Re: [RFC][PATCH 1/3] contigous big page allocator
From: Andi Kleen
Date: Wed Oct 13 2010 - 04:36:59 EST
KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> writes:
>> > My intention is not for allocating HUGEPAGE(> MAX_ORDER).
>>
>> I still believe using this for 1GB pages would be one of the more
>> interesting use cases.
>>
>
> I'm successfully allocating 1GB of continous pages at test. But I'm not sure
> requirements and users. How quick this allocation should be ?
This will always be slow. Huge pages are always pre allocated
even today through a sysctl. The use case would be have
echo XXX > /proc/sys/vm/nr_hugepages
at runtime working for 1GB too, instead of requiring a reboot
for this.
I think it's ok if that is somewhat slow, as long as it is not
incredible slow. Ideally it shouldn't cause a swap storm either
(maybe we need some way to indicate how hard the freeing code should
try?)
I guess it would only really work well if you predefine
movable zones at boot time.
-Andi
--
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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