Date: Fri, 8 Dec 2006 12:56:47 +0300 From: Dmitriy Kirhlarov <dimma@higis.ru> To: John Baldwin <jhb@freebsd.org> Cc: Gleb Smirnoff <glebius@freebsd.org>, freebsd-stable@freebsd.org Subject: Re: RELENG_6 panic under heavy load Message-ID: <20061208095646.GA1131@dkirhlarov.mow.oilspace.com> In-Reply-To: <200612061209.40253.jhb@freebsd.org> References: <20061113084430.GE59604@dimma.mow.oilspace.com> <20061116111525.GO32700@FreeBSD.org> <20061116160900.GQ32700@FreeBSD.org> <200612061209.40253.jhb@freebsd.org>
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On Wed, Dec 06, 2006 at 12:09:39PM -0500, John Baldwin wrote: > > ...) and here is something difficult to understand, when $poll tries to > > make $fork runnable, while $fork is trying to put itself in the turnstile > > that is owned by $poll > > Hmm. I'm guessing the problem is the $poll thread is suspended (not exited) > while holding the proc lock? That would appear to be the problem. That > thread can't run again to release the lock. Ah, yes, I see the bug. > Something like this should fix it: > > Index: kern_thread.c > =================================================================== > RCS file: /usr/cvs/src/sys/kern/kern_thread.c,v > retrieving revision 1.216.2.6 > diff -u -r1.216.2.6 kern_thread.c > --- kern_thread.c 2 Sep 2006 17:29:57 -0000 1.216.2.6 > +++ kern_thread.c 6 Dec 2006 17:06:26 -0000 > @@ -969,7 +969,9 @@ > TAILQ_REMOVE(&p->p_suspended, td, td_runq); > TD_CLR_SUSPENDED(td); > p->p_suspcount--; > + critical_enter(); > setrunnable(td); > + critical_exit(); > } > > /* > > What this does is force setrunnable() to be in a nested critical section so we > won't preempt during setrunnable() until either the caller of > thread_unsuspend_one() eventually releases sched_lock, or, in the case you > ran into, the thread does a PROC_UNLOCK() and calls mi_switch(). lbsd02# uptime 9:46AM up 22:45, 2 users, load averages: 7.50, 6.59, 6.32 It's work. Thank, you. Without your patch max uptime was 9 hours. I'm planning to test David's patch on weekend. WBR Dmitriy
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