From: Rusty Russell <rusty@rustcorp.com.au>
To: "David S. Miller" <davem@redhat.com>
Cc: Keith Owens <kaos@ocs.com.au>,
nigel@nrg.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH for 2.5] preemptible kernel
Date: Thu, 22 Mar 2001 09:25:47 +1100 [thread overview]
Message-ID: <m14fr35-001PKoC@mozart> (raw)
In-Reply-To: Your message of "Wed, 21 Mar 2001 01:41:25 -0800." <15032.30533.638717.696704@pizda.ninka.net>
In message <15032.30533.638717.696704@pizda.ninka.net> you write:
>
> Keith Owens writes:
> > Or have I missed something?
>
> Nope, it is a fundamental problem with such kernel pre-emption
> schemes. As a result, it would also break our big-reader locks
> (see include/linux/brlock.h).
Good point: holding a brlock has to block preemption, as per spinlocks.
> Basically, anything which uses smp_processor_id() would need to
> be holding some lock so as to not get pre-empted.
When I audited the uses of smp_processor_id() for the hotplug cpu
stuff, there were surprisingly few calls to smp_processor_id(), and
most of these will be holding a brlock, so OK already.
Rusty.
--
Premature optmztion is rt of all evl. --DK
next prev parent reply other threads:[~2001-03-23 12:44 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 [this message]
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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