> On Mon, Feb 11, 2019 at 01:42:57PM -0800, Ira Weiny wrote: > > On Mon, Feb 11, 2019 at 01:47:10PM -0700, Jason Gunthorpe wrote: > > > On Mon, Feb 11, 2019 at 12:34:17PM -0800, Davidlohr Bueso wrote: > > > > On Mon, 11 Feb 2019, ira.weiny@xxxxxxxxx wrote: > > > > > Ira Weiny (3): > > > > > mm/gup: Change "write" parameter to flags > > > > > mm/gup: Introduce get_user_pages_fast_longterm() > > > > > IB/HFI1: Use new get_user_pages_fast_longterm() > > > > > > > > Out of curiosity, are you planning on having all rdma drivers use > > > > get_user_pages_fast_longterm()? Ie: > > > > > > > > hw/mthca/mthca_memfree.c: ret = get_user_pages_fast(uaddr & > PAGE_MASK, 1, FOLL_WRITE, pages); > > > > > > This one is certainly a mistake - this should be done with a umem. > > > > It looks like this is mapping a page allocated by user space for a > > doorbell?!?! > > Many drivers do this, the 'doorbell' is a PCI -> CPU thing of some sort My surprise is why does _userspace_ allocate this memory? > > > This does not seem to be allocating memory regions. Jason, do you > > want a patch to just convert these calls and consider it legacy code? > > It needs to use umem like all the other drivers on this path. > Otherwise it doesn't get the page pinning logic right Not sure what you mean regarding the pinning logic? > > There is also something else rotten with these longterm callsites, they seem > to have very different ideas how to handle RLIMIT_MEMLOCK. > > ie vfio doesn't even touch pinned_vm.. and rdma is applying > RLIMIT_MEMLOCK to mm->pinned_vm, while vfio is using locked_vm.. No > idea which is right, but they should be the same, and this pattern should > probably be in core code someplace. Neither do I. But AFAIK pinned_vm is a subset of locked_vm. So should we be accounting both of the counters? Ira
