Re: How to handle a hugepage with bad physical memory?

From: Christoph Lameter
Date: Thu Nov 17 2005 - 13:28:50 EST

On Thu, 17 Nov 2005, Robin Holt wrote:

> > > With the new hugepages concept, would it be possible to only mark
> > > the default pagesize portion of a hugepage as bad and then return the
> > > remainder of the hugepage for normal use? What would we basically need
> > > to do to accomplish this? Are there patches in the community which we
> > > should wait to see how they progress before we do any work on this front?
> >
> > On IA64 we have one PTE for a huge page in a different region, so we
> > cannot unmap a page sized section. Other architectures may have PTEs for
> > each page sized section of a huge page. For those it may make sense
> > (but then the management of the page is done via the first page_struct,
> > which likely results in some challenging VM issues).
> I think you misunderstood me. I was talking about killing the process.
> All the mappings get destroyed. I want to reclaim as much of that huge
> page as possible.

You are right. If you can reclaim the whole page (as you can when killing
a process) then you can isolate the bad page and free the rest. There
would have to be special code for that in the hugetlb layer.

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