Messages in this thread | | | Date | Thu, 25 Aug 2022 19:53:12 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH v7 1/2] mm: migration: fix the FOLL_GET failure on following huge page |
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On Thu, 25 Aug 2022 14:39:17 +0200 Gerald Schaefer <gerald.schaefer@linux.ibm.com> wrote:
> On Wed, 24 Aug 2022 11:38:58 -0700 > Andrew Morton <akpm@linux-foundation.org> wrote: > > > On Tue, 23 Aug 2022 21:58:40 +0800 Haiyue Wang <haiyue.wang@intel.com> wrote: > > > > > Not all huge page APIs support FOLL_GET option, so move_pages() syscall > > > will fail to get the page node information for some huge pages. > > > > > > Like x86 on linux 5.19 with 1GB huge page API follow_huge_pud(), it will > > > return NULL page for FOLL_GET when calling move_pages() syscall with the > > > NULL 'nodes' parameter, the 'status' parameter has '-2' error in array. > > > > > > Note: follow_huge_pud() now supports FOLL_GET in linux 6.0. > > > Link: https://lore.kernel.org/all/20220714042420.1847125-3-naoya.horiguchi@linux.dev > > > > > > But these huge page APIs don't support FOLL_GET: > > > 1. follow_huge_pud() in arch/s390/mm/hugetlbpage.c > > > 2. follow_huge_addr() in arch/ia64/mm/hugetlbpage.c > > > It will cause WARN_ON_ONCE for FOLL_GET. > > > 3. follow_huge_pgd() in mm/hugetlb.c > > > > What happened to the proposal to fix these three sites so this patch is > > not needed? > > For s390, you can add my patch from > https://lore.kernel.org/linux-mm/20220818135717.609eef8a@thinkpad/ > to this series. >
Thanks, I added that.
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