[PATCH 7/8] scsi: ufshpb: Add "Cold" regions timer

Avri Altman
2021-01-27T15:16:48Z

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 exahust its READ_TO_EXPIRIES - another parameter.

All this does not apply to pinned regions.

Signed-off-by: Avri Altman <avri.altman@wdc.com>
---
drivers/scsi/ufs/ufshpb.c | 75 ++++++++++++++++++++++++++++++++++++++-
drivers/scsi/ufs/ufshpb.h | 7 ++++
2 files changed, 81 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshpb.c b/drivers/scsi/ufs/ufshpb.c
index cb99b57b4319..482f01c3b3ee 100644
--- a/drivers/scsi/ufs/ufshpb.c
+++ b/drivers/scsi/ufs/ufshpb.c
@@ -18,8 +18,12 @@

#define WORK_PENDING 0
#define RESET_PENDING 1
+#define TIMEOUT_WORK_PENDING 2
#define ACTIVATION_THRSHLD 4 /* 4 IOs */
#define EVICTION_THRSHLD (ACTIVATION_THRSHLD << 6) /* 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;
@@ -671,12 +675,69 @@ static int ufshpb_check_srgns_issue_state(struct ufshpb_lu *hpb,
return 0;
}

+static void ufshpb_read_to_handler(struct work_struct *work)
+{
+ struct delayed_work *dwork = to_delayed_work(work);
+ struct ufshpb_lu *hpb;
+ struct victim_select_info *lru_info;
+ struct ufshpb_region *rgn, *next_rgn;
+ unsigned long flags;
+ LIST_HEAD(expired_list);
+
+ hpb = container_of(dwork, struct ufshpb_lu, ufshpb_read_to_work);
+
+ if (test_and_set_bit(TIMEOUT_WORK_PENDING, &hpb->work_data_bits))
+ return;
+
+ spin_lock_irqsave(&hpb->rgn_state_lock, flags);
+
+ lru_info = &hpb->lru_info;
+
+ 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);
+ bool dirty, expired;
+
+ if (!timedout)
+ continue;
+
+ dirty = is_rgn_dirty(rgn);
+ expired = atomic_dec_and_test(&rgn->read_timeout_expiries);
+
+ if (dirty || expired)
+ 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);
+ hpb->stats.rb_inactive_cnt++;
+ spin_unlock_irqrestore(&hpb->rsp_list_lock, flags);
+ }
+
+ clear_bit(TIMEOUT_WORK_PENDING, &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)
+ 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 (ufshpb_mode == HPB_HOST_CONTROL) {
+ rgn->read_timeout = ktime_add_ms(ktime_get(), READ_TO_MS);
+ atomic_set(&rgn->read_timeout_expiries, READ_TO_EXPIRIES);
+ }
}

static void ufshpb_hit_lru_info(struct victim_select_info *lru_info,
@@ -1404,6 +1465,7 @@ 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) %
@@ -1536,6 +1598,8 @@ static int ufshpb_lu_hpb_init(struct ufs_hba *hba, struct ufshpb_lu *hpb)
ufshpb_normalization_work_handler);
INIT_WORK(&hpb->ufshpb_lun_reset_work,
ufshpb_reset_work_handler);
+ INIT_DELAYED_WORK(&hpb->ufshpb_read_to_work,
+ ufshpb_read_to_handler);
}

hpb->map_req_cache = kmem_cache_create("ufshpb_req_cache",
@@ -1562,6 +1626,10 @@ static int ufshpb_lu_hpb_init(struct ufs_hba *hba, struct ufshpb_lu *hpb)

ufshpb_stat_init(hpb);

+ if (ufshpb_mode == HPB_HOST_CONTROL)
+ schedule_delayed_work(&hpb->ufshpb_read_to_work,
+ msecs_to_jiffies(POLLING_INTERVAL_MS));
+
return 0;

release_m_page_cache:
@@ -1624,6 +1692,7 @@ static void ufshpb_discard_rsp_lists(struct ufshpb_lu *hpb)
static void ufshpb_cancel_jobs(struct ufshpb_lu *hpb)
{
if (ufshpb_mode == HPB_HOST_CONTROL) {
+ cancel_delayed_work_sync(&hpb->ufshpb_read_to_work);
cancel_work_sync(&hpb->ufshpb_lun_reset_work);
cancel_work_sync(&hpb->ufshpb_normalization_work);
}
@@ -1734,6 +1803,10 @@ void ufshpb_resume(struct ufs_hba *hba)
continue;
ufshpb_set_state(hpb, HPB_PRESENT);
ufshpb_kick_map_work(hpb);
+ if (ufshpb_mode == HPB_HOST_CONTROL)
+ 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 4bf77169af00..86c16a4127bd 100644
--- a/drivers/scsi/ufs/ufshpb.h
+++ b/drivers/scsi/ufs/ufshpb.h
@@ -121,6 +121,12 @@ struct ufshpb_region {

/* region reads - for host mode */
atomic64_t reads;
+
+ /* region "cold" timer - for host mode */
+ ktime_t read_timeout;
+ atomic_t read_timeout_expiries;
+ struct list_head list_expired_rgn;
+
};

#define for_each_sub_region(rgn, i, srgn) \
@@ -184,6 +190,7 @@ struct ufshpb_lu {
struct victim_select_info lru_info;
struct work_struct ufshpb_normalization_work;
struct work_struct ufshpb_lun_reset_work;
+ struct delayed_work ufshpb_read_to_work;
unsigned long work_data_bits;

/* pinned region information */
--
2.25.1