Re: [Ext2-devel] [PATCH] distributed counters for ext2 to avoid group scaning

From: Matthew Wilcox (willy@debian.org)
Date: Mon Mar 17 2003 - 15:27:26 EST


On Mon, Mar 17, 2003 at 12:23:57PM -0800, Andrew Morton wrote:
> Matthew Wilcox <willy@debian.org> wrote:
> >
> > Anyway, I think dcounters should probably be allocated from kmalloc_percpu()
> > rather than as part of the dcounter struct.
>
> That will still consume up to 4 kilobytes per 32-bit counter. We'd
> need to merge Kiran & Dipankar's interlace allocator to do this less
> grossly.

Right -- or have dcounter manage a pool of memory itself. That's maybe too
much work though.

> Which is why I'm waiting to see some profiles and benchmarks. Judging from
> the last set of profiles, in which ext2_count_free_blocks() was not present,
> this may not be justified.

If we can manage without it, that's even better of course.

-- 
"It's not Hollywood.  War is real, war is primarily not about defeat or
victory, it is about death.  I've seen thousands and thousands of dead bodies.
Do you think I want to have an academic debate on this subject?" -- Robert Fisk
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