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| author | Noah Goldstein <goldstein.w.n@gmail.com> | 2023-04-04 17:13:51 -0500 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-04-18 16:39:33 -0700 |
| commit | b0687c1119b4e8c88a651b6e876b7eae28d076e3 (patch) | |
| tree | 82529e06903d712793f28d544a531f54f5711d6c | |
| parent | 1be2edb25c72c3fe1bf955694c5521b035fcb276 (diff) | |
| download | linux-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.h | 4 | ||||
| -rw-r--r-- | lib/rbtree.c | 2 |
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) |