Messages in this thread | | | Date | Mon, 2 Dec 2013 16:46:01 +0000 | From | Al Viro <> | Subject | Re: Found it! (was Re: [3.10] Oopses in kmem_cache_allocate() via prepare_creds()) |
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On Mon, Dec 02, 2013 at 05:27:55PM +0100, Ingo Molnar wrote:
> It's not like there should be many (any?) VFS operations where a pipe > is used via i_mutex and pipe->mutex in parallel, which would improve > scalability - so I don't see the scalability advantage. (But I might > be missing something) > > Barring such kind of workload the extra mutex just adds extra > micro-costs because now two locks have to be taken on > creation/destruction, plus it adds extra complexity and races. > > So unless I'm missing something obvious, another good fix would be to > just revert pipe->mutex and rely on i_mutex as before?
You are missing the extra shitloads of complexity in ->i_mutex ordering, and ->i_mutex is already used for too many things...
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