Date: Wed, 27 Apr 2005 14:10:00 -0400 From: John Baldwin <jhb@FreeBSD.org> To: freebsd-current@FreeBSD.org Cc: Sam Lawrance <boris@brooknet.com.au> Subject: Re: kern/78474 for 5.4? (kernel stack swapout problem again) Message-ID: <200504271410.02151.jhb@FreeBSD.org> In-Reply-To: <4269C309.30702@freebsd.org> References: <1114052573.1075.10.camel@dirk.no.domain> <20050422200102.G10333@carver.gumbysoft.com> <4269C309.30702@freebsd.org>
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On Friday 22 April 2005 11:37 pm, David Xu wrote: > Doug White wrote: > >On Thu, 21 Apr 2005, David Xu wrote: > >>Sam Lawrance wrote: > >>>Will this problem: > >>> > >>>Swapped out procs not brought in immediately after child exits > >>>http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/78474 > >>> > >>>be dealt with for the release of 5.4? > >>> > >>>Perhaps I'm the only FreeBSD user with swapped out processes ;-) > >>> > >>>-Sam > >> > >>I have noticed that current spinlock implementation no longer means that > >>CPU must be in critical region (critical_enter is called), even previous > >>hack TDP_WAKEPROC0 is no longer correct, :(, I think it is the time to > >>disable swapout. > > > >I'm sorry, I can't parse your double negative. On -CURRENT critical > >sections (entered with critical_enter()) no longer disable interrupts, but > >do inhibit preemption. But spinlocks still do critical_enter() (see > >spinlock_enter()). > > I will commit the patch provided in the PR, it should work. I am just > worrying > TDP_WAKEPROC0 will not work if spinlock does not entering critical region. Read what Doug wrote. spinlock_enter() still calls critical_enter(), so all spin locks still contain critical sections. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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