Messages in this thread | | | Date | Fri, 24 Oct 2014 12:08:50 -0500 (CDT) | From | Christoph Lameter <> | Subject | Re: [RFC][PATCH 4/6] SRCU free VMAs |
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On Fri, 24 Oct 2014, Peter Zijlstra wrote:
> The hold time isn't relevant, in fact breaking up the mmap_sem such that > we require multiple acquisitions will just increase the cacheline > bouncing.
Well this wont be happening anymore once you RCUify the stuff. If you go to sleep then its best to release mmap_sem and then the bouncing wont matter.
Dropping mmap_sem there will also expose you to races you will see later too when you RCUify the code paths. That way those can be deal with beforehand.
> Also I think it makes more sense to continue an entire fault operation, > including blocking, if at all possible. Every retry will just waste more > time.
Ok then dont retry. Just drop mmap_sem before going to sleep. When you come back evaluate the situation and if we can proceed do so otherwise retry.
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