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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Aug 2025 15:35:32.3020 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 41fc2e25-db10-4c11-096d-08dddb48349f 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: BN3PEPF0000B078.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR12MB8554 Content-Type: text/plain; charset="utf-8" Before this, scanning kthread continues to scan even after migration fails. To control migration, scanning is slowed down based on the failure/success ratio obtained from migration thread. Decaying failure ratio is maintained for 1024 migration window. The ratio further contributes to approximately 10% scaling of scan_period. Signed-off-by: Raghavendra K T --- mm/kscand.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) diff --git a/mm/kscand.c b/mm/kscand.c index bf975e82357d..41321d373be7 100644 --- a/mm/kscand.c +++ b/mm/kscand.c @@ -146,6 +146,8 @@ struct kmigrated_mm_slot { spinlock_t migrate_lock; /* Head of per mm migration list */ struct list_head migrate_head; + /* Indicates weighted success, failure */ + int msuccess, mfailed, fratio; }; =20 /* System wide list of mms that maintain migration list */ @@ -812,13 +814,45 @@ static void kscand_collect_mm_slot(struct kscand_mm_s= lot *mm_slot) } } =20 +static int kmigrated_get_mstat_fratio(struct mm_struct *mm) +{ + int fratio =3D 0; + struct kmigrated_mm_slot *mm_slot =3D NULL; + struct mm_slot *slot; + + guard(spinlock)(&kscand_migrate_lock); + + slot =3D mm_slot_lookup(kmigrated_slots_hash, mm); + mm_slot =3D mm_slot_entry(slot, struct kmigrated_mm_slot, mm_slot); + + if (mm_slot) + fratio =3D mm_slot->fratio; + + return fratio; +} + +static void update_mstat_ratio(struct kmigrated_mm_slot *mm_slot, + int msuccess, int mfailed) +{ + mm_slot->msuccess =3D (mm_slot->msuccess >> 2) + msuccess; + mm_slot->mfailed =3D (mm_slot->mfailed >> 2) + mfailed; + mm_slot->fratio =3D mm_slot->mfailed * 100; + mm_slot->fratio /=3D (mm_slot->msuccess + mm_slot->mfailed); +} + +#define MSTAT_UPDATE_FREQ 1024 + static void kmigrated_migrate_mm(struct kmigrated_mm_slot *mm_slot) { + int mfailed =3D 0; + int msuccess =3D 0; + int mstat_counter; int ret =3D 0, dest =3D -1; struct mm_slot *slot; struct mm_struct *mm; struct kscand_migrate_info *info, *tmp; =20 + mstat_counter =3D MSTAT_UPDATE_FREQ; spin_lock(&mm_slot->migrate_lock); =20 slot =3D &mm_slot->mm_slot; @@ -842,11 +876,23 @@ static void kmigrated_migrate_mm(struct kmigrated_mm_= slot *mm_slot) } =20 ret =3D kmigrated_promote_folio(info, mm, dest); + mstat_counter--; + + /* TBD: encode migrated count here, currently assume folio_nr_pages */ + if (!ret) + msuccess++; + else + mfailed++; =20 kfree(info); =20 cond_resched(); spin_lock(&mm_slot->migrate_lock); + if (!mstat_counter) { + update_mstat_ratio(mm_slot, msuccess, mfailed); + msuccess =3D mfailed =3D 0; + mstat_counter =3D MSTAT_UPDATE_FREQ; + } } } clean_list_handled: @@ -882,6 +928,12 @@ static void kmigrated_migrate_folio(void) } } =20 +/* Get scan_period based on migration failure statistics */ +static int kscand_mstat_scan_period(unsigned int scan_period, int fratio) +{ + return scan_period * (1 + fratio / 10); +} + /* * This is the normal change percentage when old and new delta remain same. * i.e., either both positive or both zero. @@ -928,6 +980,7 @@ static void kmigrated_migrate_folio(void) static inline void kscand_update_mmslot_info(struct kscand_mm_slot *mm_slo= t, unsigned long total, int target_node) { + int fratio; unsigned int scan_period; unsigned long now; unsigned long scan_size; @@ -967,6 +1020,8 @@ static inline void kscand_update_mmslot_info(struct ks= cand_mm_slot *mm_slot, } =20 scan_period =3D clamp(scan_period, KSCAND_SCAN_PERIOD_MIN, KSCAND_SCAN_PE= RIOD_MAX); + fratio =3D kmigrated_get_mstat_fratio((&mm_slot->slot)->mm); + scan_period =3D kscand_mstat_scan_period(scan_period, fratio); scan_size =3D clamp(scan_size, KSCAND_SCAN_SIZE_MIN, KSCAND_SCAN_SIZE_MAX= ); =20 now =3D jiffies; --=20 2.34.1