diff mbox series

[v3,10/30] block: Fake max open zones limit when there is no limit

Message ID 20240328004409.594888-11-dlemoal@kernel.org (mailing list archive)
State Superseded
Headers show
Series Zone write plugging | expand

Commit Message

Damien Le Moal March 28, 2024, 12:43 a.m. UTC
For a zoned block device that has no limit on the number of open zones
and no limit on the number of active zones, the zone write plug free
list is initialized with 128 zone write plugs. For such case, set the
device max_open_zones queue limit to this value to indicate to the user
the potential performance penalty that may happen when writing
simultaneously to more zones than the free list size.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 block/blk-zoned.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

Comments

Christoph Hellwig March 28, 2024, 4:49 a.m. UTC | #1
On Thu, Mar 28, 2024 at 09:43:49AM +0900, Damien Le Moal wrote:
> For a zoned block device that has no limit on the number of open zones
> and no limit on the number of active zones, the zone write plug free
> list is initialized with 128 zone write plugs. For such case, set the
> device max_open_zones queue limit to this value to indicate to the user
> the potential performance penalty that may happen when writing
> simultaneously to more zones than the free list size.

Setting max_open_zone needs to go through the queue limits API and
be done on a frozen queue (probabaly my merging it into the other
assignments done later in zone revalidation that are done with
the queue frozen).
Bart Van Assche March 29, 2024, 8:37 p.m. UTC | #2
On 3/27/24 5:43 PM, Damien Le Moal wrote:
> +	 * zone write plugsso that the user is aware of the potential
                       ^^^^^^^

A space is missing.

Thanks,

Bart.
diff mbox series

Patch

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 3084dae5408e..8ad5d271d3f8 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -1570,17 +1570,24 @@  static int disk_revalidate_zone_resources(struct gendisk *disk,
 {
 	struct queue_limits *lim = &disk->queue->limits;
 	unsigned int max_nr_zwplugs;
+	bool set_max_open = false;
 	int ret;
 
 	/*
 	 * If the device has no limit on the maximum number of open and active
 	 * zones, use BLK_ZONE_DEFAULT_MAX_NR_WPLUGS for the maximum number
-	 * of zone write plugs to hash.
+	 * of zone write plugs to hash and set the max_open_zones queue limit
+	 * of the device to indicate to the user the number of pre-allocated
+	 * zone write plugsso that the user is aware of the potential
+	 * performance penalty for simultaneously writing to more zones than
+	 * this limit.
 	 */
 	max_nr_zwplugs = max(lim->max_open_zones, lim->max_active_zones);
-	if (!max_nr_zwplugs)
+	if (!max_nr_zwplugs) {
 		max_nr_zwplugs =
 			min(BLK_ZONE_DEFAULT_MAX_NR_WPLUGS, nr_zones);
+		set_max_open = true;
+	}
 
 	if (!disk->zone_wplugs_hash) {
 		ret = disk_alloc_zone_resources(disk, max_nr_zwplugs);
@@ -1596,6 +1603,9 @@  static int disk_revalidate_zone_resources(struct gendisk *disk,
 			return ret;
 	}
 
+	if (set_max_open)
+		disk_set_max_open_zones(disk, max_nr_zwplugs);
+
 	return 0;
 }