Date: Wed, 16 Apr 2008 17:12:07 -0700 From: Julian Elischer <julian@elischer.org> To: "Murty, Ravi" <ravi.murty@intel.com> Cc: freebsd-hackers@freebsd.org Subject: Re: md_spinlock_count? Message-ID: <480695D7.5050600@elischer.org> In-Reply-To: <AEBCFC23C0E40949B10BA2C224FC61B006F81861@orsmsx416.amr.corp.intel.com> References: <AEBCFC23C0E40949B10BA2C224FC61B006F81861@orsmsx416.amr.corp.intel.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Murty, Ravi wrote: > Hello All, > > > > I was looking at the code that creates a new process (fork) with a > single thread coming out on the other side. I can't figure out a couple > of things. > > > > 1. Why is the md_spinlock_count for the new thread set to 1 and not > to 0. This happens in cpu_fork and cpu_set_upcall under the amd64 tree. > 2. If this was the "per-cpu" idle thread and the AP was booting up > (running init_secondary) why does it grab sched_lock and call > spinlock_exit. It would seem simpler to set the count of the idle thread > to 0 and not have to call spinlock_exit. The only answer I can come up > with is the fact that a non-zero spinlock_count prevents interrupts from > getting disabled/renabled to some unknown value? Which version/branch? (and a filename and linenumber would be good too) You might make it easy for us to answer you :-) > > > > Thanks > > Ravi Murty > > > > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org"
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?480695D7.5050600>