From owner-freebsd-hackers  Wed Jan  5 13: 7: 2 2000
Delivered-To: freebsd-hackers@freebsd.org
Received: from lor.watermarkgroup.com (lor.watermarkgroup.com [207.202.73.33])
	by hub.freebsd.org (Postfix) with ESMTP id 43E5114C05
	for <freebsd-hackers@FreeBSD.ORG>; Wed,  5 Jan 2000 13:07:00 -0800 (PST)
	(envelope-from luoqi@watermarkgroup.com)
Received: (from luoqi@localhost)
	by lor.watermarkgroup.com (8.8.8/8.8.8) id QAA01362;
	Wed, 5 Jan 2000 16:06:57 -0500 (EST)
	(envelope-from luoqi)
Date: Wed, 5 Jan 2000 16:06:57 -0500 (EST)
From: Luoqi Chen <luoqi@watermarkgroup.com>
Message-Id: <200001052106.QAA01362@lor.watermarkgroup.com>
To: freebsd-hackers@FreeBSD.ORG, zzhang@cs.binghamton.edu
Subject: Re:  Post a signal within an interrupt handler
Sender: owner-freebsd-hackers@FreeBSD.ORG
Precedence: bulk
X-Loop: FreeBSD.ORG

> While reading the code vfs_aio.c, I find out some comments saying it is
> not safe to post a signal from the interrupt handler aio_physwakeup().  So
> it calls timeout(9) within that handler and let the timeout routine to
> post the signal. I do not understand this. Isn't the timeout mechanism
> also driven by an interrupt (clock)? 
> 
> Any enlightment is appreciated.
> 
> -Zhihui
> 
AFAIK it is safe to post a signal in an interrupt context. Maybe it has
more to do with reducing interrupt latency than safety.

-lq


To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-hackers" in the body of the message