On Thu, 2022-06-09 at 15:34 -0400, Jeff Layton wrote: > This patchset was inspired by some earlier work that David Howells did > to add a similar type. > > Currently, we take an iov_iter from the netfs layer, turn that into an > array of pages, and then pass that to the messenger which eventually > turns that back into an iov_iter before handing it back to the socket. > > This patchset adds a new ceph_msg_data_type that uses an iov_iter > directly instead of requiring an array of pages or bvecs. This allows > us to avoid an extra allocation in the buffered read path, and should > make it easier to plumb in write helpers later. > > For now, this is still just a slow, stupid implementation that hands > the socket layer a page at a time like the existing messenger does. It > doesn't yet attempt to pass through the iov_iter directly. > > I have some patches that pass the cursor's iov_iter directly to the > socket in the receive path, but it requires some infrastructure that's > not in mainline yet (iov_iter_scan(), for instance). It should be > possible to something similar in the send path as well. > > Jeff Layton (2): > libceph: add new iov_iter-based ceph_msg_data_type and > ceph_osd_data_type > ceph: use osd_req_op_extent_osd_iter for netfs reads > > fs/ceph/addr.c | 18 +--------- > include/linux/ceph/messenger.h | 5 +++ > include/linux/ceph/osd_client.h | 4 +++ > net/ceph/messenger.c | 64 +++++++++++++++++++++++++++++++++ > net/ceph/osd_client.c | 27 ++++++++++++++ > 5 files changed, 101 insertions(+), 17 deletions(-) > I've had these sitting in testing branch for a bit and they seem to work just fine. Unfortunately though, Al mentioned on IRC that he was planning to change iov_iter_get_pages to auto-advance the iterator, which will require a redesign of the first patch. I'm going to drop this series from the testing branch for now. Thanks, -- Jeff Layton <jlayton@xxxxxxxxxx>
