mm: fix missing cache flush for all tail pages of compound page
authorMuchun Song <songmuchun@bytedance.com>
Tue, 22 Mar 2022 21:41:56 +0000 (14:41 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 15 May 2022 17:54:47 +0000 (19:54 +0200)
commitea9cad1c5d9523b9da5df2e8f91c9bee2dabfad8
treecb5fbb04c0ba97d6a48ede5313012165f95063a7
parent45c05171d6e35120a967a9b782ba6cba43e74902
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 <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: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm/migrate.c