[Devel] [RFC PATCH vz9 v6 14/62] dm-ploop: move preparations of pios into the caller from worker

Alexander Atanasov alexander.atanasov at virtuozzo.com
Fri Dec 6 00:55:47 MSK 2024


Prepare pios earlier in preparation to try to execute them earlier.
Convert more places to use lock less lists.

https://virtuozzo.atlassian.net/browse/VSTOR-91820
Signed-off-by: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
---
 drivers/md/dm-ploop-map.c | 95 ++++++++++++++++++++++++---------------
 1 file changed, 60 insertions(+), 35 deletions(-)

diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index 8d165bd4fa9d..475494b951a3 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -292,11 +292,15 @@ static struct pio *ploop_split_and_chain_pio(struct ploop *ploop,
 ALLOW_ERROR_INJECTION(ploop_split_and_chain_pio, NULL);
 
 static int ploop_split_pio_to_list(struct ploop *ploop, struct pio *pio,
-			     struct list_head *ret_list)
+			     struct llist_head *ret_list)
 {
 	u32 clu_size = CLU_SIZE(ploop);
+	struct llist_node *pos, *t;
 	struct pio *split;
-	LIST_HEAD(list);
+	LLIST_HEAD(llist);
+	struct llist_node *lltmp;
+
+	WARN_ON(!pio->bi_iter.bi_size);
 
 	while (1) {
 		loff_t start = to_bytes(pio->bi_iter.bi_sector);
@@ -314,17 +318,24 @@ static int ploop_split_pio_to_list(struct ploop *ploop, struct pio *pio,
 		if (!split)
 			goto err;
 
-		list_add_tail(&split->list, &list);
+		llist_add((struct llist_node *)(&split->list), &llist);
 	}
 
-	list_splice_tail(&list, ret_list);
-	list_add_tail(&pio->list, ret_list);
+	INIT_LIST_HEAD(&pio->list);
+	llist_add((struct llist_node *)(&pio->list), &llist);
+	lltmp = llist_reverse_order(llist_del_all(&llist));
+	pio->list.next = NULL;
+	llist_add_batch(lltmp, (struct llist_node *)(&pio->list), ret_list);
+
 	return 0;
 err:
-	while ((pio = ploop_pio_list_pop(&list)) != NULL) {
+	llist_for_each_safe(pos, t, llist.first) {
+		pio = list_entry((struct list_head *)pos, typeof(*pio), list);
 		pio->bi_status = BLK_STS_RESOURCE;
+		INIT_LIST_HEAD(&pio->list);
 		ploop_pio_endio(pio);
 	}
+
 	return -ENOMEM;
 }
 ALLOW_ERROR_INJECTION(ploop_split_pio_to_list, ERRNO);
@@ -341,7 +352,7 @@ static void ploop_schedule_work(struct ploop *ploop)
 
 static void ploop_dispatch_pio(struct ploop *ploop, struct pio *pio)
 {
-	struct llist_head *list = (struct llist_head *)&ploop->pios[pio->queue_list_id];
+	struct llist_head *list = &ploop->pios[pio->queue_list_id];
 
 	lockdep_assert_not_held(&ploop->deferred_lock);
 	WARN_ON_ONCE(pio->queue_list_id >= PLOOP_LIST_COUNT);
@@ -1622,12 +1633,11 @@ ALLOW_ERROR_INJECTION(ploop_create_bvec_from_rq, NULL);
 
 static void ploop_prepare_one_embedded_pio(struct ploop *ploop,
 					   struct pio *pio,
-					   struct list_head *deferred_pios)
+					   struct llist_head *lldeferred_pios)
 {
 	struct ploop_rq *prq = pio->endio_cb_data;
 	struct request *rq = prq->rq;
 	struct bio_vec *bvec = NULL;
-	LIST_HEAD(list);
 	int ret;
 
 	if (rq->bio != rq->biotail) {
@@ -1646,16 +1656,18 @@ static void ploop_prepare_one_embedded_pio(struct ploop *ploop,
 		pio->bi_iter.bi_idx = 0;
 		pio->bi_iter.bi_bvec_done = 0;
 	} else {
-		/* Single bio already provides bvec array */
+		/* Single bio already provides bvec array
+		 * bvec is updated to the correct on submit
+		 * it is different after partial IO
+		 */
 		bvec = rq->bio->bi_io_vec;
-
 		pio->bi_iter = rq->bio->bi_iter;
 	}
 	pio->bi_iter.bi_sector = ploop_rq_pos(ploop, rq);
 	pio->bi_io_vec = bvec;
 
 	pio->queue_list_id = PLOOP_LIST_DEFERRED;
-	ret = ploop_split_pio_to_list(ploop, pio, deferred_pios);
+	ret = ploop_split_pio_to_list(ploop, pio, lldeferred_pios);
 	if (ret)
 		goto err_nomem;
 
@@ -1667,7 +1679,7 @@ static void ploop_prepare_one_embedded_pio(struct ploop *ploop,
 
 static void ploop_prepare_embedded_pios(struct ploop *ploop,
 					struct llist_node *pios,
-					struct list_head *deferred_pios)
+					struct llist_head *deferred_pios)
 {
 	struct pio *pio;
 	struct llist_node *pos, *t;
@@ -1684,12 +1696,17 @@ static void ploop_prepare_embedded_pios(struct ploop *ploop,
 }
 
 static void ploop_process_deferred_pios(struct ploop *ploop,
-					struct list_head *pios)
+					struct llist_head *pios)
 {
 	struct pio *pio;
 
-	while ((pio = ploop_pio_list_pop(pios)) != NULL)
+	struct llist_node *pos, *t;
+
+	llist_for_each_safe(pos, t, pios->first) {
+		pio = list_entry((struct list_head *)pos, typeof(*pio), list);
+		INIT_LIST_HEAD(&pio->list); /* until type is changed */
 		ploop_process_one_deferred_bio(ploop, pio);
+	}
 }
 
 static void ploop_process_one_discard_pio(struct ploop *ploop, struct pio *pio)
@@ -1787,19 +1804,13 @@ static void ploop_submit_metadata_writeback(struct ploop *ploop)
 	}
 }
 
-static void process_ploop_fsync_work(struct ploop *ploop)
+static void process_ploop_fsync_work(struct ploop *ploop, struct llist_node *llflush_pios)
 {
 	struct file *file;
 	struct pio *pio;
 	int ret;
-	struct llist_node *llflush_pios;
 	struct llist_node *pos, *t;
 
-	llflush_pios = llist_del_all(&ploop->pios[PLOOP_LIST_FLUSH]);
-
-	if (!llflush_pios)
-		return;
-
 	file = ploop_top_delta(ploop)->file;
 	/* All flushes are done as one */
 	ret = vfs_fsync(file, 0);
@@ -1818,38 +1829,39 @@ static void process_ploop_fsync_work(struct ploop *ploop)
 
 void do_ploop_run_work(struct ploop *ploop)
 {
-	LIST_HEAD(deferred_pios);
+	LLIST_HEAD(deferred_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;
+	struct llist_node *llflush_pios;
 	unsigned int old_flags = current->flags;
 
 	current->flags |= PF_IO_THREAD|PF_LOCAL_THROTTLE|PF_MEMALLOC_NOIO;
 
 	llembedded_pios = llist_del_all(&ploop->pios[PLOOP_LIST_PREPARE]);
-	smp_wmb(); /* */
-
 	lldeferred_pios = llist_del_all(&ploop->pios[PLOOP_LIST_DEFERRED]);
+	smp_wmb(); /* */
+	llresubmit = llist_del_all(&ploop->llresubmit_pios);
 	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);
 
 	/* add old deferred back to the list */
 	if (lldeferred_pios) {
 		struct llist_node *pos, *t;
 		struct pio *pio;
-
+		/* Add one by one we need last for batch add */
 		llist_for_each_safe(pos, t, lldeferred_pios) {
-			pio = list_entry((struct list_head *)pos, typeof(*pio), list);
-			INIT_LIST_HEAD(&pio->list);
-			list_add(&pio->list, &deferred_pios);
+			llist_add(pos, &deferred_pios);
 		}
 	}
 
 	ploop_prepare_embedded_pios(ploop, llembedded_pios, &deferred_pios);
 
+	llflush_pios = llist_del_all(&ploop->pios[PLOOP_LIST_FLUSH]);
+	smp_wmb(); /* */
+
 	if (llresubmit)
 		ploop_process_resubmit_pios(ploop, llist_reverse_order(llresubmit));
 
@@ -1863,8 +1875,9 @@ void do_ploop_run_work(struct ploop *ploop)
 
 	ploop_submit_metadata_writeback(ploop);
 
-	if (!llist_empty(&ploop->pios[PLOOP_LIST_FLUSH]))
-		process_ploop_fsync_work(ploop);
+	if (llflush_pios)
+		process_ploop_fsync_work(ploop, llist_reverse_order(llflush_pios));
+
 	current->flags = old_flags;
 }
 
@@ -1913,6 +1926,10 @@ static void ploop_submit_embedded_pio(struct ploop *ploop, struct pio *pio)
 	struct ploop_rq *prq = pio->endio_cb_data;
 	struct request *rq = prq->rq;
 	bool queue = true;
+	LLIST_HEAD(deferred_pios);
+	int ret = 0;
+	struct pio *spio, *stmp;
+	struct llist_node *pos, *t;
 
 	if (blk_rq_bytes(rq)) {
 		pio->queue_list_id = PLOOP_LIST_PREPARE;
@@ -1928,19 +1945,27 @@ static void ploop_submit_embedded_pio(struct ploop *ploop, struct pio *pio)
 	}
 
 	ploop_inc_nr_inflight(ploop, pio);
-	llist_add((struct llist_node *)(&pio->list), &ploop->pios[PLOOP_LIST_PREPARE]);
+	ploop_prepare_one_embedded_pio(ploop, pio, &deferred_pios);
 
+	llist_for_each_safe(pos, t, deferred_pios.first) {
+		spio = list_entry((struct list_head *)pos, typeof(*pio), list);
+		llist_add((struct llist_node *)(&spio->list), &ploop->pios[PLOOP_LIST_DEFERRED]);
+	}
 out:
 	if (queue)
 		ploop_schedule_work(ploop);
 }
 
-void ploop_submit_embedded_pios(struct ploop *ploop, struct list_head *list)
+void ploop_submit_embedded_pios(struct ploop *ploop, struct llist_node *list)
 {
 	struct pio *pio;
+	struct llist_node *pos, *t;
 
-	while ((pio = ploop_pio_list_pop(list)) != NULL)
+	llist_for_each_safe(pos, t, list) {
+		pio = list_entry((struct list_head *)pos, typeof(*pio), list);
+		INIT_LIST_HEAD(&pio->list);
 		ploop_submit_embedded_pio(ploop, pio);
+	}
 }
 
 int ploop_clone_and_map(struct dm_target *ti, struct request *rq,
-- 
2.43.0



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