From: Andi Kleen <ak@muc.de>
To: Arjan van de Ven <arjan@infradead.org>
Cc: David Howells <dhowells@redhat.com>,
Andrew Morton <akpm@osdl.org>,
Badari Pulavarty <pbadari@us.ibm.com>,
linux-aio@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: aio stress panic on 2.6.11-mm1
Date: Wed, 09 Mar 2005 12:17:19 +0100 [thread overview]
Message-ID: <m1k6ohvzk0.fsf@muc.de> (raw)
In-Reply-To: <1110366469.6280.84.camel@laptopd505.fenrus.org> (Arjan van de Ven's message of "Wed, 09 Mar 2005 12:07:48 +0100")
Arjan van de Ven <arjan@infradead.org> writes:
> On Wed, 2005-03-09 at 16:34 +0530, Suparna Bhattacharya wrote:
>> Any sense of how costly it is to use spin_lock_irq's vs spin_lock
>> (across different architectures)
>
> on x86 it makes a difference of maybe a few cycles. At most.
> However please consider using spin_lock_irqsave(); the _irq() variant,
> while it can be used correctly, is a major source of bugs since it
> unconditionally enables interrupts on unlock.
irqsave is much worse than _irq on P4.
However the spinlock already synchronizes the CPU, so some of the
cost should be mitigated.
-Andi
next prev parent reply other threads:[~2005-03-09 11:18 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20050308170107.231a145c.akpm@osdl.org>
[not found] ` <1110327267.24286.139.camel@dyn318077bld.beaverton.ibm.com>
[not found] ` <18744.1110364438@redhat.com>
2005-03-09 11:04 ` aio stress panic on 2.6.11-mm1 Suparna Bhattacharya
2005-03-09 11:05 ` Andrew Morton
2005-03-09 11:07 ` Arjan van de Ven
2005-03-09 11:17 ` Andi Kleen [this message]
2005-03-09 11:28 ` Andrew Morton
2005-03-09 11:59 ` David Howells
2005-03-09 12:12 ` [PATCH] rwsem: Make rwsems use interrupt disabling spinlocks David Howells
2005-03-09 17:35 ` Badari Pulavarty
2005-03-09 19:18 ` Badari Pulavarty
2005-03-09 19:16 ` Badari Pulavarty
2005-03-09 19:42 ` Andrew Morton
2005-03-09 20:10 ` Arjan van de Ven
2005-03-11 9:40 ` Ingo Molnar
2005-03-11 10:07 ` Andrew Morton
2005-03-11 10:25 ` Ingo Molnar
2005-03-09 11:10 ` aio stress panic on 2.6.11-mm1 Arjan van de Ven
2005-03-09 11:21 ` Andi Kleen
2005-03-09 14:48 ` Suparna Bhattacharya
2005-03-09 21:58 ` David Howells
2005-03-09 11:11 ` Andi Kleen
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