Re: [PATCH 1/3] mm/page_alloc: factor out setting of pcp->high andpcp->batch.

[Simon Jeons]

Hi Cody,
On 04/09/2013 01:39 AM, Cody P Schafer wrote:
> On 04/06/2013 06:37 PM, Simon Jeons wrote:
> > Hi Cody,
> > On 04/06/2013 04:33 AM, Cody P Schafer wrote:
> > > Creates pageset_set_batch() for use in setup_pageset().
> > > pageset_set_batch() imitates the functionality of
> > > setup_pagelist_highmark(), but uses the boot time
> > > (percpu_pagelist_fraction == 0) calculations for determining ->high
> >
> > Why need adjust pcp->high, pcp->batch during system running? What's the
> > requirement?
>
> There is currently a sysctl (which I patch later in this series) which 
> allows adjusting the ->high mark (and, indirectly, ->batch). 
> Additionally, memory hotplug changes ->high and ->batch due to the 
> zone size changing (essentially, zone->managed_pages and 
> zone->present_pages have changed) , meaning that zone_batchsize(), 
> which is used at boot to set ->batch and (indirectly) ->high has a 
> different output.

Thanks for your explain. I'm curious about this sysctl, when need adjust 
the ->high, ->batch during system running except memory hotplug which 
will change zone size?

> Note that in addition to the 2 users of this functionality mentioned 
> here, I'm currently working on anther resizer of zones (runtime NUMA 
> reconfiguration).

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