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authorEric Dumazet <edumazet@google.com>2017-09-19 16:27:05 -0700
committerDavid S. Miller <davem@davemloft.net>2017-09-19 16:32:23 -0700
commitd464e84eed02993d40ad55fdc19f4523e4deee5b (patch)
treee7d898dbf54288fac182c63a2ec7d092082f8f44 /lib/kobject_uevent.c
parent4a336a23d619e96aef37d4d054cfadcdd1b581ba (diff)
downloadlwn-d464e84eed02993d40ad55fdc19f4523e4deee5b.tar.gz
lwn-d464e84eed02993d40ad55fdc19f4523e4deee5b.zip
kobject: factorize skb setup in kobject_uevent_net_broadcast()
We can build one skb and let it be cloned in netlink. This is much faster, and use less memory (all clones will share the same skb->head) Tested: time perf record (for f in `seq 1 3000` ; do ip netns add tast$f; done) [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 4.110 MB perf.data (~179584 samples) ] real 0m24.227s # instead of 0m52.554s user 0m0.329s sys 0m23.753s # instead of 0m51.375s 14.77% ip [kernel.kallsyms] [k] __ip6addrlbl_add 14.56% ip [kernel.kallsyms] [k] netlink_broadcast_filtered 11.65% ip [kernel.kallsyms] [k] netlink_has_listeners 6.19% ip [kernel.kallsyms] [k] _raw_spin_lock_irqsave 5.66% ip [kernel.kallsyms] [k] kobject_uevent_env 4.97% ip [kernel.kallsyms] [k] memset_erms 4.67% ip [kernel.kallsyms] [k] refcount_sub_and_test 4.41% ip [kernel.kallsyms] [k] _raw_read_lock 3.59% ip [kernel.kallsyms] [k] refcount_inc_not_zero 3.13% ip [kernel.kallsyms] [k] _raw_spin_unlock_irqrestore 1.55% ip [kernel.kallsyms] [k] __wake_up 1.20% ip [kernel.kallsyms] [k] strlen 1.03% ip [kernel.kallsyms] [k] __wake_up_common 0.93% ip [kernel.kallsyms] [k] consume_skb 0.92% ip [kernel.kallsyms] [k] netlink_trim 0.87% ip [kernel.kallsyms] [k] insert_header 0.63% ip [kernel.kallsyms] [k] unmap_page_range Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'lib/kobject_uevent.c')
-rw-r--r--lib/kobject_uevent.c34
1 files changed, 19 insertions, 15 deletions
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
index 78b2a7e378c0..147db91c10d0 100644
--- a/lib/kobject_uevent.c
+++ b/lib/kobject_uevent.c
@@ -301,23 +301,26 @@ static int kobject_uevent_net_broadcast(struct kobject *kobj,
{
int retval = 0;
#if defined(CONFIG_NET)
+ struct sk_buff *skb = NULL;
struct uevent_sock *ue_sk;
/* send netlink message */
list_for_each_entry(ue_sk, &uevent_sock_list, list) {
struct sock *uevent_sock = ue_sk->sk;
- struct sk_buff *skb;
- size_t len;
if (!netlink_has_listeners(uevent_sock, 1))
continue;
- /* allocate message with the maximum possible size */
- len = strlen(action_string) + strlen(devpath) + 2;
- skb = alloc_skb(len + env->buflen, GFP_KERNEL);
- if (skb) {
+ if (!skb) {
+ /* allocate message with the maximum possible size */
+ size_t len = strlen(action_string) + strlen(devpath) + 2;
char *scratch;
+ retval = -ENOMEM;
+ skb = alloc_skb(len + env->buflen, GFP_KERNEL);
+ if (!skb)
+ continue;
+
/* add header */
scratch = skb_put(skb, len);
sprintf(scratch, "%s@%s", action_string, devpath);
@@ -325,16 +328,17 @@ static int kobject_uevent_net_broadcast(struct kobject *kobj,
skb_put_data(skb, env->buf, env->buflen);
NETLINK_CB(skb).dst_group = 1;
- retval = netlink_broadcast_filtered(uevent_sock, skb,
- 0, 1, GFP_KERNEL,
- kobj_bcast_filter,
- kobj);
- /* ENOBUFS should be handled in userspace */
- if (retval == -ENOBUFS || retval == -ESRCH)
- retval = 0;
- } else
- retval = -ENOMEM;
+ }
+
+ retval = netlink_broadcast_filtered(uevent_sock, skb_get(skb),
+ 0, 1, GFP_KERNEL,
+ kobj_bcast_filter,
+ kobj);
+ /* ENOBUFS should be handled in userspace */
+ if (retval == -ENOBUFS || retval == -ESRCH)
+ retval = 0;
}
+ consume_skb(skb);
#endif
return retval;
}