Messages in this thread | | | Date | Mon, 08 Apr 2013 10:39:19 -0700 | From | Cody P Schafer <> | Subject | Re: [PATCH 1/3] mm/page_alloc: factor out setting of pcp->high and pcp->batch. |
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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).
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