Messages in this thread | | | Date | Fri, 18 Oct 2002 07:55:55 +1000 | From | Nathan Scott <> | Subject | Re: [PATCH 1/5] Add POSIX Access Control Lists to ext2/3 |
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On Thu, Oct 17, 2002 at 12:04:08PM +0200, Andreas Gruenbacher wrote: > Hello Nathan,
hi there,
> On Thursday 17 October 2002 00:48, Nathan Scott wrote: > > They are an optimisization for the one special case (posix acls), > > and manage to pollute the VFS for that one special case ... > ... > As soon as any filesystem independent part of the kernel needs an interface > more efficient that pass-by-value we will again have exactly the same > problem.
My point is simply that a proposal to extend the VFS in this way needs to be accompanied by a compelling argument showing the performance bump that its providing.
> Going to disk and fetching EAs only causes disk accesses once; afterwards the > block is cached.
Good - this is true for both XFS and ext2/3 then. So, we are talking about using ref counting vs. copying for any in-kernel users of attrs, and you're saying there is some significant overheads with copying and I'm saying show me what kind of overheads we're talking about, please.
cheers.
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