On Mon, Nov 24, 2014 at 09:38:20AM +0100, Geert Uytterhoeven wrote: > On Mon, Nov 24, 2014 at 12:36 AM, Josh Triplett <josh@xxxxxxxxxxxxxxxx> wrote: > > On Sun, Nov 23, 2014 at 09:30:40PM +0100, Pieter Smith wrote: > >> On Sun, Nov 23, 2014 at 11:43:26AM -0800, Josh Triplett wrote: > >> > On Sun, Nov 23, 2014 at 01:46:23PM -0500, David Miller wrote: > >> > > Truly removing sendfile/sendpage means that you can't even compile NFS > >> > > into the tree. > >> > > >> > If you mean the in-kernel nfsd (CONFIG_NFSD), that already has a large > >> > stack of "select" and "depends on", both directly and indirectly; adding > >> > a "select SPLICE_SYSCALL" to it seems fine. (That select does need > >> > adding, though. Pieter, you need to test-compile more than just > >> > tinyconfig and defconfig. Try an allyesconfig with *just* splice turned > >> > off, and make sure that compiles.) > >> > >> Did exacly that. Took forever on my hardware, but no problems. > > > > Ah, I see. Looking more closely at nfsd, it looks like it already has a > > code path for filesystems that don't do splice. I think, rather than > > making nfsd select SPLICE_SYSCALL, that it would suffice to change the > > "rqstp->rq_splice_ok = true;" in svc_process_common (net/sunrpc/svc.c) > > to: > > > > rqstp->rq_splice_ok = IS_ENABLED(CONFIG_SPLICE_SYSCALL); > > > > Then nfsd should simply *always* fall back to its non-splice support. > > Hence I suggest adding to the nfsd help text: > > While nfsd works without SPLICE_SYSCALL, you may want to enable > SPLICE_SYSCALL for <...> (performance?) reasons. It already seems sufficiently unlikely to enable NFSD while disabling SPLICE_SYSCALL (in the latter case, turning on EXPERT to do so). It doesn't seem worth adding such a note to NFSD. At most, I'd say that NFSD might want a note somewhere in its documentation saying that it takes advantage of filesystems with splice support if serving files from one, and if running on a kernel that has splice. > (Hmm, does Kconfig need a "suggests", cfr. Debian package dependencies?) Perhaps, though that seems much lower priority than, for instance, transitive "select". - Josh Triplett -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
