Re: [RFC][PATCH] page reclaim throttle take2

From: David Rientjes
Date: Wed Feb 27 2008 - 03:57:19 EST


On Wed, 27 Feb 2008, Balbir Singh wrote:

> Let's forget node hotplug for the moment, but what if someone
>
> 1. Changes the machine configuration and adds more nodes, do we expect the
> kernel to be recompiled? Or is it easier to update /etc/sysctl.conf?
> 2. Uses fake NUMA nodes and increases/decreases the number of nodes across
> reboots. Should the kernel be recompiled?
>

That is why the proposal was made to make this a static configuration
option, such as CONFIG_NUM_RECLAIM_THREADS_PER_NODE, that will handle both
situations.

> I am afraid it doesn't. Consider as you scale number of CPU's with the same
> amount of memory, we'll end up making the reclaim problem worse.
>

The benchmark that have been posted suggest that memory locality is more
important than lock contention, as I've already mentioned.

David
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