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To: ebiederm@xmission.com (Eric W. Biederman)
Cc: paulmck@linux.vnet.ibm.com, Linus Torvalds <torvalds@linux-foundation.org>,
       Thomas Gleixner <tglx@linutronix.de>,
       Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@elte.hu>,
       Christoph Hellwig <hch@infradead.org>, Nick Piggin <npiggin@suse.de>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Oleg Nesterov <oleg@redhat.com>
Subject: Re: [rfc] "fair" rw spinlocks
From: Andi Kleen <andi@firstfloor.org>
References: <20091130100041.GA29610@infradead.org>
	<alpine.LFD.2.00.0911300722370.2872@localhost.localdomain>
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	<m1y6lg7q3n.fsf@fess.ebiederm.org>
	<20091207181816.GF6808@linux.vnet.ibm.com>
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Date: Mon, 07 Dec 2009 23:35:28 +0100
In-Reply-To: <m1ocma1kz6.fsf@fess.ebiederm.org> (Eric W. Biederman's message of "Mon, 07 Dec 2009 14:24:13 -0800")
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ebiederm@xmission.com (Eric W. Biederman) writes:

> "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> writes:
>>
>> Is it required that all of the processes see the signal before the
>> corresponding interrupt handler returns?  (My guess is "no", which
>> enables a trick or two, but thought I should ask.)
>
> Not that I recall.  I think it is just an I/O completed signal.

Wasn't there the sysrq SAK too? That one definitely would need
to be careful about synchronicity.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.