After commit [1] zs_page_migrate can handle the ZS_EMPTY zspage.
But I got some false in zs_page_isolate:
if (get_zspage_inuse(zspage) == 0) {
spin_unlock(&class->lock);
return false;
}
The page of this zspage was migrated in before.
The reason is commit [1] just handle the "page" but not "newpage"
then it keep the "newpage" with a empty zspage inside system.
Root cause is zs_page_isolate remove it from ZS_EMPTY list but not
call zs_page_putback "schedule_work(&pool->free_work);". Because
zs_page_migrate done the job without "schedule_work(&pool->free_work);"
Make this patch let zs_page_migrate wake up free_work if need.
[1] zsmalloc-zs_page_migrate-skip-unnecessary-loops-but-not-return-ebusy-if-zspage-is-not-inuse-fix.patch
Signed-off-by: Hui Zhu <zhuhui@xxxxxxxxxx>
---
mm/zsmalloc.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 62457eb..fb99953 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -2035,8 +2035,15 @@ int zs_page_migrate(struct address_space *mapping, struct page *newpage,
* Page migration is done so let's putback isolated zspage to
* the list if @page is final isolated subpage in the zspage.
*/
- if (!is_zspage_isolated(zspage))
- putback_zspage(class, zspage);
+ if (!is_zspage_isolated(zspage)) {
+ /*
+ * Since we allow empty zspage migration, putback of zspage
+ * should free empty zspage. Otherwise, it could make a leak
+ * until upcoming free_work is done, which isn't guaranteed.
+ */
+ if (putback_zspage(class, zspage) == ZS_EMPTY)
+ schedule_work(&pool->free_work);
+ }
reset_page(page);
put_page(page);
--
1.9.1
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