On Mon, 19 May 2014 15:18:13 +0200 "Michael Kerrisk (man-pages)" <mtk.manpages@xxxxxxxxx> wrote: > Hi Jeff, > > I just happened to notice : > > commit 57b65325fe34ec4c917bc4e555144b4a94d9e1f7 > Author: Jeff Layton <jlayton@xxxxxxxxxx> > Date: Mon Feb 3 12:13:09 2014 -0500 > > locks: skip deadlock detection on FL_FILE_PVT locks > > And then this thread: > > http://thread.gmane.org/gmane.linux.file-systems/81318/focus=81327 > From: Jeff Layton <jlayton <at> redhat.com> > Subject: [PATCH v5 13/14] locks: skip deadlock detection on FL_FILE_PVT locks > Date: 2014-01-09 14:19:46 GMT > > I think it's pretty important to document that. All implementations > of traditional process-associated (.k.a. "POSIX") locks that I've ever > come across do detect deadlocks, so it's important to note that OFD locks > do not. > > I plan to add the following text to the fcntl(2) page: > > [[ > In the current implementation, > no deadlock detection is performed for open file description locks. > (This contrasts with process-associated record locks, > for which the kernel does perform deadlock detection.) > ]] > > Okay? > > cheers, > > Michael > > (note: I'm no longer with Red Hat, so jlayton@xxxxxxxxxx no longer works) Sounds fine to me. FWIW, the deadlock detection for process-associated record locks is pretty worthless except in certain narrow circumstances. At some point, we probably should have a discussion as to whether deadlock detection is really something we want to keep. The current implementation requires a global spinlock which has obvious consequences for scalability. Thanks, -- Jeff Layton <jlayton@xxxxxxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
