From e452657576a12abce9fe2291db372145a86862bc Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 9 Oct 2012 14:09:50 +0200 Subject: [PATCH] sched/numa: Implement migration throttle Since our memory migration requires 2 scans/samples to stabilize, don't migrate faster than that. Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/n/tip-jye7o9wfton73dra5r9hobft@git.kernel.org Signed-off-by: Ingo Molnar --- include/linux/sched.h | 2 ++ kernel/sched/core.c | 1 + kernel/sched/fair.c | 16 +++++++++++++--- kernel/sched/features.h | 1 + kernel/sysctl.c | 7 +++++++ 5 files changed, 24 insertions(+), 3 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index d6818d7aa6ed..99a70eb80e90 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1524,6 +1524,7 @@ struct task_struct { #ifdef CONFIG_SCHED_NUMA int node; /* task home node */ int numa_scan_seq; + int numa_migrate_seq; u64 node_stamp; /* migration stamp */ unsigned long numa_contrib; unsigned long *numa_faults; @@ -2076,6 +2077,7 @@ extern unsigned int sysctl_sched_time_avg; extern unsigned int sysctl_timer_migration; extern unsigned int sysctl_sched_shares_window; extern unsigned int sysctl_sched_numa_task_period; +extern unsigned int sysctl_sched_numa_settle_count; int sched_proc_update_handler(struct ctl_table *table, int write, void __user *buffer, size_t *length, diff --git a/kernel/sched/core.c b/kernel/sched/core.c index b149cadbac15..c7d0b945db3d 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1543,6 +1543,7 @@ static void __sched_fork(struct task_struct *p) p->node = -1; p->node_stamp = 0ULL; p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0; + p->numa_migrate_seq = p->mm ? p->mm->numa_scan_seq : 0; p->numa_faults = NULL; #endif /* CONFIG_SCHED_NUMA */ } diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index f8eb98e92f95..592291bc8ede 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -811,9 +811,14 @@ static void account_offnode_dequeue(struct rq *rq, struct task_struct *p) } /* - * numa task sample period in ms: 2.5s + * numa task sample period in ms: 5s */ -unsigned int sysctl_sched_numa_task_period = 2500; +unsigned int sysctl_sched_numa_task_period = 5000; + +/* + * Wait for the 2-sample stuff to settle before migrating again + */ +unsigned int sysctl_sched_numa_settle_count = 2; /* * Got a PROT_NONE fault for a page on @node. @@ -859,8 +864,13 @@ void task_numa_placement(void) p->numa_faults[node] /= 2; } - if (max_node != -1 && p->node != max_node) + if (max_node != -1 && p->node != max_node) { + if (sched_feat(NUMA_SETTLE) && + (seq - p->numa_migrate_seq) <= (int)sysctl_sched_numa_settle_count) + return; + p->numa_migrate_seq = seq; sched_setnode(p, max_node); + } } /* diff --git a/kernel/sched/features.h b/kernel/sched/features.h index 64ead4904e7f..f8a7aebaa022 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -69,5 +69,6 @@ SCHED_FEAT(NUMA_TTWU_BIAS, false) SCHED_FEAT(NUMA_TTWU_TO, false) SCHED_FEAT(NUMA_PULL, true) SCHED_FEAT(NUMA_PULL_BIAS, true) +SCHED_FEAT(NUMA_SETTLE, true) #endif diff --git a/kernel/sysctl.c b/kernel/sysctl.c index c08b95e73f84..446bbefa1c30 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -353,6 +353,13 @@ static struct ctl_table kern_table[] = { .mode = 0644, .proc_handler = proc_dointvec, }, + { + .procname = "sched_numa_settle_count", + .data = &sysctl_sched_numa_settle_count, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, #endif /* CONFIG_SCHED_NUMA */ #endif /* CONFIG_SCHED_DEBUG */ { -- 2.39.5