diff options
| author | Eric Dumazet <[email protected]> | 2010-09-13 12:24:54 +0000 |
|---|---|---|
| committer | David S. Miller <[email protected]> | 2010-09-14 14:27:29 -0700 |
| commit | ef885afbf8a37689afc1d9d545e2f3e7a8276c17 (patch) | |
| tree | 8defdc814be3668f906213b5f32729341eec2aa5 /tools/perf/util/scripting-engines/trace-event-python.c | |
| parent | ab12811c89e88f2e66746790b1fe4469ccb7bdd9 (diff) | |
net: use rcu_barrier() in rollback_registered_many
netdev_wait_allrefs() waits that all references to a device vanishes.
It currently uses a _very_ pessimistic 250 ms delay between each probe.
Some users reported that no more than 4 devices can be dismantled per
second, this is a pretty serious problem for some setups.
Most of the time, a refcount is about to be released by an RCU callback,
that is still in flight because rollback_registered_many() uses a
synchronize_rcu() call instead of rcu_barrier(). Problem is visible if
number of online cpus is one, because synchronize_rcu() is then a no op.
time to remove 50 ipip tunnels on a UP machine :
before patch : real 11.910s
after patch : real 1.250s
Reported-by: Nicolas Dichtel <[email protected]>
Reported-by: Octavian Purdila <[email protected]>
Reported-by: Benjamin LaHaise <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Diffstat (limited to 'tools/perf/util/scripting-engines/trace-event-python.c')
0 files changed, 0 insertions, 0 deletions