From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xiaotian Feng Subject: Re: [Next] CPU Hotplug test failures on powerpc Date: Wed, 16 Dec 2009 14:56:01 +0800 Message-ID: <7b6bb4a50912152256j58cdc8f6u7fc0f38c60281dc8@mail.gmail.com> References: <4B2224C7.1020908@in.ibm.com> <1260786122.4165.142.camel@twins> <4B261D7A.9040802@in.ibm.com> <1260793182.4165.223.camel@twins> <1260825420.2217.40.camel@pasglop> <4B275A6B.9030200@in.ibm.com> <1260873827.4165.362.camel@twins> <4B279370.5050800@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-pw0-f42.google.com ([209.85.160.42]:41931 "EHLO mail-pw0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932717AbZLPG4F convert rfc822-to-8bit (ORCPT ); Wed, 16 Dec 2009 01:56:05 -0500 In-Reply-To: <4B279370.5050800@in.ibm.com> Sender: linux-next-owner@vger.kernel.org List-ID: To: Sachin Sant Cc: Peter Zijlstra , Benjamin Herrenschmidt , Linux/PPC Development , linux-kernel , Ingo Molnar , linux-next@vger.kernel.org On Tue, Dec 15, 2009 at 9:47 PM, Sachin Sant wrote= : > Peter Zijlstra wrote: >>> >>> I added some debug statements within the above code. This is a 2 cp= u >>> machine. >>> >>> XMON dest_cpu =3D 1024 . dead_cpu =3D 1 . nr_cpu_ids =3D 2 >>> XMON dest_cpu =3D 1024 XMON dest_cpu =3D 1024 . dead_cpu =3D 1 >>> XMON dest_cpu =3D 1024 . dead_cpu =3D 1 . nr_cpu_ids =3D 2 >>> XMON dest_cpu =3D 1024 XMON dest_cpu =3D 1024 . dead_cpu =3D 1 >>> XMON dest_cpu =3D 1024 . dead_cpu =3D 1 . nr_cpu_ids =3D 2 >>> XMON dest_cpu =3D 1024 XMON dest_cpu =3D 1024 . dead_cpu =3D 1 >>> >>> Seems to me that the control is stuck in an infinite loop and hence= the >>> machine appears to be in hung state. The dest_cpu value is always 1= 024 >>> and never changes, which result in an infinite loop. >>> >>> In working scenario the o/p is something on the following lines >>> >>> XMON dest_cpu =3D 1024 . dead_cpu =3D 1 . nr_cpu_ids =3D 2 >>> XMON dest_cpu =3D 0 XMON dest_cpu =3D 1024 . dead_cpu =3D 1 . nr_cp= u_ids =3D 2 >>> XMON dest_cpu =3D 0 XMON dest_cpu =3D 1024 . dead_cpu =3D 1 . nr_cp= u_ids =3D 2 >>> XMON dest_cpu =3D 0 >>> Let me know if i should try to record any specific value ? >>> >> >> Could you possibly print the two masks themselves? cpumask_scnprintf= () >> and friend come in handy for this. >> >> The dest_cpu=3D1024 thing seem to suggest the intersection between >> p->cpus_allowed and cpu_active_mask is empty for some reason, even >> though we forcefully reset p->cpus_allowed to the full set using >> cpuset_cpus_allowed_locked(). >> > > So here is the data related to the two masks. > > cpu_active_mask =3D 00000000,00000000,00000000,00000000,00000000,0000= 0000, > 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000= 00, > 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000= 00, > 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000= 00, > 00000000,00000000 > XMON dest_cpu =3D 1024 > How about cpu_online_mask? commit 6ad4c1 switches from cpu_online_mask to cpu_active_mask. Is there a mismatch for cpu_online_mask and cpu_active_mask? > while p->cpus_allowed =3D =C2=A000000000,00000000,00000000,00000000,0= 0000000, > 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000= 00, > 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000= 00, > 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000= 00, > 00000000,00000000,00000001 > XMON dest_cpu =3D 1024 > > In working scenario the above data looks like > > cpu_active_mask =3D 00000000,00000000,00000000,00000000,00000000,0000= 0000, > 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000= 00, > 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000= 00, > 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000= 00, > 00000000,00000002 > XMON dest_cpu =3D 1 > > while p->cpus_allowed =3D =C2=A000000000,00000000,00000000,00000000,0= 0000000, > 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000= 00, > 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000= 00, > 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000= 00, > 00000000,00000000,00000002 > XMON dest_cpu =3D 1 > > > hope i got the data correct. > > Thanks > -Sachin > > > -- > > --------------------------------- > Sachin Sant > IBM Linux Technology Center > India Systems and Technology Labs > Bangalore, India > --------------------------------- > > -- > To unsubscribe from this list: send the line "unsubscribe linux-next"= in > the body of a message to majordomo@vger.kernel.org > More majordomo info at =C2=A0http://vger.kernel.org/majordomo-info.ht= ml >