On 2019/7/25 下午9:26, Michael S. Tsirkin wrote:
Exactly, and that's the reason actually I use synchronize_rcu() there.
So the concern is still the possible synchronize_expedited()?
I think synchronize_srcu_expedited.
synchronize_expedited sends lots of IPI and is bad for realtime VMs.
Can I do this
on through another series on top of the incoming V2?
Thanks
The question is this: is this still a gain if we switch to the
more expensive srcu? If yes then we can keep the feature on,
I think we only care about the cost on srcu_read_lock() which looks
pretty tiny form my point of view. Which is basically a READ_ONCE() +
WRITE_ONCE().
Of course I can benchmark to see the difference.
if not we'll put it off until next release and think
of better solutions. rcu->srcu is just a find and replace,
don't see why we need to defer that. can be a separate patch
for sure, but we need to know how well it works.
I think I get here, let me try to do that in V2 and let's see the numbers.
Thanks
