On 2/22/23 9:25 AM, Pankaj Raghav wrote: > > On 2023-02-22 20:57, Bart Van Assche wrote: >> On 2/22/23 06:34, Pankaj Raghav wrote: >>> No functional change. Division will be costly, especially in the hot >>> path (page_is_mergeable() and bio_copy_user_iov()) >> >> Although the change looks fine to me, is there any compiler for which this >> patch makes a difference? I would expect that a compiler performs this >> optimization even without this patch. >> > > I didn't notice any for x86_64. But I was thinking this also as a way to > maintain consistency across block code where we do a shift with PAGE_SHIFT > instead of dividing with PAGE_SIZE. It won't make a difference on any architecture, it'd be a pretty awful compiler that didn't turn a division by a constant power-of-2 into a shift. -- Jens Axboe
