Date: Mon, 27 Mar 2000 16:35:51 +1000 From: "Andrew Reilly" <areilly@nsw.bigpond.net.au> To: Warner Losh <imp@village.org> Cc: Matthew Dillon <dillon@apollo.backplane.com>, Daniel Eischen <eischen@vigrid.com>, nms@otdel-1.org, freebsd-current@freebsd.org Subject: Re: Is there spinlocks/semaphores available for drivers? Message-ID: <20000327163551.A73982@gurney.reilly.home> In-Reply-To: <200003270624.XAA90617@harmony.village.org> References: <200003270607.WAA36169@apollo.backplane.com> <200003262108.QAA12802@pcnet1.pcnet.com> <200003270607.WAA36169@apollo.backplane.com> <200003270624.XAA90617@harmony.village.org>
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On Sun, Mar 26, 2000 at 11:24:50PM -0700, Warner Losh wrote: > In message <200003270607.WAA36169@apollo.backplane.com> Matthew Dillon writes: > : complex. For example, using fixed-length FIFOs rather then linked lists. > : The writer manipulates the write index variable, the reader manipulates > : the read index variable. No locking is required between reader and > : writer. > > What about wrap around? You mean queue empty or queue full? That's when you have to punt to a rate-limit mechanism. Dunno what that would be in interrupt context. -- Andrew To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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