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Date: Tue, 3 Sep 2013 10:29:43 +0200
From: Jiri Pirko <jiri@...nulli.us>
To: Veaceslav Falico <vfalico@...hat.com>
Cc: netdev@...r.kernel.org, "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Alexander Duyck <alexander.h.duyck@...el.com>,
Cong Wang <amwang@...hat.com>
Subject: Re: [PATCH RFC net-next 01/21] net: add neighbour_dev_list to save
only neighbours
Mon, Sep 02, 2013 at 11:39:05PM CEST, vfalico@...hat.com wrote:
>Currently, we distinguish neighbours (first-level linked devices) from
>non-neighbours by the neighbour bool in the netdev_adjacent. This could be
>quite time-consuming in case we would like to traverse *only* through
>neighbours - cause we'd have to traverse through all devices and check for
>this flag, and in a (quite common) scenario where we have lots of vlans on
>top of bridge, which is on top of a bond - the bonding would have to go
>through all those vlans to get its upper neighbour linked devices.
>
>This situation is really unpleasant, cause there are already a lot of cases
>when a device with slaves needs to go through them in hot path.
>
>To fix this, introduce a new upper/lower device lists structure -
>neighbour_dev_list, which contains only the neighbours. It works always in
>pair with the all_device_list structure (renamed from upper/lower_dev_list),
>i.e. both of them contain the same links, only that all_dev_list contains
>also non-neighbour device links. It's really a small change visible,
>currently, only for __netdev_adjacent_dev_insert/remove(), and doesn't
>change the main linked logic at all.
>
>Also, add some comments a fix a name collision in
>netdev_for_each_upper_dev_rcu().
>
>CC: "David S. Miller" <davem@...emloft.net>
>CC: Eric Dumazet <edumazet@...gle.com>
>CC: Jiri Pirko <jiri@...nulli.us>
>CC: Alexander Duyck <alexander.h.duyck@...el.com>
>CC: Cong Wang <amwang@...hat.com>
>Signed-off-by: Veaceslav Falico <vfalico@...hat.com>
>---
> include/linux/netdevice.h | 24 ++++---
> net/core/dev.c | 157 ++++++++++++++++++++++++++++++++++------------
> 2 files changed, 134 insertions(+), 47 deletions(-)
>
>diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
>index 3ad49b8..df50548 100644
>--- a/include/linux/netdevice.h
>+++ b/include/linux/netdevice.h
>@@ -1124,8 +1124,18 @@ struct net_device {
> struct list_head dev_list;
> struct list_head napi_list;
> struct list_head unreg_list;
>- struct list_head upper_dev_list; /* List of upper devices */
>- struct list_head lower_dev_list;
>+
>+ /* directly linked devices, like slaves for bonding */
>+ struct {
>+ struct list_head upper;
>+ struct list_head lower;
>+ } neighbour_dev_list ;
>+
>+ /* all linked devices, *including* neighbours */
>+ struct {
>+ struct list_head upper;
>+ struct list_head lower;
>+ } all_dev_list ;
I think there is need for some naming consistency for functions and
macros handling these lists.
I propose:
dev_list (drop the "neighbour") and all_dev_list
and exported functions and macros called like:
netdev_lower_get_next_priv()
netdev_lower_for_each_priv()
netdev_all_upper_get_next_rcu()
etc...
>
>
> /* currently active device features */
>@@ -2772,11 +2782,11 @@ extern struct net_device *netdev_upper_get_next_dev_rcu(struct net_device *dev,
> struct list_head **iter);
>
> /* iterate through upper list, must be called under RCU read lock */
>-#define netdev_for_each_upper_dev_rcu(dev, upper, iter) \
>- for (iter = &(dev)->upper_dev_list, \
>- upper = netdev_upper_get_next_dev_rcu(dev, &(iter)); \
>- upper; \
>- upper = netdev_upper_get_next_dev_rcu(dev, &(iter)))
>+#define netdev_for_each_upper_dev_rcu(dev, updev, iter) \
>+ for (iter = &(dev)->all_dev_list.upper, \
>+ updev= netdev_upper_get_next_dev_rcu(dev, &(iter)); \
>+ updev; \
>+ updev = netdev_upper_get_next_dev_rcu(dev, &(iter)))
>
> extern struct net_device *netdev_master_upper_dev_get(struct net_device *dev);
> extern struct net_device *netdev_master_upper_dev_get_rcu(struct net_device *dev);
>diff --git a/net/core/dev.c b/net/core/dev.c
>index 743620e..9e4eb40 100644
>--- a/net/core/dev.c
>+++ b/net/core/dev.c
>@@ -4373,9 +4373,6 @@ struct netdev_adjacent {
> /* upper master flag, there can only be one master device per list */
> bool master;
>
>- /* indicates that this dev is our first-level lower/upper device */
>- bool neighbour;
>-
> /* counter for the number of times this device was added to us */
> u16 ref_nr;
>
>@@ -4385,12 +4382,17 @@ struct netdev_adjacent {
>
> static struct netdev_adjacent *__netdev_find_adj(struct net_device *dev,
> struct net_device *adj_dev,
>- bool upper)
>+ bool upper, bool neighbour)
> {
> struct netdev_adjacent *adj;
> struct list_head *dev_list;
>
>- dev_list = upper ? &dev->upper_dev_list : &dev->lower_dev_list;
>+ if (neighbour)
>+ dev_list = upper ? &dev->neighbour_dev_list.upper :
>+ &dev->neighbour_dev_list.lower;
>+ else
>+ dev_list = upper ? &dev->all_dev_list.upper :
>+ &dev->all_dev_list.lower;
>
> list_for_each_entry(adj, dev_list, list) {
> if (adj->dev == adj_dev)
>@@ -4402,13 +4404,25 @@ static struct netdev_adjacent *__netdev_find_adj(struct net_device *dev,
> static inline struct netdev_adjacent *__netdev_find_upper(struct net_device *dev,
> struct net_device *udev)
> {
>- return __netdev_find_adj(dev, udev, true);
>+ return __netdev_find_adj(dev, udev, true, false);
> }
>
> static inline struct netdev_adjacent *__netdev_find_lower(struct net_device *dev,
> struct net_device *ldev)
> {
>- return __netdev_find_adj(dev, ldev, false);
>+ return __netdev_find_adj(dev, ldev, false, false);
>+}
>+
>+static inline struct netdev_adjacent *__netdev_find_upper_neighbour(struct net_device *dev,
>+ struct net_device *udev)
>+{
>+ return __netdev_find_adj(dev, udev, true, true);
>+}
>+
>+static inline struct netdev_adjacent *__netdev_find_lower_neighbour(struct net_device *dev,
>+ struct net_device *ldev)
>+{
>+ return __netdev_find_adj(dev, ldev, false, true);
> }
>
> /**
>@@ -4440,7 +4454,7 @@ bool netdev_has_any_upper_dev(struct net_device *dev)
> {
> ASSERT_RTNL();
>
>- return !list_empty(&dev->upper_dev_list);
>+ return !list_empty(&dev->all_dev_list.upper);
> }
> EXPORT_SYMBOL(netdev_has_any_upper_dev);
>
>@@ -4457,10 +4471,10 @@ struct net_device *netdev_master_upper_dev_get(struct net_device *dev)
>
> ASSERT_RTNL();
>
>- if (list_empty(&dev->upper_dev_list))
>+ if (list_empty(&dev->neighbour_dev_list.upper))
> return NULL;
>
>- upper = list_first_entry(&dev->upper_dev_list,
>+ upper = list_first_entry(&dev->neighbour_dev_list.upper,
> struct netdev_adjacent, list);
> if (likely(upper->master))
> return upper->dev;
>@@ -4484,7 +4498,7 @@ struct net_device *netdev_upper_get_next_dev_rcu(struct net_device *dev,
>
> upper = list_entry_rcu((*iter)->next, struct netdev_adjacent, list);
>
>- if (&upper->list == &dev->upper_dev_list)
>+ if (&upper->list == &dev->all_dev_list.upper)
> return NULL;
>
> *iter = &upper->list;
>@@ -4504,7 +4518,7 @@ struct net_device *netdev_master_upper_dev_get_rcu(struct net_device *dev)
> {
> struct netdev_adjacent *upper;
>
>- upper = list_first_or_null_rcu(&dev->upper_dev_list,
>+ upper = list_first_or_null_rcu(&dev->neighbour_dev_list.upper,
> struct netdev_adjacent, list);
> if (upper && likely(upper->master))
> return upper->dev;
>@@ -4517,11 +4531,12 @@ static int __netdev_adjacent_dev_insert(struct net_device *dev,
> bool neighbour, bool master,
> bool upper)
> {
>- struct netdev_adjacent *adj;
>+ struct netdev_adjacent *adj, *neigh = NULL;
>
>- adj = __netdev_find_adj(dev, adj_dev, upper);
>+ adj = __netdev_find_adj(dev, adj_dev, upper, false);
>
> if (adj) {
>+ /* we cannot insert a neighbour device twice */
> BUG_ON(neighbour);
> adj->ref_nr++;
> return 0;
>@@ -4533,24 +4548,50 @@ static int __netdev_adjacent_dev_insert(struct net_device *dev,
>
> adj->dev = adj_dev;
> adj->master = master;
>- adj->neighbour = neighbour;
> adj->ref_nr = 1;
>-
> dev_hold(adj_dev);
>+
>+ if (neighbour) {
>+ neigh = kmalloc(sizeof(*neigh), GFP_KERNEL);
>+ if (!neigh) {
>+ kfree(adj);
>+ return -ENOMEM;
>+ }
>+ neigh->dev = adj_dev;
>+ neigh->master = master;
>+ neigh->ref_nr = 1;
>+ dev_hold(adj_dev);
>+ }
>+
> pr_debug("dev_hold for %s, because of %s link added from %s to %s\n",
> adj_dev->name, upper ? "upper" : "lower", dev->name,
> adj_dev->name);
>+ if (neigh)
>+ pr_debug("dev_hold for %s, because of %s link added from %s"
>+ " to %s (neighbour)\n",
>+ adj_dev->name, upper ? "upper" : "lower", dev->name,
>+ adj_dev->name);
>
> if (!upper) {
>- list_add_tail_rcu(&adj->list, &dev->lower_dev_list);
>+ if (neigh)
>+ list_add_tail_rcu(&neigh->list,
>+ &dev->neighbour_dev_list.lower);
>+ list_add_tail_rcu(&adj->list, &dev->all_dev_list.lower);
> return 0;
> }
>
> /* Ensure that master upper link is always the first item in list. */
>- if (master)
>- list_add_rcu(&adj->list, &dev->upper_dev_list);
>- else
>- list_add_tail_rcu(&adj->list, &dev->upper_dev_list);
>+ if (master) {
>+ if (neigh)
>+ list_add_rcu(&neigh->list,
>+ &dev->neighbour_dev_list.upper);
>+ list_add_rcu(&adj->list, &dev->all_dev_list.upper);
>+ } else {
>+ if (neigh)
>+ list_add_tail_rcu(&neigh->list,
>+ &dev->neighbour_dev_list.upper);
>+ list_add_tail_rcu(&adj->list, &dev->all_dev_list.upper);
>+ }
>
> return 0;
> }
>@@ -4574,17 +4615,36 @@ static inline int __netdev_lower_dev_insert(struct net_device *dev,
> void __netdev_adjacent_dev_remove(struct net_device *dev,
> struct net_device *adj_dev, bool upper)
> {
>- struct netdev_adjacent *adj;
>+ struct netdev_adjacent *adj, *neighbour;
>
>- if (upper)
>+ if (upper) {
> adj = __netdev_find_upper(dev, adj_dev);
>- else
>+ neighbour = __netdev_find_upper_neighbour(dev, adj_dev);
>+ } else {
> adj = __netdev_find_lower(dev, adj_dev);
>+ neighbour = __netdev_find_lower_neighbour(dev, adj_dev);
>+ }
>
>- if (!adj)
>+ if (!adj) {
>+ pr_err("tried to remove %s device %s from %s\n",
>+ upper ? "upper" : "lower", dev->name, adj_dev->name);
> BUG();
>+ }
>
> if (adj->ref_nr > 1) {
>+ pr_debug("rec_cnt-- for link to %s, because of %s link removed"
>+ " from %s to %s, remains %d\n",
>+ adj_dev->name, upper ? "upper" : "lower", dev->name,
>+ adj_dev->name, adj->ref_nr-1);
>+ if (neighbour) {
>+ pr_debug("rec_cnt-- for link to %s, because of %s link"
>+ " removed from %s to %s, remain %d (neigh)\n",
>+ adj_dev->name, upper ? "upper" : "lower",
>+ dev->name, adj_dev->name,
>+ neighbour->ref_nr-1);
>+ BUG_ON(adj->ref_nr != neighbour->ref_nr);
>+ neighbour->ref_nr--;
>+ }
> adj->ref_nr--;
> return;
> }
>@@ -4595,6 +4655,15 @@ void __netdev_adjacent_dev_remove(struct net_device *dev,
> adj_dev->name);
> dev_put(adj_dev);
> kfree_rcu(adj, rcu);
>+ if (neighbour) {
>+ pr_debug("dev_put for %s, because of %s link removed from %s"
>+ " to %s (neighbour)\n",
>+ adj_dev->name, upper ? "upper" : "lower", dev->name,
>+ adj_dev->name);
>+ list_del_rcu(&neighbour->list);
>+ dev_put(adj_dev);
>+ kfree_rcu(neighbour, rcu);
>+ }
> }
>
> static inline void __netdev_upper_dev_remove(struct net_device *dev,
>@@ -4675,12 +4744,14 @@ static int __netdev_upper_dev_link(struct net_device *dev,
> return ret;
>
> /* Now that we linked these devs, make all the upper_dev's
>- * upper_dev_list visible to every dev's lower_dev_list and vice
>+ * all_dev_list.upper visible to every dev's all_dev_list.lower an
> * versa, and don't forget the devices itself. All of these
> * links are non-neighbours.
> */
>- list_for_each_entry(i, &dev->lower_dev_list, list) {
>- list_for_each_entry(j, &upper_dev->upper_dev_list, list) {
>+ list_for_each_entry(i, &dev->all_dev_list.lower, list) {
>+ list_for_each_entry(j, &upper_dev->all_dev_list.upper, list) {
>+ pr_debug("Interlinking %s with %s, non-neighbour\n",
>+ i->dev->name, j->dev->name);
> ret = __netdev_adjacent_dev_link(i->dev, j->dev);
> if (ret)
> goto rollback_mesh;
>@@ -4688,14 +4759,18 @@ static int __netdev_upper_dev_link(struct net_device *dev,
> }
>
> /* add dev to every upper_dev's upper device */
>- list_for_each_entry(i, &upper_dev->upper_dev_list, list) {
>+ list_for_each_entry(i, &upper_dev->all_dev_list.upper, list) {
>+ pr_debug("linking %s's upper device %s with %s\n", upper_dev->name,
>+ i->dev->name, dev->name);
> ret = __netdev_adjacent_dev_link(dev, i->dev);
> if (ret)
> goto rollback_upper_mesh;
> }
>
> /* add upper_dev to every dev's lower device */
>- list_for_each_entry(i, &dev->lower_dev_list, list) {
>+ list_for_each_entry(i, &dev->all_dev_list.lower, list) {
>+ pr_debug("linking %s's lower device %s with %s\n", dev->name,
>+ i->dev->name, upper_dev->name);
> ret = __netdev_adjacent_dev_link(i->dev, upper_dev);
> if (ret)
> goto rollback_lower_mesh;
>@@ -4706,7 +4781,7 @@ static int __netdev_upper_dev_link(struct net_device *dev,
>
> rollback_lower_mesh:
> to_i = i;
>- list_for_each_entry(i, &dev->lower_dev_list, list) {
>+ list_for_each_entry(i, &dev->all_dev_list.lower, list) {
> if (i == to_i)
> break;
> __netdev_adjacent_dev_unlink(i->dev, upper_dev);
>@@ -4716,7 +4791,7 @@ rollback_lower_mesh:
>
> rollback_upper_mesh:
> to_i = i;
>- list_for_each_entry(i, &upper_dev->upper_dev_list, list) {
>+ list_for_each_entry(i, &upper_dev->all_dev_list.upper, list) {
> if (i == to_i)
> break;
> __netdev_adjacent_dev_unlink(dev, i->dev);
>@@ -4727,8 +4802,8 @@ rollback_upper_mesh:
> rollback_mesh:
> to_i = i;
> to_j = j;
>- list_for_each_entry(i, &dev->lower_dev_list, list) {
>- list_for_each_entry(j, &upper_dev->upper_dev_list, list) {
>+ list_for_each_entry(i, &dev->all_dev_list.lower, list) {
>+ list_for_each_entry(j, &upper_dev->all_dev_list.upper, list) {
> if (i == to_i && j == to_j)
> break;
> __netdev_adjacent_dev_unlink(i->dev, j->dev);
>@@ -4797,17 +4872,17 @@ void netdev_upper_dev_unlink(struct net_device *dev,
> * devices from all upper_dev's upper devices and vice
> * versa, to maintain the graph relationship.
> */
>- list_for_each_entry(i, &dev->lower_dev_list, list)
>- list_for_each_entry(j, &upper_dev->upper_dev_list, list)
>+ list_for_each_entry(i, &dev->all_dev_list.lower, list)
>+ list_for_each_entry(j, &upper_dev->all_dev_list.upper, list)
> __netdev_adjacent_dev_unlink(i->dev, j->dev);
>
> /* remove also the devices itself from lower/upper device
> * list
> */
>- list_for_each_entry(i, &dev->lower_dev_list, list)
>+ list_for_each_entry(i, &dev->all_dev_list.lower, list)
> __netdev_adjacent_dev_unlink(i->dev, upper_dev);
>
>- list_for_each_entry(i, &upper_dev->upper_dev_list, list)
>+ list_for_each_entry(i, &upper_dev->all_dev_list.upper, list)
> __netdev_adjacent_dev_unlink(dev, i->dev);
>
> call_netdevice_notifiers(NETDEV_CHANGEUPPER, dev);
>@@ -6069,8 +6144,10 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
> INIT_LIST_HEAD(&dev->napi_list);
> INIT_LIST_HEAD(&dev->unreg_list);
> INIT_LIST_HEAD(&dev->link_watch_list);
>- INIT_LIST_HEAD(&dev->upper_dev_list);
>- INIT_LIST_HEAD(&dev->lower_dev_list);
>+ INIT_LIST_HEAD(&dev->neighbour_dev_list.upper);
>+ INIT_LIST_HEAD(&dev->neighbour_dev_list.lower);
>+ INIT_LIST_HEAD(&dev->all_dev_list.upper);
>+ INIT_LIST_HEAD(&dev->all_dev_list.lower);
> dev->priv_flags = IFF_XMIT_DST_RELEASE;
> setup(dev);
>
>--
>1.8.4
>
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