diff --git a/tools/testing/selftests/cgroup/test_zswap.c b/tools/testing/selftests/cgroup/test_zswap.c
index 1ac779072775..d50acc1b83ac 100644
--- a/tools/testing/selftests/cgroup/test_zswap.c
+++ b/tools/testing/selftests/cgroup/test_zswap.c
@@ -346,7 +346,16 @@ static int attempt_writeback(const char *cgroup, void *arg)
 	 * it can't writeback to swap.
 	 */
 	ret = cg_write_numeric(cgroup, "memory.reclaim", memsize);
-	if (!wb_enabled)
+
+	/*
+	 * When writeback is enabled, memory.reclaim may still fail to reclaim
+	 * the requested amount of memory due to a slow swap device.
+	 * Ignore -EAGAIN here. The caller determines pass/fail based on the
+	 * zswap writeback counter.
+	 */
+	if (wb_enabled && ret == -EAGAIN)
+		ret = 0;
+	else if (!wb_enabled)
 		ret = (ret == -EAGAIN) ? 0 : -1;
 
 out: