Messages in this thread | | | Date | Tue, 26 Jun 2012 02:17:45 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [PATCH 02/11] memcg: Reclaim when more than one page needed. |
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On Tue, 26 Jun 2012, Glauber Costa wrote:
> > Nope, have you checked the output of /sys/kernel/slab/.../order when > > running slub? On my workstation 127 out of 316 caches have order-2 or > > higher by default. > > > > Well, this is still on the side of my argument, since this is still a majority > of them being low ordered.
Ok, so what happens if I pass slub_min_order=2 on the command line? We never retry?
> The code here does not necessarily have to retry - > if I understand it correctly - we just retry for very small allocations > because that is where our likelihood of succeeding is. >
Well, the comment for NR_PAGES_TO_RETRY says
/* * We need a number that is small enough to be likely to have been * reclaimed even under pressure, but not too big to trigger unnecessary * retries */
and mmzone.h says
/* * PAGE_ALLOC_COSTLY_ORDER is the order at which allocations are deemed * costly to service. That is between allocation orders which should * coalesce naturally under reasonable reclaim pressure and those which * will not. */ #define PAGE_ALLOC_COSTLY_ORDER 3
so I'm trying to reconcile which one is correct.
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