Message-ID: <4B4245BB.5070302@kernel.org>
Date: Mon, 04 Jan 2010 11:47:07 -0800
From: Yinghai Lu <yinghai@kernel.org>
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To: "H. Peter Anvin" <hpa@zytor.com>
CC: "Eric W. Biederman" <ebiederm@xmission.com>,
       Jesse Brandeburg <jesse.brandeburg@gmail.com>,
       Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
       "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       NetDEV list <netdev@vger.kernel.org>,
       Jesse Brandeburg <jesse.brandeburg@intel.com>
Subject: Re: [PATCH 2/2] x86: get more exact nr_irqs
References: <4B347AEE.6030705@kernel.org> <20091228094707.GH24690@elte.hu>	<4B398ECD.1080506@kernel.org>	<4807377b1001031906s6b1ee576jc021da2642bb4147@mail.gmail.com>	<4B415E73.1050801@kernel.org> <4B41918D.3000605@kernel.org>	<m1fx6lizc3.fsf@fess.ebiederm.org>	<86802c441001041103s5abd6d3ai4e6ccbfc68323f3c@mail.gmail.com> <m1bph9he9m.fsf@fess.ebiederm.org> <4B4241E2.1020008@zytor.com>
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On 01/04/2010 11:30 AM, H. Peter Anvin wrote:
> On 01/04/2010 11:16 AM, Eric W. Biederman wrote:
>>
>> If we care about memory use efficiency let's replace irq_desc_ptrs
>> with a rbtree or a radix_tree.  Something that moves the memory use
>> penalty onto those machines that have a lot of irqs.
>>
> 
> rbtree doesn't make much sense for something that is addressed by index,
> and doesn't need to answer questions of the form "give me the highest
> member <= X".  A hash table or radix tree makes sense, depending on the
> expected sparseness of the index.

will check if we can use radix with it like powerpc

YH
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