From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752173AbbASEyC (ORCPT ); Sun, 18 Jan 2015 23:54:02 -0500 Received: from mail-qg0-f44.google.com ([209.85.192.44]:60422 "EHLO mail-qg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751185AbbASEv4 (ORCPT ); Sun, 18 Jan 2015 23:51:56 -0500 From: Xunlei Pang To: linux-kernel@vger.kernel.org Cc: Peter Zijlstra , Juri Lelli , Xunlei Pang Subject: [PATCH 3/5] sched/deadline: Fix wrong cpudl_find() in check_preempt_equal_dl() Date: Mon, 19 Jan 2015 04:49:38 +0000 Message-Id: <1421642980-10045-3-git-send-email-pang.xunlei@linaro.org> X-Mailer: git-send-email 2.2.1 In-Reply-To: <1421642980-10045-1-git-send-email-pang.xunlei@linaro.org> References: <1421642980-10045-1-git-send-email-pang.xunlei@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In check_preempt_equal_dl(), cpudl_find() is called with a NULL later_mask, thus cpudl_find() here doesn't check cpudl::free_cpus at all. This patch takles this issue by always passing a non-NULL later_mask to cpudl_find(), thereby fixing this issue. Signed-off-by: Xunlei Pang --- kernel/sched/cpudeadline.c | 8 +++----- kernel/sched/deadline.c | 15 +++++++++++---- 2 files changed, 14 insertions(+), 9 deletions(-) diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c index c6acb07..f331fcf 100644 --- a/kernel/sched/cpudeadline.c +++ b/kernel/sched/cpudeadline.c @@ -97,7 +97,7 @@ static inline int cpudl_maximum(struct cpudl *cp) * cpudl_find - find the best (later-dl) CPU in the system * @cp: the cpudl max-heap context * @p: the task - * @later_mask: a mask to fill in with the selected CPUs (or NULL) + * @later_mask: a mask to fill in with the selected CPUs (not NULL) * * Returns: int - best CPU (heap maximum if suitable) */ @@ -107,15 +107,13 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p, int best_cpu = -1; const struct sched_dl_entity *dl_se = &p->dl; - if (later_mask && - cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) { + if (cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) { best_cpu = cpumask_any(later_mask); goto out; } else if (cpumask_test_cpu(cpudl_maximum(cp), &p->cpus_allowed) && dl_time_before(dl_se->deadline, cp->elements[0].dl)) { best_cpu = cpudl_maximum(cp); - if (later_mask) - cpumask_set_cpu(best_cpu, later_mask); + cpumask_set_cpu(best_cpu, later_mask); } out: diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index e7b2722..82d900f 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -943,14 +943,23 @@ out: return cpu; } +static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask_dl); + static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p) { + struct cpumask *later_mask = + this_cpu_cpumask_var_ptr(local_cpu_mask_dl); + + /* Make sure the mask is initialized first */ + if (unlikely(!later_mask)) + return; + /* * Current can't be migrated, useless to reschedule, * let's hope p can move out. */ if (rq->curr->nr_cpus_allowed == 1 || - cpudl_find(&rq->rd->cpudl, rq->curr, NULL) == -1) + cpudl_find(&rq->rd->cpudl, rq->curr, later_mask) == -1) return; /* @@ -958,7 +967,7 @@ static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p) * see if it is pushed or pulled somewhere else. */ if (p->nr_cpus_allowed != 1 && - cpudl_find(&rq->rd->cpudl, p, NULL) != -1) + cpudl_find(&rq->rd->cpudl, p, later_mask) != -1) return; resched_curr(rq); @@ -1145,8 +1154,6 @@ next_node: return NULL; } -static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask_dl); - static int find_later_rq(struct task_struct *task) { struct sched_domain *sd; -- 1.9.1