From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yx0-f181.google.com (mail-yx0-f181.google.com [209.85.210.181]) by ozlabs.org (Postfix) with ESMTP id 608A7B7334 for ; Thu, 15 Oct 2009 11:33:38 +1100 (EST) Received: by yxe11 with SMTP id 11so355870yxe.15 for ; Wed, 14 Oct 2009 17:33:37 -0700 (PDT) MIME-Version: 1.0 Sender: glikely@secretlab.ca In-Reply-To: <1255564276.9651.14.camel@concordia> References: <91cec5c64da4ca31a025fc7c45d9f1b93c8b98da.1255499081.git.michael@ellerman.id.au> <1255564276.9651.14.camel@concordia> From: Grant Likely Date: Wed, 14 Oct 2009 18:33:17 -0600 Message-ID: Subject: Re: [PATCH 6/6] powerpc: Enable sparse irq_descs on powerpc To: michael@ellerman.id.au Content-Type: text/plain; charset=ISO-8859-1 Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Oct 14, 2009 at 5:51 PM, Michael Ellerman wrote: > On Wed, 2009-10-14 at 12:44 -0600, Grant Likely wrote: >> Why not make sparse IRQs manditory for all platforms? =A0Is there a >> performance concern with doing so? =A0From a maintenance perspective, >> I'd rather see IRQ descs manged in one way only to keep the code >> simple. > > I agree on the maintenance angle. My thinking was we'd run with it > optional but default y for a release or two, and if no one complains we > can make it mandatory. > > It does make some code paths bigger, and looking up an irq_desc is going > to take slightly more cycles. I don't think it's a big issue, but I > thought we should try it for a while before making it mandatory. The > code has only been tested on x86 and sh as far as I know. No guts, no glory. I say throw it into linux-next to give it some time before the next merge window. I don't think you'll get any better results by having it optional for a few releases (in fact, I suspect that people who do have problems will just end up turning it off and waiting for someone else to report/fix the problems). If this is the direction IRQ handling is going, then just make the change and force any bugs to be dealt with before the next release. > ps. thanks for the review You're welcome. g. --=20 Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd.