Date: Tue, 15 Apr 2025 01:30:34 -0400 From: "Kevin P. Neal" <kpn@neutralgood.org> To: Jos Chrispijn <josc@cloudzeeland.nl> Cc: FreeBSD Mailing List <freebsd-questions@freebsd.org> Subject: Re: Device "psm" is Giant locked Message-ID: <Z_3u-poXfG0zZLYD@neutralgood.org> In-Reply-To: <e420b0a8-9c78-4a51-9c75-08d6a5c02365@cloudzeeland.nl>
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On Fri, Apr 11, 2025 at 12:40:00PM +0200, Jos Chrispijn wrote: > [Proxmox 8.4 with FreeBSD 13.5] > After updating I ran into this: > "Device "psm" is Giant locked and may be..." > Is this a left over from back in the days when each *nix system had > just one CPU? > Is it solved in BSD 14? > Thanks, Jos The "Giant" lock was the first step towards support for multiple CPUs, yes. Finer grained locking was then added, and more and more parts of the kernel were then over time removed from the giant lock because that finer grained locking made it safe. Not all parts of the kernel were updated for a variety of reasons. I'm running 13.5 and I see this in my dmesg.boot file: atkbd0: [GIANT-LOCKED] So the entire kernel is locked when using the atkbd device. That's actually fine since the drivers for the keyboard and the PS/2 mouse are infrequently running even on systems that use those drivers. You simply can't type fast enough to cause a performance issue with the PS/2 keyboard driver under the giant lock. Same with the mouse. Anyway, does your computer even have PS/2 ports on it? I'm under the impression those are rare these days. No PS/2 ports means no issues with the giant lock. I wouldn't worry about that message. >From looking at my dmesg.boot file I also see this: atkbdc0: non-PNP ISA device will be removed from GENERIC in FreeBSD 15. The psm man page says that the psm driver requires the atkbdc driver, which I think means FreeBSD 15 won't support PS/2 keyboard and mouse ports. It follows that messages about these particular giant lock messages will be likewise gone. You can ask on the freebsd-hackers list for an answer from someone who actually does kernel development if you are still worried. -- Kevin P. Neal http://www.pobox.com/~kpn/ "Not even the dumbest terrorist would choose an encryption program that allowed the U.S. government to hold the key." -- (Fortune magazine is smarter than the US government, Oct 29 2001, page 196.)help
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