Re: [QUICKLIST 1/5] Quicklists for page table pages V4

From: Christoph Lameter
Date: Fri Mar 23 2007 - 11:08:57 EST


On Thu, 22 Mar 2007, Andrew Morton wrote:

> > About 40% on fork+exit. See
> >
> > http://marc.info/?l=linux-ia64&m=110942798406005&w=2
> >
>
> afacit that two-year-old, totally-different patch has nothing to do with my
> repeatedly-asked question. It appears to be consolidating three separate
> quicklist allocators into one common implementation.

Yes it shows the performance gains from the quicklist approach. This the
work Robin Holt did on the problem. The problem is how to validate the
patch because there should be no change at all on ia64 and on i386 we
basically measure the overhead of the slab allocations. One could
measure the impact x86_64 because this introduces quicklists to that
platform.

The earlier discussion focused on avoiding zeroing of pte as far as I can
recall.

> but it crashes early in the page allocator (i386) and I don't see why. It
> makes me wonder if we have a use-after-free which is hidden by the presence
> of the quicklist buffering or something.

This was on i386? Could be hidden now by the slab use ther.

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