From: Mario Smarduch <mario.smarduch@huawei.com>
To: Ryan <ryanphilips19@googlemail.com>
Cc: linux-newbie@vger.kernel.org
Subject: Re: A spinlock_irqsave question
Date: Mon, 29 Apr 2013 11:12:33 +0200 [thread overview]
Message-ID: <517E3981.5060103@huawei.com> (raw)
In-Reply-To: <CANMsd03Ea55cV5aoDP0jfA9_+wgW81omLjzvQLN+-w-hgNyzXQ@mail.gmail.com>
On 4/29/2013 10:30 AM, Ryan wrote:
>
>
>
> spinlock_irqsave() <== Disables the IRQ?
>
> <== No IRQs (that means no KB
> interrupt,Interrupts from touch screen... etc..)
>
>
>
> spinlock_irqrestore()
spin_lock_irqsave(lock,flags)/ affects the running
CPU, it does not disable any device IRQ. Device
interrupts may be taken by other CPUs. There is a whole
other set of calls that deal with individual IRQs.
>
>
> Is my understanding correct?
> So the "time spend between spinlock_irqsave and spinlock_restore
> should be very short?
>
> For example there should not be something like this? Am i correct?
>
>
> spinlock_irqsave()
>
> mdelay(1000);
>
>
> spinlock_irqrestore()
Yes, but much shorter then mdelay(1000)
>
>
>
>
> Also, what is meant by "spinlock_irqsave" disabled irq locally?
spin_lock_irqsave()disables interrupts on the CPU it's issued.
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next prev parent reply other threads:[~2013-04-29 9:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-29 8:30 A spinlock_irqsave question Ryan
2013-04-29 9:12 ` Mario Smarduch [this message]
2013-04-29 9:21 ` Ryan
2013-04-30 8:54 ` Mario Smarduch
2013-05-03 6:45 ` Ryan
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