, n, h, hash_link) { > if (e->queue_index == queue_index) > tun_flow_delete(tun, e); > } > @@ -287,10 +290,11 @@ static void tun_flow_cleanup(unsigned long data) > > spin_lock_bh(&tun->lock); > for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { > + struct hlist_head *h = flex_array_get(tun->flows, i); > struct tun_flow_entry *e; > struct hlist_node *n; > > - hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { > + hlist_for_each_entry_safe(e, n, h, hash_link) { > unsigned long this_timer; > count++; > this_timer = e->updated + delay; > @@ -317,7 +321,7 @@ static void tun_flow_update(struct tun_struct *tun, u32 > rxhash, > if (!rxhash) > return; > else > - head = &tun->flows[tun_hashfn(rxhash)]; > + head = flex_array_get(tun->flows, tun_hashfn(rxhash)); > > rcu_read_lock(); > > @@ -380,7 +384,8 @@ static u16 tun_select_queue(struct net_device *dev, > struct sk_buff *skb, > > txq = skb_get_hash(skb); > if (txq) { > - e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); > + e = tun_flow_find(flex_array_get(tun->flows, > + tun_hashfn(txq)), txq); > if (e) { > tun_flow_save_rps_rxhash(e, txq); > txq = e->queue_index; > @@ -760,8 +765,8 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, > struct net_device *dev) > rxhash = skb_get_hash(skb); > if (rxhash) { > struct tun_flow_entry *e; > - e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], > - rxhash); > + e = tun_flow_find(flex_array_get(tun->flows, > + tun_hashfn(rxhash)), rxhash); > if (e) > tun_flow_save_rps_rxhash(e, rxhash); > } > @@ -896,23 +901,40 @@ static const struct net_device_ops tap_netdev_ops = { > #endif > }; > > -static void tun_flow_init(struct tun_struct *tun) > +static int tun_flow_init(struct tun_struct *tun) > { > - int i; > + struct flex_array *buckets; > + int i, err; > + > + buckets = flex_array_alloc(sizeof(struct hlist_head), > + TUN_NUM_FLOW_ENTRIES, GFP_KERNEL); > + if (!buckets) > + return -ENOMEM; > + > + err = flex_array_prealloc(buckets, 0, TUN_NUM_FLOW_ENTRIES, GFP_KERNEL); > + if (err) { > + flex_array_free(buckets); > + return -ENOMEM; > + } > > + tun->flows = buckets; > for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) > - INIT_HLIST_HEAD(&tun->flows[i]); > + INIT_HLIST_HEAD((struct hlist_head *) > + flex_array_get(buckets, i)); > > tun->ageing_time = TUN_FLOW_EXPIRE; > setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); > mod_timer(&tun->flow_gc_timer, > round_jiffies_up(jiffies + tun->ageing_time)); > + > + return 0; > } > > static void tun_flow_uninit(struct tun_struct *tun) > { > del_timer_sync(&tun->flow_gc_timer); > tun_flow_flush(tun); > + flex_array_free(tun->flows); > } > > /* Initialize net device. */ > @@ -1674,7 +1696,10 @@ static int tun_set_iff(struct net *net, struct file > *file, struct ifreq *ifr) > goto err_free_dev; > > tun_net_init(dev); > - tun_flow_init(tun); > + > + err = tun_flow_init(tun); > + if (err < 0) > + goto err_free_dev; > > dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | > TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | > -- > 1.8.3.1 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/