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

[Cody P Schafer <cody@linux.vnet.ibm.com>]

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.

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).

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>