Add vdev property to toggle adding io to vdev queue

Added vdev property to toggle queueing io to vdev queue when
reading / writing from / to vdev. The intention behind this
property is to improve IOPS performance when using o_direct.

Signed-off-by: MigeljanImeri <ImeriMigel@gmail.com>

Author: MigeljanImeri

include/sys/fs/zfs.h

@@ -385,6 +385,7 @@ typedef enum {
 	VDEV_PROP_TRIM_SUPPORT,
 	VDEV_PROP_TRIM_ERRORS,
 	VDEV_PROP_SLOW_IOS,
+	VDEV_PROP_QUEUE_IO,
 	VDEV_NUM_PROPS
 } vdev_prop_t;
 

include/sys/vdev_impl.h

@@ -466,6 +466,7 @@ struct vdev {
 	uint64_t	vdev_io_t;
 	uint64_t	vdev_slow_io_n;
 	uint64_t	vdev_slow_io_t;
+	uint64_t	vdev_queue_io;
 };
 
 #define	VDEV_PAD_SIZE		(8 << 10)

lib/libzfs/libzfs.abi

@@ -5899,7 +5899,8 @@
       <enumerator name='VDEV_PROP_TRIM_SUPPORT' value='49'/>
       <enumerator name='VDEV_PROP_TRIM_ERRORS' value='50'/>
       <enumerator name='VDEV_PROP_SLOW_IOS' value='51'/>
-      <enumerator name='VDEV_NUM_PROPS' value='52'/>
+      <enumerator name='VDEV_PROP_QUEUE_IO' value='52'/>
+      <enumerator name='VDEV_NUM_PROPS' value='53'/>
     </enum-decl>
     <typedef-decl name='vdev_prop_t' type-id='1573bec8' id='5aa5c90c'/>
     <class-decl name='zpool_load_policy' size-in-bits='256' is-struct='yes' visibility='default' id='2f65b36f'>

man/man7/vdevprops.7

@@ -157,6 +157,11 @@ If this device should perform new allocations, used to disable a device
 when it is scheduled for later removal.
 See
 .Xr zpool-remove 8 .
+.It Sy queue_io
+Add io to the vdev queue when reading or writing to this vdev.
+Disabling this property can sometimes improve performance for direct IOs.
+It is not recommended to disable for spinning disk devices, as starvation
+could occur.
 .El
 .Ss User Properties
 In addition to the standard native properties, ZFS supports arbitrary user

module/zcommon/zpool_prop.c

@@ -470,6 +470,9 @@ vdev_prop_init(void)
 	zprop_register_index(VDEV_PROP_TRIM_SUPPORT, "trim_support", 0,
 	    PROP_READONLY, ZFS_TYPE_VDEV, "on | off", "TRIMSUP",
 	    boolean_table, sfeatures);
+	zprop_register_index(VDEV_PROP_QUEUE_IO, "queue_io", 1,
+	    PROP_DEFAULT, ZFS_TYPE_VDEV, "on | off", "QUEUE_IO",
+	    boolean_table, sfeatures);
 
 	/* default index properties */
 	zprop_register_index(VDEV_PROP_FAILFAST, "failfast", B_TRUE,

module/zfs/vdev.c

@@ -718,6 +718,8 @@ vdev_alloc_common(spa_t *spa, uint_t id, uint64_t guid, vdev_ops_t *ops)
 	vd->vdev_slow_io_n = vdev_prop_default_numeric(VDEV_PROP_SLOW_IO_N);
 	vd->vdev_slow_io_t = vdev_prop_default_numeric(VDEV_PROP_SLOW_IO_T);
 
+	vd->vdev_queue_io = vdev_prop_default_numeric(VDEV_PROP_QUEUE_IO);
+
 	list_link_init(&vd->vdev_config_dirty_node);
 	list_link_init(&vd->vdev_state_dirty_node);
 	list_link_init(&vd->vdev_initialize_node);
@@ -3860,6 +3862,12 @@ vdev_load(vdev_t *vd)
 		if (error && error != ENOENT)
 			vdev_dbgmsg(vd, "vdev_load: zap_lookup(zap=%llu) "
 			    "failed [error=%d]", (u_longlong_t)zapobj, error);
+
+		error = vdev_prop_get_int(vd, VDEV_PROP_QUEUE_IO,
+		    &vd->vdev_queue_io);
+		if (error && error != ENOENT)
+			vdev_dbgmsg(vd, "vdev_load: zap_lookup(zap=%llu) "
+			    "failed [error=%d]", (u_longlong_t)zapobj, error);
 	}
 
 	/*
@@ -6095,6 +6103,15 @@ vdev_prop_set(vdev_t *vd, nvlist_t *innvl, nvlist_t *outnvl)
 			}
 			vd->vdev_slow_io_t = intval;
 			break;
+		case VDEV_PROP_QUEUE_IO:
+			if (nvpair_value_uint64(elem, &intval) != 0) {
+				error = EINVAL;
+				break;
+			}
+			if (vd->vdev_ops->vdev_op_leaf) {
+				vd->vdev_queue_io = intval;
+			}
+			break;
 		default:
 			/* Most processing is done in vdev_props_set_sync */
 			break;
@@ -6458,6 +6475,7 @@ vdev_prop_get(vdev_t *vd, nvlist_t *innvl, nvlist_t *outnvl)
 			case VDEV_PROP_IO_T:
 			case VDEV_PROP_SLOW_IO_N:
 			case VDEV_PROP_SLOW_IO_T:
+			case VDEV_PROP_QUEUE_IO:
 				err = vdev_prop_get_int(vd, prop, &intval);
 				if (err && err != ENOENT)
 					break;

module/zfs/vdev_queue.c

@@ -922,6 +922,12 @@ vdev_queue_io(zio_t *zio)
 	zio->io_flags |= ZIO_FLAG_DONT_QUEUE;
 	zio->io_timestamp = gethrtime();
 
+	if (!zio->io_vd->vdev_queue_io &&
+	    !(zio->io_flags & ZIO_FLAG_NODATA)) {
+		zio->io_queue_state = ZIO_QS_NONE;
+		return (zio);
+	}
+
 	mutex_enter(&vq->vq_lock);
 	vdev_queue_io_add(vq, zio);
 	nio = vdev_queue_io_to_issue(vq);
@@ -954,6 +960,10 @@ vdev_queue_io_done(zio_t *zio)
 	vq->vq_io_complete_ts = now;
 	vq->vq_io_delta_ts = zio->io_delta = now - zio->io_timestamp;
 
+	if (zio->io_queue_state == ZIO_QS_NONE) {
+		return;
+	}
+
 	mutex_enter(&vq->vq_lock);
 	vdev_queue_pending_remove(vq, zio);
 

tests/runfiles/common.run

@@ -548,8 +548,8 @@ tags = ['functional', 'cli_root', 'zpool_scrub']
 [tests/functional/cli_root/zpool_set]
 tests = ['zpool_set_001_pos', 'zpool_set_002_neg', 'zpool_set_003_neg',
     'zpool_set_ashift', 'zpool_set_features', 'vdev_set_001_pos',
-    'user_property_001_pos', 'user_property_002_neg',
-    'zpool_set_clear_userprop']
+    'user_property_001_pos', 'user_property_002_neg', 
+    'zpool_set_clear_userprop','vdev_set_queue_io']
 tags = ['functional', 'cli_root', 'zpool_set']
 
 [tests/functional/cli_root/zpool_split]

tests/zfs-tests/tests/Makefile.am

@@ -1245,6 +1245,7 @@ nobase_dist_datadir_zfs_tests_tests_SCRIPTS += \
 	functional/cli_root/zpool_set/setup.ksh \
 	functional/cli_root/zpool/setup.ksh \
 	functional/cli_root/zpool_set/vdev_set_001_pos.ksh \
+	functional/cli_root/zpool_set/vdev_set_queue_io.ksh \
 	functional/cli_root/zpool_set/zpool_set_common.kshlib \
 	functional/cli_root/zpool_set/zpool_set_001_pos.ksh \
 	functional/cli_root/zpool_set/zpool_set_002_neg.ksh \

tests/zfs-tests/tests/functional/cli_root/zpool_get/vdev_get.cfg

@@ -76,4 +76,5 @@ typeset -a properties=(
     trim_support
     trim_errors
     slow_ios
+    queue_io
 )

tests/zfs-tests/tests/functional/cli_root/zpool_set/vdev_set_queue_io.ksh

@@ -0,0 +1,96 @@
+#!/bin/ksh -p
+# SPDX-License-Identifier: CDDL-1.0
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or https://opensource.org/licenses/CDDL-1.0.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright (c) 2024 by Triad National Security, LLC.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+#
+# DESCRIPTION:
+# Toggling vdev queue_io property while reading from vdev should not cause panic.
+#
+# STRATEGY:
+# 1. Create a zpool
+# 2. Write a file to the pool.
+# 3. Start reading from file, while also toggling the queue_io property on / off.
+#
+
+verify_runnable "global"
+
+command -v fio > /dev/null || log_unsupported "fio missing"
+log_must save_tunable DIO_ENABLED
+log_must set_tunable32 DIO_ENABLED 1
+
+function toggle_queue_io
+{
+	zpool set queue_io=off $TESTPOOL1 $FILEDEV
+	sleep 0.1
+	zpool set queue_io=on $TESTPOOL1 $FILEDEV
+	sleep 0.1
+}
+
+function cleanup
+{
+	log_must destroy_pool $TESTPOOL1
+	rm -f $FILEDEV
+	log_must restore_tunable DIO_ENABLED
+}
+
+log_assert "Toggling vdev queue_io property while reading from vdev should not cause panic"
+log_onexit cleanup
+
+# 1. Create a pool
+
+FILEDEV="$TEST_BASE_DIR/filedev.$$"
+log_must truncate -s $(($MINVDEVSIZE * 2)) $FILEDEV
+log_must create_pool $TESTPOOL1 $FILEDEV
+
+mntpnt=$(get_prop mountpoint $TESTPOOL1)
+
+# 2. Write a file to the pool, while also toggling the queue_io property on / off.
+
+log_must eval "fio --filename=$mntpnt/foobar --name=write-file \
+		--rw=write --size=$MINVDEVSIZE --bs=128k --numjobs=1 --direct=1 \
+		--ioengine=sync --runtime=10 &"
+
+ITERATIONS=30
+
+for i in $(seq $ITERATIONS); do
+	log_must toggle_queue_io
+done;
+wait
+
+# 3. Starting reading from file, while also toggling the queue_io property on / off.
+
+log_must eval "fio --filename=$mntpnt/foobar --name=read-file \
+		--rw=read --size=$MINVDEVSIZE --bs=128k --numjobs=1 --direct=1 \
+		--ioengine=sync --time_based --runtime=10 &"
+
+for i in $(seq $ITERATIONS); do
+	log_must toggle_queue_io
+done;
+wait
+
+log_pass "Toggling vdev queue_io property while reading from vdev does not cause panic"