kern/172166: Deadlock in the networking code, possible due to a bug in the SCHED_ULE

[Alexander Motin]

The following reply was made to PR kern/172166; it has been noted by GNATS.

From: Alexander Motin <mav at FreeBSD.org>
To: Eugene Grosbein <egrosbein at rdtc.ru>
Cc: bug-followup at FreeBSD.org, eugen at eg.sd.rdtc.ru, 
 Andriy Gapon <avg at FreeBSD.org>
Subject: Re: kern/172166: Deadlock in the networking code, possible due to
 a bug in the SCHED_ULE
Date: Tue, 02 Oct 2012 10:53:49 +0300

 On 02.10.2012 10:48, Eugene Grosbein wrote:
 > 02.10.2012 13:58, Alexander Motin ÐÉÛÅÔ:
 >> About rw_lock priority propagation locking(9) tells:
 >> The rw_lock locks have priority propagation like mutexes, but priority
 >> can be propagated only to an exclusive holder.  This limitation comes
 >> from the fact that shared owners are anonymous.
 >>
 >> What's about idle stealing threshold, it was fixed in HEAD at r239194,
 >> but wasn't merged yet. It should be trivial to merge it.
 >
 > Would it fix my problem with 6-CPU box?
 > Your commit log talks about "8 or more cores".
 
 Hmm. Then I see no reason why threads were not stolen, unless they are 
 bound to specific CPU. Check `sysctl kern.sched.steal_thresh` output to 
 be sure.
 
 -- 
 Alexander Motin