The patch titled
Subject: mm, hugetlb, soft_offline: save compound page order before page migration
has been removed from the -mm tree. Its filename was
mm-hugetlb-soft_offline-save-compound-page-order-before-page-migration.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Alexandru Moise <00moses.alexander00@xxxxxxxxx>
Subject: mm, hugetlb, soft_offline: save compound page order before page migration
This fixes a bug in madvise() where if you'd try to soft offline a
hugepage via madvise(), while walking the address range you'd end up,
using the wrong page offset due to attempting to get the compound order of
a former but presently not compound page, due to dissolving the huge page
(since c3114a8).
As a result I ended up with all my free pages except one being
offlined.
Link: http://lkml.kernel.org/r/20170912204306.GA12053@xxxxxxxxx
Fixes: c3114a84f7f9 ("mm: hugetlb: soft-offline: dissolve source hugepage after successful migration")
Signed-off-by: Alexandru Moise <00moses.alexander00@xxxxxxxxx>
Cc: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Hillf Danton <hdanton@xxxxxxxx>
Cc: Shaohua Li <shli@xxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/madvise.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff -puN mm/madvise.c~mm-hugetlb-soft_offline-save-compound-page-order-before-page-migration mm/madvise.c
--- a/mm/madvise.c~mm-hugetlb-soft_offline-save-compound-page-order-before-page-migration
+++ a/mm/madvise.c
@@ -625,18 +625,26 @@ static int madvise_inject_error(int beha
{
struct page *page;
struct zone *zone;
+ unsigned int order;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- for (; start < end; start += PAGE_SIZE <<
- compound_order(compound_head(page))) {
+
+ for (; start < end; start += PAGE_SIZE << order) {
int ret;
ret = get_user_pages_fast(start, 1, 0, &page);
if (ret != 1)
return ret;
+ /*
+ * When soft offlining hugepages, after migrating the page
+ * we dissolve it, therefore in the second loop "page" will
+ * no longer be a compound page, and order will be 0.
+ */
+ order = compound_order(compound_head(page));
+
if (PageHWPoison(page)) {
put_page(page);
continue;
_
Patches currently in -mm which might be from 00moses.alexander00@xxxxxxxxx are
mm-madvise-enable-soft-offline-of-hugetlb-pages-at-pud-level.patch
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