migrate_pages: try to split pages on queuing
We are not able to migrate THPs. It means it's not enough to split only
PMD on migration -- we need to split compound page under it too.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 5f7f9dac..973434e 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -489,14 +489,33 @@
struct page *page;
struct queue_pages *qp = walk->private;
unsigned long flags = qp->flags;
- int nid;
+ int nid, ret;
pte_t *pte;
spinlock_t *ptl;
- split_huge_pmd(vma, pmd, addr);
- if (pmd_trans_unstable(pmd))
- return 0;
+ if (pmd_trans_huge(*pmd)) {
+ ptl = pmd_lock(walk->mm, pmd);
+ if (pmd_trans_huge(*pmd)) {
+ page = pmd_page(*pmd);
+ if (is_huge_zero_page(page)) {
+ spin_unlock(ptl);
+ split_huge_pmd(vma, pmd, addr);
+ } else {
+ get_page(page);
+ spin_unlock(ptl);
+ lock_page(page);
+ ret = split_huge_page(page);
+ unlock_page(page);
+ put_page(page);
+ if (ret)
+ return 0;
+ }
+ } else {
+ spin_unlock(ptl);
+ }
+ }
+retry:
pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
for (; addr != end; pte++, addr += PAGE_SIZE) {
if (!pte_present(*pte))
@@ -513,6 +532,21 @@
nid = page_to_nid(page);
if (node_isset(nid, *qp->nmask) == !!(flags & MPOL_MF_INVERT))
continue;
+ if (PageTail(page) && PageAnon(page)) {
+ get_page(page);
+ pte_unmap_unlock(pte, ptl);
+ lock_page(page);
+ ret = split_huge_page(page);
+ unlock_page(page);
+ put_page(page);
+ /* Failed to split -- skip. */
+ if (ret) {
+ pte = pte_offset_map_lock(walk->mm, pmd,
+ addr, &ptl);
+ continue;
+ }
+ goto retry;
+ }
if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
migrate_page_add(page, qp->pagelist, flags);