From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752668AbeFDKBR (ORCPT ); Mon, 4 Jun 2018 06:01:17 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:34396 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752416AbeFDKBO (ORCPT ); Mon, 4 Jun 2018 06:01:14 -0400 From: Srikar Dronamraju To: Ingo Molnar , Peter Zijlstra Cc: LKML , Mel Gorman , Rik van Riel , Srikar Dronamraju , Thomas Gleixner Subject: [PATCH 09/19] sched/numa: Modify migrate_swap to accept additional params Date: Mon, 4 Jun 2018 15:30:18 +0530 X-Mailer: git-send-email 2.7.4 In-Reply-To: <1528106428-19992-1-git-send-email-srikar@linux.vnet.ibm.com> References: <1528106428-19992-1-git-send-email-srikar@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18060410-0008-0000-0000-000002437372 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18060410-0009-0000-0000-000021A93244 Message-Id: <1528106428-19992-10-git-send-email-srikar@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-06-04_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1805220000 definitions=main-1806040123 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There are checks in migrate_swap_stop that check if the task/cpu combination is as per migrate_swap_arg before migrating. However atleast one of the two tasks to be swapped by migrate_swap could have migrated to a completely different cpu before updating the migrate_swap_arg. The new cpu where the task is currently running could be a different node too. If the task has migrated, numa balancer might end up placing a task in a wrong node. Instead of achieving node consolidation, it may end up spreading the load across nodes. To avoid that pass the cpus as additional parameters. While here, place migrate_swap under CONFIG_NUMA_BALANCING. Signed-off-by: Srikar Dronamraju --- kernel/sched/core.c | 9 ++++++--- kernel/sched/fair.c | 3 ++- kernel/sched/sched.h | 3 ++- 3 files changed, 10 insertions(+), 5 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 092f7c4..68849c2 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1178,6 +1178,7 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu) __set_task_cpu(p, new_cpu); } +#ifdef CONFIG_NUMA_BALANCING static void __migrate_swap_task(struct task_struct *p, int cpu) { if (task_on_rq_queued(p)) { @@ -1259,16 +1260,17 @@ static int migrate_swap_stop(void *data) /* * Cross migrate two tasks */ -int migrate_swap(struct task_struct *cur, struct task_struct *p) +int migrate_swap(struct task_struct *cur, struct task_struct *p, + int target_cpu, int curr_cpu) { struct migration_swap_arg arg; int ret = -EINVAL; arg = (struct migration_swap_arg){ .src_task = cur, - .src_cpu = task_cpu(cur), + .src_cpu = curr_cpu, .dst_task = p, - .dst_cpu = task_cpu(p), + .dst_cpu = target_cpu, }; if (arg.src_cpu == arg.dst_cpu) @@ -1293,6 +1295,7 @@ int migrate_swap(struct task_struct *cur, struct task_struct *p) out: return ret; } +#endif /* CONFIG_NUMA_BALANCING */ /* * wait_task_inactive - wait for a thread to unschedule. diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 35c4a75..46d773c 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1810,7 +1810,8 @@ static int task_numa_migrate(struct task_struct *p) return ret; } - ret = migrate_swap(p, env.best_task); + ret = migrate_swap(p, env.best_task, env.best_cpu, env.src_cpu); + if (ret != 0) trace_sched_stick_numa(p, env.src_cpu, task_cpu(env.best_task)); put_task_struct(env.best_task); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 15750c2..211841e 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1068,7 +1068,8 @@ enum numa_faults_stats { }; extern void sched_setnuma(struct task_struct *p, int node); extern int migrate_task_to(struct task_struct *p, int cpu); -extern int migrate_swap(struct task_struct *, struct task_struct *); +extern int migrate_swap(struct task_struct *p, struct task_struct *t, + int cpu, int scpu); #endif /* CONFIG_NUMA_BALANCING */ #ifdef CONFIG_SMP -- 1.8.3.1