On Fri, May 08, 2020 at 11:04:45AM -0700, Dan Williams wrote: > On Fri, May 8, 2020 at 9:16 AM Christoph Hellwig <hch@xxxxxx> wrote: > > > > Hi all, > > > > various bio based drivers use queue->queuedata despite already having > > set up disk->private_data, which can be used just as easily. This > > series cleans them up to only use a single private data pointer. > > ...but isn't the queue pretty much guaranteed to be cache hot and the > gendisk cache cold? I'm not immediately seeing what else needs the > gendisk in the I/O path. Is there another motivation I'm missing? ->private_data is right next to the ->queue pointer, pat0 and part_tbl which are all used in the I/O submission path (generic_make_request / generic_make_request_checks). This is mostly a prep cleanup patch to also remove the pointless queue argument from ->make_request - then ->queue is an extra dereference and extra churn.
