Date: Thu, 22 Nov 2007 17:47:41 +0200 From: Dan Epure <gepu@iogyte.ro> To: Robert Watson <rwatson@FreeBSD.org> Cc: freebsd-current@freebsd.org, freebsd-stable@freebsd.org, csjp@FreeBSD.org, jhb@FreeBSD.org Subject: Re: pseudo terminals in 7.0 - pts implementation Message-ID: <20071122154741.GA73724@iogyte.ro> In-Reply-To: <20071122085228.M60495@fledge.watson.org> References: <20071118012616.GF19354@iogyte.ro> <20071118144243.B97497@fledge.watson.org> <20071121215807.F60495@fledge.watson.org> <20071122065956.GH19354@iogyte.ro> <20071122085228.M60495@fledge.watson.org>
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Hi, For the moment this feature is only available in HEAD. I think the limit is "only" 512 master/slave pairs. Should be enough for this year. Is it going to be merged in 6.3 ? Thanks again. On Thu, Nov 22, 2007 at 08:53:36AM +0000, Robert Watson wrote: > > On Thu, 22 Nov 2007, Dan Epure wrote: > >> Thank you for your answer. In this case the first problem (gnu screen) >> does not deserve any attention because it is related to the ptmx clonig. >> My goal is to find a way to increase the number os pseudo terminal. the >> traditional 256 pty is not sufficient for my needs. Is there any way to do >> this on freebsd other than using ptmx cloning ? > > John Baldwin has just merged support for up to 1024 ptys using the > traditional pty driver, I believe, to HEAD, and plans (or perhaps has > already) merged it to 7.0. I see no reason not to further merge it to 6.x. > I've stuck him on the CC list also. > > Robert N M Watson > Computer Laboratory > University of Cambridge > >> >> >> On Wed, Nov 21, 2007 at 10:00:02PM +0000, Robert Watson wrote: >>> >>> On Sun, 18 Nov 2007, Robert Watson wrote: >>> >>>> On Sun, 18 Nov 2007, Dan Epure wrote: >>>> >>>>> 7.0-BETA3 still has issues regarding the pts implementation . problems >>>>> found: 1. - GNU screen: starting a screen, opening a few windows and >>>>> quiting screen leaves the allocated pseudo terminal in use. 100 screen >>>>> user, using each one opening 10 windows will deplete the default of >>>>> 1000 >>>>> pseudo terminals leaving the system unusable. 2. - 'ls /dev/ptmx' >>>>> creates >>>>> an additional entry in /dev/pty/. when the number of entries equals >>>>> kern.pts.max the system became unusable. >>>> >>>> The first of these is likely a reference management bug of some sort -- >>>> I >>>> find that if I close a pty in screen by exiting the shell, the pts >>>> device >>>> is GC'd properly, but if I close it by killing the session with ctrl-k, >>>> then the pts device is not properly GC'd and processes hung off it not >>>> properly killed. I believe that closing the master device is not >>>> properly >>>> kicking the slave device and causing its consumers to exit, hence the >>>> pts >>>> device not being closd and released. Christian was taking a look at >>>> this >>>> a couple of days ago, and I've CC'd him. >>>> >>>> The second problem is more tricky, and has to do with the cloning model. >>>> Similar problems can exist with other variations on the ptmx >>>> implementation, and I need to give some thought to how to address this. >>> >>> Dan, >>> >>> So, thinking a bit more about the second problem, I think it is inherrent >>> to the way we've designed the /dev/ptmx cloning model, which is >>> unfortunate. My current leaning is to disable the ptmx mechanism in 7.0 >>> and put together a revised one for 7.1. The reason to do this is to >>> avoid >>> encoding the user<->kernel interface for allocating pty's via ptmx along >>> the current lines, which we'd then need to continue supporting in future >>> releases. I'm going to spend a bit of time over the next day or two >>> looking at revising the interface to fix these problems. >>> >>> Robert N M Watson >>> Computer Laboratory >>> University of Cambridge >> > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org"
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