Date: Tue, 12 Dec 2006 20:49:21 +0800 From: David Xu <davidxu@freebsd.org> To: freebsd-stable@freebsd.org Cc: stable@freebsd.org, Dmitriy Kirhlarov <dimma@higis.ru> Subject: Re: RELENG_6 panic under heavy load Message-ID: <200612122049.21525.davidxu@freebsd.org> In-Reply-To: <20061212122221.GE39171@dkirhlarov.mow.oilspace.com> References: <20061113084430.GE59604@dimma.mow.oilspace.com> <200612071118.52922.davidxu@freebsd.org> <20061212122221.GE39171@dkirhlarov.mow.oilspace.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tuesday 12 December 2006 20:22, Dmitriy Kirhlarov wrote: > On Thu, Dec 07, 2006 at 11:18:52AM +0800, David Xu wrote: > > On Thursday 16 November 2006 19:15, Gleb Smirnoff wrote: > > > On Thu, Nov 16, 2006 at 01:24:36PM +0300, Gleb Smirnoff wrote: > > > T> I wonder why UMA was suspected to be the problem. Dima gave > > > T> me access to the core. Here are more details from the trace: > > > > > > It looks like a race between two threads in one process. Look here: > > > > Can you try the patch ? > > http://people.freebsd.org/~davidxu/patch/ksegrp_preempt.patch > > I've tested it. This patch works also, but with a little bit different > behaviour. With patch from jhb@ I got LA 7-8, with this patch I have > LA 5-6, same as on unpatched system. But it seems to me, that system > is less interactive, compared to jhb@ patch. > > WBR > Dmitriy jhb patch is incomplete, it implies that every place a thread is doing state transition and waking another thread up should be patched, there is other code in kern_sig.c unpatched, though I don't know other places, but the code maybe_preempt_in_ksegrp should be synced with maybe_preempt, it should fix all problems. the LA you have seen is lower than jhb might be a nature of KSEGRP, but I am not sure, if you program forces all threads to be system-scope, it might fix the problem. David Xu
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200612122049.21525.davidxu>