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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Aug 2025 15:35:43.6135 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 7b8e64ff-ff82-4a95-0f12-08dddb483b63 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: DS1PEPF00017098.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH3PR12MB8076 Content-Type: text/plain; charset="utf-8" Support below tunables: scan_enable: turn on or turn off mm_struct scanning scan_period: initial scan_period (default: 2sec) scan_sleep_ms: sleep time between two successive round of scanning and migration. mms_to_scan: total mm_struct to scan before taking a pause. target_node: default regular node to which migration of accessed pages is done (this is only fall back mechnism, otherwise target_node heuristic is used). Signed-off-by: Raghavendra K T --- mm/kscand.c | 205 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 205 insertions(+) diff --git a/mm/kscand.c b/mm/kscand.c index 41321d373be7..a73606f7ca3c 100644 --- a/mm/kscand.c +++ b/mm/kscand.c @@ -21,6 +21,7 @@ #include #include #include +#include =20 #include #include "internal.h" @@ -173,6 +174,171 @@ static bool kscand_eligible_srcnid(int nid) return !node_is_toptier(nid); } =20 +#ifdef CONFIG_SYSFS +static ssize_t scan_sleep_ms_show(struct kobject *kobj, + struct kobj_attribute *attr, + char *buf) +{ + return sysfs_emit(buf, "%u\n", kscand_scan_sleep_ms); +} + +static ssize_t scan_sleep_ms_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + unsigned int msecs; + int err; + + err =3D kstrtouint(buf, 10, &msecs); + if (err) + return -EINVAL; + + kscand_scan_sleep_ms =3D msecs; + kscand_sleep_expire =3D 0; + wake_up_interruptible(&kscand_wait); + + return count; +} + +static struct kobj_attribute scan_sleep_ms_attr =3D + __ATTR_RW(scan_sleep_ms); + +static ssize_t mm_scan_period_ms_show(struct kobject *kobj, + struct kobj_attribute *attr, + char *buf) +{ + return sysfs_emit(buf, "%u\n", kscand_mm_scan_period_ms); +} + +/* If a value less than MIN or greater than MAX asked for store value is c= lamped */ +static ssize_t mm_scan_period_ms_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + unsigned int msecs, stored_msecs; + int err; + + err =3D kstrtouint(buf, 10, &msecs); + if (err) + return -EINVAL; + + stored_msecs =3D clamp(msecs, KSCAND_SCAN_PERIOD_MIN, KSCAND_SCAN_PERIOD_= MAX); + + kscand_mm_scan_period_ms =3D stored_msecs; + kscand_sleep_expire =3D 0; + wake_up_interruptible(&kscand_wait); + + return count; +} + +static struct kobj_attribute mm_scan_period_ms_attr =3D + __ATTR_RW(mm_scan_period_ms); + +static ssize_t mms_to_scan_show(struct kobject *kobj, + struct kobj_attribute *attr, + char *buf) +{ + return sysfs_emit(buf, "%lu\n", kscand_mms_to_scan); +} + +static ssize_t mms_to_scan_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + unsigned long val; + int err; + + err =3D kstrtoul(buf, 10, &val); + if (err) + return -EINVAL; + + kscand_mms_to_scan =3D val; + kscand_sleep_expire =3D 0; + wake_up_interruptible(&kscand_wait); + + return count; +} + +static struct kobj_attribute mms_to_scan_attr =3D + __ATTR_RW(mms_to_scan); + +static ssize_t scan_enabled_show(struct kobject *kobj, + struct kobj_attribute *attr, + char *buf) +{ + return sysfs_emit(buf, "%u\n", kscand_scan_enabled ? 1 : 0); +} + +static ssize_t scan_enabled_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + unsigned int val; + int err; + + err =3D kstrtouint(buf, 10, &val); + if (err || val > 1) + return -EINVAL; + + if (val) { + kscand_scan_enabled =3D true; + need_wakeup =3D true; + } else + kscand_scan_enabled =3D false; + + kscand_sleep_expire =3D 0; + wake_up_interruptible(&kscand_wait); + + return count; +} + +static struct kobj_attribute scan_enabled_attr =3D + __ATTR_RW(scan_enabled); + +static ssize_t target_node_show(struct kobject *kobj, + struct kobj_attribute *attr, + char *buf) +{ + return sysfs_emit(buf, "%u\n", kscand_target_node); +} + +static ssize_t target_node_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int err, node; + + err =3D kstrtoint(buf, 10, &node); + if (err) + return -EINVAL; + + kscand_sleep_expire =3D 0; + if (!node_is_toptier(node)) + return -EINVAL; + + kscand_target_node =3D node; + wake_up_interruptible(&kscand_wait); + + return count; +} +static struct kobj_attribute target_node_attr =3D + __ATTR_RW(target_node); + +static struct attribute *kscand_attr[] =3D { + &scan_sleep_ms_attr.attr, + &mm_scan_period_ms_attr.attr, + &mms_to_scan_attr.attr, + &scan_enabled_attr.attr, + &target_node_attr.attr, + NULL, +}; + +struct attribute_group kscand_attr_group =3D { + .attrs =3D kscand_attr, + .name =3D "kscand", +}; +#endif + static inline int kscand_has_work(void) { return !list_empty(&kscand_scan.mm_head); @@ -1231,11 +1397,45 @@ static int kscand(void *none) return 0; } =20 +#ifdef CONFIG_SYSFS +extern struct kobject *mm_kobj; +static int __init kscand_init_sysfs(struct kobject **kobj) +{ + int err; + + err =3D sysfs_create_group(*kobj, &kscand_attr_group); + if (err) { + pr_err("failed to register kscand group\n"); + goto err_kscand_attr; + } + + return 0; + +err_kscand_attr: + sysfs_remove_group(*kobj, &kscand_attr_group); + return err; +} + +static void __init kscand_exit_sysfs(struct kobject *kobj) +{ + sysfs_remove_group(kobj, &kscand_attr_group); +} +#else +static inline int __init kscand_init_sysfs(struct kobject **kobj) +{ + return 0; +} +static inline void __init kscand_exit_sysfs(struct kobject *kobj) +{ +} +#endif + static inline void kscand_destroy(void) { kmem_cache_destroy(kscand_slot_cache); /* XXX: move below to kmigrated thread */ kmem_cache_destroy(kmigrated_slot_cache); + kscand_exit_sysfs(mm_kobj); } =20 void __kscand_enter(struct mm_struct *mm) @@ -1421,6 +1621,10 @@ static int __init kscand_init(void) return -ENOMEM; } =20 + err =3D kscand_init_sysfs(&mm_kobj); + if (err) + goto err_init_sysfs; + init_list(); err =3D start_kscand(); if (err) @@ -1437,6 +1641,7 @@ static int __init kscand_init(void) =20 err_kscand: stop_kscand(); +err_init_sysfs: kscand_destroy(); =20 return err; --=20 2.34.1