Date: Wed, 10 Nov 2004 01:45:43 -0800
From: Andrew Morton <akpm@osdl.org>
To: Thomas Hood <jdthood@yahoo.co.uk>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH] Documentation/preempt-locking.txt clarification
Message-Id: <20041110014543.143b8ff3.akpm@osdl.org>
In-Reply-To: <1100078840.3654.822.camel@thanatos>
References: <1073302283.1903.85.camel@thanatos.hubertnet>
	<1074561880.26456.26.camel@localhost>
	<1100074907.3654.780.camel@thanatos>
	<20041110005742.35828d2b.akpm@osdl.org>
	<1100078840.3654.822.camel@thanatos>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1364
Lines: 28

Thomas Hood <jdthood@yahoo.co.uk> wrote:
>
> On Wed, 2004-11-10 at 09:57, Andrew Morton wrote:
>  > I guess it's saying ...
> 
>  Thanks for the explanation.  I include a new patch which incorporates
>  your example.  I am in no position to judge the _truth_ of the
>  statements in this document; I am only hoping to _understand_ them.  :)

I think the statement is in fact false.  Ingo, what's your take on this
paragraph, from preempt-locking.txt?


  An additional concern is proper usage of local_irq_disable and
  local_irq_save.  These may be used to protect from preemption, however,
  on exit, if preemption may be enabled, a test to see if preemption is
  required should be done.  If these are called from the spin_lock and
  read/write lock macros, the right thing is done.  They may also be called
  within a spin-lock protected region, however, if they are ever called
  outside of this context, a test for preemption should be made.  Do note
  that calls from interrupt context or bottom half/ tasklets are also
  protected by preemption locks and so may use the versions which do not
  check preemption.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/