Re: [PATCH 0/9] re-shrink 'struct page' when SLUB is on.

From: Dave Hansen
Date: Mon Jan 13 2014 - 12:17:40 EST


On 01/12/2014 05:44 PM, Joonsoo Kim wrote:
> We only touch one struct page on small allocation.
> In 64-byte case, we always use one cacheline for touching struct page, since
> it is aligned to cacheline size. However, in 56-byte case, we possibly use
> two cachelines because struct page isn't aligned to cacheline size.

I think you're completely correct that this can _happen_, but I'm a bit
unconvinced that what you're talking about is the thing which dominates
the results. I'm sure it plays a role, but the tests I was doing were
doing tens of millions of allocations and touching a _lot_ of 'struct
pages'. I would not expect these effects to be observable across such a
large sample of pages.
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