Messages in this thread | | | Subject | Re: [patch] SLQB slab allocator | From | "Zhang, Yanmin" <> | Date | Tue, 03 Feb 2009 09:34:04 +0800 |
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On Mon, 2009-02-02 at 10:00 -0500, Christoph Lameter wrote: > On Mon, 2 Feb 2009, Pekka Enberg wrote: > > > Hi Yanmin, > > > > On Mon, 2009-02-02 at 11:38 +0800, Zhang, Yanmin wrote: > > > Can we add a checking about free memory page number/percentage in function > > > allocate_slab that we can bypass the first try of alloc_pages when memory > > > is hungry? > > > > If the check isn't too expensive, I don't any reason not to. How would > > you go about checking how much free pages there are, though? Is there > > something in the page allocator that we can use for this? > > If the free memory is low then reclaim needs to be run to increase the > free memory. I think reclaim did start often with Hugh's case. There would be no swap if not.
> Falling back immediately incurs the overhead of going through > the order 0 queues. The falling back is temporal. Later on when there is enough free pages available, new slab allocations go back to higher order automatically. This is to save the first high-order allocation try because it often fails if memory is hungry.
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