mm/page_owner: ask users about default setting of PAGE_OWNER

Since this commit 48c96a3685795 ("mm/page_owner: keep track
of page owners") doesn't enable the page_owner by default
even though CONFIG_PAGE_OWNER is enabled.

Add configuration option CONFIG_PAGE_OWNER_ENABLE_DEFAULT to
allow user to enable it by default through the defconfig file.

CRs-Fixed: 1006743
Change-Id: I9b565a34e2068bf575974eaf3dc9f7820bdd7a96
Signed-off-by: Trilok Soni <tsoni@codeaurora.org>
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
diff --git a/mm/page_owner.c b/mm/page_owner.c
index 60634dc..d2db436 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -25,7 +25,8 @@
 	depot_stack_handle_t handle;
 };
 
-static bool page_owner_disabled = true;
+static bool page_owner_disabled =
+	!IS_ENABLED(CONFIG_PAGE_OWNER_ENABLE_DEFAULT);
 DEFINE_STATIC_KEY_FALSE(page_owner_inited);
 
 static depot_stack_handle_t dummy_handle;
@@ -41,6 +42,9 @@
 	if (strcmp(buf, "on") == 0)
 		page_owner_disabled = false;
 
+	if (strcmp(buf, "off") == 0)
+		page_owner_disabled = true;
+
 	return 0;
 }
 early_param("page_owner", early_page_owner_param);