From: Jamie Lokier <jamie@shareable.org>
To: Manfred Spraul <manfred@colorfullife.com>
Cc: lse-tech@lists.sourceforge.net, linux-kernel@vger.kernel.org
Subject: Re: [RFC,PATCH] use rcu for fasync_lock
Date: Sun, 21 Dec 2003 15:08:11 +0000 [thread overview]
Message-ID: <20031221150811.GL3438@mail.shareable.org> (raw)
In-Reply-To: <3FE5B56E.30507@colorfullife.com>
Manfred Spraul wrote:
> The wakeup happens at irq time. The band info is necessary for
> send_sigio(). Calling f_poll at irq time is not an option - it will
> definitively cause breakage.
Agree * 3.
> schedule_work() for every call is IMHO not an option.
Agree, the latency would suck and it wouldn't even work for RT processes.
> And even that is not reliable: fasync users might expect seperate
> POLL_OUT and POLL_IN signals.
They might, although they probably shouldn't (band is a bitmask for a
reason).
Anyway, you can handle all these problems by computing the band at
signal delivery time. Yes it sounds like it would complicate the
signal delivery code, but sigio should really be handled specially
anyway, so that a signal queue entry for every fd is guaranteed and
queue overflow is not possible. Somebody already has a patch for
that, it might be worth working from.
-- Jamie
next prev parent reply other threads:[~2003-12-21 15:08 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-20 18:20 [RFC,PATCH] use rcu for fasync_lock Manfred Spraul
2003-12-20 21:10 ` [Lse-tech] " Stephen Hemminger
2003-12-20 21:35 ` Manfred Spraul
2003-12-21 11:36 ` Jamie Lokier
2003-12-21 12:40 ` Manfred Spraul
2003-12-21 14:14 ` Jamie Lokier
2003-12-21 14:59 ` Manfred Spraul
2003-12-21 15:08 ` Jamie Lokier [this message]
2004-01-02 21:15 ` Bill Davidsen
2004-01-02 22:41 ` Jamie Lokier
2004-01-03 1:09 ` Mike Fedyk
2004-01-03 21:28 ` Jamie Lokier
2004-01-04 19:01 ` Ingo Oeser
2004-01-04 19:20 ` Davide Libenzi
2004-01-05 21:17 ` Ingo Oeser
2004-01-05 22:24 ` Davide Libenzi
2003-12-21 15:14 ` Davide Libenzi
2003-12-21 15:17 ` Davide Libenzi
2003-12-21 15:28 ` Jamie Lokier
2003-12-21 18:38 ` OGAWA Hirofumi
2003-12-21 19:14 ` Manfred Spraul
2003-12-21 20:51 ` Linus Torvalds
2003-12-21 21:08 ` Manfred Spraul
2003-12-21 21:19 ` Linus Torvalds
2003-12-21 21:54 ` Manfred Spraul
2003-12-21 22:05 ` Linus Torvalds
2003-12-25 1:21 ` Manfred Spraul
2003-12-25 15:11 ` OGAWA Hirofumi
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