From: Roman Gushchin Date: Mon, 1 Jul 2024 18:59:32 +0000 (+0000) Subject: mm: memcg: add cache line padding to mem_cgroup_per_node X-Git-Tag: v6.11-rc1~85^2~83 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6df13230b612af81ce04f20bb37a02e58ef71925;p=thirdparty%2Fkernel%2Flinux.git mm: memcg: add cache line padding to mem_cgroup_per_node Memcg v1-specific fields serve a buffer function between read-mostly and update often parts of the mem_cgroup_per_node structure. If CONFIG_MEMCG_V1 is not set and these fields are not present, an explicit cacheline padding is needed. Link: https://lkml.kernel.org/r/20240701185932.704807-2-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin Suggested-by: Shakeel Butt Acked-by: Shakeel Butt Cc: Johannes Weiner Cc: Michal Hocko Cc: Muchun Song Signed-off-by: Andrew Morton --- diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 8b5b3ddeba052..60418934827c7 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -95,14 +95,16 @@ struct mem_cgroup_per_node { #ifdef CONFIG_MEMCG_V1 /* * Memcg-v1 only stuff in middle as buffer between read mostly fields - * and update often fields to avoid false sharing. Once v1 stuff is - * moved in a separate struct, an explicit padding is needed. + * and update often fields to avoid false sharing. If v1 stuff is + * not present, an explicit padding is needed. */ struct rb_node tree_node; /* RB tree node */ unsigned long usage_in_excess;/* Set to the value by which */ /* the soft limit is exceeded*/ bool on_tree; +#else + CACHELINE_PADDING(_pad1_); #endif /* Fields which get updated often at the end. */