From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.mail.elte.hu (mx2.mail.elte.hu [157.181.151.9]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id F06BE67BF7 for ; Tue, 21 Nov 2006 04:27:42 +1100 (EST) Date: Mon, 20 Nov 2006 18:26:42 +0100 From: Ingo Molnar To: Sergei Shtylyov Subject: Re: [PATCH] 2.6.18-rt7: PowerPC: fix breakage in threaded fasteoi type IRQ handlers Message-ID: <20061120172642.GA8683@elte.hu> References: <200611192243.34850.sshtylyov@ru.mvista.com> <1163966437.5826.99.camel@localhost.localdomain> <20061119200650.GA22949@elte.hu> <1163967590.5826.104.camel@localhost.localdomain> <20061119202348.GA27649@elte.hu> <1163985380.5826.139.camel@localhost.localdomain> <20061120100144.GA27812@elte.hu> <4561C9EC.3020506@ru.mvista.com> <20061120165621.GA1504@elte.hu> <4561DFE1.4020708@ru.mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <4561DFE1.4020708@ru.mvista.com> Cc: dwalker@mvista.com, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , * Sergei Shtylyov wrote: > Hello. > > Ingo Molnar wrote: > > >>>on PPC64, 'get the vector' initiates an ACK as well - is that done > >>>before handle_irq() is done? > > >> Exactly. How else do_IRQ() would know the vector? > > >the reason i'm asking is that in this case masking is a bit late at this > >point and there's a chance for a repeat interrupt. > > How's that? Acknowledge != EOI on OpenPIC (as well as 8259). > Acknoledging sets the bit in the in-service register preventing all > the interrupts with same or lower prioriry from being accepted. ah, ok. The x86 APIC does that automatically, and only an EOI has to be passed. So i guess we are in wild agreement ;) i'm hacking up something now to see whether it makes sense to introduce a central threaded flow type, or whether it's better the branch off the current flow types (as the code does it right now). Ingo From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966251AbWKTR2E (ORCPT ); Mon, 20 Nov 2006 12:28:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S966253AbWKTR2D (ORCPT ); Mon, 20 Nov 2006 12:28:03 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:12684 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S966246AbWKTR1o (ORCPT ); Mon, 20 Nov 2006 12:27:44 -0500 Date: Mon, 20 Nov 2006 18:26:42 +0100 From: Ingo Molnar To: Sergei Shtylyov Cc: Benjamin Herrenschmidt , linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org, dwalker@mvista.com Subject: Re: [PATCH] 2.6.18-rt7: PowerPC: fix breakage in threaded fasteoi type IRQ handlers Message-ID: <20061120172642.GA8683@elte.hu> References: <200611192243.34850.sshtylyov@ru.mvista.com> <1163966437.5826.99.camel@localhost.localdomain> <20061119200650.GA22949@elte.hu> <1163967590.5826.104.camel@localhost.localdomain> <20061119202348.GA27649@elte.hu> <1163985380.5826.139.camel@localhost.localdomain> <20061120100144.GA27812@elte.hu> <4561C9EC.3020506@ru.mvista.com> <20061120165621.GA1504@elte.hu> <4561DFE1.4020708@ru.mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4561DFE1.4020708@ru.mvista.com> User-Agent: Mutt/1.4.2.2i X-ELTE-SpamScore: -4.1 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-4.1 required=5.9 tests=ALL_TRUSTED,AWL,BAYES_20 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts -2.0 BAYES_20 BODY: Bayesian spam probability is 5 to 20% [score: 0.0937] 1.1 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Sergei Shtylyov wrote: > Hello. > > Ingo Molnar wrote: > > >>>on PPC64, 'get the vector' initiates an ACK as well - is that done > >>>before handle_irq() is done? > > >> Exactly. How else do_IRQ() would know the vector? > > >the reason i'm asking is that in this case masking is a bit late at this > >point and there's a chance for a repeat interrupt. > > How's that? Acknowledge != EOI on OpenPIC (as well as 8259). > Acknoledging sets the bit in the in-service register preventing all > the interrupts with same or lower prioriry from being accepted. ah, ok. The x86 APIC does that automatically, and only an EOI has to be passed. So i guess we are in wild agreement ;) i'm hacking up something now to see whether it makes sense to introduce a central threaded flow type, or whether it's better the branch off the current flow types (as the code does it right now). Ingo