The patch titled
Subject: mm: move PageDoubleMap bit
has been added to the -mm tree. Its filename is
mm-move-pagedoublemap-bit.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-move-pagedoublemap-bit.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-move-pagedoublemap-bit.patch
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: move PageDoubleMap bit
Patch series "Fix PageDoubleMap".
This is a purely theoretical problem for now as none of the filesystems
which use PG_private_2 (ie PG_fscache) are being converted at this time,
but it's confusing to leave it like this.
This patch (of 2):
PG_private_2 is defined as being PF_ANY (applicable to tail pages as well
as regular & head pages). That means that the first tail page of a
double-map page will appear to have Private2 set. Use the Workingset bit
instead which is defined as PF_HEAD so any attempt to access the
Workingset bit on a tail page will redirect to the head page's Workingset
bit.
Link: https://lkml.kernel.org/r/20200629151933.15671-1-willy@xxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20200629151933.15671-2-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/page-flags.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/include/linux/page-flags.h~mm-move-pagedoublemap-bit
+++ a/include/linux/page-flags.h
@@ -164,7 +164,7 @@ enum pageflags {
PG_slob_free = PG_private,
/* Compound pages. Stored in first tail page's flags */
- PG_double_map = PG_private_2,
+ PG_double_map = PG_workingset,
/* non-lru isolated movable page */
PG_isolated = PG_reclaim,
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-debug-do-not-dereference-i_ino-blindly.patch
mm-account-pmd-tables-like-pte-tables.patch
mm-move-pagedoublemap-bit.patch
mm-simplify-pagedoublemap-with-pf_second-policy.patch
harden-autofs-ioctl-table.patch
