From: Keith Owens <kaos@ocs.com.au>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: nigel@nrg.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH for 2.5] preemptible kernel
Date: Tue, 20 Mar 2001 20:32:15 +1100 [thread overview]
Message-ID: <851.985080735@ocs3.ocs-net> (raw)
In-Reply-To: Your message of "Tue, 20 Mar 2001 19:43:50 +1100." <m14fHk9-001PKgC@mozart>
On Tue, 20 Mar 2001 19:43:50 +1100,
Rusty Russell <rusty@rustcorp.com.au> wrote:
>The third is that preemtivity conflicts with the naive
>quiescent-period approach proposed for module unloading in 2.5, and
>useful for several other things (eg. hotplugging CPUs). This method
>relies on knowing that when a schedule() has occurred on every CPU, we
>know noone is holding certain references.
>
>This, too, is soluble, but it means that synchronize_kernel() must
>guarantee that each task which was running or preempted in kernel
>space when it was called, has been non-preemtively scheduled before
>synchronize_kernel() can exit. Icky.
The preemption patch only allows preemption from interrupt and only for
a single level of preemption. That coexists quite happily with
synchronize_kernel() which runs in user context. Just count user
context schedules (preempt_count == 0), not preemptive schedules.
next prev parent reply other threads:[~2001-03-20 9:33 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 [this message]
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
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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