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dm mpath: optimize NVMe bio-based support

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All code that deals with pg_init is not used with bio-based NVMe mode.
This includes skipping initialization of pg_init related variables.

Also, pg_init related members on 'struct multipath' have been grouped
together.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mike Snitzer 2017-12-10 15:37:21 -05:00
parent cd02538445
commit 848b8aefd4
1 changed files with 95 additions and 76 deletions
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145
drivers/md/dm-mpath.c
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@ -64,36 +64,30 @@ struct priority_group {
/* Multipath context */
struct multipath {
struct list_head list;
struct dm_target *ti;
const char *hw_handler_name;
char *hw_handler_params;
unsigned long flags; /* Multipath state flags */
spinlock_t lock;
unsigned nr_priority_groups;
struct list_head priority_groups;
wait_queue_head_t pg_init_wait; /* Wait for pg_init completion */
enum dm_queue_mode queue_mode;
struct pgpath *current_pgpath;
struct priority_group *current_pg;
struct priority_group *next_pg; /* Switch to this PG if set */
unsigned long flags; /* Multipath state flags */
atomic_t nr_valid_paths; /* Total number of usable paths */
unsigned nr_priority_groups;
struct list_head priority_groups;
const char *hw_handler_name;
char *hw_handler_params;
wait_queue_head_t pg_init_wait; /* Wait for pg_init completion */
unsigned pg_init_retries; /* Number of times to retry pg_init */
unsigned pg_init_delay_msecs; /* Number of msecs before pg_init retry */
atomic_t nr_valid_paths; /* Total number of usable paths */
atomic_t pg_init_in_progress; /* Only one pg_init allowed at once */
atomic_t pg_init_count; /* Number of times pg_init called */
enum dm_queue_mode queue_mode;
struct mutex work_mutex;
struct work_struct trigger_event;
struct dm_target *ti;
struct work_struct process_queued_bios;
struct bio_list queued_bios;
@ -135,10 +129,10 @@ static struct pgpath *alloc_pgpath(void)
{
struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL);
if (pgpath) {
if (!pgpath)
return NULL;
pgpath->is_active = true;
INIT_DELAYED_WORK(&pgpath->activate_path, activate_path_work);
}
return pgpath;
}
@ -193,13 +187,8 @@ static struct multipath *alloc_multipath(struct dm_target *ti)
if (m) {
INIT_LIST_HEAD(&m->priority_groups);
spin_lock_init(&m->lock);
set_bit(MPATHF_QUEUE_IO, &m->flags);
atomic_set(&m->nr_valid_paths, 0);
atomic_set(&m->pg_init_in_progress, 0);
atomic_set(&m->pg_init_count, 0);
m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT;
INIT_WORK(&m->trigger_event, trigger_event);
init_waitqueue_head(&m->pg_init_wait);
mutex_init(&m->work_mutex);
m->queue_mode = DM_TYPE_NONE;
@ -235,6 +224,14 @@ static int alloc_multipath_stage2(struct dm_target *ti, struct multipath *m)
}
}
if (m->queue_mode != DM_TYPE_NVME_BIO_BASED) {
set_bit(MPATHF_QUEUE_IO, &m->flags);
atomic_set(&m->pg_init_in_progress, 0);
atomic_set(&m->pg_init_count, 0);
m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT;
init_waitqueue_head(&m->pg_init_wait);
}
dm_table_set_type(ti->table, m->queue_mode);
return 0;
@ -339,6 +336,9 @@ static void __switch_pg(struct multipath *m, struct priority_group *pg)
{
m->current_pg = pg;
if (m->queue_mode == DM_TYPE_NVME_BIO_BASED)
return;
/* Must we initialise the PG first, and queue I/O till it's ready? */
if (m->hw_handler_name) {
set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags);
@ -384,6 +384,7 @@ static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes)
unsigned bypassed = 1;
if (!atomic_read(&m->nr_valid_paths)) {
if (m->queue_mode != DM_TYPE_NVME_BIO_BASED)
clear_bit(MPATHF_QUEUE_IO, &m->flags);
goto failed;
}
@ -528,8 +529,7 @@ static int multipath_clone_and_map(struct dm_target *ti, struct request *rq,
clone = blk_get_request(q, rq->cmd_flags | REQ_NOMERGE, GFP_ATOMIC);
if (IS_ERR(clone)) {
/* EBUSY, ENODEV or EWOULDBLOCK: requeue */
bool queue_dying = blk_queue_dying(q);
if (queue_dying) {
if (blk_queue_dying(q)) {
atomic_inc(&m->pg_init_in_progress);
activate_or_offline_path(pgpath);
}
@ -563,21 +563,28 @@ static int __multipath_map_bio(struct multipath *m, struct bio *bio, struct dm_m
/* Do we need to select a new pgpath? */
pgpath = READ_ONCE(m->current_pgpath);
/* MPATHF_QUEUE_IO will never be set for NVMe */
queue_io = test_bit(MPATHF_QUEUE_IO, &m->flags);
if (!pgpath || !queue_io)
pgpath = choose_pgpath(m, mpio->nr_bytes);
if ((pgpath && queue_io) ||
(!pgpath && test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))) {
if ((!pgpath && test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) ||
(pgpath && queue_io)) {
/* Queue for the daemon to resubmit */
spin_lock_irqsave(&m->lock, flags);
bio_list_add(&m->queued_bios, bio);
spin_unlock_irqrestore(&m->lock, flags);
if (m->queue_mode == DM_TYPE_NVME_BIO_BASED) {
queue_work(kmultipathd, &m->process_queued_bios);
} else {
/* PG_INIT_REQUIRED cannot be set without QUEUE_IO */
if (queue_io || test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags))
pg_init_all_paths(m);
else if (!queue_io)
queue_work(kmultipathd, &m->process_queued_bios);
}
return DM_MAPIO_SUBMITTED;
}
@ -750,34 +757,11 @@ static int parse_path_selector(struct dm_arg_set *as, struct priority_group *pg,
return 0;
}
static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps,
struct dm_target *ti)
static int setup_scsi_dh(struct block_device *bdev, struct multipath *m, char **error)
{
int r;
struct pgpath *p;
struct multipath *m = ti->private;
struct request_queue *q = NULL;
struct request_queue *q = bdev_get_queue(bdev);
const char *attached_handler_name;
/* we need at least a path arg */
if (as->argc < 1) {
ti->error = "no device given";
return ERR_PTR(-EINVAL);
}
p = alloc_pgpath();
if (!p)
return ERR_PTR(-ENOMEM);
r = dm_get_device(ti, dm_shift_arg(as), dm_table_get_mode(ti->table),
&p->path.dev);
if (r) {
ti->error = "error getting device";
goto bad;
}
if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags) || m->hw_handler_name)
q = bdev_get_queue(p->path.dev->bdev);
int r;
if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags)) {
retain:
@ -809,23 +793,56 @@ retain:
char b[BDEVNAME_SIZE];
printk(KERN_INFO "dm-mpath: retaining handler on device %s\n",
bdevname(p->path.dev->bdev, b));
bdevname(bdev, b));
goto retain;
}
if (r < 0) {
ti->error = "error attaching hardware handler";
dm_put_device(ti, p->path.dev);
goto bad;
*error = "error attaching hardware handler";
return r;
}
if (m->hw_handler_params) {
r = scsi_dh_set_params(q, m->hw_handler_params);
if (r < 0) {
ti->error = "unable to set hardware "
"handler parameters";
dm_put_device(ti, p->path.dev);
*error = "unable to set hardware handler parameters";
return r;
}
}
}
return 0;
}
static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps,
struct dm_target *ti)
{
int r;
struct pgpath *p;
struct multipath *m = ti->private;
/* we need at least a path arg */
if (as->argc < 1) {
ti->error = "no device given";
return ERR_PTR(-EINVAL);
}
p = alloc_pgpath();
if (!p)
return ERR_PTR(-ENOMEM);
r = dm_get_device(ti, dm_shift_arg(as), dm_table_get_mode(ti->table),
&p->path.dev);
if (r) {
ti->error = "error getting device";
goto bad;
}
if (m->queue_mode != DM_TYPE_NVME_BIO_BASED) {
INIT_DELAYED_WORK(&p->activate_path, activate_path_work);
r = setup_scsi_dh(p->path.dev->bdev, m, &ti->error);
if (r) {
dm_put_device(ti, p->path.dev);
goto bad;
}
}
@ -836,7 +853,6 @@ retain:
}
return p;
bad:
free_pgpath(p);
return ERR_PTR(r);
@ -1152,16 +1168,19 @@ static void multipath_wait_for_pg_init_completion(struct multipath *m)
static void flush_multipath_work(struct multipath *m)
{
if (m->hw_handler_name) {
set_bit(MPATHF_PG_INIT_DISABLED, &m->flags);
smp_mb__after_atomic();
flush_workqueue(kmpath_handlerd);
multipath_wait_for_pg_init_completion(m);
flush_workqueue(kmultipathd);
flush_work(&m->trigger_event);
clear_bit(MPATHF_PG_INIT_DISABLED, &m->flags);
smp_mb__after_atomic();
}
flush_workqueue(kmultipathd);
flush_work(&m->trigger_event);
}
static void multipath_dtr(struct dm_target *ti)