Messages in this thread | | | Date | Fri, 30 Mar 2012 16:04:57 +0200 | From | Andi Kleen <> | Subject | Re: [PATCH 05/13] XFS: Fix lock ASSERT on UP |
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On Fri, Mar 30, 2012 at 03:13:48PM +1100, Dave Chinner wrote: > On Fri, Mar 30, 2012 at 01:52:01AM +0200, Andi Kleen wrote: > > On Thu, Mar 29, 2012 at 07:21:14PM -0400, Christoph Hellwig wrote: > > > On Tue, Mar 27, 2012 at 05:47:09PM -0700, Andi Kleen wrote: > > > > From: Andi Kleen <ak@linux.intel.com> > > > > > > > > ASSERT(!spin_is_locked()) doesn't work on UP builds. Replace with a standard > > > > lockdep_assert_held() > > > > > > The "standard" is assert_spin_locked() - which not only is much cheaper > > > but also has the advantage of working in non-lockdep builds. > > > > But then you have it unconditional, not just on debug builds. > > And the problem with that is what? There is so little overhead to the > check it doesn't matter that it is enabled in production kernels...
It's really interesting how much you guys argue for your buggy construct which you clearly never tested on a UP build...
Not sure if that is a hot path, but on highly contended locks every cache line fetch is quite expensive on larger systems.
also I doubt the thing really catches bugs, and if it did you would be probably better off with a sparse notation or so.
Anyways I will turn it into the normal assert.
-Andi -- ak@linux.intel.com -- Speaking for myself only.
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