Messages in this thread | | | Subject | Re: Infinite looping observed in __offline_pages | From | "Aneesh Kumar K.V" <> | Date | Thu, 23 Aug 2018 08:31:34 +0530 |
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On 08/23/2018 12:28 AM, Mike Kravetz wrote: > On 08/22/2018 02:30 AM, Aneesh Kumar K.V wrote: >> commit 2e9d754ac211f2af3731f15df3cd8cd070b4cc54 >> Author: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> >> Date: Tue Aug 21 14:17:55 2018 +0530 >> >> mm/hugetlb: filter out hugetlb pages if HUGEPAGE migration is not supported. >> >> When scanning for movable pages, filter out Hugetlb pages if hugepage migration >> is not supported. Without this we hit infinte loop in __offline pages where we >> do >> pfn = scan_movable_pages(start_pfn, end_pfn); >> if (pfn) { /* We have movable pages */ >> ret = do_migrate_range(pfn, end_pfn); >> goto repeat; >> } >> >> We do support hugetlb migration ony if the hugetlb pages are at pmd level. Here > > I thought migration at pgd level was added for POWER? commit 94310cbcaa3c > (mm/madvise: enable (soft|hard) offline of HugeTLB pages at PGD level). > Only remember, because I did not fully understand the use case. :) >
yes. We hit the issue on older distro kernels.
>> we just check for Kernel config. The gigantic page size check is done in >> page_huge_active. >> >> Reported-by: Haren Myneni <haren@linux.vnet.ibm.com> >> CC: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> >> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> >> >> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >> index 4eb6e824a80c..f9bdea685cf4 100644 >> --- a/mm/memory_hotplug.c >> +++ b/mm/memory_hotplug.c >> @@ -1338,7 +1338,8 @@ static unsigned long scan_movable_pages(unsigned long start, unsigned long end) >> return pfn; >> if (__PageMovable(page)) >> return pfn; >> - if (PageHuge(page)) { >> + if (IS_ENABLED(CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION) && >> + PageHuge(page)) { > > How about using hugepage_migration_supported instead? It would automatically > catch those non-migratable huge page sizes. Something like: >
Will do that.
> if (PageHuge(page) && > hugepage_migration_supported(page_hstate(page))) { >
-aneesh
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