[Devel] [RFC PATCH vz9 v2 10/11] ploop: convert the rest of the lists to use llist variant

Alexander Atanasov alexander.atanasov at virtuozzo.com
Mon Oct 14 11:51:15 MSK 2024


convert the rest of the lists to use lockless list variant

Signed-off-by: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
---
 drivers/md/dm-ploop-map.c    | 119 ++++++++++++++++++++++-------------
 drivers/md/dm-ploop-target.c |   6 +-
 drivers/md/dm-ploop.h        |   4 +-
 3 files changed, 79 insertions(+), 50 deletions(-)

diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index d93e96857d02..6b929c478dd0 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -340,8 +340,7 @@ ALLOW_ERROR_INJECTION(ploop_split_pio_to_list, ERRNO);
 static void ploop_dispatch_pio(struct ploop *ploop, struct pio *pio,
 			       bool *is_data, bool *is_flush)
 {
-	struct list_head *list = &ploop->pios[pio->queue_list_id];
-	unsigned long flags;
+	struct llist_head *list = (struct llist_head *)&ploop->pios[pio->queue_list_id];
 
 	lockdep_assert_not_held(&ploop->deferred_lock);
 	WARN_ON_ONCE(pio->queue_list_id >= PLOOP_LIST_COUNT);
@@ -351,9 +350,7 @@ static void ploop_dispatch_pio(struct ploop *ploop, struct pio *pio,
 	else
 		*is_data = true;
 
-	spin_lock_irqsave(&ploop->deferred_lock, flags);
-	list_add_tail(&pio->list, list);
-	spin_unlock_irqrestore(&ploop->deferred_lock, flags);
+	llist_add((struct llist_node *)(&pio->list), list);
 }
 
 void ploop_dispatch_pios(struct ploop *ploop, struct pio *pio,
@@ -812,7 +809,7 @@ static void ploop_advance_local_after_bat_wb(struct ploop *ploop,
 		wait_llist_pending = llist_reverse_order(wait_llist_pending);
 		llist_for_each_safe(pos, t, wait_llist_pending) {
 			pio = list_entry((struct list_head *)pos, typeof(*pio), list);
-			list_add(&pio->list, &list);
+			list_add_tail(&pio->list, &list);
 		}
 	}
 
@@ -1148,13 +1145,10 @@ static void ploop_attach_end_action(struct pio *pio, struct ploop_index_wb *piwb
 static void ploop_queue_resubmit(struct pio *pio)
 {
 	struct ploop *ploop = pio->ploop;
-	unsigned long flags;
 
 	pio->queue_list_id = PLOOP_LIST_INVALID;
 
-	spin_lock_irqsave(&ploop->deferred_lock, flags);
-	list_add_tail(&pio->list, &ploop->resubmit_pios);
-	spin_unlock_irqrestore(&ploop->deferred_lock, flags);
+	llist_add((struct llist_node *)(&pio->list), &ploop->llresubmit_pios);
 
 	queue_work(ploop->wq, &ploop->worker);
 }
@@ -1409,20 +1403,21 @@ static void ploop_submit_cow_index_wb(struct ploop_cow *cow)
 }
 
 static void ploop_process_delta_cow(struct ploop *ploop,
-				    struct list_head *cow_list)
+				    struct llist_node *cow_llist)
 {
 	struct ploop_cow *cow;
 	struct pio *aux_pio;
 
-	if (list_empty(cow_list))
-		return;
-
-	while ((aux_pio = ploop_pio_list_pop(cow_list)) != NULL) {
+	struct llist_node *pos, *t;
+	llist_for_each_safe(pos, t, cow_llist) {
+		aux_pio = list_entry((struct list_head *)pos, typeof(*aux_pio), list);
 		cow = aux_pio->endio_cb_data;
 		if (unlikely(aux_pio->bi_status != BLK_STS_OK)) {
 			ploop_complete_cow(cow, aux_pio->bi_status);
 			continue;
 		}
+		/* until type is changed */
+		INIT_LIST_HEAD(&aux_pio->list);
 
 		if (cow->dst_clu == BAT_ENTRY_NONE) {
 			/*
@@ -1678,13 +1673,17 @@ static void ploop_prepare_one_embedded_pio(struct ploop *ploop,
 }
 
 static void ploop_prepare_embedded_pios(struct ploop *ploop,
-					struct list_head *pios,
+					struct llist_node *pios,
 					struct list_head *deferred_pios)
 {
 	struct pio *pio;
+	struct llist_node *pos, *t;
 
-	while ((pio = ploop_pio_list_pop(pios)) != NULL)
+	llist_for_each_safe(pos, t, pios) {
+		pio = list_entry((struct list_head *)pos, typeof(*pio), list);
+		INIT_LIST_HEAD(&pio->list); /* until type is changed */
 		ploop_prepare_one_embedded_pio(ploop, pio, deferred_pios);
+	}
 }
 
 static void ploop_process_deferred_pios(struct ploop *ploop,
@@ -1746,21 +1745,28 @@ static void ploop_process_one_discard_pio(struct ploop *ploop, struct pio *pio)
 }
 
 static void ploop_process_discard_pios(struct ploop *ploop,
-				       struct list_head *pios)
+				       struct llist_node *discpios)
 {
 	struct pio *pio;
+	struct llist_node *pos, *t;
 
-	while ((pio = ploop_pio_list_pop(pios)) != NULL)
+	llist_for_each_safe(pos, t, discpios) {
+		pio = list_entry((struct list_head *)pos, typeof(*pio), list);
+		INIT_LIST_HEAD(&pio->list);
 		ploop_process_one_discard_pio(ploop, pio);
+	}
 }
 
 static void ploop_process_resubmit_pios(struct ploop *ploop,
-					struct list_head *pios)
+					struct llist_node *llpios)
 {
 	struct pio *pio;
+	struct llist_node *pos, *t;
 
-	while ((pio = ploop_pio_list_pop(pios)) != NULL) {
+	llist_for_each_safe(pos, t, llpios) {
+		pio = list_entry((struct list_head *)pos, typeof(*pio), list);
 		pio->queue_list_id = PLOOP_LIST_INVALID;
+		INIT_LIST_HEAD(&pio->list); /* Until type is changed */
 		ploop_submit_rw_mapped(ploop, pio);
 	}
 }
@@ -1785,18 +1791,21 @@ static void ploop_submit_metadata_writeback(struct ploop *ploop)
 
 static void process_ploop_fsync_work(struct ploop *ploop)
 {
-	LIST_HEAD(flush_pios);
 	struct file *file;
 	struct pio *pio;
 	int ret;
-	spin_lock_irq(&ploop->deferred_lock);
-	list_splice_init(&ploop->pios[PLOOP_LIST_FLUSH], &flush_pios);
-	spin_unlock_irq(&ploop->deferred_lock);
+	struct llist_node *llflush_pios;
+	struct llist_node *pos, *t;
+
+	llflush_pios = llist_del_all(&ploop->pios[PLOOP_LIST_FLUSH]);
 
 	file = ploop_top_delta(ploop)->file;
+	/* All flushes are done as one */
 	ret = vfs_fsync(file, 0);
 
-	while ((pio = ploop_pio_list_pop(&flush_pios)) != NULL) {
+	llist_for_each_safe(pos, t, llflush_pios) {
+		pio = list_entry((struct list_head *)pos, typeof(*pio), list);
+		INIT_LIST_HEAD(&pio->list); /* Until type is changed */
 		if (unlikely(ret)) {
 			pio->bi_status = errno_to_blk_status(ret);
 			if (static_branch_unlikely(&ploop_standby_check))
@@ -1809,32 +1818,54 @@ static void process_ploop_fsync_work(struct ploop *ploop)
 void do_ploop_work(struct work_struct *ws)
 {
 	struct ploop *ploop = container_of(ws, struct ploop, worker);
-	LIST_HEAD(embedded_pios);
 	LIST_HEAD(deferred_pios);
-	LIST_HEAD(discard_pios);
-	LIST_HEAD(cow_pios);
-	LIST_HEAD(resubmit_pios);
+	struct llist_node *llembedded_pios;
+	struct llist_node *lldeferred_pios;
+	struct llist_node *lldiscard_pios;
+	struct llist_node *llcow_pios;
+	struct llist_node *llresubmit;
 	bool do_fsync = false;
 	unsigned int old_flags = current->flags;
 
 	current->flags |= PF_IO_THREAD|PF_LOCAL_THROTTLE|PF_MEMALLOC_NOIO;
 
 	spin_lock_irq(&ploop->deferred_lock);
-	list_splice_init(&ploop->pios[PLOOP_LIST_PREPARE], &embedded_pios);
-	list_splice_init(&ploop->pios[PLOOP_LIST_DEFERRED], &deferred_pios);
-	list_splice_init(&ploop->pios[PLOOP_LIST_DISCARD], &discard_pios);
-	list_splice_init(&ploop->pios[PLOOP_LIST_COW], &cow_pios);
-	list_splice_init(&ploop->resubmit_pios, &resubmit_pios);
-	if (!list_empty(&ploop->pios[PLOOP_LIST_FLUSH]))
+	llembedded_pios = llist_del_all(&ploop->pios[PLOOP_LIST_PREPARE]);
+	lldeferred_pios = llist_del_all(&ploop->pios[PLOOP_LIST_DEFERRED]);
+	lldiscard_pios = llist_del_all(&ploop->pios[PLOOP_LIST_DISCARD]);
+	llcow_pios = llist_del_all(&ploop->pios[PLOOP_LIST_COW]);
+	llresubmit = llist_del_all(&ploop->llresubmit_pios);
+
+	if (!llist_empty(&ploop->pios[PLOOP_LIST_FLUSH]))
 		do_fsync = true;
+
 	spin_unlock_irq(&ploop->deferred_lock);
 
-	ploop_prepare_embedded_pios(ploop, &embedded_pios, &deferred_pios);
+	/* add old deferred to the list */
+	if (lldeferred_pios) {
+		struct llist_node *pos, *t;
+		struct pio *pio;
+
+		llist_for_each_safe(pos, t, llist_reverse_order(lldeferred_pios)) {
+			pio = list_entry((struct list_head *)pos, typeof(*pio), list);
+			INIT_LIST_HEAD(&pio->list);
+			list_add_tail(&pio->list, &deferred_pios);
+		}
+	}
+
+	ploop_prepare_embedded_pios(ploop, llembedded_pios, &deferred_pios);
+
+	if (llresubmit)
+		ploop_process_resubmit_pios(ploop, llist_reverse_order(llresubmit));
+
 
-	ploop_process_resubmit_pios(ploop, &resubmit_pios);
 	ploop_process_deferred_pios(ploop, &deferred_pios);
-	ploop_process_discard_pios(ploop, &discard_pios);
-	ploop_process_delta_cow(ploop, &cow_pios);
+
+	if (lldiscard_pios)
+		ploop_process_discard_pios(ploop, llist_reverse_order(lldiscard_pios));
+
+	if (llcow_pios)
+		ploop_process_delta_cow(ploop, llist_reverse_order(llcow_pios));
 
 	ploop_submit_metadata_writeback(ploop);
 
@@ -1868,18 +1899,16 @@ static void ploop_submit_embedded_pio(struct ploop *ploop, struct pio *pio)
 		worker = &ploop->fsync_worker;
 	}
 
-	spin_lock_irqsave(&ploop->deferred_lock, flags);
 	if (unlikely(ploop->stop_submitting_pios)) {
 		llist_add((struct llist_node *)(&pio->list), &ploop->llsuspended_pios);
 		queue = false;
-		goto unlock;
+		goto out;
 	}
 
 	ploop_inc_nr_inflight(ploop, pio);
-	list_add_tail(&pio->list, &ploop->pios[pio->queue_list_id]);
-unlock:
-	spin_unlock_irqrestore(&ploop->deferred_lock, flags);
+	llist_add((struct llist_node *)(&pio->list), &ploop->pios[pio->queue_list_id]);
 
+out:
 	if (queue)
 		queue_work(ploop->wq, worker);
 }
diff --git a/drivers/md/dm-ploop-target.c b/drivers/md/dm-ploop-target.c
index 94d6f661f50c..f12c6912f8d0 100644
--- a/drivers/md/dm-ploop-target.c
+++ b/drivers/md/dm-ploop-target.c
@@ -140,7 +140,7 @@ static bool ploop_has_pending_activity(struct ploop *ploop)
 
 	spin_lock_irq(&ploop->deferred_lock);
 	for (i = 0; i < PLOOP_LIST_COUNT; i++)
-		has |= !list_empty(&ploop->pios[i]);
+		has |= !llist_empty(&ploop->pios[i]);
 	spin_unlock_irq(&ploop->deferred_lock);
 
 	return has;
@@ -373,9 +373,9 @@ static int ploop_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	init_llist_head(&ploop->llsuspended_pios);
 
 	for (i = 0; i < PLOOP_LIST_COUNT; i++)
-		INIT_LIST_HEAD(&ploop->pios[i]);
+		init_llist_head(&ploop->pios[i]);
 
-	INIT_LIST_HEAD(&ploop->resubmit_pios);
+	init_llist_head(&ploop->llresubmit_pios);
 	init_llist_head(&ploop->enospc_pios);
 
 	INIT_LIST_HEAD(&ploop->cluster_lk_list);
diff --git a/drivers/md/dm-ploop.h b/drivers/md/dm-ploop.h
index 7e7f82aa1402..66c7ce20dd60 100644
--- a/drivers/md/dm-ploop.h
+++ b/drivers/md/dm-ploop.h
@@ -196,9 +196,9 @@ struct ploop {
 	spinlock_t inflight_lock;
 	spinlock_t deferred_lock;
 
-	struct list_head pios[PLOOP_LIST_COUNT];
+	struct llist_head pios[PLOOP_LIST_COUNT];
 
-	struct list_head resubmit_pios; /* After partial IO */
+	struct llist_head llresubmit_pios; /* After partial IO */
 	struct llist_head enospc_pios; /* Delayed after ENOSPC */
 
 	atomic_t service_pios;
-- 
2.43.0



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