* Re: [PATCH 0/7] ppc: remove cli()/sti() from arch/ppc/*
[not found] <20050104214048.21749.85722.89116@localhost.localdomain>
@ 2005-01-05 2:19 ` Brian Gerst
2005-01-05 2:44 ` Jim Nelson
0 siblings, 1 reply; 4+ messages in thread
From: Brian Gerst @ 2005-01-05 2:19 UTC (permalink / raw)
To: James Nelson; +Cc: linuxppc-dev, paulus, linux-kernel
James Nelson wrote:
> This series of patches is to remove the last cli()/sti() function calls in arch/ppc.
>
> These are the only instances in active code that grep could find.
Are you sure none of these need real spinlocks instead of just disabling
interrupts?
--
Brian Gerst
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 0/7] ppc: remove cli()/sti() from arch/ppc/*
2005-01-05 2:19 ` [PATCH 0/7] ppc: remove cli()/sti() from arch/ppc/* Brian Gerst
@ 2005-01-05 2:44 ` Jim Nelson
2005-01-05 9:26 ` Christoph Hellwig
0 siblings, 1 reply; 4+ messages in thread
From: Jim Nelson @ 2005-01-05 2:44 UTC (permalink / raw)
To: Brian Gerst; +Cc: linuxppc-dev, paulus, linux-kernel
Brian Gerst wrote:
> James Nelson wrote:
>
>> This series of patches is to remove the last cli()/sti() function
>> calls in arch/ppc.
>>
>> These are the only instances in active code that grep could find.
>
>
> Are you sure none of these need real spinlocks instead of just
> disabling interrupts?
>
> --
> Brian Gerst
>
These are for single-processor systems, mostly evaluation boards and
embedded processors. I coudn't find any reference to multiprocessor
setups for the processors in question after a peruse of the code or a
quick google on the boards in question.
Jim
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 0/7] ppc: remove cli()/sti() from arch/ppc/*
2005-01-05 2:44 ` Jim Nelson
@ 2005-01-05 9:26 ` Christoph Hellwig
2005-01-05 11:19 ` Jim Nelson
0 siblings, 1 reply; 4+ messages in thread
From: Christoph Hellwig @ 2005-01-05 9:26 UTC (permalink / raw)
To: Jim Nelson; +Cc: linuxppc-dev, Brian Gerst, paulus, linux-kernel
On Tue, Jan 04, 2005 at 09:44:06PM -0500, Jim Nelson wrote:
> Brian Gerst wrote:
>
> >James Nelson wrote:
> >
> >>This series of patches is to remove the last cli()/sti() function
> >>calls in arch/ppc.
> >>
> >>These are the only instances in active code that grep could find.
> >
> >
> >Are you sure none of these need real spinlocks instead of just
> >disabling interrupts?
> >
> >--
> > Brian Gerst
> >
> These are for single-processor systems, mostly evaluation boards and
> embedded processors. I coudn't find any reference to multiprocessor
> setups for the processors in question after a peruse of the code or a
> quick google on the boards in question.
think CONFIG_PREEMPT. In either case a spinlock becomes
lock_irq_disable in the !SMP, !PREEMPT case but it documents the
intention a whole lot better.
Also you're locking only in a single plpace which is a ***BIG*** warning
sign. At least look at the other users of the data structure, it's
extremly likely they'll need locking aswell.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 0/7] ppc: remove cli()/sti() from arch/ppc/*
2005-01-05 9:26 ` Christoph Hellwig
@ 2005-01-05 11:19 ` Jim Nelson
0 siblings, 0 replies; 4+ messages in thread
From: Jim Nelson @ 2005-01-05 11:19 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: linuxppc-dev, Brian Gerst, paulus, linux-kernel
Christoph Hellwig wrote:
> On Tue, Jan 04, 2005 at 09:44:06PM -0500, Jim Nelson wrote:
>
>>Brian Gerst wrote:
>>
>>
>>>James Nelson wrote:
>>>
>>>
>>>>This series of patches is to remove the last cli()/sti() function
>>>>calls in arch/ppc.
>>>>
>>>>These are the only instances in active code that grep could find.
>>>
>>>
>>>Are you sure none of these need real spinlocks instead of just
>>>disabling interrupts?
>>>
>>>--
>>> Brian Gerst
>>>
>>
>>These are for single-processor systems, mostly evaluation boards and
>>embedded processors. I coudn't find any reference to multiprocessor
>>setups for the processors in question after a peruse of the code or a
>>quick google on the boards in question.
>
>
> think CONFIG_PREEMPT. In either case a spinlock becomes
> lock_irq_disable in the !SMP, !PREEMPT case but it documents the
> intention a whole lot better.
>
> Also you're locking only in a single plpace which is a ***BIG*** warning
> sign. At least look at the other users of the data structure, it's
> extremly likely they'll need locking aswell.
>
Some of the cli() uses were in shutdown and IRQ setup code, where you'd just need
to disable interrupts. There are a few files that will need a more thourough
going-through, however.
I'll start checking those later.
Jim
^ permalink raw reply [flat|nested] 4+ messages in thread
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2005-01-05 2:19 ` [PATCH 0/7] ppc: remove cli()/sti() from arch/ppc/* Brian Gerst
2005-01-05 2:44 ` Jim Nelson
2005-01-05 9:26 ` Christoph Hellwig
2005-01-05 11:19 ` Jim Nelson
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