Re: [PATCH 06/14] block: lift setting the readahead size into the block layer

From: Johannes Thumshirn
Date: Wed Jul 22 2020 - 03:14:16 EST


On 22/07/2020 08:27, Christoph Hellwig wrote:
> + q->backing_dev_info->ra_pages =
> + max(queue_io_opt(q) * 2 / PAGE_SIZE, VM_READAHEAD_PAGES);

Dumb question, wouldn't a '>> PAGE_SHIFT' be better instead of a potentially
costly division?

Or aren't we caring at all as it's a) not in the fast-path and b) compilers
can optimize it to a shift?