From c2d2dad24503d7e2eb7cba354fcc73f95fa78d7a Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 14 Nov 2025 14:06:45 +0000 Subject: rbtree: inline rb_first() Patch series "rbree: inline rb_first() and rb_last()". Inline these two small helpers, heavily used in TCP and FQ packet scheduler, and in many other places. This reduces kernel text size, and brings an 1.5 % improvement on network TCP stress test. This patch (of 2): This is a very small function, inlining it saves cpu cycles by reducing register pressure and removing call/ret overhead. It also reduces vmlinux text size by 744 bytes on a typical x86_64 build. Before: size vmlinux text data bss dec hex filename 34812525 22177365 5685248 62675138 3bc58c2 vmlinux After: size vmlinux text data bss dec hex filename 34811781 22177365 5685248 62674394 3bc55da 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/20251114140646.3817319-1-edumazet@google.com Link: https://lkml.kernel.org/r/20251114140646.3817319-2-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 8d2ba3749866..484554900f7d 100644 --- a/include/linux/rbtree.h +++ b/include/linux/rbtree.h @@ -43,7 +43,21 @@ extern void rb_erase(struct rb_node *, struct rb_root *); /* Find logical next and previous nodes in a tree */ extern struct rb_node *rb_next(const struct rb_node *); extern struct rb_node *rb_prev(const struct rb_node *); -extern struct rb_node *rb_first(const struct rb_root *); + +/* + * This function returns the first node (in sort order) of the tree. + */ +static inline struct rb_node *rb_first(const struct rb_root *root) +{ + struct rb_node *n; + + n = root->rb_node; + if (!n) + return NULL; + while (n->rb_left) + n = n->rb_left; + return n; +} extern struct rb_node *rb_last(const struct rb_root *); /* Postorder iteration - always visit the parent after its children */ -- cgit