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Diffstat (limited to 'mm/migrate.c')
-rw-r--r--mm/migrate.c34
1 files changed, 24 insertions, 10 deletions
diff --git a/mm/migrate.c b/mm/migrate.c
index c606752f6d2a..51b55f2d2db5 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1139,6 +1139,9 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page,
int rc = MIGRATEPAGE_SUCCESS;
struct page *newpage;
+ if (!thp_migration_supported() && PageTransHuge(page))
+ return -ENOMEM;
+
newpage = get_new_page(page, private);
if (!newpage)
return -ENOMEM;
@@ -1160,14 +1163,6 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page,
goto out;
}
- if (unlikely(PageTransHuge(page) && !PageTransHuge(newpage))) {
- lock_page(page);
- rc = split_huge_page(page);
- unlock_page(page);
- if (rc)
- goto out;
- }
-
rc = __unmap_and_move(page, newpage, force, mode);
if (rc == MIGRATEPAGE_SUCCESS)
set_page_owner_migrate_reason(newpage, reason);
@@ -1381,6 +1376,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
retry = 0;
list_for_each_entry_safe(page, page2, from, lru) {
+retry:
cond_resched();
if (PageHuge(page))
@@ -1394,6 +1390,26 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
switch(rc) {
case -ENOMEM:
+ /*
+ * THP migration might be unsupported or the
+ * allocation could've failed so we should
+ * retry on the same page with the THP split
+ * to base pages.
+ *
+ * Head page is retried immediately and tail
+ * pages are added to the tail of the list so
+ * we encounter them after the rest of the list
+ * is processed.
+ */
+ if (PageTransHuge(page)) {
+ lock_page(page);
+ rc = split_huge_page_to_list(page, from);
+ unlock_page(page);
+ if (!rc) {
+ list_safe_reset_next(page, page2, lru);
+ goto retry;
+ }
+ }
nr_failed++;
goto out;
case -EAGAIN:
@@ -1480,8 +1496,6 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr,
/* FOLL_DUMP to ignore special (like zero) pages */
follflags = FOLL_GET | FOLL_DUMP;
- if (!thp_migration_supported())
- follflags |= FOLL_SPLIT;
page = follow_page(vma, addr, follflags);
err = PTR_ERR(page);