From: Roland Dreier <roland@topspin.com>
To: root@chaos.analogic.com
Cc: Linux kernel <linux-kernel@vger.kernel.org>
Subject: Re: poll() in 2.6 and beyond
Date: 02 Mar 2004 15:21:10 -0800 [thread overview]
Message-ID: <5265dmrg2h.fsf@topspin.com> (raw)
In-Reply-To: <Pine.LNX.4.53.0403021808240.9351@chaos>
Richard> There are two routines where the CPU is actually given
Richard> up, do_select() and do_poll(). Search for
Richard> schedule_timeout(). Once the scheduler has the CPU, it's
Richard> available for any of the other drivers. It's also
Richard> available for the timer queues, other tasks, and the
Richard> interrupts.
OK, fine, I can't argue with that. But it has nothing to do with the
discussion at hand.
You still haven't said where poll_wait() sleeps in kernel 2.4. You
claimed it was in add_wait_queue(), but add_wait_queue() doesn't sleep
(it's just a list_add() guarded by a lock).
Also, why would another driver for the same poll() call run? There's
only one thread around that cares about this call to poll() -- the
userspace process that originally called poll(). If one driver
sleeps, no other drivers will run until that driver wakes up.
- Roland
next prev parent reply other threads:[~2004-03-02 23:21 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-02 18:21 poll() in 2.6 and beyond Richard B. Johnson
2004-03-02 20:04 ` Roland Dreier
2004-03-02 20:24 ` Richard B. Johnson
2004-03-02 21:00 ` Roland Dreier
2004-03-02 21:26 ` Richard B. Johnson
2004-03-02 21:39 ` Roland Dreier
2004-03-02 21:59 ` Richard B. Johnson
2004-03-02 22:41 ` Dave Dillow
2004-03-02 22:56 ` Roland Dreier
2004-03-02 23:16 ` Richard B. Johnson
2004-03-02 23:21 ` Roland Dreier [this message]
[not found] <1vmPm-4lU-11@gated-at.bofh.it>
[not found] ` <1vonq-6dr-37@gated-at.bofh.it>
[not found] ` <1voGY-6vC-41@gated-at.bofh.it>
[not found] ` <1vpjt-7dl-17@gated-at.bofh.it>
[not found] ` <1vpCV-7wY-41@gated-at.bofh.it>
[not found] ` <1vpWa-7Py-19@gated-at.bofh.it>
2004-03-02 22:53 ` Bill Davidsen
2004-03-02 22:57 ` Roland Dreier
2004-03-02 23:32 ` Richard B. Johnson
2004-03-03 0:07 ` John Muir
2004-03-03 1:18 ` Richard B. Johnson
2004-03-03 4:04 ` Roland Dreier
2004-03-03 12:38 ` Richard B. Johnson
2004-03-03 14:29 ` Davide Libenzi
2004-03-03 3:57 ` David Dillow
2004-03-03 18:23 ` Richard B. Johnson
2004-03-03 19:29 ` Dave Dillow
2004-03-03 20:10 ` Richard B. Johnson
2004-03-03 22:25 ` Linus Torvalds
2004-03-03 22:42 ` Richard B. Johnson
2004-03-03 23:14 ` Linus Torvalds
2004-03-03 22:52 ` Linus Torvalds
2004-03-03 23:07 ` Richard B. Johnson
-- strict thread matches above, loose matches on Subject: below --
2004-03-03 3:06 linux
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