-
Haiyue Wang authored
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 This is an temporary solution to mitigate the side effect of the race condition fix by calling follow_page() with FOLL_GET set for huge pages. After supporting follow huge page by FOLL_GET is done, this fix can be reverted safely. Link: https://lkml.kernel.org/r/20220823135841.934465-2-haiyue.wang@intel.com Link: https://lkml.kernel.org/r/20220812084921.409142-1-haiyue.wang@intel.com Fixes: 4cd61484 ("mm: migration: fix possible do_pages_stat_array racing with memory offline") Signed-off-by: Haiyue Wang <haiyue.wang@intel.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: David Hildenbrand <david@redhat.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
83156821