The patch titled
Subject: mm/migrate.c: handle freed page at the first place
has been added to the -mm tree. Its filename is
mm-migrate-handle-freed-page-at-the-first-place.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-migrate-handle-freed-page-at-the-first-place.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-migrate-handle-freed-page-at-the-first-place.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
Subject: mm/migrate.c: handle freed page at the first place
When doing migration if the freed page is met, we just return without
migrating it since it is pointless to migrate a freed page. But, the
current code allocates target page unconditionally before handling freed
page, if the page is freed, the newly allocated will be just freed. It
doesn't make too much sense and is just a waste of time although migrating
freed page is rare.
So, handle freed page at the before that to avoid unnecessary page
allocation and free.
Link: http://lkml.kernel.org/r/1573755869-106954-1-git-send-email-yang.shi@xxxxxxxxxxxxxxxxx
Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/migrate.c | 14 +++++---------
1 file changed, 5 insertions(+), 9 deletions(-)
--- a/mm/migrate.c~mm-migrate-handle-freed-page-at-the-first-place
+++ a/mm/migrate.c
@@ -1168,15 +1168,11 @@ static ICE_noinline int unmap_and_move(n
enum migrate_reason reason)
{
int rc = MIGRATEPAGE_SUCCESS;
- struct page *newpage;
+ struct page *newpage = NULL;
if (!thp_migration_supported() && PageTransHuge(page))
return -ENOMEM;
- newpage = get_new_page(page, private);
- if (!newpage)
- return -ENOMEM;
-
if (page_count(page) == 1) {
/* page was freed from under us. So we are done. */
ClearPageActive(page);
@@ -1187,13 +1183,13 @@ static ICE_noinline int unmap_and_move(n
__ClearPageIsolated(page);
unlock_page(page);
}
- if (put_new_page)
- put_new_page(newpage, private);
- else
- put_page(newpage);
goto out;
}
+ newpage = get_new_page(page, private);
+ if (!newpage)
+ return -ENOMEM;
+
rc = __unmap_and_move(page, newpage, force, mode);
if (rc == MIGRATEPAGE_SUCCESS)
set_page_owner_migrate_reason(newpage, reason);
_
Patches currently in -mm which might be from yang.shi@xxxxxxxxxxxxxxxxx are
mm-mempolicy-fix-the-wrong-return-value-and-potential-pages-leak-of-mbind.patch
mm-rmap-use-vm_bug_on_page-in-__page_check_anon_rmap.patch
mm-vmscan-remove-unused-scan_control-parameter-from-pageout.patch
mm-migrate-handle-freed-page-at-the-first-place.patch
mm-shmem-use-proper-gfp-flags-for-shmem_writepage.patch
