On Mon, Nov 09, 2020 at 12:36:15PM -0500, Chuck Lever wrote: > > On Nov 9, 2020, at 12:32 PM, Trond Myklebust <trondmy@xxxxxxxxxxxxxxx> wrote: > > On Mon, 2020-11-09 at 12:12 -0500, Chuck Lever wrote: > >> I assume you mean the client side only. Those issues aren't a factor > >> on the server. Not setting SOCK_ZEROCOPY here should be enough to > >> prevent the use of zero-copy on the client. > >> > >> However, the client loses the benefits of sending a page at a time. > >> Is there a desire to remedy that somehow? > > > > What about splice reads on the server side? > > On the server, this path formerly used kernel_sendpages(), which I > assumed is similar to the sendmsg zero-copy mechanism. How does > kernel_sendpages() mitigate against page instability? We turn it off when gss integrity or privacy services is used, to prevent spurious checksum failures (grep for RQ_SPLICE_OK). But maybe that's not the only problematic case, I don't know. --b.
