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Message-ID: <3E2CF327.8030107@colorfullife.com>
Date: Tue, 21 Jan 2003 08:13:43 +0100
From: Manfred Spraul <manfred@colorfullife.com>
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To: Alan <alan@lxorguk.ukuu.org.uk>, Zwane Mwaikambo <zwane@holomorphy.com>
CC: linux-kernel@vger.kernel.org
Subject: Re: [PATCH][2.5] smp_call_function_mask
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Alan wrote:

>On Fri, 2003-01-17 at 05:18, Zwane Mwaikambo wrote:
>> +	/* Wait for response */
>> +	while (atomic_read(&data.started) != num_cpus)
>> +		barrier();
>
>Only old old intel x86 that does -bad- things as it
>generates a lot of bus locked cycles. Better to do
>
>	while(atomic_read(&data.started) != num_cpus)
>		while(data.started.value != num_cpus)
>		{
>			barrier();
>			cpu_relax();
>		}
>
>I would think ?
>
>  
>
from 2.5.52, <asm-i386/atomic.h>
    #define atomic_read(v)          ((v)->counter)
AFAIK atomic_read never contained locked bus cycles.

Btw, Zwane, what about removing non_atomic from the prototype?

--
    Manfred

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