On Wed, Jan 24, 2024 at 07:59:54PM +0800, Ming Lei wrote: > Requests are added to plug list in reverse order, and both virtio-blk > and nvme retrieves request from plug list in order, so finally requests > are submitted to hardware in reverse order via nvme_queue_rqs() or > virtio_queue_rqs, see: > > io_uring submit_bio vdb 6302096 4096 > io_uring submit_bio vdb 12235072 4096 > io_uring submit_bio vdb 7682280 4096 > io_uring submit_bio vdb 11912464 4096 > io_uring virtio_queue_rqs vdb 11912464 4096 > io_uring virtio_queue_rqs vdb 7682280 4096 > io_uring virtio_queue_rqs vdb 12235072 4096 > io_uring virtio_queue_rqs vdb 6302096 4096 > > > May this reorder be one problem for virtio-blk and nvme-pci? For nvme, it depends. Usually it's probably not a problem, though some pci ssd's have optimizations for sequential IO that might not work if these get reordered.
