static struct page_ext_operations *page_ext_ops[] always contains debug_guardpage_ops,
static struct page_ext_operations *page_ext_ops[] = {
&debug_guardpage_ops,
#ifdef CONFIG_PAGE_OWNER
&page_owner_ops,
#endif
...
}
but for it to work, CONFIG_DEBUG_PAGEALLOC must be enabled first.
If someone has CONFIG_PAGE_EXTENSION, but has none of its users,
eg: (CONFIG_PAGE_OWNER, CONFIG_DEBUG_PAGEALLOC, CONFIG_IDLE_PAGE_TRACKING), we can shrink page_ext_init()
to a simple retq.
$ size vmlinux (before patch)
text data bss dec hex filename
14356698 5681582 1687748 21726028 14b834c vmlinux
$ size vmlinux (after patch)
text data bss dec hex filename
14356008 5681538 1687748 21725294 14b806e vmlinux
On the other hand, it might does not even make sense, since if someone
enables CONFIG_PAGE_EXTENSION, I would expect him to enable also at least
one of its users, but I wanted to see what you guys think.
Signed-off-by: Oscar Salvador <osalvador@xxxxxxxxxxxxxxxxxx>
---
mm/page_ext.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/page_ext.c b/mm/page_ext.c
index 2c16216c29b6..5295ef331165 100644
--- a/mm/page_ext.c
+++ b/mm/page_ext.c
@@ -59,7 +59,9 @@
*/
static struct page_ext_operations *page_ext_ops[] = {
+#ifdef CONFIG_DEBUG_PAGEALLOC
&debug_guardpage_ops,
+#endif
#ifdef CONFIG_PAGE_OWNER
&page_owner_ops,
#endif
--
2.13.5
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