Date: Sat, 09 Feb 2002 10:50:45 -0500 (EST) From: John Baldwin <jhb@FreeBSD.org> To: Julian Elischer <julian@elischer.org> Cc: current@freebsd.org Subject: RE: cred stuff.. Message-ID: <XFMail.020209105045.jhb@FreeBSD.org> In-Reply-To: <Pine.BSF.4.21.0202090031480.5404-100000@InterJet.elischer.org>
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On 09-Feb-02 Julian Elischer wrote: > > > On Fri, 8 Feb 2002, Julian Elischer wrote: > >> John, (peter? others?) >> >> How is it that getting a ucred reference is guarded by PROC_LOCK(p) >> but freeing it is guarded by mtx_lock(&Giant); >> ? >> >> Call me naive, but shouldn't they be guarded by the same thing? > > In fact, if we had good atomic reference counting primatives, > couldn't we just forget the locks entirely for this? We had a long bikeshed about that a while back but people complained that refcount_t wasn't generic enough, although it is well-suited to this specific instance. We can always come back and optimize the ucred mutex later, but there are really more important things to be doing at this point. :) It works for now, Giant is a much bigger problem that the ucred mutex. >> Julian >> >> >> On Fri, 8 Feb 2002, Julian Elischer wrote: >> >> > I'm a little worried about invariants because the behaviour when >> > INVARIANTS is set wil be different to teh behaviour when it is off, which >> > is 'strange' to say the least. Normally the behaviour si the same but you >> > just check for invariant conditions. >> > >> > >> > On Fri, 8 Feb 2002, John Baldwin wrote: >> > >> > > >> > > On 08-Feb-02 Julian Elischer wrote: >> > > > >> > > > I'd like to commit the code to keep the ucred across userland, >> > > > with the code to clear it to NULL kept under DEBUG ifdefs. >> > > >> > > Use INVARIANTS for the ifdef macro name, but sure. >> > > >> > > -- >> > > >> > > John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ >> > > "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ >> > > >> > >> > >> > To Unsubscribe: send mail to majordomo@FreeBSD.org >> > with "unsubscribe freebsd-current" in the body of the message >> > >> >> >> To Unsubscribe: send mail to majordomo@FreeBSD.org >> with "unsubscribe freebsd-current" in the body of the message >> > -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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