From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm/zbud: reuse unbuddied[0] as buddied in zbud_pool
Patch series "Cleanups for zbud", v2.
This series contains just cleanups to save some possible memory in
zbud_pool and avoid exporting any unneeded zbud API. More details can be
found in the respective changelogs
This patch (of 2):
Since commit 9d8c5b5284e4 ("mm: zbud: fix condition check on allocation
size"), zbud_pool.unbuddied[0] is always unused. We can reuse it as
buddied field to save some possible memory.
Link: https://lkml.kernel.org/r/20210608114515.206992-1-linmiaohe@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20210608114515.206992-2-linmiaohe@xxxxxxxxxx
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Seth Jennings <sjenning@xxxxxxxxxx>
Cc: Dan Streetman <ddstreet@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/zbud.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- a/mm/zbud.c~mm-zbud-reuse-unbuddied-as-buddied-in-zbud_pool
+++ a/mm/zbud.c
@@ -93,8 +93,14 @@
*/
struct zbud_pool {
spinlock_t lock;
- struct list_head unbuddied[NCHUNKS];
- struct list_head buddied;
+ union {
+ /*
+ * Reuse unbuddied[0] as buddied on the ground that
+ * unbuddied[0] is unused.
+ */
+ struct list_head buddied;
+ struct list_head unbuddied[NCHUNKS];
+ };
struct list_head lru;
u64 pages_nr;
const struct zbud_ops *ops;
_
