ilog2() is relatively expensive (especially without bit-scan instructions).
Replace the comparisons 'ilog2(x) >= y' with '(x >> y) != 0'.
Signed-off-by: David Laight <david.laight@xxxxxxxxxx>
---
lib/generic-radix-tree.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/lib/generic-radix-tree.c b/lib/generic-radix-tree.c
index 5695fe547f9d..d5e97b51308d 100644
--- a/lib/generic-radix-tree.c
+++ b/lib/generic-radix-tree.c
@@ -57,7 +57,7 @@ void *__genradix_ptr(struct __genradix *radix, size_t offset)
struct genradix_node *n = genradix_root_to_node(r);
unsigned level = genradix_root_to_depth(r);
- if (ilog2(offset) >= genradix_depth_shift(level))
+ if (offset >> genradix_depth_shift(level))
return NULL;
while (1) {
@@ -115,7 +115,7 @@ void *__genradix_ptr_alloc(struct __genradix *radix, size_t offset,
n = genradix_root_to_node(r);
level = genradix_root_to_depth(r);
- if (n && ilog2(offset) < genradix_depth_shift(level))
+ if (n && !(offset >> genradix_depth_shift(level)))
break;
new_node = genradix_alloc_node(gfp_mask);
@@ -171,7 +171,7 @@ void *__genradix_iter_peek(struct genradix_iter *iter,
n = genradix_root_to_node(r);
level = genradix_root_to_depth(r);
- if (ilog2(iter->offset) >= genradix_depth_shift(level))
+ if (iter->offset >> genradix_depth_shift(level))
return NULL;
while (level) {
--
2.25.1
-
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