Re: 2.6.28-rc8 big regression in VM

From: Wu Fengguang
Date: Thu Dec 25 2008 - 05:50:25 EST


On Wed, Dec 17, 2008 at 02:49:04PM +0200, Lukas Hejtmanek wrote:
> On Wed, Dec 17, 2008 at 08:44:21PM +0800, Wu Fengguang wrote:
> > So the cache memory shrinks a lot.
> >
> > Maybe your 'free' command is reporting wrong numbers?
> > Or it's not a quite reproducible problem?
>
> it depends, I think that 100MB of caches which is not dropped is not quite OK.
>
> While using the system without reboots for a long time, 'undroppable' amount
> of caches rises until the system is unusable.

Hi Lukas,

Did the undroppable memory keep growing?

If not, we could take it as a feature instead of bug: the memory
mapped pages are being protected from being freed. It's not a
regression either: the feature was there before 2.6.27.

But sure we change that if it's not the desirable behavior.

Thanks,
Fengguang

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/