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

[Simon Jeons <simon.jeons@gmail.com>]

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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