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From: Suleiman Souhlal <ssouhlal@FreeBSD.org>
To: Andi Kleen <ak@suse.de>
Cc: Edward Falk <efalk@google.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Fix x86_64 _spin_lock_irqsave()
Date: Thu, 24 Aug 2006 13:04:12 +0200	[thread overview]
Message-ID: <44ED87AC.8070106@FreeBSD.org> (raw)
In-Reply-To: <p7364gifx8o.fsf@verdi.suse.de>

Andi Kleen wrote:
> Edward Falk <efalk@google.com> writes:
> 
> 
>>Add spin_lock_string_flags and _raw_spin_lock_flags() to
>>asm-x86_64/spinlock.h so that _spin_lock_irqsave() has the same
>>semantics on x86_64 as it does on i386 and does *not* have interrupts
>>disabled while it is waiting for the lock.
> 
> 
> Did it fix anything for you?

I think this was to work around the fact that some buggy drivers try to 
grab spinlocks without disabling interrupts when they should, which 
would cause deadlocks when trying to rendez-vous every cpu via IPIs.

It's a bad idea to spin with interrupts disabled when they could very 
well be enabled, anyway.

-- Suleiman

  reply	other threads:[~2006-08-24 11:04 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-08-24  2:57 [PATCH] Fix x86_64 _spin_lock_irqsave() Edward Falk
2006-08-24  3:10 ` Nick Piggin
2006-08-24  4:48   ` Andrew Morton
2006-08-24 15:53     ` Martin Bligh
2006-08-26  7:52       ` Keith Owens
2006-08-24  6:45 ` Andi Kleen
2006-08-24 11:04   ` Suleiman Souhlal [this message]
2006-08-24 11:13     ` Arjan van de Ven
2006-08-24 11:32     ` Andi Kleen
2006-08-24 12:33       ` Suleiman Souhlal
2006-08-24 13:21         ` Arjan van de Ven
2006-08-24 13:44           ` Suleiman Souhlal
2006-08-25  4:38   ` Andrew Morton
2006-08-25  5:33     ` Nick Piggin
2006-08-25  6:21     ` Andi Kleen

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