From: Mel Gorman Date: Mon, 7 Oct 2013 10:28:58 +0000 (+0100) Subject: sched/numa: Select a preferred node with the most numa hinting faults X-Git-Tag: v3.13-rc1~148^2~70 X-Git-Url: http://pileus.org/git/?a=commitdiff_plain;h=688b7585d16ab57a17aa4422a3b290b3a55fa679;p=~andy%2Flinux sched/numa: Select a preferred node with the most numa hinting faults 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 Reviewed-by: Rik van Riel Cc: Andrea Arcangeli Cc: Johannes Weiner Cc: Srikar Dronamraju Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1381141781-10992-21-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar --- diff --git a/include/linux/sched.h b/include/linux/sched.h index a810e95bca2..b1fc75e7187 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1344,6 +1344,7 @@ 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 6808d35fd7e..d15cd70f85b 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1633,6 +1633,7 @@ 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; p->numa_work.next = &p->numa_work; p->numa_faults = NULL; #endif /* CONFIG_NUMA_BALANCING */ diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 0bb3e0aa110..9efd34f63e8 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -879,7 +879,8 @@ static unsigned int task_scan_max(struct task_struct *p) static void task_numa_placement(struct task_struct *p) { - int seq; + int seq, nid, max_nid = -1; + unsigned long max_faults = 0; if (!p->mm) /* for example, ksmd faulting in a user's mm */ return; @@ -889,7 +890,19 @@ static void task_numa_placement(struct task_struct *p) p->numa_scan_seq = seq; p->numa_scan_period_max = task_scan_max(p); - /* FIXME: Scheduling placement policy hints go here */ + /* Find the node with the highest number of faults */ + for_each_online_node(nid) { + unsigned long faults = p->numa_faults[nid]; + p->numa_faults[nid] >>= 1; + if (faults > max_faults) { + max_faults = faults; + max_nid = nid; + } + } + + /* Update the tasks preferred node if necessary */ + if (max_faults && max_nid != p->numa_preferred_nid) + p->numa_preferred_nid = max_nid; } /*