git: DragonFly_RELEASE_2_8 kernel - x86_64 - Add additional checks to lwp_wait() & friends

[Matthew Dillon]

commit 486177ef9c4bdd3da9da4afc6cbc965a1d3b179c
Author: Matthew Dillon <dillon at apollo.backplane.com>
Date:   Sat Oct 23 09:35:14 2010 -0700

    kernel - x86_64 - Add additional checks to lwp_wait() & friends
    
    * lwp_wait() must defer reaping of a lwp that is still running on another
      cpu (i.e. in the midst of exiting).
    
    * It shouldn't be possible for this to happen but just incase the thread
      gets switched out after TDF_EXITING has been set, also make sure
      the threat is no longer on the LWKT run queue.
    
    * Remove old debugging in the LWKT scheduler path.
    
    * Protect gd_freetd (per-cpu td cache) with a critical section.  Again
      this case should not occur as new threads are not allocated from
      interrupts, but protect it anyway.  Also assert that the cached free
      td is in no way still scheduled.
    
      Note that this cache is required to ensure that the td does not
      end up in the MP-accessible objcache before it has been fully
      descheduled.

Summary of changes:
 sys/kern/kern_exit.c   |    6 +++---
 sys/kern/lwkt_thread.c |   48 +++++++++++++-----------------------------------
 2 files changed, 16 insertions(+), 38 deletions(-)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/486177ef9c4bdd3da9da4afc6cbc965a1d3b179c


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