From 308ff6a6e76813528667912a5349d182a32ffdce Mon Sep 17 00:00:00 2001 From: Muchun Song Date: Tue, 22 Mar 2022 14:41:56 -0700 Subject: mm: fix missing cache flush for all tail pages of compound page commit 2771739a7162782c0aa6424b2e3dd874e884a15d upstream. The D-cache maintenance inside move_to_new_page() only consider one page, there is still D-cache maintenance issue for tail pages of compound page (e.g. THP or HugeTLB). THP migration is only enabled on x86_64, ARM64 and powerpc, while powerpc and arm64 need to maintain the consistency between I-Cache and D-Cache, which depends on flush_dcache_page() to maintain the consistency between I-Cache and D-Cache. But there is no issues on arm64 and powerpc since they already considers the compound page cache flushing in their icache flush function. HugeTLB migration is enabled on arm, arm64, mips, parisc, powerpc, riscv, s390 and sh, while arm has handled the compound page cache flush in flush_dcache_page(), but most others do not. In theory, the issue exists on many architectures. Fix this by not using flush_dcache_folio() since it is not backportable. Link: https://lkml.kernel.org/r/20220210123058.79206-3-songmuchun@bytedance.com Fixes: 290408d4a250 ("hugetlb: hugepage migration core") Signed-off-by: Muchun Song Reviewed-by: Zi Yan Cc: Axel Rasmussen Cc: David Rientjes Cc: Fam Zheng Cc: Kirill A. Shutemov Cc: Lars Persson Cc: Mike Kravetz Cc: Peter Xu Cc: Xiongchun Duan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/migrate.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'mm') diff --git a/mm/migrate.c b/mm/migrate.c index 278e6f3fa62c..495bdac5cf92 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1010,9 +1010,12 @@ static int move_to_new_page(struct page *newpage, struct page *page, if (!PageMappingFlags(page)) page->mapping = NULL; - if (likely(!is_zone_device_page(newpage))) - flush_dcache_page(newpage); + if (likely(!is_zone_device_page(newpage))) { + int i, nr = compound_nr(newpage); + for (i = 0; i < nr; i++) + flush_dcache_page(newpage + i); + } } out: return rc; -- cgit v1.2.3