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| author | Eric Dumazet <edumazet@google.com> | 2012-08-22 17:19:46 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-08-22 21:50:36 -0700 |
| commit | 0115e8e30d6fcdd4b8faa30d3ffd90859a591f51 (patch) | |
| tree | 725026e2192e57b98366947ab53c73689ca040a8 /net/core/dst.c | |
| parent | bf277b0ccea7d2422b85e232017ce3fddbe9c49c (diff) | |
| download | linux-0115e8e30d6fcdd4b8faa30d3ffd90859a591f51.tar.gz linux-0115e8e30d6fcdd4b8faa30d3ffd90859a591f51.tar.bz2 linux-0115e8e30d6fcdd4b8faa30d3ffd90859a591f51.zip | |
net: remove delay at device dismantle
I noticed extra one second delay in device dismantle, tracked down to
a call to dst_dev_event() while some call_rcu() are still in RCU queues.
These call_rcu() were posted by rt_free(struct rtable *rt) calls.
We then wait a little (but one second) in netdev_wait_allrefs() before
kicking again NETDEV_UNREGISTER.
As the call_rcu() are now completed, dst_dev_event() can do the needed
device swap on busy dst.
To solve this problem, add a new NETDEV_UNREGISTER_FINAL, called
after a rcu_barrier(), but outside of RTNL lock.
Use NETDEV_UNREGISTER_FINAL with care !
Change dst_dev_event() handler to react to NETDEV_UNREGISTER_FINAL
Also remove NETDEV_UNREGISTER_BATCH, as its not used anymore after
IP cache removal.
With help from Gao feng
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Mahesh Bandewar <maheshb@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/dst.c')
| -rw-r--r-- | net/core/dst.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/core/dst.c b/net/core/dst.c index 56d63612e1e4..f6593d238e9a 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -374,7 +374,7 @@ static int dst_dev_event(struct notifier_block *this, unsigned long event, struct dst_entry *dst, *last = NULL; switch (event) { - case NETDEV_UNREGISTER: + case NETDEV_UNREGISTER_FINAL: case NETDEV_DOWN: mutex_lock(&dst_gc_mutex); for (dst = dst_busy_list; dst; dst = dst->next) { |