mm: fix missing reclaim of low-reliable page cache

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4SK3S
CVE: NA

--------------------------------

Low-reliable memory is located in ZONE_MOVABLE, so gfp
should contain GFP_HIGHMEM and GFP_MOVABLE when reclaim
memory.
Signed-off-by: NChen Wandun <chenwandun@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

mm/vmscan.c

@@ -4042,8 +4042,8 @@ unsigned long shrink_page_cache(gfp_t mask)
 {
 	unsigned long nr_pages;
 
-	/* We reclaim the highmem zone too, it is useful for 32bit arch */
-	nr_pages = __shrink_page_cache(mask | __GFP_HIGHMEM);
+	/* reclaim from movable zone */
+	nr_pages = __shrink_page_cache(mask | __GFP_HIGHMEM | __GFP_MOVABLE);
 
 	return nr_pages;
 }