In order not to hang on to “cold” regions, we shall inactivate a
region that has no READ access for a predefined amount of time -
READ_TO_MS. For that purpose we shall monitor the active regions list,
polling it on every POLLING_INTERVAL_MS. On timeout expiry we shall add
the region to the "to-be-inactivated" list, unless it is clean and did
not exhaust its READ_TO_EXPIRIES - another parameter.

All this does not apply to pinned regions.

Signed-off-by: Avri Altman <avri.alt...@wdc.com>
Reviewed-by: Daejun Park <daejun7.p...@samsung.com>
---
 drivers/scsi/ufs/ufshpb.c | 74 +++++++++++++++++++++++++++++++++++++--
 drivers/scsi/ufs/ufshpb.h |  8 +++++
 2 files changed, 79 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/ufs/ufshpb.c b/drivers/scsi/ufs/ufshpb.c
index 0352d269c1e9..8d067cf72ae2 100644
--- a/drivers/scsi/ufs/ufshpb.c
+++ b/drivers/scsi/ufs/ufshpb.c
@@ -18,6 +18,9 @@
 
 #define ACTIVATION_THRESHOLD 8 /* 8 IOs */
 #define EVICTION_THRESHOLD (ACTIVATION_THRESHOLD << 5) /* 256 IOs */
+#define READ_TO_MS 1000
+#define READ_TO_EXPIRIES 100
+#define POLLING_INTERVAL_MS 200
 
 /* memory management */
 static struct kmem_cache *ufshpb_mctx_cache;
@@ -1032,12 +1035,63 @@ static int ufshpb_check_srgns_issue_state(struct 
ufshpb_lu *hpb,
        return 0;
 }
 
+static void ufshpb_read_to_handler(struct work_struct *work)
+{
+       struct ufshpb_lu *hpb = container_of(work, struct ufshpb_lu,
+                                            ufshpb_read_to_work.work);
+       struct victim_select_info *lru_info = &hpb->lru_info;
+       struct ufshpb_region *rgn, *next_rgn;
+       unsigned long flags;
+       LIST_HEAD(expired_list);
+
+       if (test_and_set_bit(TIMEOUT_WORK_RUNNING, &hpb->work_data_bits))
+               return;
+
+       spin_lock_irqsave(&hpb->rgn_state_lock, flags);
+
+       list_for_each_entry_safe(rgn, next_rgn, &lru_info->lh_lru_rgn,
+                                list_lru_rgn) {
+               bool timedout = ktime_after(ktime_get(), rgn->read_timeout);
+
+               if (timedout) {
+                       rgn->read_timeout_expiries--;
+                       if (is_rgn_dirty(rgn) ||
+                           rgn->read_timeout_expiries == 0)
+                               list_add(&rgn->list_expired_rgn, &expired_list);
+                       else
+                               rgn->read_timeout = ktime_add_ms(ktime_get(),
+                                                        READ_TO_MS);
+               }
+       }
+
+       spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
+
+       list_for_each_entry_safe(rgn, next_rgn, &expired_list,
+                                list_expired_rgn) {
+               list_del_init(&rgn->list_expired_rgn);
+               spin_lock_irqsave(&hpb->rsp_list_lock, flags);
+               ufshpb_update_inactive_info(hpb, rgn->rgn_idx);
+               spin_unlock_irqrestore(&hpb->rsp_list_lock, flags);
+       }
+
+       ufshpb_kick_map_work(hpb);
+
+       clear_bit(TIMEOUT_WORK_RUNNING, &hpb->work_data_bits);
+
+       schedule_delayed_work(&hpb->ufshpb_read_to_work,
+                             msecs_to_jiffies(POLLING_INTERVAL_MS));
+}
+
 static void ufshpb_add_lru_info(struct victim_select_info *lru_info,
                                struct ufshpb_region *rgn)
 {
        rgn->rgn_state = HPB_RGN_ACTIVE;
        list_add_tail(&rgn->list_lru_rgn, &lru_info->lh_lru_rgn);
        atomic_inc(&lru_info->active_cnt);
+       if (rgn->hpb->is_hcm) {
+               rgn->read_timeout = ktime_add_ms(ktime_get(), READ_TO_MS);
+               rgn->read_timeout_expiries = READ_TO_EXPIRIES;
+       }
 }
 
 static void ufshpb_hit_lru_info(struct victim_select_info *lru_info,
@@ -1825,6 +1879,7 @@ static int ufshpb_alloc_region_tbl(struct ufs_hba *hba, 
struct ufshpb_lu *hpb)
 
                INIT_LIST_HEAD(&rgn->list_inact_rgn);
                INIT_LIST_HEAD(&rgn->list_lru_rgn);
+               INIT_LIST_HEAD(&rgn->list_expired_rgn);
 
                if (rgn_idx == hpb->rgns_per_lu - 1) {
                        srgn_cnt = ((hpb->srgns_per_lu - 1) %
@@ -1846,6 +1901,7 @@ static int ufshpb_alloc_region_tbl(struct ufs_hba *hba, 
struct ufshpb_lu *hpb)
                }
 
                rgn->rgn_flags = 0;
+               rgn->hpb = hpb;
        }
 
        return 0;
@@ -2069,9 +2125,12 @@ static int ufshpb_lu_hpb_init(struct ufs_hba *hba, 
struct ufshpb_lu *hpb)
        INIT_LIST_HEAD(&hpb->list_hpb_lu);
 
        INIT_WORK(&hpb->map_work, ufshpb_map_work_handler);
-       if (hpb->is_hcm)
+       if (hpb->is_hcm) {
                INIT_WORK(&hpb->ufshpb_normalization_work,
                          ufshpb_normalization_work_handler);
+               INIT_DELAYED_WORK(&hpb->ufshpb_read_to_work,
+                                 ufshpb_read_to_handler);
+       }
 
        hpb->map_req_cache = kmem_cache_create("ufshpb_req_cache",
                          sizeof(struct ufshpb_req), 0, 0, NULL);
@@ -2105,6 +2164,10 @@ static int ufshpb_lu_hpb_init(struct ufs_hba *hba, 
struct ufshpb_lu *hpb)
        ufshpb_stat_init(hpb);
        ufshpb_param_init(hpb);
 
+       if (hpb->is_hcm)
+               schedule_delayed_work(&hpb->ufshpb_read_to_work,
+                                     msecs_to_jiffies(POLLING_INTERVAL_MS));
+
        return 0;
 
 release_pre_req_mempool:
@@ -2171,9 +2234,10 @@ static void ufshpb_discard_rsp_lists(struct ufshpb_lu 
*hpb)
 
 static void ufshpb_cancel_jobs(struct ufshpb_lu *hpb)
 {
-       if (hpb->is_hcm)
+       if (hpb->is_hcm) {
+               cancel_delayed_work_sync(&hpb->ufshpb_read_to_work);
                cancel_work_sync(&hpb->ufshpb_normalization_work);
-
+       }
        cancel_work_sync(&hpb->map_work);
 }
 
@@ -2281,6 +2345,10 @@ void ufshpb_resume(struct ufs_hba *hba)
                        continue;
                ufshpb_set_state(hpb, HPB_PRESENT);
                ufshpb_kick_map_work(hpb);
+               if (hpb->is_hcm)
+                       schedule_delayed_work(&hpb->ufshpb_read_to_work,
+                               msecs_to_jiffies(POLLING_INTERVAL_MS));
+
        }
 }
 
diff --git a/drivers/scsi/ufs/ufshpb.h b/drivers/scsi/ufs/ufshpb.h
index b863540e28d6..448062a94760 100644
--- a/drivers/scsi/ufs/ufshpb.h
+++ b/drivers/scsi/ufs/ufshpb.h
@@ -115,6 +115,7 @@ struct ufshpb_subregion {
 };
 
 struct ufshpb_region {
+       struct ufshpb_lu *hpb;
        struct ufshpb_subregion *srgn_tbl;
        enum HPB_RGN_STATE rgn_state;
        int rgn_idx;
@@ -132,6 +133,10 @@ struct ufshpb_region {
        /* region reads - for host mode */
        spinlock_t rgn_lock;
        unsigned int reads;
+       /* region "cold" timer - for host mode */
+       ktime_t read_timeout;
+       unsigned int read_timeout_expiries;
+       struct list_head list_expired_rgn;
 };
 
 #define for_each_sub_region(rgn, i, srgn)                              \
@@ -223,6 +228,9 @@ struct ufshpb_lu {
        /* for selecting victim */
        struct victim_select_info lru_info;
        struct work_struct ufshpb_normalization_work;
+       struct delayed_work ufshpb_read_to_work;
+       unsigned long work_data_bits;
+#define TIMEOUT_WORK_RUNNING 0
 
        /* pinned region information */
        u32 lu_pinned_start;
-- 
2.25.1

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