linux-kernel - Re: [PATCH -V2] acpi: don't cond

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Date:	Mon, 28 Dec 2009 14:12:33 +0300
From:	Alexey Starikovskiy <astarikovskiy@...e.de>
To:	Xiaotian Feng <dfeng@...hat.com>
CC:	Pavel Machek <pavel@....cz>,
	Alexey Starikovskiy <aystarik@...il.com>,
	Lin Ming <ming.m.lin@...el.com>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Len Brown <lenb@...nel.org>,
	"Moore, Robert" <robert.moore@...el.com>
Subject: Re: [PATCH -V2] acpi: don't cond_resched if irq is disabled

Xiaotian Feng пишет:
> On 12/12/2009 01:34 AM, Pavel Machek wrote:
>>
>>>>> If there are none, fine.
>>>>>
>>>>>> #ifdef CONFIG_PREEMPT
>>>>>> # define preemptible()  (preempt_count() == 0&&  !irqs_disabled())
>>>>>> # define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
>>>>>> #else
>>>>>> # define preemptible()  0
>>>>>> # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
>>>>>> #endif
>>>>>>
>>>>
>>>> Well, normally we want low latency even for !CONFIG_PREEMPT kernels.
>>>>
>>>> Actually, explicit preemption points are NOPs for CONFIG_PREEMPT
>>>> kernels, right?
>>
>>> Right. Do you have code?
>>
>> I'd prefer to spend my time with patches to areas that actually do
>> take cleanup patches.
> 
> What's the status of this now? We can still see the sleeping function
> call warning or enable irq at resume stage.
> If acpi wants low latency even for !CONFIG_PREEMPT kernels, what's wrong
> with V2 patch?
> 
> We should not set any preemption points in irq or atomic. Since we have
> a simple fix, and it did fix bugs, why should
> we make things more complex?
We should not do anything complex here, you are right.
Consider me ACK your patch.

Thanks,
Alex

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