On Wednesday, June 12, 2013 2:36:52 pm Alfred Perlstein wrote: > On 6/12/13 11:01 AM, Luigi Rizzo wrote: > > hi, > > is it possible to run copyin() or copyout() in one of these cases: > > 1. while holding a spinlock > > 2. while holding a regular mutex/lock > > 3. while holding a read lock (on an RWLOCK or RMLOCK) > > 4. while holding a write lock (on an RWLOCK or RMLOCK) > > > > I suspect #1 is forbidden, but am a bit unclear for the > > other cases. > No on all of the above unless the memory is wired.
If the memory is wired you can hold anything you want since it's basically a memcpy at that point. Various sysctl handlers that need to hold locks while writing things out use sysctl_wire_old_buffer() for exactly this reason. -- John Baldwin _______________________________________________ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
