Hello, On 2/7/20 12:47 AM, Linus Torvalds wrote: > Instead, it could just calculate the nbuckets first, and then do the > "log2()" on that: > > /* Use at least 2 buckets, select_bucket() is undefined > behavior with 1 bucket */ > nbuckets = max_t(u32, 2, roundup_pow_of_two(num_possible_cpus())); > smap->bucket_log = ilog2(buckets); Isn't it kind of ineffective to first round to a power of two and then take the ilog2 of it? At a first glance I'd say that ilog2(roundup_pow_of_two(x)) == ilog(x - 1) + 1 for x > 1. (Maybe even for x == 1? Didn't care to check, I think it doesn't matter for the case at hand.) This RHS might be easier to optimize for the compiler?! Best regards Uwe
Attachment:
signature.asc
Description: OpenPGP digital signature
