Messages in this thread | | | Subject | Re: [2.6.27-rc5] inotify_read's ev_mutex vs do_page_fault's mmap_sem... | From | Peter Zijlstra <> | Date | Wed, 10 Sep 2008 11:59:31 +0200 |
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On Wed, 2008-09-10 at 19:50 +1000, Nick Piggin wrote: > 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.
Will you send your x86_64 patch to be the first?
> 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?
Humm, no - we don't actually have that information there - I guess one could add it to lockdep_map and set it from the various init routines, but I'm not sure its worth it - just add might_sleep() along with might_lock() :-)
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