Messages in this thread | | | Date | Fri, 27 Jul 2012 09:42:54 +0100 | From | Mel Gorman <> | Subject | Re: [PATCH -alternative] mm: hugetlbfs: Close race during teardown of hugetlbfs shared page tables V2 (resend) |
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On Thu, Jul 26, 2012 at 01:42:26PM -0400, Rik van Riel wrote: > On 07/23/2012 12:04 AM, Hugh Dickins wrote: > > >Please don't be upset if I say that I don't like either of your patches. > >Mainly for obvious reasons - I don't like Mel's because anything with > >trylock retries and nested spinlocks worries me before I can even start > >to think about it; and I don't like Michal's for the same reason as Mel, > >that it spreads more change around in common paths than we would like. > > I have a naive question. > > In huge_pmd_share, we protect ourselves by taking > the mapping->i_mmap_mutex. > > Is there any reason we could not take the i_mmap_mutex > in the huge_pmd_unshare path? >
We do, in 3.4 at least - callers of __unmap_hugepage_range hold the i_mmap_mutex. Locking changes in mmotm and there is a patch there that needs to be reverted. What tree are you looking at?
-- Mel Gorman SUSE Labs
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