Messages in this thread | | | Subject | Re: [Lhms-devel] [PATCH 1/10] hot-add-mem x86_64: acpi motherboard fix | From | keith mannthey <> | Date | Mon, 07 Aug 2006 17:56:56 -0700 |
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On Tue, 2006-08-08 at 09:31 +0900, KAMEZAWA Hiroyuki wrote: > On Mon, 07 Aug 2006 11:39:27 -0700 > keith mannthey <kmannth@us.ibm.com> wrote: > > > On Sat, 2006-08-05 at 14:51 +0900, KAMEZAWA Hiroyuki wrote: > > > On Fri, 4 Aug 2006 07:13:51 -0600 > > > Keith Mannthey <kmannth@us.ibm.com> wrote: > > > > I have worked to integrate the feedback I recived on the last round of patches > > > > and welcome more ideas/advice. Thanks to everyone who has provied input on > > > > these patches already. > > > > > > > Just from review... > > > > > > If new zone , which was empty at boot, are added into the system. > > > build_all_zonelists() has to be called. (see online_pages() in memory_hotplug.c) > > > it looks x86_64's __add_pages() doesn't calles it. > > > > With RESERVE there are not empty zones. All zones (including add-areas) > > are setup during boot and hot add areas reserved in the bootmem > > allocator. > > > > Zones don't change size there is no adding to the zone just on-lining on > > pages at are already present in the zone. > > > Hmm, curious. > please explain. > == > int __add_pages(struct zone *z, unsigned long start_pfn, unsigned long nr_pages) > { > int err = -EIO; > unsigned long pfn; > unsigned long total = 0, mem = 0; > for (pfn = start_pfn; pfn < start_pfn + nr_pages; pfn++) { > if (pfn_valid(pfn)) { > online_page(pfn_to_page(pfn)); > err = 0; > mem++; > } > total++; > } > if (!err) { > z->spanned_pages += total; > z->present_pages += mem; -------------------------------(*)
It is an accounting issue. What I meant by re-sizing is there is no change to node_mem_map (with reserve CONFIG_FLAT_NODE_MEM_MAP is set). When the original size for the zone is setup it views that add areas as a "hole" in the e820 space.
See arch/x86_64/mm/init.c size_zones.
> == > It looks contents of zone is increased at (*). Do I see old code ? > > == > static inline int populated_zone(struct zone *zone) > { > return (!!zone->present_pages); > } > == > "empty zone" I said means a zone which is not populated.
I know of no x86_64 hardware the supports empty node hot-add memory. If it exists I would recommend using SPARSEMEM based hot-add. On HW I am aware of there is always some memory present in a node at boot.
Thanks, Keith
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