Re: [PATCH -alternative] mm: hugetlbfs: Close race during teardownof hugetlbfs shared page tables V2 (resend)

[Mel Gorman]

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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/