Messages in this thread | | | From | Nick Piggin <> | Subject | Re: [2.6.27-rc5] inotify_read's ev_mutex vs do_page_fault's mmap_sem... | Date | Wed, 10 Sep 2008 19:50:27 +1000 |
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On Wednesday 10 September 2008 18:37, Ingo Molnar wrote: > * Nick Piggin <nickpiggin@yahoo.com.au> wrote: > > On Wednesday 10 September 2008 17:57, Peter Zijlstra wrote:
> > > Sure, how about the below - untested - uncompiled, might eat kittens, > > > etc.. > > > > > > Just sprinkle something like: > > > > > > might_lock_read(&mm->mmap_sem); > > > > > > in the right places. > > > > Ahh, very nice, thanks! I'll give that a try... > > cool! Please send in an RFC patch once you have something that boots - > we can stick it into tip/core/locking and see whether there's any new > messages on a wide range of systems and workloads. (and we'd also check > whether the number of kittens is an invariant.)
Well I have verified it boots, and have used the annotation in some of x86-64's user copy routines (luckily no flood of bugs I was scared of, phew!)
So I would like to request you merge Peter's patch, and we'll hopefully start seeing the annotations being used. FWIW, I don't suppose lockdep can determine that it is a sleeping lock, and do the appropriate might_sleep checks at this point as well?
Thanks, Nick
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