From 94984bfed58ca129f7e259ce09973ed0b3f540a8 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 14 Nov 2025 14:06:46 +0000 Subject: rbtree: inline rb_last() This is a very small function, inlining it saves cpu cycles in TCP by reducing register pressure and removing call/ret overhead. It also reduces vmlinux text size by 122 bytes on a typical x86_64 build. Before: size vmlinux text data bss dec hex filename 34811781 22177365 5685248 62674394 3bc55da vmlinux After: size vmlinux text data bss dec hex filename 34811659 22177365 5685248 62674272 3bc5560 vmlinux [ojeda@kernel.org: fix rust build] Link: https://lkml.kernel.org/r/20251120085518.1463498-1-ojeda@kernel.org Link: https://lkml.kernel.org/r/20251114140646.3817319-3-edumazet@google.com Signed-off-by: Eric Dumazet Signed-off-by: Miguel Ojeda Reviewed-by: Kuan-Wei Chiu Cc: Jakub Kacinski Cc: Neal Cardwell Cc: Paolo Abeni Cc: Alice Ryhl Cc: Stehen Rothwell Signed-off-by: Andrew Morton --- include/linux/rbtree.h | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h index 484554900f7d..4091e978aef2 100644 --- a/include/linux/rbtree.h +++ b/include/linux/rbtree.h @@ -58,7 +58,21 @@ static inline struct rb_node *rb_first(const struct rb_root *root) n = n->rb_left; return n; } -extern struct rb_node *rb_last(const struct rb_root *); + +/* + * This function returns the last node (in sort order) of the tree. + */ +static inline struct rb_node *rb_last(const struct rb_root *root) +{ + struct rb_node *n; + + n = root->rb_node; + if (!n) + return NULL; + while (n->rb_right) + n = n->rb_right; + return n; +} /* Postorder iteration - always visit the parent after its children */ extern struct rb_node *rb_first_postorder(const struct rb_root *); -- cgit v1.2.3