Message-ID: <4B4241E2.1020008@zytor.com>
Date: Mon, 04 Jan 2010 11:30:42 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.5) Gecko/20091209 Fedora/3.0-4.fc12 Thunderbird/3.0
MIME-Version: 1.0
To: "Eric W. Biederman" <ebiederm@xmission.com>
CC: Yinghai Lu <yinghai@kernel.org>,
       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>
In-Reply-To: <m1bph9he9m.fsf@fess.ebiederm.org>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 752
Lines: 19

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.

	-hpa

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/