From: Rusty Russell <rusty@rustcorp.com.au>
To: nigel@nrg.org
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH for 2.5] preemptible kernel
Date: Thu, 05 Apr 2001 03:51:11 +1000 [thread overview]
Message-ID: <m14krR1-001PKbC@mozart> (raw)
In-Reply-To: Your message of "Sun, 01 Apr 2001 14:07:42 MST." <Pine.LNX.4.05.10104011347060.14420-100000@cosmic.nrg.org>
In message <Pine.LNX.4.05.10104011347060.14420-100000@cosmic.nrg.org> you write
:
> > Setting a running task's flags brings races, AFAICT, and checking
> > p->state is NOT sufficient, consider wait_event(): you need p->has_cpu
> > here I think.
>
> My thought here was that if p->state is anything other than TASK_RUNNING
> or TASK_RUNNING|TASK_PREEMPTED, then that task is already at a
> synchonize point,
Right. Theoretically possible to set p->state and not sleep, but it's
not a bad assumption.
> > schedule():
> > if (!(prev->state & TASK_PREEMPTED) && prev->syncing)
> > if (--sync_count == 0) wake_up(&syncing_task);
>
> Don't forget to reset prev->syncing.
Right.
> I agree with you about wait queues, but didn't use them here because
> of the problem of avoiding deadlock on the runqueue lock, which the
> wait queues also use.
And right again. Yeah, it has to be done manually. Ack, can I
retract that Email?
Rusty.
--
Premature optmztion is rt of all evl. --DK
next prev parent reply other threads:[~2001-04-05 7:59 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-03-15 1:25 [PATCH for 2.5] preemptible kernel Nigel Gamble
2001-03-17 17:34 ` Pavel Machek
2001-03-19 21:01 ` Nigel Gamble
2001-03-20 8:43 ` Rusty Russell
2001-03-20 9:32 ` Keith Owens
2001-03-21 0:48 ` Nigel Gamble
2001-03-21 1:23 ` Keith Owens
2001-03-21 3:35 ` Nigel Gamble
2001-03-21 8:04 ` george anzinger
2001-03-21 9:04 ` Keith Owens
2001-03-21 14:32 ` Rusty Russell
2001-03-23 20:42 ` Nigel Gamble
2001-03-28 11:47 ` Dipankar Sarma
2001-03-21 9:19 ` Keith Owens
2001-03-21 9:41 ` David S. Miller
2001-03-21 10:05 ` Andrew Morton
2001-03-22 0:20 ` Nigel Gamble
2001-03-21 10:57 ` george anzinger
2001-03-21 11:30 ` David S. Miller
2001-03-21 17:07 ` george anzinger
2001-03-21 18:18 ` Nigel Gamble
2001-03-21 22:25 ` Rusty Russell
2001-03-21 15:46 ` Andrea Arcangeli
2001-03-28 10:20 ` Dipankar Sarma
2001-03-28 20:51 ` george anzinger
2001-03-29 9:43 ` Dipankar Sarma
2001-03-30 6:32 ` Keith Owens
2001-03-21 0:24 ` Nigel Gamble
2001-03-30 0:26 ` Nigel Gamble
2001-03-30 20:11 ` Rusty Russell
2001-04-01 7:48 ` george anzinger
2001-04-01 21:13 ` Nigel Gamble
2001-04-02 19:56 ` george anzinger
2001-04-04 17:59 ` Rusty Russell
2001-04-01 21:07 ` Nigel Gamble
2001-04-04 17:51 ` Rusty Russell [this message]
2001-03-20 18:25 ` Roger Larsson
2001-03-20 22:06 ` Nigel Gamble
2001-03-20 22:27 ` george anzinger
-- strict thread matches above, loose matches on Subject: below --
2001-04-06 23:52 Paul McKenney
2001-04-07 0:45 ` Andi Kleen
2001-04-07 1:25 Paul McKenney
2001-04-07 19:59 ` Rusty Russell
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