From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755910AbcIFItp (ORCPT ); Tue, 6 Sep 2016 04:49:45 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:58374 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754068AbcIFItl (ORCPT ); Tue, 6 Sep 2016 04:49:41 -0400 Date: Tue, 6 Sep 2016 10:48:39 +0200 From: Peter Zijlstra To: Byungchul Park Cc: mingo@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched/fair: Fix update_min_vruntime() to get proper min_vruntime Message-ID: <20160906084839.GG10153@twins.programming.kicks-ass.net> References: <1473138317-8789-1-git-send-email-byungchul.park@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1473138317-8789-1-git-send-email-byungchul.park@lge.com> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 06, 2016 at 02:05:17PM +0900, Byungchul Park wrote: > From 295895be8befbab040d6054bb8186c03daabcedd Mon Sep 17 00:00:00 2001 > From: Byungchul Park > Date: Tue, 6 Sep 2016 12:22:26 +0900 > Subject: [PATCH] sched/fair: Fix update_min_vruntime() to get proper > min_vruntime > > Commit 97a7142 'sched/fair: Make update_min_vruntime() more readable' > introduces a bug that cfs_rq gets a wrong min_vruntime if > !cfs_rq->rb_leftmost && cfs_rq->curr. This fixes it and makes it more > readable and simple. Urgh, I actually stared at that patch for quite a time and somehow convinced myself it was good. I actually considered that scenario I think. /me thinks more.. Argh, I'm an idiot, you're right. By using min_vruntime() on cfs_rq->curr we take the leftmost and fail to advance min_vruntime in that case. I'll ask Ingo to take the patch out.