summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorNoah Goldstein <goldstein.w.n@gmail.com>2023-04-04 17:13:51 -0500
committerAndrew Morton <akpm@linux-foundation.org>2023-04-18 16:39:33 -0700
commitb0687c1119b4e8c88a651b6e876b7eae28d076e3 (patch)
tree82529e06903d712793f28d544a531f54f5711d6c
parent1be2edb25c72c3fe1bf955694c5521b035fcb276 (diff)
downloadlinux-b0687c1119b4e8c88a651b6e876b7eae28d076e3.tar.gz
linux-b0687c1119b4e8c88a651b6e876b7eae28d076e3.tar.bz2
linux-b0687c1119b4e8c88a651b6e876b7eae28d076e3.zip
lib/rbtree: use '+' instead of '|' for setting color.
This has a slight benefit for x86 and has no effect on other targets. The benefit to x86 is it change the codegen for setting a node to block from `mov %r0, %r1; or $RB_BLACK, %r1` to `lea RB_BLACK(%r0), %r1` which saves an instructions. In all other cases it just replace ALU with ALU (or -> and) which perform the same on all machines I am aware of. Total instructions in rbtree.o: Before - 802 After - 782 so it saves about 20 `mov` instructions. Link: https://lkml.kernel.org/r/20230404221350.3806566-1-goldstein.w.n@gmail.com Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com> Cc: Michel Lespinasse <michel@lespinasse.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--include/linux/rbtree_augmented.h4
-rw-r--r--lib/rbtree.c2
2 files changed, 3 insertions, 3 deletions
diff --git a/include/linux/rbtree_augmented.h b/include/linux/rbtree_augmented.h
index d1c53e9d8c75..7ee7ed5de722 100644
--- a/include/linux/rbtree_augmented.h
+++ b/include/linux/rbtree_augmented.h
@@ -156,13 +156,13 @@ RB_DECLARE_CALLBACKS(RBSTATIC, RBNAME, \
static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
{
- rb->__rb_parent_color = rb_color(rb) | (unsigned long)p;
+ rb->__rb_parent_color = rb_color(rb) + (unsigned long)p;
}
static inline void rb_set_parent_color(struct rb_node *rb,
struct rb_node *p, int color)
{
- rb->__rb_parent_color = (unsigned long)p | color;
+ rb->__rb_parent_color = (unsigned long)p + color;
}
static inline void
diff --git a/lib/rbtree.c b/lib/rbtree.c
index c4ac5c2421f2..5114eda6309c 100644
--- a/lib/rbtree.c
+++ b/lib/rbtree.c
@@ -58,7 +58,7 @@
static inline void rb_set_black(struct rb_node *rb)
{
- rb->__rb_parent_color |= RB_BLACK;
+ rb->__rb_parent_color += RB_BLACK;
}
static inline struct rb_node *rb_red_parent(struct rb_node *red)