On 12/12/18 8:32 AM, Christoph Hellwig wrote: > On Wed, Dec 12, 2018 at 08:22:37AM -0700, Jens Axboe wrote: >> That one is a little worse, since we only need a full page if we >> use all 256 segments. I don't want to make the fast case of >> 16 bytes single segment allocs get a full page, so we have to >> track if we used kmalloc() or mempool_alloc() for this particular >> range. >> >> I guess I could abuse ->end_io for that, set it if we end up >> punting to mempool. I'll do that. > > How about a full emergency page hanging off struct nvme_ctrl, > and then in the completion path we can do: > > if (req->special_vec.bv_page == ctrl->discard_emergency_page) > // clear some bit in ctrl->flags > else > kfree(page_address(req->special_vec.bv_page) + That's not a bad idea, then we don't have to track it. -- Jens Axboe
