mm: fix missing cache flush for all tail pages of compound page
authorMuchun Song <songmuchun@bytedance.com>
Mon, 28 Feb 2022 23:00:33 +0000 (10:00 +1100)
committerStephen Rothwell <sfr@canb.auug.org.au>
Mon, 28 Feb 2022 23:00:33 +0000 (10:00 +1100)
commitd8ad4be3a37f7069af4e181d76f760719599d984
tree893567dcb45b8350d73e6f8d52576ee32cc212f0
parent47a3e10abb78e3ee9cbc42ce8f259798378b2b06
mm: fix missing cache flush for all tail pages of compound page

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 <songmuchun@bytedance.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lars Persson <lars.persson@axis.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
mm/migrate.c