On Wed, Jan 18, 2017 at 04:37:40AM +0000, Colin Percival wrote: > On 01/17/17 02:06, Konstantin Belousov wrote: > > On Tue, Jan 17, 2017 at 04:57:23AM +0000, Colin Percival wrote: > >> I think I've tracked an NFS problem down to sosend returning ERESTART; it > >> looks like it's easy to work around this, but I'm not sure *why* sosend is > >> returning ERESTART... or for that matter *how* since I can't find anywhere > >> in relevant code where that gets returned. > > ERESTART is most likely returned by msleep(9) or similar call down the > > path when unblocked signal is pending with the restart disposition. > > Thanks, looks like that was exactly it -- if the TCP send buffer was full > we would call sbwait, and if a signal arrived it would return ERESTART. > It looks like setting the SB_NOINTR flag will prevent this; I'm testing a > patch right now. > > (Google bait in case anyone else trips over this: FreeBSD 11.0 NFS client > dropping TCP connections under concurrent I/O load.)
Note that passing SB_NOINTR unconditionally or even only for mounts with nointr (default) option is wrong. You make the socket operation uninterruptible, process terminate-ability becomes depended on the external factor, the behaviour of the remote system. _______________________________________________ freebsd-net@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
