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Date: Wed, 14 Jul 2004 14:01:32 -0700
From: Alfred Perlstein <alfred@freebsd.org>
To: Don Lewis <truckman@FreeBSD.org>
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Subject: Re: cvs commit: src/sys/kern kern_event.c src/sys/sys eventvar.h
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* Don Lewis <truckman@FreeBSD.org> [040714 13:38] wrote:
> On 14 Jul, Alfred Perlstein wrote:
> > * Doug Rabson <dfr@nlsystems.com> [040714 12:01] wrote:
> 
> >> Seems to me that the best thing to do is to defer the psigio() to a 
> >> taskqueue that will run in a simpler locking environment.
> > 
> > I was thinking that, but I'm worried about "stale delivery",
> > perhaps we need to record the generation count (process start time)
> > in the sigio as well as the request sent, so that we don't send
> > a signal to the wrong process.
> 
> This is already handled in the sigio infrastructure.  Both struct proc
> and struct pgrp have a list of their potential sigio sources. When the
> process or process group goes away, the exit code disables sigio
> delivery.

Yes, but if the delivery of the signal becomes async, then we lose
this.

-- 
- Alfred Perlstein
- Research Engineering Development Inc.
- email: bright@mu.org cell: 408-480-4684