Re: [RFC][patch 2/5] mm: Node-setup agnostic free_bootmem()

["Yinghai Lu" <yhlu.kernel@gmail.com>]

On Wed, Apr 16, 2008 at 12:17 PM, Johannes Weiner <hannes@saeurebad.de> wrote:
> Hi,
>
>
>
>  Ingo Molnar <mingo@elte.hu> writes:
>
>  > * Yinghai Lu <yhlu.kernel@gmail.com> wrote:
>  >
>  >> >  Yes, it should work well with cross nodes case.
>  >> >
>  >> >  but please add boundary check on free_bootmem_node too.
>  >>
>  >> also please note: it will have problem span nodes box.
>  >>
>  >> for example: node 0: 0-2g, 4-6g, node1: 2-4g, 6-8g. and if ramdisk sit
>  >> creoss 2G boundary. you will only free the range before 2g.
>  >
>  > yes. Such systems _will_ become more common - so the "this is rare"
>  > arguments are incorrect. bootmem has to be robust enough to deal with
>  > it.
>
>  Ingo, I never doubted any of this, I was just asking more than once if
>  and when this might happen.  And I don't want the allocator become
>  fragile, just not completely ignorant about bogus input.
>
>  But the situation is still not clear for me.  Ingo, how are these
>  node spanning pfn ranges represented in the kernel?  How many node
>  descriptors will you have in the case Yinghai described and how will
>  they look like?

according to patch from Suresh in x86.git, one node still only have one bdata.

YH

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