linux-kernel - Re: [PATCH 3/3] x86: add local_tlb_flush_kernel

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Message-ID: <4FEAA7A1.9020307@kernel.org>
Date:	Wed, 27 Jun 2012 15:26:41 +0900
From:	Minchan Kim <minchan@...nel.org>
To:	Alex Shi <alex.shi@...el.com>
CC:	Seth Jennings <sjenning@...ux.vnet.ibm.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	devel@...verdev.osuosl.org,
	Dan Magenheimer <dan.magenheimer@...cle.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Robert Jennings <rcj@...ux.vnet.ibm.com>,
	Nitin Gupta <ngupta@...are.org>
Subject: Re: [PATCH 3/3] x86: add local_tlb_flush_kernel_range()

Hello,

On 06/27/2012 03:14 PM, Alex Shi wrote:

> On 06/27/2012 01:53 PM, Minchan Kim wrote:
> 
>> On 06/26/2012 01:14 AM, Seth Jennings wrote:
>>
>>> This patch adds support for a local_tlb_flush_kernel_range()
>>> function for the x86 arch.  This function allows for CPU-local
>>> TLB flushing, potentially using invlpg for single entry flushing,
>>> using an arch independent function name.
>>>
>>> Signed-off-by: Seth Jennings <sjenning@...ux.vnet.ibm.com>
>>
>>
>> Anyway, we don't matter INVLPG_BREAK_EVEN_PAGES's optimization point is 8 or something.
> 
> 
> Different CPU type has different balance point on the invlpg replacing
> flush all. and some CPU never get benefit from invlpg, So, it's better
> to use different value for different CPU, not a fixed
> INVLPG_BREAK_EVEN_PAGES.


I think it could be another patch as further step and someone who are
very familiar with architecture could do better than.
So I hope it could be merged if it doesn't have real big problem.

Thanks for the comment, Alex.


-- 
Kind regards,
Minchan Kim
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