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From: Frank Cusack <fcusack@fcusack.com>
To: lkml <linux-kernel@vger.kernel.org>
Subject: preemption when running in the kernel
Date: Fri, 7 Nov 2003 04:04:27 -0800	[thread overview]
Message-ID: <20031107040427.A32421@google.com> (raw)

(2.4 kernel)

When a process is running in the kernel, can it be pre-empted at
any time?  (Unless you explicity disable preemption.)  I think not,
because wouldn't it be unsafe to grab a spinlock?  Or does grabbing a
spinlock disable preemption.  I mean spin_lock(), not spin_lock_irqsave().

Secondly, can multiple processes be in the kernel at the same time?  I
think so, that's the reason for the fine grained locks instead of the BKL.
Or do fine grained locks only serve to allow preemption.

thanks!
/fc


             reply	other threads:[~2003-11-07 22:18 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-11-07 12:04 Frank Cusack [this message]
2003-11-08 13:01 ` preemption when running in the kernel Ingo Oeser
2003-11-09  0:23   ` Robert Love
2003-11-09 10:04     ` Frank Cusack
2003-11-09 17:56       ` Robert Love

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