alinux: mm: vmscan: make it sane reclaim if cgwb_v1 is enabled

AliOS Cloud Kernel has cgroup writeback support for v1, so the reclaim could be
treated as sane reclaim if cgwb_v1 is enabled.
Reviewed-by: NGavin Shan <shan.gavin@linux.alibaba.com>
Reviewed-by: NXunlei Pang <xlpang@linux.alibaba.com>
Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NCaspar Zhang <caspar@linux.alibaba.com>
Signed-off-by: NYang Shi <yang.shi@linux.alibaba.com>

mm/vmscan.c

@@ -260,7 +260,9 @@ static bool sane_reclaim(struct scan_control *sc)
 	if (!memcg)
 		return true;
 #ifdef CONFIG_CGROUP_WRITEBACK
-	if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
+	/* AliOS Cloud Kernel has cgroup writeback support for v1 */
+	if (cgroup_subsys_on_dfl(memory_cgrp_subsys) ||
+	    cgwb_v1)
 		return true;
 #endif
 	return false;