wakeup_flags patch.

[John Baldwin]

On Sunday 01 July 2007 07:08:35 pm Jeff Roberson wrote:
> http://people.freebsd.org/~jeff/wakeupflags.diff
> 
> It didn't workout very cleanly since the flags have to go through three 
> layers.  I could define wakeup and sleepq flags to be the same and skip a 
> bunch of conditionals.  However, we'd then have to know which flags were 
> free to use in each case.  Are there any further opinions on the style?
> 
> This patch does not include an implementation for WAKEUP_LOCAL.  I'm still 
> working on that in SCHED_SMP.  Ironically, it does include an 
> implementation for WAKEUP_TAIL, however, I don't have any users of that. 
> :-)

You can find the pre-threadlock patch for 7.x of what Y! uses for accept() at 
www.freebsd.org/~jhb/patches/justone.patch

It has two features your WAKEUP_TAIL doesn't have (one of which I mentioned 
earlier): 1) it doesn't wakeup threads from swapped out processes (you aren't 
getting a thread that is "hot" in the cache if you have to go page it back in 
from disk), and 2) it returns a success/fail to the caller so that it can 
fallback to its traditional behavior if we couldn't find a "hot" thread to 
resume.

-- 
John Baldwin