Re: [PATCH 02/12] mm: supporting variables and functions forbalanced zone aging

From: Andrew Morton
Date: Thu Dec 01 2005 - 05:37:12 EST


Wu Fengguang <wfg@xxxxxxxxxxxxxxxx> wrote:
>
> The zone aging rates are currently imbalanced,

ZONE_DMA is out of whack. It shouldn't be, and I'm not aware of anyone
getting in and working out why. I certainly wouldn't want to go and add
all this stuff without having a good understanding of _why_ it's out of
whack. Perhaps it's just some silly bug, like the thing I pointed at in
the previous email.

> the gap can be as large as 3 times,

What's the testcase?

> which can severely damage read-ahead requests and shorten their
> effective life time.

Have you any performance numbers for this?
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