From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from zcars04e.nortel.com (zcars04e.nortel.com [47.129.242.56]) (using TLSv1 with cipher EDH-RSA-DES-CBC3-SHA (168/168 bits)) (Client CN "", Issuer "NORTEL" (not verified)) by ozlabs.org (Postfix) with ESMTPS id AC5F1DDFFC for ; Thu, 14 May 2009 05:45:11 +1000 (EST) Message-ID: <4A0B233B.8010105@nortel.com> Date: Wed, 13 May 2009 13:44:59 -0600 From: "Chris Friesen" MIME-Version: 1.0 To: Andi Kleen Subject: Re: question about softirqs References: <20090512081237.GA16403@elte.hu> <4A09933B.8010606@nortel.com> <874ovpmmdq.fsf@basil.nowhere.org> <4A0AC9EC.6070908@nortel.com> <20090513141532.GT19296@one.firstfloor.org> <87my9hkrmw.fsf@basil.nowhere.org> <4A0AE19D.9040509@nortel.com> <20090513170122.GZ19296@one.firstfloor.org> <4A0B19A9.1090206@nortel.com> <20090513191354.GB19296@one.firstfloor.org> In-Reply-To: <20090513191354.GB19296@one.firstfloor.org> Content-Type: text/plain; charset=ISO-8859-1 Cc: Peter Zijlstra , netdev@vger.kernel.org, Ingo Molnar , Steven Rostedt , linuxppc-dev@ozlabs.org, paulus@samba.org, Thomas Gleixner , David Miller List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Andi Kleen wrote: > On Wed, May 13, 2009 at 01:04:09PM -0600, Chris Friesen wrote: >> Andi Kleen wrote: >> >>> network packets are normally processed by the network packet interrupt's >>> softirq or alternatively in the NAPI poll loop. >> If we have a high priority task, ksoftirqd may not get a chance to run. > > In this case the next interrupt will also process them. It will just > go more slowly because interrupts limit the work compared to ksoftirqd. I realize that they will eventually get processed. My point is that the documentation (in-kernel, online, and in various books) says that softirqs will be processed _on the return from a syscall_. As we all agree, this is not necessarily the case. Chris