From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: [parisc-linux] Proposal for implementing IRQ affinity Date: 31 Aug 2004 15:44:14 -0400 Message-ID: <1093981554.5296.14.camel@mulgrave> References: <1093923097.3870.18.camel@mulgrave> <20040831171421.GC20353@colo.lackof.org> <1093974552.3643.22.camel@mulgrave> <20040831183415.GG20353@colo.lackof.org> Mime-Version: 1.0 Content-Type: text/plain Cc: PARISC list To: Grant Grundler Return-Path: In-Reply-To: <20040831183415.GG20353@colo.lackof.org> 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, 2004-08-31 at 14:34, Grant Grundler wrote: > Ok. Why? Because the only interrupts we can control the affinity of are the true 32/64 CPU interrupts. Everything else is effectively hanging off one of these. If we try to pretend that we can change the affinity of the subordinate interrupts, we'll end up confusing irqbalanced > I'd really like one method to convert GSI to local interrupt numbers. > Doing away with local translations and directly indexing into a global > array seems the most obvious to me. I know, but our interrupt structure isn't a flat array, it's a tree with the root being a given CPU interrupt. Obviously, since we have to give some cookie to the devices to identify the interrupt, we end up having a numeric array. > But we still want dino/PCI to work. So we have to replace the > existing abstraction with another one... Yes, the abstraction for dino/PCI is that we allocate extra interrupts to the region, but they're unequivocally tied to the give CPU interrupt line the dino happens to be using. > A single global array can implement a hierarchy as well. > Entries just contain indexes into other parts of the array. Yes, but we need to expose only the cpu interrupts to irqbalanced. The problem is that for the purposes of affinity, we can't treat the fictitious subordinate interrupts as being ordinary independent interrupts. James _______________________________________________ parisc-linux mailing list parisc-linux@lists.parisc-linux.org http://lists.parisc-linux.org/mailman/listinfo/parisc-linux