Re: [PATCH RFC] v1 expedited "big hammer" RCU grace periods

[Linus Torvalds]

On Thu, 23 Apr 2009, Paul E. McKenney wrote:
> 
> Hmmm...  I need to ask Jeff Chua what HZ he was running with.  Because if
> there was some read-side critical section soaking up 30 milliseconds,
> all that hammering will do is slow things down...

The original bug report comes from simply bootup:

  "I'm loading all the firewall rules during boot-up and this 6 secs 
   slowness is really not very nice to wait for."

IOW, the problematic case likely effectively has _nothing_ else going on. 
Sure, there might be some parallelism (the bootup scripts are getting 
better for that), but hopefully not 6 seconds worth, and not likely any 
complex critical sections.

		Linus
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