On Fri, Dec 14, 2012 at 10:42:47PM +0100, Pawel Jakub Dawidek wrote: > On Fri, Dec 14, 2012 at 11:52:15AM -0500, John Baldwin wrote: > > On Thursday, December 13, 2012 6:12:44 am Pawel Jakub Dawidek wrote: > > > On Wed, Dec 12, 2012 at 11:06:52PM +0200, Konstantin Belousov wrote: > > > > On Wed, Dec 12, 2012 at 03:45:04PM +0000, Pawel Jakub Dawidek wrote: > > > > > Author: pjd > > > > > Date: Wed Dec 12 15:45:03 2012 > > > > > New Revision: 244154 > > > > > URL: http://svnweb.freebsd.org/changeset/base/244154 > > > > > > > > > > Log: > > > > > Use kern.max_pid sysctl to obtain maximum PID number instead of > > > > > using local > > > > > define. > > > > It is pid_max, not max_pid. > > > > > > > > But the change is wrong. The kern.pid_max only limits newly allocated > > > > pids, > > > > it does not magically moves existing pids, which are out of range, to > > > > the > > > > limited region. See the corresponding commit log for the description. > > > > It was added to make it easier to run FreeBSD 1.x binaries on the modern > > > > kernels. > > > > > > I saw CTLFLAG_TUN on the sysctl and assumed it is read-only... > > > How about defining BSD_PID_MAX in sys/proc.h, which would be visible by > > > userland as well and setting PID_MAX to BSD_PID_MAX? > > > > > > This would also help bsnmpd. > > > > > > http://people.freebsd.org/~pjd/patches/PID_MAX.patch > > > > This doesn't help your actual use case though where you want to boot a > > kernel > > with a different PID_MAX. I would much rather our tools learn such > > constants > > from the kernel via sysctl than have them compiled in. So, I would add a > > new > > sysctl which exports the true PID_MAX constant (and is read-only and never > > changes) and use that in ps, etc. > > In that case I'd prefer to make existing kern.pid_max sysctl read-only > and make it loader tunable. I don't expect there are many users of this > sysctl... > No, I described you the purpose of the sysctl. Requiring reboot just for running the old binaries is not useful. Please do not break it.
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