From: Yang Shi shy828301@gmail.com
mainline inclusion from mainline-v5.14-rc1 commit b0b515bfb3f4f3dc208862989e38ee5268a1003f category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IAFONL CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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The old behavior didn't split THP if migration is failed due to lack of memory on the target node. But the THP migration does split THP, so keep the old behavior for misplaced NUMA page migration.
Link: https://lkml.kernel.org/r/20210518200801.7413-6-shy828301@gmail.com Signed-off-by: Yang Shi shy828301@gmail.com Acked-by: Mel Gorman mgorman@suse.de Cc: Christian Borntraeger borntraeger@de.ibm.com Cc: Gerald Schaefer gerald.schaefer@linux.ibm.com Cc: Heiko Carstens hca@linux.ibm.com Cc: Huang Ying ying.huang@intel.com Cc: Hugh Dickins hughd@google.com Cc: Kirill A. Shutemov kirill.shutemov@linux.intel.com Cc: Michal Hocko mhocko@suse.com Cc: Vasily Gorbik gor@linux.ibm.com Cc: Zi Yan ziy@nvidia.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Nanyong Sun sunnanyong@huawei.com --- mm/migrate.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/mm/migrate.c b/mm/migrate.c index ce7b7989286b..33badf35219e 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1487,6 +1487,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, struct page *page2; int swapwrite = current->flags & PF_SWAPWRITE; int rc, nr_subpages; + bool nosplit = (reason == MR_NUMA_MISPLACED);
if (!swapwrite) current->flags |= PF_SWAPWRITE; @@ -1527,8 +1528,9 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, * pages are added to the tail of the list so * we encounter them after the rest of the list * is processed. + * THP NUMA faulting doesn't split THP to retry. */ - if (is_thp) { + if (is_thp && !nosplit) { lock_page(page); rc = split_huge_page_to_list(page, from); unlock_page(page);