Date: Sun, 20 Feb 2005 18:05:36 +1030 From: "Daniel O'Connor" <doconnor@gsoft.com.au> To: freebsd-hackers@freebsd.org Cc: Peter Jeremy <PeterJeremy@optushome.com.au> Subject: Re: Signalling a process from a INTR_FAST handler Message-ID: <200502201805.43307.doconnor@gsoft.com.au> In-Reply-To: <20050220054251.GB28983@cirb503493.alcatel.com.au> References: <20050220054251.GB28983@cirb503493.alcatel.com.au>
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On Sun, 20 Feb 2005 16:12, Peter Jeremy wrote:
> I have a hardware interrupt handler that has to forward a signal to
> userland and that I'd like to mark INTR_FAST. AFAIK, the normal way
> to forward a signal is:
> if ((p = pfind(sc->pid_to_signal)) != NULL) {
> psignal(p, SIGUSR2);
> PROC_UNLOCK(p);
> }
>
> But pfind(9) does a PROC_LOCK() which implies it can sleep and therefore
> can't be used by an INTR_FAST handler.
>
> Firstly, am I correct? If so, is there an alternative approach I can use?
I think you are, and I think the only way to do it is to schedule another
kernel [heavy] thread to do the wakeup.
--
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
-- Andrew Tanenbaum
GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C
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