zvol: Enable zvol threading functionality on FreeBSD

Make zvol I/O requests processing asynchronous on FreeBSD side in some
cases. Clone zvol threading logic and required module parameters from
Linux side. Make zvol threadpool creation/destruction logic shared for
both Linux and FreeBSD.
The IO requests are processed asynchronously in next cases:
- volmode=geom: if IO request thread is geom thread or cannot sleep.
- volmode=cdev: if IO request passed thru struct cdevsw .d_strategy
routine, mean is AIO request.
In all other cases the IO requests are processed synchronously. The
volthreading zvol property is ignored on FreeBSD side.

Sponsored-by: vStack, Inc.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: @ImAwsumm
Signed-off-by: Fedor Uporov <fuporov.vstack@gmail.com>
Closes #17169
This commit is contained in:
Fedor Uporov
2025-05-08 22:25:40 +03:00
committed by GitHub
parent f13d760aa8
commit 1a8f5ad3b0
8 changed files with 253 additions and 244 deletions
+5 -138
View File
@@ -51,21 +51,13 @@ static void zvol_request_impl(zvol_state_t *zv, struct bio *bio,
struct request *rq, boolean_t force_sync);
static unsigned int zvol_major = ZVOL_MAJOR;
static unsigned int zvol_request_sync = 0;
static unsigned int zvol_prefetch_bytes = (128 * 1024);
static unsigned long zvol_max_discard_blocks = 16384;
/*
* Switch taskq at multiple of 512 MB offset. This can be set to a lower value
* to utilize more threads for small files but may affect prefetch hits.
*/
#define ZVOL_TASKQ_OFFSET_SHIFT 29
#ifndef HAVE_BLKDEV_GET_ERESTARTSYS
static unsigned int zvol_open_timeout_ms = 1000;
#endif
static unsigned int zvol_threads = 0;
static unsigned int zvol_blk_mq_threads = 0;
static unsigned int zvol_blk_mq_actual_threads;
static boolean_t zvol_use_blk_mq = B_FALSE;
@@ -82,8 +74,6 @@ static boolean_t zvol_use_blk_mq = B_FALSE;
*/
static unsigned int zvol_blk_mq_blocks_per_thread = 8;
static unsigned int zvol_num_taskqs = 0;
#ifndef BLKDEV_DEFAULT_RQ
/* BLKDEV_MAX_RQ was renamed to BLKDEV_DEFAULT_RQ in the 5.16 kernel */
#define BLKDEV_DEFAULT_RQ BLKDEV_MAX_RQ
@@ -117,45 +107,8 @@ struct zvol_state_os {
boolean_t use_blk_mq;
};
typedef struct zv_taskq {
uint_t tqs_cnt;
taskq_t **tqs_taskq;
} zv_taskq_t;
static zv_taskq_t zvol_taskqs;
static struct ida zvol_ida;
typedef struct zv_request_stack {
zvol_state_t *zv;
struct bio *bio;
struct request *rq;
} zv_request_t;
typedef struct zv_work {
struct request *rq;
struct work_struct work;
} zv_work_t;
typedef struct zv_request_task {
zv_request_t zvr;
taskq_ent_t ent;
} zv_request_task_t;
static zv_request_task_t *
zv_request_task_create(zv_request_t zvr)
{
zv_request_task_t *task;
task = kmem_alloc(sizeof (zv_request_task_t), KM_SLEEP);
taskq_init_ent(&task->ent);
task->zvr = zvr;
return (task);
}
static void
zv_request_task_free(zv_request_task_t *task)
{
kmem_free(task, sizeof (*task));
}
/*
* This is called when a new block multiqueue request comes in. A request
* contains one or more BIOs.
@@ -1793,59 +1746,14 @@ zvol_init(void)
{
int error;
/*
* zvol_threads is the module param the user passes in.
*
* zvol_actual_threads is what we use internally, since the user can
* pass zvol_thread = 0 to mean "use all the CPUs" (the default).
*/
static unsigned int zvol_actual_threads;
if (zvol_threads == 0) {
/*
* See dde9380a1 for why 32 was chosen here. This should
* probably be refined to be some multiple of the number
* of CPUs.
*/
zvol_actual_threads = MAX(num_online_cpus(), 32);
} else {
zvol_actual_threads = MIN(MAX(zvol_threads, 1), 1024);
error = zvol_init_impl();
if (error) {
printk(KERN_INFO "ZFS: zvol_init_impl() failed %d\n", error);
return (error);
}
/*
* Use atleast 32 zvol_threads but for many core system,
* prefer 6 threads per taskq, but no more taskqs
* than threads in them on large systems.
*
* taskq total
* cpus taskqs threads threads
* ------- ------- ------- -------
* 1 1 32 32
* 2 1 32 32
* 4 1 32 32
* 8 2 16 32
* 16 3 11 33
* 32 5 7 35
* 64 8 8 64
* 128 11 12 132
* 256 16 16 256
*/
zv_taskq_t *ztqs = &zvol_taskqs;
uint_t num_tqs = MIN(num_online_cpus(), zvol_num_taskqs);
if (num_tqs == 0) {
num_tqs = 1 + num_online_cpus() / 6;
while (num_tqs * num_tqs > zvol_actual_threads)
num_tqs--;
}
uint_t per_tq_thread = zvol_actual_threads / num_tqs;
if (per_tq_thread * num_tqs < zvol_actual_threads)
per_tq_thread++;
ztqs->tqs_cnt = num_tqs;
ztqs->tqs_taskq = kmem_alloc(num_tqs * sizeof (taskq_t *), KM_SLEEP);
error = register_blkdev(zvol_major, ZVOL_DRIVER);
if (error) {
kmem_free(ztqs->tqs_taskq, ztqs->tqs_cnt * sizeof (taskq_t *));
ztqs->tqs_taskq = NULL;
printk(KERN_INFO "ZFS: register_blkdev() failed %d\n", error);
return (error);
}
@@ -1864,25 +1772,6 @@ zvol_init(void)
1024);
}
for (uint_t i = 0; i < num_tqs; i++) {
char name[32];
(void) snprintf(name, sizeof (name), "%s_tq-%u",
ZVOL_DRIVER, i);
ztqs->tqs_taskq[i] = taskq_create(name, per_tq_thread,
maxclsyspri, per_tq_thread, INT_MAX,
TASKQ_PREPOPULATE | TASKQ_DYNAMIC);
if (ztqs->tqs_taskq[i] == NULL) {
for (int j = i - 1; j >= 0; j--)
taskq_destroy(ztqs->tqs_taskq[j]);
unregister_blkdev(zvol_major, ZVOL_DRIVER);
kmem_free(ztqs->tqs_taskq, ztqs->tqs_cnt *
sizeof (taskq_t *));
ztqs->tqs_taskq = NULL;
return (-ENOMEM);
}
}
zvol_init_impl();
ida_init(&zvol_ida);
return (0);
}
@@ -1890,21 +1779,9 @@ zvol_init(void)
void
zvol_fini(void)
{
zv_taskq_t *ztqs = &zvol_taskqs;
zvol_fini_impl();
unregister_blkdev(zvol_major, ZVOL_DRIVER);
if (ztqs->tqs_taskq == NULL) {
ASSERT3U(ztqs->tqs_cnt, ==, 0);
} else {
for (uint_t i = 0; i < ztqs->tqs_cnt; i++) {
ASSERT3P(ztqs->tqs_taskq[i], !=, NULL);
taskq_destroy(ztqs->tqs_taskq[i]);
}
kmem_free(ztqs->tqs_taskq, ztqs->tqs_cnt *
sizeof (taskq_t *));
ztqs->tqs_taskq = NULL;
}
zvol_fini_impl();
ida_destroy(&zvol_ida);
}
@@ -1915,19 +1792,9 @@ MODULE_PARM_DESC(zvol_inhibit_dev, "Do not create zvol device nodes");
module_param(zvol_major, uint, 0444);
MODULE_PARM_DESC(zvol_major, "Major number for zvol device");
module_param(zvol_threads, uint, 0444);
MODULE_PARM_DESC(zvol_threads, "Number of threads to handle I/O requests. Set"
"to 0 to use all active CPUs");
module_param(zvol_request_sync, uint, 0644);
MODULE_PARM_DESC(zvol_request_sync, "Synchronously handle bio requests");
module_param(zvol_max_discard_blocks, ulong, 0444);
MODULE_PARM_DESC(zvol_max_discard_blocks, "Max number of blocks to discard");
module_param(zvol_num_taskqs, uint, 0444);
MODULE_PARM_DESC(zvol_num_taskqs, "Number of zvol taskqs");
module_param(zvol_prefetch_bytes, uint, 0644);
MODULE_PARM_DESC(zvol_prefetch_bytes, "Prefetch N bytes at zvol start+end");