Messages in this thread | | | From | Ilya Dryomov <> | Date | Mon, 26 Jun 2023 18:07:18 +0200 | Subject | Re: [PATCH net-next v5 04/16] ceph: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage() |
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On Mon, Jun 26, 2023 at 5:30 PM David Howells <dhowells@redhat.com> wrote: > > Ilya Dryomov <idryomov@gmail.com> wrote: > > > write_partial_message_data() is net/ceph/messenger_v1.c specific, so it > > doesn't apply here. I would suggest squashing the two net/ceph patches > > into one since even the titles are the same. > > I would, but they're now applied to net-next, so we need to patch that.
I don't see a problem with that given that the patches themselves have major issues (i.e. it's not just a commit message/title nit).
> > > > * Write as much as possible. The socket is expected to be corked, > > > - * so we don't bother with MSG_MORE/MSG_SENDPAGE_NOTLAST here. > > > + * so we don't bother with MSG_MORE here. > > > * > > > * Return: > > > - * 1 - done, nothing (else) to write > > > + * >0 - done, nothing (else) to write > > > > It would be nice to avoid making tweaks like this to the outer > > interface as part of switching to a new internal API. > > Ok. I'll change that and wrap the sendmsg in a loop. Though, as I asked in > an earlier reply, why is MSG_DONTWAIT used here?
See my reply there.
> > > > + if (WARN_ON(!iov_iter_is_bvec(&con->v2.out_iter))) > > > + return -EINVAL; > > > > Previously, this WARN_ON + error applied only to the "try sendpage" > > path. There is a ton of kvec usage in net/ceph/messenger_v2.c, so I'm > > pretty sure that placing it here breaks everything. > > This should have been removed as MSG_SPLICE_PAGES now accepts KVEC and XARRAY > iterators also. > > Btw, is it feasible to use con->v2.out_iter_sendpage to apply MSG_SPLICE_PAGES > to the iterator to be transmitted as a whole? It seems to be set depending on > iterator type.
I'm not sure I understand what you mean by "transmitted as a whole". con->v2.out_iter_sendpage is set only when zerocopy is desired. If the underlying data is not guaranteed to remain stable, zerocopy behavior is not safe.
Thanks,
Ilya
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