From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754582Ab3F1GOs (ORCPT ); Fri, 28 Jun 2013 02:14:48 -0400 Received: from e31.co.us.ibm.com ([32.97.110.149]:49135 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752108Ab3F1GOr (ORCPT ); Fri, 28 Jun 2013 02:14:47 -0400 Date: Fri, 28 Jun 2013 11:44:28 +0530 From: Srikar Dronamraju To: Mel Gorman Cc: Peter Zijlstra , Ingo Molnar , Andrea Arcangeli , Johannes Weiner , Linux-MM , LKML Subject: Re: [PATCH 3/8] sched: Select a preferred node with the most numa hinting faults Message-ID: <20130628061428.GB17195@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <1372257487-9749-1-git-send-email-mgorman@suse.de> <1372257487-9749-4-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <1372257487-9749-4-git-send-email-mgorman@suse.de> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13062806-7282-0000-0000-000018BF4DF2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Mel Gorman [2013-06-26 15:38:02]: > This patch selects a preferred node for a task to run on based on the > NUMA hinting faults. This information is later used to migrate tasks > towards the node during balancing. > > Signed-off-by: Mel Gorman > --- > include/linux/sched.h | 1 + > kernel/sched/core.c | 10 ++++++++++ > kernel/sched/fair.c | 16 ++++++++++++++-- > kernel/sched/sched.h | 2 +- > 4 files changed, 26 insertions(+), 3 deletions(-) > > diff --git a/include/linux/sched.h b/include/linux/sched.h > index 72861b4..ba46a64 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -1507,6 +1507,7 @@ struct task_struct { > struct callback_head numa_work; > > unsigned long *numa_faults; > + int numa_preferred_nid; > #endif /* CONFIG_NUMA_BALANCING */ > > struct rcu_head rcu; > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index f332ec0..019baae 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -1593,6 +1593,7 @@ static void __sched_fork(struct task_struct *p) > p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0; > p->numa_migrate_seq = p->mm ? p->mm->numa_scan_seq - 1 : 0; > p->numa_scan_period = sysctl_numa_balancing_scan_delay; > + p->numa_preferred_nid = -1; Though we may not want to inherit faults, I think the tasks generally share pages with their siblings, parent. So will it make sense to inherit the preferred node? > p->numa_work.next = &p->numa_work; > p->numa_faults = NULL; > #endif /* CONFIG_NUMA_BALANCING */ > @@ -5713,6 +5714,15 @@ enum s_alloc { > > struct sched_domain_topology_level; > > +#ifdef CONFIG_NUMA_BALANCING > + > +/* Set a tasks preferred NUMA node */ > +void sched_setnuma(struct task_struct *p, int nid) > +{ > + p->numa_preferred_nid = nid; > +} > +#endif /* CONFIG_NUMA_BALANCING */ > + > typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu); > typedef const struct cpumask *(*sched_domain_mask_f)(int cpu); > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 904fd6f..f8c3f61 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -793,7 +793,8 @@ unsigned int sysctl_numa_balancing_scan_delay = 1000; > > static void task_numa_placement(struct task_struct *p) > { > - int seq; > + int seq, nid, max_nid = 0; > + unsigned long max_faults = 0; > > if (!p->mm) /* for example, ksmd faulting in a user's mm */ > return; > @@ -802,7 +803,18 @@ static void task_numa_placement(struct task_struct *p) > return; > p->numa_scan_seq = seq; > > - /* FIXME: Scheduling placement policy hints go here */ > + /* Find the node with the highest number of faults */ > + for (nid = 0; nid < nr_node_ids; nid++) { > + unsigned long faults = p->numa_faults[nid]; > + p->numa_faults[nid] >>= 1; > + if (faults > max_faults) { > + max_faults = faults; > + max_nid = nid; > + } > + } > + > + if (max_faults && max_nid != p->numa_preferred_nid) > + sched_setnuma(p, max_nid); > } > > /* > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > index 9c26d88..65a0cf0 100644 > --- a/kernel/sched/sched.h > +++ b/kernel/sched/sched.h > @@ -504,7 +504,7 @@ DECLARE_PER_CPU(struct rq, runqueues); > #define raw_rq() (&__raw_get_cpu_var(runqueues)) > > #ifdef CONFIG_NUMA_BALANCING > -extern void sched_setnuma(struct task_struct *p, int node, int shared); > +extern void sched_setnuma(struct task_struct *p, int nid); > static inline void task_numa_free(struct task_struct *p) > { > kfree(p->numa_faults); > -- > 1.8.1.4 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: email@kvack.org -- Thanks and Regards Srikar Dronamraju