From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752501AbbCQCn6 (ORCPT ); Mon, 16 Mar 2015 22:43:58 -0400 Received: from mga03.intel.com ([134.134.136.65]:34367 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751423AbbCQCn4 (ORCPT ); Mon, 16 Mar 2015 22:43:56 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.11,413,1422950400"; d="scan'208";a="666191952" Date: Tue, 17 Mar 2015 10:25:50 +0800 From: Wanpeng Li To: Ingo Molnar Cc: Peter Zijlstra , Juri Lelli , linux-kernel@vger.kernel.org, Wanpeng Li Subject: Re: [PATCH RESEND v2] sched/deadline: fix rt runtime corrupt when dl refuse a smaller bandwidth Message-ID: <20150317022550.GC3953@kernel> Reply-To: Wanpeng Li References: <1426231680-12056-1-git-send-email-wanpeng.li@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1426231680-12056-1-git-send-email-wanpeng.li@linux.intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ping Ingo, ;-) On Fri, Mar 13, 2015 at 03:28:00PM +0800, Wanpeng Li wrote: >Dl class will refuse the bandwidth being set to some value smaller >than the currently allocated bandwidth in any of the root_domains >through sched_rt_runtime_us and sched_rt_period_us. RT runtime will >be set according to sched_rt_runtime_us before dl class verify if >the new bandwidth is suitable in the case of !CONFIG_RT_GROUP_SCHED. > >However, rt runtime will be corrupt if dl refuse the new bandwidth >since there is no undo to reset the rt runtime to the old value. > >This patch fix it by verifying new bandwidth for deadline in advance. > >Acked-by: Juri Lelli >Signed-off-by: Wanpeng Li >--- > kernel/sched/core.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > >diff --git a/kernel/sched/core.c b/kernel/sched/core.c >index 97fe79c..e884909 100644 >--- a/kernel/sched/core.c >+++ b/kernel/sched/core.c >@@ -7815,7 +7815,7 @@ static int sched_rt_global_constraints(void) > } > #endif /* CONFIG_RT_GROUP_SCHED */ > >-static int sched_dl_global_constraints(void) >+static int sched_dl_global_validate(void) > { > u64 runtime = global_rt_runtime(); > u64 period = global_rt_period(); >@@ -7916,11 +7916,11 @@ int sched_rt_handler(struct ctl_table *table, int write, > if (ret) > goto undo; > >- ret = sched_rt_global_constraints(); >+ ret = sched_dl_global_validate(); > if (ret) > goto undo; > >- ret = sched_dl_global_constraints(); >+ ret = sched_rt_global_constraints(); > if (ret) > goto undo; > >-- >1.9.1