Date: Tue, 5 Jun 2007 15:25:29 -0400 From: John Baldwin <jhb@freebsd.org> To: Jeff Roberson <jroberson@chesapeake.net> Cc: Attilio Rao <attilio@freebsd.org>, cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/kern kern_mutex.c Message-ID: <200706051525.29852.jhb@freebsd.org> In-Reply-To: <20070605121953.V606@10.0.0.1> References: <200706051857.l55IvAYP094328@repoman.freebsd.org> <200706051511.56553.jhb@freebsd.org> <20070605121953.V606@10.0.0.1>
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On Tuesday 05 June 2007 03:20:42 pm Jeff Roberson wrote: > On Tue, 5 Jun 2007, John Baldwin wrote: > > > On Tuesday 05 June 2007 02:57:09 pm Attilio Rao wrote: > >> attilio 2007-06-05 18:57:09 UTC > >> > >> FreeBSD src repository > >> > >> Modified files: > >> sys/kern kern_mutex.c > >> Log: > >> Fix a problem with not-preemptive kernels caming from mis-merging of > >> existing code with the new thread_lock patch. > >> This also cleans up a bit unlock operation for mutexes. > >> > >> Approved by: jhb, jeff(mentor) > > > > Specifically, this retires the explicit preemption code in mtx_unlock() > > (inherited from BSD/OS) in the #ifndef PREEMPTION case. We now only do > > preemptions as a scheduling decision in the scheduler and only > > #ifdef PREEMPTION. > > I believe we also should replace thread_lock() and thread_unlock() with > calls to spinlock_enter()/exit() on !SMP and make thread_set_lock() a > no-op for this case. Does that sounds right to everyone? Probably. spinlocks in general already do that. -- John Baldwin
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