Re: [PATCH v4 2/3] mm/hugetlb: check for reserved hugepages during memory offline

From	Michal Hocko <mhocko@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH v4 2/3] mm/hugetlb: check for reserved hugepages during memory offline
Date	2016-09-30 08:40 +0200
Message-ID	<smZEd-6EC-3@gated-at.bofh.it> (permalink)
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On Thu 29-09-16 10:09:37, Mike Kravetz wrote:
> On 09/29/2016 05:30 AM, Michal Hocko wrote:
> > On Mon 26-09-16 19:28:10, Gerald Schaefer wrote:
[...]
> >> Fix this by adding a return value to dissolve_free_huge_pages() and
> >> checking h->free_huge_pages vs. h->resv_huge_pages. Note that this may
> >> lead to the situation where dissolve_free_huge_page() returns an error
> >> and all free hugepages that were dissolved before that error are lost,
> >> while the memory block still cannot be set offline.
> > 
> > Hmm, OK offline failure is certainly a better option than an application
> > failure.
> 
> I agree.
> 
> However, if the reason for the offline is that a dimm within the huge page
> is starting to fail, then one could make an argument that forced offline of
> the huge page would be more desirable.  We really don't know the reason for
> the offline.  So, I think the approach of this patch is best.

I though that memory which was already reported to be faulty would be
marked HWPoison and removed from the allocator. But it's been quite some
time since I've looked in that area...
-- 
Michal Hocko
SUSE Labs

Thread

[PATCH v4 0/3] mm/hugetlb: memory offline issues with hugepages Gerald Schaefer <gerald.schaefer@de.ibm.com> - 2016-09-26 19:30 +0200
  [PATCH v4 2/3] mm/hugetlb: check for reserved hugepages during memory offline Gerald Schaefer <gerald.schaefer@de.ibm.com> - 2016-09-26 19:30 +0200
    Re: [PATCH v4 2/3] mm/hugetlb: check for reserved hugepages during  memory offline Michal Hocko <mhocko@kernel.org> - 2016-09-29 14:40 +0200
      Re: [PATCH v4 2/3] mm/hugetlb: check for reserved hugepages during  memory offline Mike Kravetz <mike.kravetz@oracle.com> - 2016-09-29 19:20 +0200
        Re: [PATCH v4 2/3] mm/hugetlb: check for reserved hugepages during  memory offline Michal Hocko <mhocko@kernel.org> - 2016-09-30 08:40 +0200
  [PATCH v4 3/3] mm/hugetlb: improve locking in dissolve_free_huge_pages() Gerald Schaefer <gerald.schaefer@de.ibm.com> - 2016-09-26 19:30 +0200
    Re: [PATCH v4 3/3] mm/hugetlb: improve locking in  dissolve_free_huge_pages() Michal Hocko <mhocko@kernel.org> - 2016-09-29 14:40 +0200
  [PATCH v4 1/3] mm/hugetlb: fix memory offline with hugepage size > memory block size Gerald Schaefer <gerald.schaefer@de.ibm.com> - 2016-09-26 19:30 +0200
    Re: [PATCH v4 1/3] mm/hugetlb: fix memory offline with hugepage size  > memory block size Michal Hocko <mhocko@kernel.org> - 2016-09-29 14:20 +0200
  Re: [PATCH v4 0/3] mm/hugetlb: memory offline issues with hugepages Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> - 2016-09-29 08:20 +0200

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