Date: Sun, 24 Sep 2000 12:20:01 -0700 From: Alfred Perlstein <bright@wintelcom.net> To: Dag-Erling Smorgrav <des@ofug.org> Cc: Warner Losh <imp@village.org>, The Hermit Hacker <scrappy@hub.org>, Bruce Evans <bde@zeta.org.au>, freebsd-smp@FreeBSD.ORG Subject: Re: 'interrupt-level buffer overflows' for sio device? Message-ID: <20000924122000.P9141@fw.wintelcom.net> In-Reply-To: <20000924121359.O9141@fw.wintelcom.net>; from bright@wintelcom.net on Sun, Sep 24, 2000 at 12:14:00PM -0700 References: <Pine.BSF.4.21.0009080008090.527-100000@thelab.hub.org> <200009080314.VAA50701@harmony.village.org> <xzp7l817ij1.fsf@flood.ping.uio.no> <20000924113008.N9141@fw.wintelcom.net> <xzpn1gxd48d.fsf@flood.ping.uio.no> <20000924121359.O9141@fw.wintelcom.net>
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* Alfred Perlstein <bright@wintelcom.net> [000924 12:14] wrote: > * Dag-Erling Smorgrav <des@ofug.org> [000924 11:39] wrote: > > Alfred Perlstein <bright@wintelcom.net> writes: > > > This is basically a result of the entire kernel running at the > > > equivelant of splhigh, all interrupts are blocked until a context > > > switch in kernel land. > > > > > > There's work in progress to mpsafe the drivers (at least for > > > ethernet, more will arrive later). > > > > OK. Assuming I wanted to try and help with this work, where would be a > > good place to start finding out what needs to be done? > Er, let me follow up in order to clarify a few things... > Have a look at what was recently done to the fxp driver, basically > protect the instance of the driver from itself, ie, if you see > splfoo() in the driver, identify what it's trying to protect against > and figure where the mutex needs to be. This basically means that any time you see spl, you'll want to see what exactly the spl is protecting and use a mutex in that structure or subsystem. Also, all the instances of locking using mutual exclusion need to be replaced with msleep interlocking against a conditional variable. For a detailed explanation of such things you might want to have a look at: http://people.freebsd.org/~jasone/smp/ http://people.freebsd.org/~alfred/mpsafe/ http://www.technokratis.com/code/mbuf/mtx_journal I'm hoping you're going to be at BSDcon. -- -Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org] "I have the heart of a child; I keep it in a jar on my desk." To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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