dm zoned: per-device reclaim

Instead of having one reclaim workqueue for the entire set we should
be allocating a reclaim workqueue per device; doing so will reduce
contention and should boost performance for a multi-device setup.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-zoned-reclaim.c

@@ -21,6 +21,8 @@ struct dmz_reclaim {
 	struct dm_kcopyd_throttle kc_throttle;
 	int			kc_err;
 
+	int			dev_idx;
+
 	unsigned long		flags;
 
 	/* Last target access time */
@@ -198,8 +200,8 @@ static int dmz_reclaim_buf(struct dmz_reclaim *zrc, struct dm_zone *dzone)
 	struct dmz_metadata *zmd = zrc->metadata;
 	int ret;
 
-	DMDEBUG("(%s): Chunk %u, move buf zone %u (weight %u) to data zone %u (weight %u)",
-		dmz_metadata_label(zmd),
+	DMDEBUG("(%s/%u): Chunk %u, move buf zone %u (weight %u) to data zone %u (weight %u)",
+		dmz_metadata_label(zmd), zrc->dev_idx,
 		dzone->chunk, bzone->id, dmz_weight(bzone),
 		dzone->id, dmz_weight(dzone));
 
@@ -237,8 +239,8 @@ static int dmz_reclaim_seq_data(struct dmz_reclaim *zrc, struct dm_zone *dzone)
 	struct dmz_metadata *zmd = zrc->metadata;
 	int ret = 0;
 
-	DMDEBUG("(%s): Chunk %u, move data zone %u (weight %u) to buf zone %u (weight %u)",
-		dmz_metadata_label(zmd),
+	DMDEBUG("(%s/%u): Chunk %u, move data zone %u (weight %u) to buf zone %u (weight %u)",
+		dmz_metadata_label(zmd), zrc->dev_idx,
 		chunk, dzone->id, dmz_weight(dzone),
 		bzone->id, dmz_weight(bzone));
 
@@ -295,8 +297,8 @@ static int dmz_reclaim_rnd_data(struct dmz_reclaim *zrc, struct dm_zone *dzone)
 	if (!szone)
 		return -ENOSPC;
 
-	DMDEBUG("(%s): Chunk %u, move %s zone %u (weight %u) to %s zone %u",
-		dmz_metadata_label(zmd), chunk,
+	DMDEBUG("(%s/%u): Chunk %u, move %s zone %u (weight %u) to %s zone %u",
+		dmz_metadata_label(zmd), zrc->dev_idx, chunk,
 		dmz_is_cache(dzone) ? "cache" : "rnd",
 		dzone->id, dmz_weight(dzone),
 		dmz_is_rnd(szone) ? "rnd" : "seq", szone->id);
@@ -369,8 +371,8 @@ static int dmz_do_reclaim(struct dmz_reclaim *zrc)
 	/* Get a data zone */
 	dzone = dmz_get_zone_for_reclaim(zmd, dmz_target_idle(zrc));
 	if (!dzone) {
-		DMDEBUG("(%s): No zone found to reclaim",
-			dmz_metadata_label(zmd));
+		DMDEBUG("(%s/%u): No zone found to reclaim",
+			dmz_metadata_label(zmd), zrc->dev_idx);
 		return -EBUSY;
 	}
 
@@ -417,24 +419,26 @@ static int dmz_do_reclaim(struct dmz_reclaim *zrc)
 out:
 	if (ret) {
 		if (ret == -EINTR)
-			DMDEBUG("(%s): reclaim zone %u interrupted",
-				dmz_metadata_label(zmd), rzone->id);
+			DMDEBUG("(%s/%u): reclaim zone %u interrupted",
+				dmz_metadata_label(zmd), zrc->dev_idx,
+				rzone->id);
 		else
-			DMDEBUG("(%s): Failed to reclaim zone %u, err %d",
-				dmz_metadata_label(zmd), rzone->id, ret);
+			DMDEBUG("(%s/%u): Failed to reclaim zone %u, err %d",
+				dmz_metadata_label(zmd), zrc->dev_idx,
+				rzone->id, ret);
 		dmz_unlock_zone_reclaim(dzone);
 		return ret;
 	}
 
 	ret = dmz_flush_metadata(zrc->metadata);
 	if (ret) {
-		DMDEBUG("(%s): Metadata flush for zone %u failed, err %d",
-			dmz_metadata_label(zmd), rzone->id, ret);
+		DMDEBUG("(%s/%u): Metadata flush for zone %u failed, err %d",
+			dmz_metadata_label(zmd), zrc->dev_idx, rzone->id, ret);
 		return ret;
 	}
 
-	DMDEBUG("(%s): Reclaimed zone %u in %u ms",
-		dmz_metadata_label(zmd),
+	DMDEBUG("(%s/%u): Reclaimed zone %u in %u ms",
+		dmz_metadata_label(zmd), zrc->dev_idx,
 		rzone->id, jiffies_to_msecs(jiffies - start));
 	return 0;
 }
@@ -461,10 +465,20 @@ static unsigned int dmz_reclaim_percentage(struct dmz_reclaim *zrc)
  */
 static bool dmz_should_reclaim(struct dmz_reclaim *zrc, unsigned int p_unmap)
 {
-	unsigned int nr_reclaim = dmz_nr_rnd_zones(zrc->metadata);
+	unsigned int nr_reclaim;
+
+	nr_reclaim = dmz_nr_rnd_zones(zrc->metadata);
 
-	if (dmz_nr_cache_zones(zrc->metadata))
+	if (dmz_nr_cache_zones(zrc->metadata)) {
+		/*
+		 * The first device in a multi-device
+		 * setup only contains cache zones, so
+		 * never start reclaim there.
+		 */
+		if (zrc->dev_idx == 0)
+			return false;
 		nr_reclaim += dmz_nr_cache_zones(zrc->metadata);
+	}
 
 	/* Reclaim when idle */
 	if (dmz_target_idle(zrc) && nr_reclaim)
@@ -488,7 +502,7 @@ static void dmz_reclaim_work(struct work_struct *work)
 {
 	struct dmz_reclaim *zrc = container_of(work, struct dmz_reclaim, work.work);
 	struct dmz_metadata *zmd = zrc->metadata;
-	unsigned int p_unmap;
+	unsigned int p_unmap, nr_unmap_rnd = 0, nr_rnd = 0;
 	int ret;
 
 	if (dmz_dev_is_dying(zmd))
@@ -514,8 +528,11 @@ static void dmz_reclaim_work(struct work_struct *work)
 		zrc->kc_throttle.throttle = min(75U, 100U - p_unmap / 2);
 	}
 
-	DMDEBUG("(%s): Reclaim (%u): %s, %u%% free zones (%u/%u cache %u/%u random)",
-		dmz_metadata_label(zmd),
+	nr_unmap_rnd = dmz_nr_unmap_rnd_zones(zmd);
+	nr_rnd = dmz_nr_rnd_zones(zmd);
+
+	DMDEBUG("(%s/%u): Reclaim (%u): %s, %u%% free zones (%u/%u cache %u/%u random)",
+		dmz_metadata_label(zmd), zrc->dev_idx,
 		zrc->kc_throttle.throttle,
 		(dmz_target_idle(zrc) ? "Idle" : "Busy"),
 		p_unmap, dmz_nr_unmap_cache_zones(zmd),
@@ -536,7 +553,7 @@ static void dmz_reclaim_work(struct work_struct *work)
  * Initialize reclaim.
  */
 int dmz_ctr_reclaim(struct dmz_metadata *zmd,
-		    struct dmz_reclaim **reclaim)
+		    struct dmz_reclaim **reclaim, int idx)
 {
 	struct dmz_reclaim *zrc;
 	int ret;
@@ -547,6 +564,7 @@ int dmz_ctr_reclaim(struct dmz_metadata *zmd,
 
 	zrc->metadata = zmd;
 	zrc->atime = jiffies;
+	zrc->dev_idx = idx;
 
 	/* Reclaim kcopyd client */
 	zrc->kc = dm_kcopyd_client_create(&zrc->kc_throttle);
@@ -558,8 +576,8 @@ int dmz_ctr_reclaim(struct dmz_metadata *zmd,
 
 	/* Reclaim work */
 	INIT_DELAYED_WORK(&zrc->work, dmz_reclaim_work);
-	zrc->wq = alloc_ordered_workqueue("dmz_rwq_%s", WQ_MEM_RECLAIM,
-					  dmz_metadata_label(zmd));
+	zrc->wq = alloc_ordered_workqueue("dmz_rwq_%s_%d", WQ_MEM_RECLAIM,
+					  dmz_metadata_label(zmd), idx);
 	if (!zrc->wq) {
 		ret = -ENOMEM;
 		goto err;

drivers/md/dm-zoned-target.c

@@ -41,6 +41,7 @@ struct dm_chunk_work {
  */
 struct dmz_target {
 	struct dm_dev		*ddev[DMZ_MAX_DEVS];
+	unsigned int		nr_ddevs;
 
 	unsigned long		flags;
 
@@ -50,9 +51,6 @@ struct dmz_target {
 	/* For metadata handling */
 	struct dmz_metadata     *metadata;
 
-	/* For reclaim */
-	struct dmz_reclaim	*reclaim;
-
 	/* For chunk work */
 	struct radix_tree_root	chunk_rxtree;
 	struct workqueue_struct *chunk_wq;
@@ -404,14 +402,15 @@ static void dmz_handle_bio(struct dmz_target *dmz, struct dm_chunk_work *cw,
 		dm_per_bio_data(bio, sizeof(struct dmz_bioctx));
 	struct dmz_metadata *zmd = dmz->metadata;
 	struct dm_zone *zone;
-	int ret;
+	int i, ret;
 
 	/*
 	 * Write may trigger a zone allocation. So make sure the
 	 * allocation can succeed.
 	 */
 	if (bio_op(bio) == REQ_OP_WRITE)
-		dmz_schedule_reclaim(dmz->reclaim);
+		for (i = 0; i < dmz->nr_ddevs; i++)
+			dmz_schedule_reclaim(dmz->dev[i].reclaim);
 
 	dmz_lock_metadata(zmd);
 
@@ -431,6 +430,7 @@ static void dmz_handle_bio(struct dmz_target *dmz, struct dm_chunk_work *cw,
 	if (zone) {
 		dmz_activate_zone(zone);
 		bioctx->zone = zone;
+		dmz_reclaim_bio_acc(zone->dev->reclaim);
 	}
 
 	switch (bio_op(bio)) {
@@ -577,7 +577,6 @@ static int dmz_queue_chunk_work(struct dmz_target *dmz, struct bio *bio)
 
 	bio_list_add(&cw->bio_list, bio);
 
-	dmz_reclaim_bio_acc(dmz->reclaim);
 	if (queue_work(dmz->chunk_wq, &cw->work))
 		dmz_get_chunk_work(cw);
 out:
@@ -822,7 +821,7 @@ static int dmz_fixup_devices(struct dm_target *ti)
 static int dmz_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 {
 	struct dmz_target *dmz;
-	int ret;
+	int ret, i;
 
 	/* Check arguments */
 	if (argc < 1 || argc > 2) {
@@ -842,6 +841,7 @@ static int dmz_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		kfree(dmz);
 		return -ENOMEM;
 	}
+	dmz->nr_ddevs = argc;
 	ti->private = dmz;
 
 	/* Get the target zoned block device */
@@ -916,10 +916,12 @@ static int dmz_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	mod_delayed_work(dmz->flush_wq, &dmz->flush_work, DMZ_FLUSH_PERIOD);
 
 	/* Initialize reclaim */
-	ret = dmz_ctr_reclaim(dmz->metadata, &dmz->reclaim);
-	if (ret) {
-		ti->error = "Zone reclaim initialization failed";
-		goto err_fwq;
+	for (i = 0; i < dmz->nr_ddevs; i++) {
+		ret = dmz_ctr_reclaim(dmz->metadata, &dmz->dev[i].reclaim, i);
+		if (ret) {
+			ti->error = "Zone reclaim initialization failed";
+			goto err_fwq;
+		}
 	}
 
 	DMINFO("(%s): Target device: %llu 512-byte logical sectors (%llu blocks)",
@@ -952,11 +954,13 @@ static int dmz_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 static void dmz_dtr(struct dm_target *ti)
 {
 	struct dmz_target *dmz = ti->private;
+	int i;
 
 	flush_workqueue(dmz->chunk_wq);
 	destroy_workqueue(dmz->chunk_wq);
 
-	dmz_dtr_reclaim(dmz->reclaim);
+	for (i = 0; i < dmz->nr_ddevs; i++)
+		dmz_dtr_reclaim(dmz->dev[i].reclaim);
 
 	cancel_delayed_work_sync(&dmz->flush_work);
 	destroy_workqueue(dmz->flush_wq);
@@ -1025,9 +1029,11 @@ static int dmz_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
 static void dmz_suspend(struct dm_target *ti)
 {
 	struct dmz_target *dmz = ti->private;
+	int i;
 
 	flush_workqueue(dmz->chunk_wq);
-	dmz_suspend_reclaim(dmz->reclaim);
+	for (i = 0; i < dmz->nr_ddevs; i++)
+		dmz_suspend_reclaim(dmz->dev[i].reclaim);
 	cancel_delayed_work_sync(&dmz->flush_work);
 }
 
@@ -1037,9 +1043,11 @@ static void dmz_suspend(struct dm_target *ti)
 static void dmz_resume(struct dm_target *ti)
 {
 	struct dmz_target *dmz = ti->private;
+	int i;
 
 	queue_delayed_work(dmz->flush_wq, &dmz->flush_work, DMZ_FLUSH_PERIOD);
-	dmz_resume_reclaim(dmz->reclaim);
+	for (i = 0; i < dmz->nr_ddevs; i++)
+		dmz_resume_reclaim(dmz->dev[i].reclaim);
 }
 
 static int dmz_iterate_devices(struct dm_target *ti,
@@ -1100,7 +1108,10 @@ static int dmz_message(struct dm_target *ti, unsigned int argc, char **argv,
 	int r = -EINVAL;
 
 	if (!strcasecmp(argv[0], "reclaim")) {
-		dmz_schedule_reclaim(dmz->reclaim);
+		int i;
+
+		for (i = 0; i < dmz->nr_ddevs; i++)
+			dmz_schedule_reclaim(dmz->dev[i].reclaim);
 		r = 0;
 	} else
 		DMERR("unrecognized message %s", argv[0]);

drivers/md/dm-zoned.h

@@ -54,6 +54,7 @@ struct dmz_reclaim;
 struct dmz_dev {
 	struct block_device	*bdev;
 	struct dmz_metadata	*metadata;
+	struct dmz_reclaim	*reclaim;
 
 	char			name[BDEVNAME_SIZE];
 	uuid_t			uuid;
@@ -229,23 +230,6 @@ static inline void dmz_activate_zone(struct dm_zone *zone)
 	atomic_inc(&zone->refcount);
 }
 
-/*
- * Deactivate a zone. This decrement the zone reference counter
- * indicating that all BIOs to the zone have completed when the count is 0.
- */
-static inline void dmz_deactivate_zone(struct dm_zone *zone)
-{
-	atomic_dec(&zone->refcount);
-}
-
-/*
- * Test if a zone is active, that is, has a refcount > 0.
- */
-static inline bool dmz_is_active(struct dm_zone *zone)
-{
-	return atomic_read(&zone->refcount);
-}
-
 int dmz_lock_zone_reclaim(struct dm_zone *zone);
 void dmz_unlock_zone_reclaim(struct dm_zone *zone);
 struct dm_zone *dmz_get_zone_for_reclaim(struct dmz_metadata *zmd, bool idle);
@@ -272,7 +256,7 @@ int dmz_merge_valid_blocks(struct dmz_metadata *zmd, struct dm_zone *from_zone,
 /*
  * Functions defined in dm-zoned-reclaim.c
  */
-int dmz_ctr_reclaim(struct dmz_metadata *zmd, struct dmz_reclaim **zrc);
+int dmz_ctr_reclaim(struct dmz_metadata *zmd, struct dmz_reclaim **zrc, int idx);
 void dmz_dtr_reclaim(struct dmz_reclaim *zrc);
 void dmz_suspend_reclaim(struct dmz_reclaim *zrc);
 void dmz_resume_reclaim(struct dmz_reclaim *zrc);
@@ -285,4 +269,22 @@ void dmz_schedule_reclaim(struct dmz_reclaim *zrc);
 bool dmz_bdev_is_dying(struct dmz_dev *dmz_dev);
 bool dmz_check_bdev(struct dmz_dev *dmz_dev);
 
+/*
+ * Deactivate a zone. This decrement the zone reference counter
+ * indicating that all BIOs to the zone have completed when the count is 0.
+ */
+static inline void dmz_deactivate_zone(struct dm_zone *zone)
+{
+	dmz_reclaim_bio_acc(zone->dev->reclaim);
+	atomic_dec(&zone->refcount);
+}
+
+/*
+ * Test if a zone is active, that is, has a refcount > 0.
+ */
+static inline bool dmz_is_active(struct dm_zone *zone)
+{
+	return atomic_read(&zone->refcount);
+}
+
 #endif /* DM_ZONED_H */