From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Bristot de Oliveira Subject: [PATCH V2 0/2] rt: Increase/decrease the nr of migratory tasks when enabling/disabling migration Date: Mon, 26 Jun 2017 17:07:13 +0200 Message-ID: Cc: "Luis Claudio R . Goncalves" , Clark Williams , Luiz Capitulino , Sebastian Andrzej Siewior , Thomas Gleixner , Steven Rostedt , Peter Zijlstra , Ingo Molnar , LKML To: linux-rt-users Return-path: Received: from mx1.redhat.com ([209.132.183.28]:46192 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751473AbdFZPLj (ORCPT ); Mon, 26 Jun 2017 11:11:39 -0400 Sender: linux-rt-users-owner@vger.kernel.org List-ID: This is the continuation of the: [RFC] rt: Some fixes for migrate_disable/enable However, migrate_disable/enable was reworked during the 4.11-rt window, so it turns out that 2 of 3 problems were fixed. Good! But there is still one problem, which is the dl/rt_nr_migratory inc/dec. The problem is reproducible with the following command [in a 4 CPU box]: # chrt -f 1 taskset -c 3 cat /dev/full | taskset -c 0-2 grep 'batman' By applying only the patch 1/2, it is possible to see the problem with the following command: # cat /proc/sched_debug | grep rt_nr_migratory .rt_nr_migratory : 18446744073709542849 .rt_nr_migratory : 18446744073709538566 .rt_nr_migratory : 18446744073709548257 .rt_nr_migratory : 0 The detailed description of the bug, and the fix, is in the log of the patch 2/2. Changes from V1: - Print .dl/rt_nr_migratory only if CONFIG_SMP is set (Ingo Molnar) - Use helper functions to reduce duplicated code (Ingo Molnar) Changes from RFC: - The problems addressed in the patches: x rt: Update nr_cpus_allowed if the affinity of a task changes while its migration is disabled x rt: Checks if task needs migration when re-enabling migration were fixed, so these patches are not needed anymore, while patch: x rt: Increase/decrease the nr of migratory tasks when enabling/disabling migration is still needed, so it was reworked for the new implementation. - The patch showing the rt/dl_nr_migratory was added. Daniel Bristot de Oliveira (2): sched/debug: Inform the number of rt/dl task that can migrate rt: Increase/decrease the nr of migratory tasks when enabling/disabling migration kernel/sched/core.c | 49 ++++++++++++++++++++++++++++++++++++++++++++----- kernel/sched/debug.c | 17 +++++++++++++++-- 2 files changed, 59 insertions(+), 7 deletions(-) -- 2.9.4