Re: [patch 42/52] fs: icache per-cpu last_ino allocator

From: Andi Kleen
Date: Thu Jun 24 2010 - 12:20:10 EST


On Fri, Jun 25, 2010 at 01:52:43AM +1000, Nick Piggin wrote:
>
> That's right. More or less it just requires alloc_inode to be exported,
> adding more branches in new_inode would not be a good way to go.

One test/branch shouldn't hurt much.

> > I guess the main customer is sockets only.
>
> I guess. Sockets and ram based filesystems. Interestingly I don't know
> really what it's for (in socket code it's mostly for reporting and
> hashing it seems). It sure isn't guaranteed to be unique.

Maybe it could be generated lazily on access for those?
I suppose stat on a socket is relatively rare.
The only problem is would need an accessor.

But ok out of scope.

> Well I think glibc will convert 64 bit stat struct to 32bit for
> old apps. It detects if the ino can't fit in 32 bits.

... and will fail the stat.

-Andi

--
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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