From 930aa174fcc8b0efaad102fd80f677b92f35eaa2 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Mon, 7 Oct 2013 11:29:37 +0100 Subject: [PATCH] sched/numa: Remove the numa_balancing_scan_period_reset sysctl With scan rate adaptions based on whether the workload has properly converged or not there should be no need for the scan period reset hammer. Get rid of it. 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/1381141781-10992-60-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar --- Documentation/sysctl/kernel.txt | 11 +++-------- include/linux/mm_types.h | 3 --- include/linux/sched/sysctl.h | 1 - kernel/sched/core.c | 1 - kernel/sched/fair.c | 18 +----------------- kernel/sysctl.c | 7 ------- 6 files changed, 4 insertions(+), 37 deletions(-) diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index d48bca45b6f2..84f17800f8b5 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -374,15 +374,13 @@ guarantee. If the target workload is already bound to NUMA nodes then this feature should be disabled. Otherwise, if the system overhead from the feature is too high then the rate the kernel samples for NUMA hinting faults may be controlled by the numa_balancing_scan_period_min_ms, -numa_balancing_scan_delay_ms, numa_balancing_scan_period_reset, -numa_balancing_scan_period_max_ms, numa_balancing_scan_size_mb and -numa_balancing_settle_count sysctls. +numa_balancing_scan_delay_ms, numa_balancing_scan_period_max_ms, +numa_balancing_scan_size_mb and numa_balancing_settle_count sysctls. ============================================================== numa_balancing_scan_period_min_ms, numa_balancing_scan_delay_ms, -numa_balancing_scan_period_max_ms, numa_balancing_scan_period_reset, -numa_balancing_scan_size_mb +numa_balancing_scan_period_max_ms, numa_balancing_scan_size_mb Automatic NUMA balancing scans tasks address space and unmaps pages to detect if pages are properly placed or if the data should be migrated to a @@ -418,9 +416,6 @@ rate for each task. numa_balancing_scan_size_mb is how many megabytes worth of pages are scanned for a given scan. -numa_balancing_scan_period_reset is a blunt instrument that controls how -often a tasks scan delay is reset to detect sudden changes in task behaviour. - numa_balancing_settle_count is how many scan periods must complete before the schedule balancer stops pushing the task towards a preferred node. This gives the scheduler a chance to place the task on an alternative node if the diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index a30f9ca66557..a3198e5aaf4e 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -420,9 +420,6 @@ struct mm_struct { */ unsigned long numa_next_scan; - /* numa_next_reset is when the PTE scanner period will be reset */ - unsigned long numa_next_reset; - /* Restart point for scanning and setting pte_numa */ unsigned long numa_scan_offset; diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h index bf8086b2506e..10d16c4fbe89 100644 --- a/include/linux/sched/sysctl.h +++ b/include/linux/sched/sysctl.h @@ -47,7 +47,6 @@ extern enum sched_tunable_scaling sysctl_sched_tunable_scaling; extern unsigned int sysctl_numa_balancing_scan_delay; extern unsigned int sysctl_numa_balancing_scan_period_min; extern unsigned int sysctl_numa_balancing_scan_period_max; -extern unsigned int sysctl_numa_balancing_scan_period_reset; extern unsigned int sysctl_numa_balancing_scan_size; extern unsigned int sysctl_numa_balancing_settle_count; diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 8cfd51f62241..89c5ae836f66 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1721,7 +1721,6 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p) #ifdef CONFIG_NUMA_BALANCING if (p->mm && atomic_read(&p->mm->mm_users) == 1) { p->mm->numa_next_scan = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_delay); - p->mm->numa_next_reset = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_period_reset); p->mm->numa_scan_seq = 0; } diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 66237ff8b01e..da6fa22be000 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -826,7 +826,6 @@ update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se) */ unsigned int sysctl_numa_balancing_scan_period_min = 1000; unsigned int sysctl_numa_balancing_scan_period_max = 60000; -unsigned int sysctl_numa_balancing_scan_period_reset = 60000; /* Portion of address space to scan in MB */ unsigned int sysctl_numa_balancing_scan_size = 256; @@ -1685,24 +1684,9 @@ void task_numa_work(struct callback_head *work) if (p->flags & PF_EXITING) return; - if (!mm->numa_next_reset || !mm->numa_next_scan) { + if (!mm->numa_next_scan) { mm->numa_next_scan = now + msecs_to_jiffies(sysctl_numa_balancing_scan_delay); - mm->numa_next_reset = now + - msecs_to_jiffies(sysctl_numa_balancing_scan_period_reset); - } - - /* - * Reset the scan period if enough time has gone by. Objective is that - * scanning will be reduced if pages are properly placed. As tasks - * can enter different phases this needs to be re-examined. Lacking - * proper tracking of reference behaviour, this blunt hammer is used. - */ - migrate = mm->numa_next_reset; - if (time_after(now, migrate)) { - p->numa_scan_period = task_scan_min(p); - next_scan = now + msecs_to_jiffies(sysctl_numa_balancing_scan_period_reset); - xchg(&mm->numa_next_reset, next_scan); } /* diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 42f616a74f40..e509b90a8002 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -370,13 +370,6 @@ static struct ctl_table kern_table[] = { .mode = 0644, .proc_handler = proc_dointvec, }, - { - .procname = "numa_balancing_scan_period_reset", - .data = &sysctl_numa_balancing_scan_period_reset, - .maxlen = sizeof(unsigned int), - .mode = 0644, - .proc_handler = proc_dointvec, - }, { .procname = "numa_balancing_scan_period_max_ms", .data = &sysctl_numa_balancing_scan_period_max, -- 2.34.1