From patchwork Mon Aug 18 13:37:19 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pankaj Gupta X-Patchwork-Id: 381012 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id CE4921400D2 for ; Mon, 18 Aug 2014 23:39:31 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751867AbaHRNit (ORCPT ); Mon, 18 Aug 2014 09:38:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:12867 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751743AbaHRNis (ORCPT ); Mon, 18 Aug 2014 09:38:48 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s7IDcZ7o026686 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 18 Aug 2014 09:38:35 -0400 Received: from dhcp223-82.pnq.redhat.com ([10.65.223.17]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s7IDbNm9011293 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Mon, 18 Aug 2014 09:38:29 -0400 From: Pankaj Gupta To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org Cc: davem@davemloft.net, jasowang@redhat.com, mst@redhat.com, dgibson@redhat.com, vfalico@gmail.com, edumazet@google.com, vyasevic@redhat.com, hkchu@google.com, wuzhy@linux.vnet.ibm.com, xemul@parallels.com, therbert@google.com, bhutchings@solarflare.com, xii@google.com, stephen@networkplumber.org, Pankaj Gupta Subject: [RFC 3/4] tuntap: reduce the size of tun_struct by using flex array Date: Mon, 18 Aug 2014 19:07:19 +0530 Message-Id: <1408369040-1216-4-git-send-email-pagupta@redhat.com> In-Reply-To: <1408369040-1216-1-git-send-email-pagupta@redhat.com> References: <1408369040-1216-1-git-send-email-pagupta@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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 files changed, 37 insertions(+), 12 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index acaaf67..7dd495f 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -65,6 +65,7 @@ #include #include #include +#include #include #include #include @@ -186,7 +187,7 @@ 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; @@ -247,10 +248,11 @@ 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); @@ -262,10 +264,11 @@ 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); } @@ -285,10 +288,11 @@ 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; @@ -315,7 +319,7 @@ 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(); @@ -378,7 +382,8 @@ 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; @@ -758,8 +763,8 @@ 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); } @@ -894,23 +899,40 @@ 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. */ @@ -1659,7 +1681,10 @@ 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 |