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Subject: Re: Inconsistency in changing the state of task ??
From: Robert Love <rml@tech9.net>
To: prash_t@softhome.net
Cc: linux-kernel@vger.kernel.org
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On Thu, 2003-03-06 at 08:11, prash_t@softhome.net wrote:

> Thanks Robert for the reply.
> But I notice that __set_current_state() is same as current->state. So, I 
> didn't understand the safety factor on using __set_current_state( ). 

There is no safety with __set_current_state().  It is just an
abstraction.

The safety comes from set_current_state(), which ensures memory
ordering.

This is an issue not just on SMP, but on a weakly ordered processor like
Alpha.

> Also why should I use __set_current_state() instead of set_current_state() 
> when the later is SMP safe.

You only use __set_current_state() if you know you do not need to ensure
memory ordering constraints.

	Robert Love

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