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From: Alex Nixon <alex.nixon@citrix.com>
To: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>,
	Jeremy Fitzhardinge <Jeremy.Fitzhardinge@citrix.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] X86: Change the default value of nr_irqs from 32 to NR_IRQs
Date: Wed, 20 Aug 2008 00:19:57 +0100	[thread overview]
Message-ID: <48AB551D.6010708@citrix.com> (raw)
In-Reply-To: <86802c440808191352g75c99737kcb8c9c20d59c8f7b@mail.gmail.com>

Yinghai Lu wrote:
> when !CONFIG_HAVE_SPARSE_IRQ, with dyn_array, could allocate irq_desc
> and etc as less as possible.
> when CONFIG_HAVE_SPARESE_IRQ, no actually meaning for nr_irqs.
> 
> YH

So I believe the only case this affects is !CONFIG_HAVE_SPARSE_IRQ

The worry is that with CONFIG_HAVE_DYN_ARRAY we may waste memory by 
pre-allocating more irq_descs than may be necessary (NR_IRQs vs 32)?

With !CONFIG_HAVE_DYN_ARRAY however, a static array of size NR_IRQS is 
allocated instead - so doesn't defaulting nr_irqs back to NR_IRQS just 
revert to the old behaviour (with the exception of the irq_descs being 
allocated in pre_alloc_dyn_array instead)?

- Alex

  reply	other threads:[~2008-08-19 23:20 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-19 16:55 [PATCH] X86: Change the default value of nr_irqs from 32 to NR_IRQs Alex Nixon
2008-08-19 17:44 ` Yinghai Lu
     [not found]   ` <0E902970173AF84089673FA54B7FE78A2CA11D@lonpexch01.citrite.net>
2008-08-19 18:24     ` Yinghai Lu
2008-08-19 18:32       ` Alex Nixon
2008-08-19 19:00         ` Yinghai Lu
2008-08-19 19:50           ` Alex Nixon
2008-08-19 20:52             ` Yinghai Lu
2008-08-19 23:19               ` Alex Nixon [this message]
2008-08-20 23:23                 ` Alex Nixon
2008-08-20 23:47                   ` Yinghai Lu
2008-08-21 23:21                     ` Jeremy Fitzhardinge
2008-08-20 23:23     ` Jeremy Fitzhardinge

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