Messages in this thread | | | Date | Mon, 8 Apr 2013 15:20:44 +0300 | Subject | Re: [PATCH 3/3] mm: when handling percpu_pagelist_fraction, use on_each_cpu() to set percpu pageset fields. | From | Gilad Ben-Yossef <> |
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On Fri, Apr 5, 2013 at 11:33 PM, Cody P Schafer <cody@linux.vnet.ibm.com> wrote: > In free_hot_cold_page(), we rely on pcp->batch remaining stable. > Updating it without being on the cpu owning the percpu pageset > potentially destroys this stability. > > Change for_each_cpu() to on_each_cpu() to fix.
Are you referring to this? -
1329 if (pcp->count >= pcp->high) { 1330 free_pcppages_bulk(zone, pcp->batch, pcp); 1331 pcp->count -= pcp->batch; 1332 }
I'm probably missing the obvious but won't it be simpler to do this in free_hot_cold_page() -
1329 if (pcp->count >= pcp->high) { 1330 unsigned int batch = ACCESS_ONCE(pcp->batch); 1331 free_pcppages_bulk(zone, batch, pcp); 1332 pcp->count -= batch; 1333 }
Now the batch value used is stable and you don't have to IPI every CPU in the system just to change a config knob...
Thanks, Gilad
-- Gilad Ben-Yossef Chief Coffee Drinker gilad@benyossef.com Israel Cell: +972-52-8260388 US Cell: +1-973-8260388 http://benyossef.com
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