Messages in this thread | | | Date | Fri, 12 Apr 2013 17:22:37 +0200 | From | Andi Kleen <> | Subject | Re: [PATCH 0/6] mm/hugetlb: gigantic hugetlb page pools shrink supporting |
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On Fri, Apr 12, 2013 at 07:29:07AM +0800, Wanpeng Li wrote: > Ping Andi, > On Thu, Apr 04, 2013 at 05:09:08PM +0800, Wanpeng Li wrote: > >order >= MAX_ORDER pages are only allocated at boot stage using the > >bootmem allocator with the "hugepages=xxx" option. These pages are never > >free after boot by default since it would be a one-way street(>= MAX_ORDER > >pages cannot be allocated later), but if administrator confirm not to > >use these gigantic pages any more, these pinned pages will waste memory > >since other users can't grab free pages from gigantic hugetlb pool even > >if OOM, it's not flexible. The patchset add hugetlb gigantic page pools > >shrink supporting. Administrator can enable knob exported in sysctl to > >permit to shrink gigantic hugetlb pool.
I originally didn't allow this because it's only one way and it seemed dubious. I've been recently working on a new patchkit to allocate GB pages from CMA. With that freeing actually makes sense, as the pages can be reallocated.
-Andi
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