diff options
| -rw-r--r-- | drivers/md/dm-round-robin.c | 60 |
1 files changed, 48 insertions, 12 deletions
diff --git a/drivers/md/dm-round-robin.c b/drivers/md/dm-round-robin.c index 0558ab3d7235..4ace1da17db8 100644 --- a/drivers/md/dm-round-robin.c +++ b/drivers/md/dm-round-robin.c @@ -17,7 +17,7 @@ #include <linux/module.h> #define DM_MSG_PREFIX "multipath round-robin" -#define RR_MIN_IO 1 +#define RR_MIN_IO 1000 #define RR_VERSION "1.1.0" /*----------------------------------------------------------------- @@ -47,19 +47,44 @@ struct selector { struct list_head valid_paths; struct list_head invalid_paths; spinlock_t lock; + struct dm_path * __percpu *current_path; + struct percpu_counter repeat_count; }; +static void set_percpu_current_path(struct selector *s, struct dm_path *path) +{ + int cpu; + + for_each_possible_cpu(cpu) + *per_cpu_ptr(s->current_path, cpu) = path; +} + static struct selector *alloc_selector(void) { struct selector *s = kmalloc(sizeof(*s), GFP_KERNEL); - if (s) { - INIT_LIST_HEAD(&s->valid_paths); - INIT_LIST_HEAD(&s->invalid_paths); - spin_lock_init(&s->lock); - } + if (!s) + return NULL; + + INIT_LIST_HEAD(&s->valid_paths); + INIT_LIST_HEAD(&s->invalid_paths); + spin_lock_init(&s->lock); + + s->current_path = alloc_percpu(struct dm_path *); + if (!s->current_path) + goto out_current_path; + set_percpu_current_path(s, NULL); + + if (percpu_counter_init(&s->repeat_count, 0, GFP_KERNEL)) + goto out_repeat_count; return s; + +out_repeat_count: + free_percpu(s->current_path); +out_current_path: + kfree(s); + return NULL;; } static int rr_create(struct path_selector *ps, unsigned argc, char **argv) @@ -80,6 +105,8 @@ static void rr_destroy(struct path_selector *ps) free_paths(&s->valid_paths); free_paths(&s->invalid_paths); + free_percpu(s->current_path); + percpu_counter_destroy(&s->repeat_count); kfree(s); ps->context = NULL; } @@ -130,11 +157,6 @@ static int rr_add_path(struct path_selector *ps, struct dm_path *path, return -EINVAL; } - if (repeat_count > 1) { - DMWARN_LIMIT("repeat_count > 1 is deprecated, using 1 instead"); - repeat_count = 1; - } - /* allocate the path */ pi = kmalloc(sizeof(*pi), GFP_KERNEL); if (!pi) { @@ -161,6 +183,9 @@ static void rr_fail_path(struct path_selector *ps, struct dm_path *p) struct path_info *pi = p->pscontext; spin_lock_irqsave(&s->lock, flags); + if (p == *this_cpu_ptr(s->current_path)) + set_percpu_current_path(s, NULL); + list_move(&pi->list, &s->invalid_paths); spin_unlock_irqrestore(&s->lock, flags); } @@ -183,15 +208,26 @@ static struct dm_path *rr_select_path(struct path_selector *ps, size_t nr_bytes) unsigned long flags; struct selector *s = ps->context; struct path_info *pi = NULL; + struct dm_path *current_path = NULL; + + current_path = *this_cpu_ptr(s->current_path); + if (current_path) { + percpu_counter_dec(&s->repeat_count); + if (percpu_counter_read_positive(&s->repeat_count) > 0) + return current_path; + } spin_lock_irqsave(&s->lock, flags); if (!list_empty(&s->valid_paths)) { pi = list_entry(s->valid_paths.next, struct path_info, list); list_move_tail(&pi->list, &s->valid_paths); + percpu_counter_set(&s->repeat_count, pi->repeat_count); + set_percpu_current_path(s, pi->path); + current_path = pi->path; } spin_unlock_irqrestore(&s->lock, flags); - return pi ? pi->path : NULL; + return current_path; } static struct path_selector_type rr_ps = { |