ilog2() is relatively expensive (especially without bit-scan instructions). Replace the comparisons 'ilog2(x) >= y' with '(x >> y) != 0'.
Signed-off-by: David Laight <[email protected]> --- 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 - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
