The struct page_counter has explicit padding for better cache alignment.
The commit c6f53ed8f213a ("mm, memcg: cg2 memory{.swap,}.peak write
handlers") added a field to the struct page_counter and accidently
increased its size. Let's move the failcnt field which is v1-only field
to the same cacheline of usage to reduce the size of struct
page_counter.
Signed-off-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>
---
include/linux/page_counter.h | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/include/linux/page_counter.h b/include/linux/page_counter.h
index e4bd8fd427be..d649b6bbbc87 100644
--- a/include/linux/page_counter.h
+++ b/include/linux/page_counter.h
@@ -9,10 +9,12 @@
struct page_counter {
/*
- * Make sure 'usage' does not share cacheline with any other field. The
- * memcg->memory.usage is a hot member of struct mem_cgroup.
+ * Make sure 'usage' does not share cacheline with any other field in
+ * v2. The memcg->memory.usage is a hot member of struct mem_cgroup.
*/
atomic_long_t usage;
+ unsigned long failcnt; /* v1-only field */
+
CACHELINE_PADDING(_pad1_);
/* effective memory.min and memory.min usage tracking */
@@ -28,7 +30,6 @@ struct page_counter {
unsigned long watermark;
/* Latest cg2 reset watermark */
unsigned long local_watermark;
- unsigned long failcnt; /* v1-only field */
/* Keep all the read most fields in a separete cacheline. */
CACHELINE_PADDING(_pad2_);
--
2.43.5
