Date: Sun, 02 May 2004 11:18:15 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: bde@zeta.org.au Cc: freebsd-current@freebsd.org Subject: Re: sio: lots of silo overflows on Asus K8V with Moxa Smartio C104H/PCI Message-ID: <20040502.111815.74057370.imp@bsdimp.com> In-Reply-To: <20040502130027.O1806@gamplex.bde.org> References: <20040430102504.477152ce.bm@malepartus.de> <20040501.162455.37300016.imp@bsdimp.com> <20040502130027.O1806@gamplex.bde.org>
next in thread | previous in thread | raw e-mail | index | archive | help
In message: <20040502130027.O1806@gamplex.bde.org>
Bruce Evans <bde@zeta.org.au> writes:
: No, but siointr() doesn't go near the tty layer or almost any other
: layer. It uses pseudo-dma and schedules a SWI to transfer data between
: its buffers and the tty layer. Fast interrupt handlers cannot call
: other layers because they cannot reasonable lock other layers or
: vice versa. (Even the call to the scheduler to schedule a SWI in the
: current implementation is a layering violation.)
So it is also safe to call the tty layer w/o giant held from the SWI?
I guess that was my question. Or is the SWI wrapped in Giant when I
wasn't looking...
Warner
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20040502.111815.74057370.imp>