From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id AEECBB6EF6 for ; Wed, 16 Dec 2009 18:18:27 +1100 (EST) Subject: Re: [Next] CPU Hotplug test failures on powerpc From: Peter Zijlstra To: Sachin Sant In-Reply-To: <4B288413.2070704@in.ibm.com> References: <4B2224C7.1020908@in.ibm.com> <7b6bb4a50912152225p4f5dde13re83c439407c16eaf@mail.gmail.com> <4B288131.2050306@in.ibm.com> <7b6bb4a50912152245v61a7f1ebgb41f4857134f3476@mail.gmail.com> <4B288413.2070704@in.ibm.com> Content-Type: text/plain; charset="UTF-8" Date: Wed, 16 Dec 2009 08:18:10 +0100 Message-ID: <1260947890.8023.1281.camel@laptop> Mime-Version: 1.0 Cc: linux-kernel , Linux/PPC Development , linux-next@vger.kernel.org, Xiaotian Feng , Ingo Molnar List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, 2009-12-16 at 12:24 +0530, Sachin Sant wrote: > Xiaotian Feng wrote: > > On Wed, Dec 16, 2009 at 2:41 PM, Sachin Sant wrote: > > > >> Xiaotian Feng wrote: > >> > >>> Does this testcase hotplug cpu 0 off? > >>> > >>> > >> No, i don't think so. It skips cpu0 during online/offline > >> process. > >> > > > > Then how could this happen ? Looks like cpu 0 is offline .... > > 0:mon> <4>IRQ 17 affinity broken off cpu 0 > > <4>IRQ 18 affinity broken off cpu 0 > > <4>IRQ 19 affinity broken off cpu 0 > > <4>IRQ 264 affinity broken off cpu 0 > > <4>cpu 0 (hwid 0) Ready to die... > > <7>clockevent: decrementer mult[83126e97] shift[32] cpu[0] > > > Sorry i was looking at only one script. Looking more closely > at the test there are 6 different sub tests. The rest of the > tests do seem to hotplug CPU 0. Ooh, cute, so you can actually hotplug cpu 0.. no wonder that didn't get exposed on x86. Still, the only time cpu_active_mask should not be equal to cpu_online_mask is when we're in the middle of a hotplug, we clear active early and set it late, but its all done under the hotplug mutex, so we can at most have 1 cpu differences with online mask. Unless of course, I messed up, which appears to be rather likely given these problems ;-)