> On 4 Mar 2019, at 14.04, Igor Konopko <igor.j.konopko@xxxxxxxxx> wrote: > > > >> On 04.03.2019 13:22, Hans Holmberg wrote: >>> On Mon, Mar 4, 2019 at 12:44 PM Javier González <javier@xxxxxxxxxxx> wrote: >>> >>> >>> >>>> On 4 Mar 2019, at 12.30, Hans Holmberg <hans@xxxxxxxxxxxxx> wrote: >>>> >>>> On Mon, Mar 4, 2019 at 10:05 AM Javier González <javier@xxxxxxxxxxx> wrote: >>>>>> On 27 Feb 2019, at 18.14, Igor Konopko <igor.j.konopko@xxxxxxxxx> wrote: >>>>>> >>>>>> Current lightnvm and pblk implementation does not care >>>>>> about NVMe max data transfer size, which can be smaller >>>>>> than 64*K=256K. This patch fixes issues related to that. >>>> >>>> Could you describe *what* issues you are fixing? > > I'm fixing the issue related to controllers which NVMe max data transfer size is lower that 256K (for example 128K, which happens for existing NVMe controllers and NVMe spec compliant). Such a controllers are not able to handle command which contains 64 PPAs, since the the size of DMAed buffer will be above the capabilities of such a controller. > OK. Then let’s try to get support for this ASAP. If the rest agree on a feature bit then it should be straightforward. If not, let’s at least add a warning if MDTS < 64 so that people are able to identify where the missing performance went when updating the kernel if they are not using MDTS on their OCSSD implementations. Javier
