@@ -56,6 +56,9 @@ struct net {
struct list_head dev_base_head;
struct hlist_head *dev_name_head;
struct hlist_head *dev_index_head;
+ /* fast consecutive name allocation (e.g. eth0, eth1, ...) */
+ char fcna_name[IFNAMSIZ];
+ int fcna_no;
/* core fib_rules */
struct list_head rules_ops;
@@ -226,8 +226,12 @@ static int list_netdevice(struct net_device *dev)
*/
static void unlist_netdevice(struct net_device *dev)
{
+ struct net *net = dev_net(dev);
+
ASSERT_RTNL();
+ net->fcna_no = -1;
+
/* Unlink dev from the device chain */
write_lock_bh(&dev_base_lock);
list_del_rcu(&dev->dev_list);
@@ -872,6 +876,16 @@ static int __dev_alloc_name(struct net *net, const char *name, char *buf)
if (p[1] != 'd' || strchr(p + 2, '%'))
return -EINVAL;
+ /* avoid fast allocation for strange templates like "fan%dcy" */
+ if (net->fcna_no >= 0 && p[2] == 0 &&
+ net->fcna_name[p - name] == 0 &&
+ memcmp(name, net->fcna_name, p - name) == 0) {
+ snprintf(buf, IFNAMSIZ, name, ++net->fcna_no);
+ if (!__dev_get_by_name(net, buf))
+ return net->fcna_no;
+ net->fcna_no = -1;
+ }
+
/* Use one page as a bit array of possible slots */
inuse = (unsigned long *) get_zeroed_page(GFP_ATOMIC);
if (!inuse)
@@ -894,8 +908,15 @@ static int __dev_alloc_name(struct net *net, const char *name, char *buf)
}
snprintf(buf, IFNAMSIZ, name, i);
- if (!__dev_get_by_name(net, buf))
+ if (!__dev_get_by_name(net, buf)) {
+ if (p[2] == 0) {
+ memcpy(net->fcna_name, name, p - name);
+ net->fcna_name[p - name] = 0;
+ net->fcna_no = i;
+ } else
+ net->fcna_no = -1;
return i;
+ }
/* It is possible to run out of possible slots
* when the name is long and there isn't enough space left
This patch speeds up the network device name allocation for the case where a significant number of devices of the same type are created consecutively. Tests performed on a PPC750 @ 800Mhz machine with per device sysctl and sysfs entries disabled: Without the patch With the patch real 0m 43.43s real 0m 0.49s user 0m 0.00s user 0m 0.00s sys 0m 43.43s sys 0m 0.48s Signed-off-by: Octavian Purdila <opurdila@ixiacom.com> --- include/net/net_namespace.h | 3 +++ net/core/dev.c | 23 ++++++++++++++++++++++- 2 files changed, 25 insertions(+), 1 deletions(-)