Commit a4602b62 authored Feb 21, 2018 by Khalid Aziz Committed by David S. Miller Mar 18, 2018

mm: Allow arch code to override copy_highpage()



Some architectures can support metadata for memory pages and when a
page is copied, its metadata must also be copied. Sparc processors
from M7 onwards support metadata for memory pages. This metadata
provides tag based protection for access to memory pages. To maintain
this protection, the tag data must be copied to the new page when a
page is migrated across NUMA nodes. This patch allows arch specific
code to override default copy_highpage() and copy metadata along
with page data upon migration.

Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Khalid Aziz <khalid@gonehiking.org>
Reviewed-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 2c2d57b5

include/linux/highmem.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -237,6 +237,8 @@ static inline void copy_user_highpage(struct page to, struct page from,

		#endif

		#ifndef __HAVE_ARCH_COPY_HIGHPAGE

		static inline void copy_highpage(struct page to, struct page from)
		{
		char vfrom, vto;
		@@ -248,4 +250,6 @@ static inline void copy_highpage(struct page to, struct page from)
		kunmap_atomic(vfrom);
		}

		#endif

		#endif /* _LINUX_HIGHMEM_H */

Admin message