Re: [QUICKLIST 0/4] Arch independent quicklists V2

[Nick Piggin]

Andrew Morton wrote:
> > On Tue, 13 Mar 2007 00:13:25 -0700 (PDT) Christoph Lameter <clameter@xxxxxxx> wrote:
> > Page table pages have the characteristics that they are typically zero
> > or in a known state when they are freed.
>
>
> Well if they're zero then perhaps they should be released to the page allocator
> to satisfy the next __GFP_ZERO request.  If that request is for a pagetable
> page, we break even (except we get to remove special-case code).  If that
> __GFP_ZERO allocation was or some application other than for a pagetable, we
> win.
>
> iow, can we just nuke 'em?

Page allocator still requires interrupts to be disabled, which this doesn't.

Considering there isn't much else that frees known zeroed pages, I wonder if
it is worthwhile.

Last time the zeroidle discussion came up was IIRC not actually real performance
gain, just cooking the 1024 CPU threaded pagefault numbers ;)

--
SUSE Labs, Novell Inc.
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