From 66790e9a735b5c42349c48881e496b6946a55c05 Mon Sep 17 00:00:00 2001 From: Stefan Roesch Date: Mon, 18 Dec 2023 15:10:52 -0800 Subject: mm/ksm: add sysfs knobs for advisor This adds four new knobs for the KSM advisor to influence its behaviour. The knobs are: - advisor_mode: none: no advisor (default) scan-time: scan time advisor - advisor_max_cpu: 70 (default, cpu usage percent) - advisor_min_pages_to_scan: 500 (default) - advisor_max_pages_to_scan: 30000 (default) - advisor_target_scan_time: 200 (default in seconds) The new values will take effect on the next scan round. Link: https://lkml.kernel.org/r/20231218231054.1625219-3-shr@devkernel.io Signed-off-by: Stefan Roesch Acked-by: David Hildenbrand Cc: Johannes Weiner Cc: Rik van Riel Signed-off-by: Andrew Morton --- mm/ksm.c | 148 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 148 insertions(+) (limited to 'mm/ksm.c') diff --git a/mm/ksm.c b/mm/ksm.c index 599f7d209c68..ce3001745562 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -338,6 +338,25 @@ enum ksm_advisor_type { }; static enum ksm_advisor_type ksm_advisor; +#ifdef CONFIG_SYSFS +/* + * Only called through the sysfs control interface: + */ + +/* At least scan this many pages per batch. */ +static unsigned long ksm_advisor_min_pages_to_scan = 500; + +static void set_advisor_defaults(void) +{ + if (ksm_advisor == KSM_ADVISOR_NONE) { + ksm_thread_pages_to_scan = DEFAULT_PAGES_TO_SCAN; + } else if (ksm_advisor == KSM_ADVISOR_SCAN_TIME) { + advisor_ctx = (const struct advisor_ctx){ 0 }; + ksm_thread_pages_to_scan = ksm_advisor_min_pages_to_scan; + } +} +#endif /* CONFIG_SYSFS */ + static inline void advisor_start_scan(void) { if (ksm_advisor == KSM_ADVISOR_SCAN_TIME) @@ -3721,6 +3740,130 @@ static ssize_t smart_scan_store(struct kobject *kobj, } KSM_ATTR(smart_scan); +static ssize_t advisor_mode_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + const char *output; + + if (ksm_advisor == KSM_ADVISOR_NONE) + output = "[none] scan-time"; + else if (ksm_advisor == KSM_ADVISOR_SCAN_TIME) + output = "none [scan-time]"; + + return sysfs_emit(buf, "%s\n", output); +} + +static ssize_t advisor_mode_store(struct kobject *kobj, + struct kobj_attribute *attr, const char *buf, + size_t count) +{ + enum ksm_advisor_type curr_advisor = ksm_advisor; + + if (sysfs_streq("scan-time", buf)) + ksm_advisor = KSM_ADVISOR_SCAN_TIME; + else if (sysfs_streq("none", buf)) + ksm_advisor = KSM_ADVISOR_NONE; + else + return -EINVAL; + + /* Set advisor default values */ + if (curr_advisor != ksm_advisor) + set_advisor_defaults(); + + return count; +} +KSM_ATTR(advisor_mode); + +static ssize_t advisor_max_cpu_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%u\n", ksm_advisor_max_cpu); +} + +static ssize_t advisor_max_cpu_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int err; + unsigned long value; + + err = kstrtoul(buf, 10, &value); + if (err) + return -EINVAL; + + ksm_advisor_max_cpu = value; + return count; +} +KSM_ATTR(advisor_max_cpu); + +static ssize_t advisor_min_pages_to_scan_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%lu\n", ksm_advisor_min_pages_to_scan); +} + +static ssize_t advisor_min_pages_to_scan_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int err; + unsigned long value; + + err = kstrtoul(buf, 10, &value); + if (err) + return -EINVAL; + + ksm_advisor_min_pages_to_scan = value; + return count; +} +KSM_ATTR(advisor_min_pages_to_scan); + +static ssize_t advisor_max_pages_to_scan_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%lu\n", ksm_advisor_max_pages_to_scan); +} + +static ssize_t advisor_max_pages_to_scan_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int err; + unsigned long value; + + err = kstrtoul(buf, 10, &value); + if (err) + return -EINVAL; + + ksm_advisor_max_pages_to_scan = value; + return count; +} +KSM_ATTR(advisor_max_pages_to_scan); + +static ssize_t advisor_target_scan_time_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%lu\n", ksm_advisor_target_scan_time); +} + +static ssize_t advisor_target_scan_time_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int err; + unsigned long value; + + err = kstrtoul(buf, 10, &value); + if (err) + return -EINVAL; + if (value < 1) + return -EINVAL; + + ksm_advisor_target_scan_time = value; + return count; +} +KSM_ATTR(advisor_target_scan_time); + static struct attribute *ksm_attrs[] = { &sleep_millisecs_attr.attr, &pages_to_scan_attr.attr, @@ -3743,6 +3886,11 @@ static struct attribute *ksm_attrs[] = { &use_zero_pages_attr.attr, &general_profit_attr.attr, &smart_scan_attr.attr, + &advisor_mode_attr.attr, + &advisor_max_cpu_attr.attr, + &advisor_min_pages_to_scan_attr.attr, + &advisor_max_pages_to_scan_attr.attr, + &advisor_target_scan_time_attr.attr, NULL, }; -- cgit