Re: [PATCH][RFC] slub: increasing order reduces memory usage of some key caches

From: Vegard Nossum
Date: Wed Jul 16 2008 - 10:34:04 EST


On Wed, Jul 16, 2008 at 4:03 PM, Christoph Lameter
<cl@xxxxxxxxxxxxxxxxxxxx> wrote:
> Richard Kennedy wrote:
>
>> before
>> dentry 82136 82137 208 19 1 : tunables 0 0 0 : slabdata 4323 4323 0
>> after
>> dentry 79482 79482 208 39 2 : tunables 0 0 0 : slabdata 2038 2038 0
>
> 19 objects with an order 1 alloc and 208 byte size? Urgh. 8192/208 = 39 and not 19.
>
> Kmemcheck or something else active? We seem to be loosing 50% of our memory.

Hm, I don't think so? I thought that those 1 and 2 were not orders,
but in fact the number of pages. Which seems correct, since now you
have 4096 / 208 = 19 :-)

(His patch bumps order from 0 to 1, so the number of pages were bumped
from 1 to 2.)

Or..?


Vegard

--
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
-- E. W. Dijkstra, EWD1036
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