| Message ID | 20240701185932.704807-2-roman.gushchin@linux.dev (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [1/2] mm: memcg: drop obsolete cache line padding in struct mem_cgroup | expand |
On Mon, Jul 01, 2024 at 06:59:32PM GMT, Roman Gushchin wrote: > 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. > > Suggested-by: Shakeel Butt <shakeel.butt@linux.dev> > Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 8b5b3ddeba05..60418934827c 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. */
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. Suggested-by: Shakeel Butt <shakeel.butt@linux.dev> Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> --- include/linux/memcontrol.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)