Date: Thu, 31 Jan 2008 13:08:29 +0100
From: Ingo Molnar <mingo@elte.hu>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: Andi Kleen <ak@suse.de>, Ingo Molnar <mingo@redhat.com>,
       "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/5] x86: c_p_a clflush_cache_range fix
Message-ID: <20080131120829.GB12571@elte.hu>
References: <1201764962.12950.23.camel@caritas-dev.intel.com> <200801310840.25221.ak@suse.de> <1201768073.21226.2.camel@caritas-dev.intel.com>
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* Huang, Ying <ying.huang@intel.com> wrote:

> +++ b/arch/x86/kernel/cpu/common.c
> @@ -274,8 +274,10 @@ void __init cpu_detect(struct cpuinfo_x8
>  		if (c->x86 >= 0x6)
>  			c->x86_model += ((tfms >> 16) & 0xF) << 4;
>  		c->x86_mask = tfms & 15;
> -		if (cap0 & (1<<19))
> +		if (cap0 & (1<<19)) {
>  			c->x86_cache_alignment = ((misc >> 8) & 0xff) * 8;
> +			c->x86_clflush_size = ((misc >> 8) & 0xff) * 8;
> +		}

thanks!

> @@ -317,6 +319,7 @@ static void __init early_cpu_detect(void
>  	struct cpuinfo_x86 *c = &boot_cpu_data;
>  
>  	c->x86_cache_alignment = 32;
> +	c->x86_clflush_size = 32;

i suspect 32 is a good lower limit (it's not a big issue to do too 
finegrained flushes, and CLFLUSH is valid with arbitrary alignment) - 
and this will be overriden with 64 later on.

	Ingo
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