On 04/07/2013 08:39 AM, KOSAKI Motohiro wrote: > (4/5/13 4:33 PM), Cody P Schafer wrote: >> No off-cpu users of the percpu pagesets exist. >> >> zone_pcp_update()'s goal is to adjust the ->high and ->mark members of a >> percpu pageset based on a zone's ->managed_pages. We don't need to drain >> the entire percpu pageset just to modify these fields. Avoid calling >> setup_pageset() (and the draining required to call it) and instead just >> set the fields' values. >> >> This does change the behavior of zone_pcp_update() as the percpu >> pagesets will not be drained when zone_pcp_update() is called (they will >> end up being shrunk, not completely drained, later when a 0-order page >> is freed in free_hot_cold_page()). >> >> Signed-off-by: Cody P Schafer <c...@linux.vnet.ibm.com> > > NAK. > > 1) zone_pcp_update() is only used from memory hotplug and it require page > drain.
I'm looking at this code because I'm currently working on a patchset which adds another interface which modifies zone sizes, so "only used from memory hotplug" is a temporary thing (unless I discover that zone_pcp_update() is not intended to do what I want it to do). > 2) stop_machin is used for avoiding race. just removing it is insane. What race? Is there a cross cpu access to ->high & ->batch that makes using on_each_cpu() instead of stop_machine() inappropriate? It is absolutely not just being removed. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
