mm/page_owner: don't define fields on struct page_ext by hard-coding

There is a memory waste problem if we define field on struct page_ext by
hard-coding.  Entry size of struct page_ext includes the size of those
fields even if it is disabled at runtime.  Now, extra memory request at
runtime is possible so page_owner don't need to define it's own fields
by hard-coding.

This patch removes hard-coded define and uses extra memory for storing
page_owner information in page_owner.  Most of code are just mechanical
changes.

Link: http://lkml.kernel.org/r/1471315879-32294-7-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 6 deletions

diff --git a/include/linux/page_ext.h b/include/linux/page_ext.h
index 179bdc4a470c..9298c393ddaa 100644
--- a/include/linux/page_ext.h
+++ b/include/linux/page_ext.h
@@ -44,12 +44,6 @@ enum page_ext_flags {
  */
 struct page_ext {
         unsigned long flags;
-#ifdef CONFIG_PAGE_OWNER
-        unsigned int order;
-        gfp_t gfp_mask;
-        int last_migrate_reason;
-        depot_stack_handle_t handle;
-#endif
 };
 
 extern void pgdat_page_ext_init(struct pglist_data *pgdat);