Subject: sched, numa: migrates_degrades_locality() From: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Date: Mon Jul 22 14:02:54 CEST 2013 It just makes heaps of sense; so add it and make both it and migrate_improve_locality() a sched_feat(). Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/n/tip-fwfjk3f8a29o3zx03h1ejb0y@xxxxxxxxxxxxxx --- kernel/sched/fair.c | 35 +++++++++++++++++++++++++++++++++-- kernel/sched/features.h | 2 ++ 2 files changed, 35 insertions(+), 2 deletions(-) --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4323,7 +4323,7 @@ static bool migrate_improves_locality(st { int src_nid, dst_nid; - if (!sched_feat(NUMA_BALANCE)) + if (!sched_feat(NUMA_BALANCE) || !sched_feat(NUMA_FAULTS_UP)) return false; if (!p->numa_faults || !(env->sd->flags & SD_NUMA)) @@ -4336,7 +4336,30 @@ static bool migrate_improves_locality(st p->numa_migrate_seq >= sysctl_numa_balancing_settle_count) return false; - if (p->numa_preferred_nid == dst_nid) + if (task_faults(p, dst_nid) > task_faults(p, src_nid)) + return true; + + return false; +} + +static bool migrate_degrades_locality(struct task_struct *p, struct lb_env *env) +{ + int src_nid, dst_nid; + + if (!sched_feat(NUMA_BALANCE) || !sched_feat(NUMA_FAULTS_DOWN)) + return false; + + if (!p->numa_faults || !(env->sd->flags & SD_NUMA)) + return false; + + src_nid = cpu_to_node(env->src_cpu); + dst_nid = cpu_to_node(env->dst_cpu); + + if (src_nid == dst_nid || + p->numa_migrate_seq >= sysctl_numa_balancing_settle_count) + return false; + + if (task_faults(p, dst_nid) < task_faults(p, src_nid)) return true; return false; @@ -4347,6 +4370,12 @@ static inline bool migrate_improves_loca { return false; } + +static inline bool migrate_degrades_locality(struct task_struct *p, + struct lb_env *env) +{ + return false; +} #endif /* @@ -4409,6 +4438,8 @@ int can_migrate_task(struct task_struct * 3) too many balance attempts have failed. */ tsk_cache_hot = task_hot(p, rq_clock_task(env->src_rq), env->sd); + if (!tsk_cache_hot) + tsk_cache_hot = migrate_degrades_locality(p, env); if (migrate_improves_locality(p, env)) { #ifdef CONFIG_SCHEDSTATS --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -70,4 +70,6 @@ SCHED_FEAT(LB_MIN, false) SCHED_FEAT(NUMA, false) SCHED_FEAT(NUMA_FORCE, false) SCHED_FEAT(NUMA_BALANCE, true) +SCHED_FEAT(NUMA_FAULTS_UP, true) +SCHED_FEAT(NUMA_FAULTS_DOWN, false) #endif -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>