John Birrell wrote: > On Wed, Nov 29, 2006 at 12:04:03PM -0500, John Baldwin wrote: >> On Monday 20 November 2006 16:38, Rene Ladan wrote: >>> Hi, >>> >>> I got the attached panic on CURRENT 2006-11-17. >>> >>> It was preceded by a lot of 'calcru' messages. >> The calcru messages you can ignore. >> >> This is the real problem: >> >> panic: blockable sleep lock (sleep mutex) tty >> _at_ /usr/src-current/sys/kern/kern_event.c:1670 >> >> This panic is due to the recent changes to printf to try to buffer the printf >> output. It now runs cnputc() under a critical section and syscons(4) tries >> to do a ttwakeup() which invokes KNOTE() and tries to lock a regular mutex >> while inside the critical section. I'm not sure how best to fix this. > > I would like to go back to using a printf buffer on the stack > (like I had in my original implementation). The downside of > doing that is that it places more stress on the stack and for > things like cam, that is an issue, so I am told. > > -- > John Birrell It's probably less of an issue now that it used to be, since I/O is decoupled through GEOM threads. In 4.x, you could have a stack that went from the syscall, through VFS, UFS, the block layer, CAM, and finally the device driver. When I was working on RAIDFrame, adding just a couple hundred bytes of stack usage would cause it to blow out. But as I said, it might not be as much of an issue now. ScottReceived on Wed Nov 29 2006 - 21:41:02 UTC
This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:39:03 UTC