From d1902fc41a7d2ea3b97ff203f02e93d16b3baa18 Mon Sep 17 00:00:00 2001 From: Shakeel Butt Date: Thu, 27 Feb 2025 23:58:08 -0800 Subject: [PATCH] page_counter: reduce struct page_counter size 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. Link: https://lkml.kernel.org/r/20250228075808.207484-4-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt Cc: Johannes Weiner Cc: Michal Hocko Cc: Muchun Song Cc: Roman Gushchin (Cruise) Signed-off-by: Andrew Morton --- 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_); -- 2.49.0