From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id C82B42C0095 for ; Wed, 24 Jul 2013 14:46:32 +1000 (EST) Message-ID: <1374641175.3916.111.camel@pasglop> Subject: Re: [PATCH] powerpc: VPHN topology change updates all siblings From: Benjamin Herrenschmidt To: Robert Jennings Date: Wed, 24 Jul 2013 14:46:15 +1000 In-Reply-To: <20130723123344.GA11611@linux.vnet.ibm.com> References: <20130723123344.GA11611@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Cc: stable@vger.kernel.org, Paul Mackerras , Nathan Fontenot , linuxppc-dev@lists.ozlabs.org, Jan Stancek List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2013-07-23 at 07:33 -0500, Robert Jennings wrote: > When an associativity level change is found for one thread, the > siblings threads need to be updated as well. This is done today > for PRRN in stage_topology_update() but is missing for VPHN in > update_cpu_associativity_changes_mask(). > > All threads should be updated to move to the new node. Without this > patch, a single thread may be flagged for a topology change, leaving it > in a different node from its siblings, which is incorrect. This causes > problems for the scheduler where overlapping scheduler groups are created > and a loop is formed in those groups. > > Reported-by: Jan Stancek > Signed-off-by: Robert Jennings > Cc: Patch breaks the UP build ... Cheers, Ben.