Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759750Ab2JLPYt (ORCPT ); Fri, 12 Oct 2012 11:24:49 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:39076 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758028Ab2JLPYr (ORCPT ); Fri, 12 Oct 2012 11:24:47 -0400 Subject: RE: [PATCH] genirq: for edge interrupt IRQS_ONESHOT support with irq thread From: anish kumar To: "Liu, Chuansheng" Cc: Thomas Gleixner , "linux-kernel@vger.kernel.org" In-Reply-To: <27240C0AC20F114CBF8149A2696CBE4A195A6B@SHSMSX101.ccr.corp.intel.com> References: <1350045084.13178.19.camel@cliu38-desktop-build> <27240C0AC20F114CBF8149A2696CBE4A19587A@SHSMSX101.ccr.corp.intel.com> <27240C0AC20F114CBF8149A2696CBE4A1958B9@SHSMSX101.ccr.corp.intel.com> <27240C0AC20F114CBF8149A2696CBE4A195A6B@SHSMSX101.ccr.corp.intel.com> Content-Type: text/plain; charset="UTF-8" Date: Sat, 13 Oct 2012 00:24:38 +0900 Message-ID: <1350055478.8329.24.camel@anish-Inspiron-N5050> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1575 Lines: 28 On Fri, 2012-10-12 at 14:57 +0000, Liu, Chuansheng wrote: > > On SMP an interrupt which is raised after the ack() again before the > > handler finishes, can invoke another delivery on a different CPU, > > which then sees the IRQ_INPROGESS flag, masks it and flags it > > PENDING. When the primary handler on the first CPU returns, it sees > > the PENDING flag, unmasks and invokes the handler another time. > In this case, when IRQ_INPROGRESS flag is set, on another CPU, it will > mask and ack it, if before the primary handler on the first CPU returns, > the edge interrupt is raised again, it will be lost, right? Why will the interrupt be raised again?Is not it masked?I read tglx statement as this:if the interrupt is being handled on one core, then the delivery of new interrupt can be on the second core and in that case it will see IRQ_INPROGRESS flag and it will *mask* it and set the flag as pending.So there is no chance of any new interrupt. > So I think set PENDING just confirm one time, it just depends on primary handler > execution time and irq frequency. > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/