From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Grundler Subject: Re: [parisc-linux] Proposal for implementing IRQ affinity Date: Tue, 31 Aug 2004 12:06:35 -0600 Message-ID: <20040831180635.GF20353@colo.lackof.org> References: <1093923097.3870.18.camel@mulgrave> <20040831171421.GC20353@colo.lackof.org> <20040831174357.GQ16196@parcelfarce.linux.theplanet.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: PARISC list To: Matthew Wilcox Return-Path: In-Reply-To: <20040831174357.GQ16196@parcelfarce.linux.theplanet.co.uk> List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: parisc-linux-bounces@lists.parisc-linux.org On Tue, Aug 31, 2004 at 06:43:57PM +0100, Matthew Wilcox wrote: ... > > I'd rather see one global array (at least 256 entries) with the CPU > > (and similar devices) getting a fixed number of consecutive entries. > > We should probably reserve the first 16 entries for EISA/ISA support > > like we did before. > > I'm not sure that's a good idea. In linux-ia64-test-2.6.8.1/arch/ia64/kernel/iosapic.c: unsigned int gsi_base; /* first GSI assigned to this IOSAPIC */ Looks like that's what ia64 is doing and I don't see a problem with it. One of the drawbacks of IRQ regions is they are 32 or 64 entries wide regardless of many are actually used. > It would give the impression that all > Lasi interrupts could be independently retargetted, which isn't true. James mentioned this is a problem in his proprosal as well. If we don't provide /proc/irq//smp_affinity, I don't see how someone could be confused about it. Each IRQ entry will have it's own function pointer to indicate if it supports redirection or not. I don't see how this related to single global array vs multiple arrays. > Note that Dino is a little more advanced and has two IRR registers, > so we could theoretically do some cool stuff with that ... but it's not > important enough, IMO. I agree. grant _______________________________________________ parisc-linux mailing list parisc-linux@lists.parisc-linux.org http://lists.parisc-linux.org/mailman/listinfo/parisc-linux