From c3b9bc5bbfc3750570d788afffd431263ef695c6 Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Tue, 11 Aug 2015 16:30:12 +0530 Subject: [PATCH] sched/numa: Disable sched_numa_balancing on UMA systems Commit 2a1ed24 ("sched/numa: Prefer NUMA hotness over cache hotness") sets sched feature NUMA to true. However this can enable NUMA hinting faults on a UMA system. This commit ensures that NUMA hinting faults occur only on a NUMA system by setting/resetting sched_numa_balancing. This commit: - Makes sched_numa_balancing common to CONFIG_SCHED_DEBUG and !CONFIG_SCHED_DEBUG. Earlier it was only in !CONFIG_SCHED_DEBUG. - Checks for sched_numa_balancing instead of sched_feat(NUMA). Signed-off-by: Srikar Dronamraju Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mel Gorman Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1439290813-6683-3-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 14 +++++--------- kernel/sched/fair.c | 4 ++-- kernel/sched/sched.h | 6 ------ 3 files changed, 7 insertions(+), 17 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 2656af00ea5e..ca665f8bec98 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2115,22 +2115,18 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p) } #ifdef CONFIG_NUMA_BALANCING -#ifdef CONFIG_SCHED_DEBUG +__read_mostly bool sched_numa_balancing; + void set_numabalancing_state(bool enabled) { + sched_numa_balancing = enabled; +#ifdef CONFIG_SCHED_DEBUG if (enabled) sched_feat_set("NUMA"); else sched_feat_set("NO_NUMA"); -} -#else -__read_mostly bool sched_numa_balancing; - -void set_numabalancing_state(bool enabled) -{ - sched_numa_balancing = enabled; -} #endif /* CONFIG_SCHED_DEBUG */ +} #ifdef CONFIG_PROC_SYSCTL int sysctl_numa_balancing(struct ctl_table *table, int write, diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 3a6ac5598bff..e8f0828f4137 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5562,10 +5562,10 @@ static int migrate_degrades_locality(struct task_struct *p, struct lb_env *env) unsigned long src_faults, dst_faults; int src_nid, dst_nid; - if (!p->numa_faults || !(env->sd->flags & SD_NUMA)) + if (!sched_numa_balancing) return -1; - if (!sched_feat(NUMA)) + if (!p->numa_faults || !(env->sd->flags & SD_NUMA)) return -1; src_nid = cpu_to_node(env->src_cpu); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index d0b303d675d6..0d8f885b215b 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1004,14 +1004,8 @@ extern struct static_key sched_feat_keys[__SCHED_FEAT_NR]; #endif /* SCHED_DEBUG && HAVE_JUMP_LABEL */ #ifdef CONFIG_NUMA_BALANCING -#define sched_feat_numa(x) sched_feat(x) -#ifdef CONFIG_SCHED_DEBUG -#define sched_numa_balancing sched_feat_numa(NUMA) -#else extern bool sched_numa_balancing; -#endif /* CONFIG_SCHED_DEBUG */ #else -#define sched_feat_numa(x) (0) #define sched_numa_balancing (0) #endif /* CONFIG_NUMA_BALANCING */ -- 2.20.1