Date: Fri, 21 Sep 2001 12:00:14 -0700 (PDT) From: John Baldwin <jhb@FreeBSD.org> To: Julian Elischer <julian@elischer.org> Cc: current@FreeBSD.org, Julian Elischer <julian@FreeBSD.org>, Jun Kuriyama <kuriyama@imgsrc.co.jp>, Dag-Erling Smorgrav <des@ofug.org>, Josef Karthauser <joe@tao.org.uk> Subject: Re: Problems with interrupts on -current. Message-ID: <XFMail.010921120014.jhb@FreeBSD.org> In-Reply-To: <Pine.BSF.4.21.0109211156140.37053-100000@InterJet.elischer.org>
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On 21-Sep-01 Julian Elischer wrote: > I must say I'm worried, but stumped.. > I cannot see this problem here, and I cannot think of a change in the > KSE support stuff that would have this effect. > > There was soem small change in the statistics gathering code that > is done at clock time, but nothing so low-level as to > effect the further generation of clock ticks. > > It does sound as thuogh statclock has been stopped though. Really bad things can happen if another interrupt comes in during statclock and causes a preemption. In the preemptive kernel I had to wrap fast interrupt handlers in a critical section. I'll see if I can't resurrect that. The problem is that during a fast interrupt handler, we don't acknowledge the interrupt until we return from the interrupt handler, so if we preempt it may be a while before we get back to the interrupted process so it can finish the interrupt handler and ack the interrupt in the PIC. -- John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.baldwin.cx/~john/pgpkey.asc "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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