Messages in this thread | | | Date | Tue, 30 Sep 2008 12:41:22 -0700 | From | Gary Hade <> | Subject | Re: [PATCH] mm: show node to memory section relationship with symlinks in sysfs |
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On Tue, Sep 30, 2008 at 08:50:37AM -0700, Dave Hansen wrote: > On Tue, 2008-09-30 at 17:06 +0900, Yasunori Goto wrote: > > > +#define section_nr_to_nid(section_nr) pfn_to_nid(section_nr_to_pfn(section_nr)) > > > #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ > > > > If the first page of the section is not valid, then this section_nr_to_nid() > > doesn't return correct value. > > > > I tested this patch. In my box, the start_pfn of node 1 is 1200400, but > > section_nr_to_pfn(mem_blk->phys_index) returns 1200000. As a result, > > the section is linked to node 0. > > Crap, I was worried about that. > > Gary, this means that we have a N:1 relationship between NUMA nodes and > sections. This normally isn't a problem because sections don't really > care about nodes and they layer underneath them.
So, using Yasunori-san's example the memory section starting at pfn 1200000 actually resides on both node 0 and node 1.
> > We'll probably need multiple symlinks in each section directory.
or perhaps symlinks to the same section directory from >1 node directory.
Gary
-- Gary Hade System x Enablement IBM Linux Technology Center 503-578-4503 IBM T/L: 775-4503 garyhade@us.ibm.com http://www.ibm.com/linux/ltc
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