From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org ([63.228.1.57]:24002 "EHLO gate.crashing.org") by vger.kernel.org with ESMTP id S1161070AbWJDDOs (ORCPT ); Tue, 3 Oct 2006 23:14:48 -0400 Subject: Re: [PATCH] update generic irq for parisc From: Benjamin Herrenschmidt In-Reply-To: <1157827893.3462.19.camel@mulgrave.il.steeleye.com> References: <1157827893.3462.19.camel@mulgrave.il.steeleye.com> Content-Type: text/plain Date: Wed, 04 Oct 2006 13:14:38 +1000 Message-Id: <1159931678.8469.2.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org To: James Bottomley Cc: linux-arch@vger.kernel.org List-ID: On Sat, 2006-09-09 at 13:51 -0500, James Bottomley wrote: > We have had a specific problem with the current generic linux IRQ code > for ages, in that indirection via function pointers is horribly > expensive for us (basically, the CPU pipes stall). We'd like to use the > new genirq infrastructure to mitigate some of the problem. > > I didn't want simply to move the irq handlers back into our arch code > again, since that would remove all the benefits of common handling code. > What I did was template out the common code in a way that keeps it > common but allows an architecture to modify it (for us to put our acks > and eoi's in as functions instead of function pointers). > > If everyone is OK with this, I'll introduce a new type of interrupt with > a specific handler (so for our heavily called interrupts like timer and > IPI we don't even need to indirect through action->handler()). I don't have any objection to this patch as long as the current behaviour with function pointers still works fine (which seems to be the case from a quick look through the patch). On PowerPC, we have a huge variety of interrupt controllers and cascaded controllers and thus we can't really apply your shortcut. Ben.