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nvme: take node locality into account when selecting a path

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Make current_path an array with an entry for every possible node, and
cache the best path on a per-node basis.  Take the node distance into
account when selecting it.  This is primarily useful for dual-ported PCIe
devices which are connected to PCIe root ports on different sockets.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
This commit is contained in:
Christoph Hellwig 2018-09-11 09:51:29 +02:00
parent 73383adfad
commit f333444708
3 changed files with 54 additions and 28 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

7
drivers/nvme/host/core.c
View file

@ -2908,9 +2908,14 @@ static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ctrl *ctrl,
unsigned nsid, struct nvme_id_ns *id)
{
struct nvme_ns_head *head;
size_t size = sizeof(*head);
int ret = -ENOMEM;
head = kzalloc(sizeof(*head), GFP_KERNEL);
#ifdef CONFIG_NVME_MULTIPATH
size += num_possible_nodes() * sizeof(struct nvme_ns *);
#endif
head = kzalloc(size, GFP_KERNEL);
if (!head)
goto out;
ret = ida_simple_get(&ctrl->subsys->ns_ida, 1, 0, GFP_KERNEL);

48
drivers/nvme/host/multipath.c
View file

@ -117,29 +117,55 @@ static const char *nvme_ana_state_names[] = {
[NVME_ANA_CHANGE] = "change",
};
static struct nvme_ns *__nvme_find_path(struct nvme_ns_head *head)
void nvme_mpath_clear_current_path(struct nvme_ns *ns)
{
struct nvme_ns *ns, *fallback = NULL;
struct nvme_ns_head *head = ns->head;
int node;
if (!head)
return;
for_each_node(node) {
if (ns == rcu_access_pointer(head->current_path[node]))
rcu_assign_pointer(head->current_path[node], NULL);
}
}
static struct nvme_ns *__nvme_find_path(struct nvme_ns_head *head, int node)
{
int found_distance = INT_MAX, fallback_distance = INT_MAX, distance;
struct nvme_ns *found = NULL, *fallback = NULL, *ns;
list_for_each_entry_rcu(ns, &head->list, siblings) {
if (ns->ctrl->state != NVME_CTRL_LIVE ||
test_bit(NVME_NS_ANA_PENDING, &ns->flags))
continue;
distance = node_distance(node, dev_to_node(ns->ctrl->dev));
switch (ns->ana_state) {
case NVME_ANA_OPTIMIZED:
rcu_assign_pointer(head->current_path, ns);
return ns;
if (distance < found_distance) {
found_distance = distance;
found = ns;
}
break;
case NVME_ANA_NONOPTIMIZED:
if (distance < fallback_distance) {
fallback_distance = distance;
fallback = ns;
}
break;
default:
break;
}
}
if (fallback)
rcu_assign_pointer(head->current_path, fallback);
return fallback;
if (!found)
found = fallback;
if (found)
rcu_assign_pointer(head->current_path[node], found);
return found;
}
static inline bool nvme_path_is_optimized(struct nvme_ns *ns)
@ -150,10 +176,12 @@ static inline bool nvme_path_is_optimized(struct nvme_ns *ns)
inline struct nvme_ns *nvme_find_path(struct nvme_ns_head *head)
{
struct nvme_ns *ns = srcu_dereference(head->current_path, &head->srcu);
int node = numa_node_id();
struct nvme_ns *ns;
ns = srcu_dereference(head->current_path[node], &head->srcu);
if (unlikely(!ns || !nvme_path_is_optimized(ns)))
ns = __nvme_find_path(head);
ns = __nvme_find_path(head, node);
return ns;
}
@ -200,7 +228,7 @@ static bool nvme_ns_head_poll(struct request_queue *q, blk_qc_t qc)
int srcu_idx;
srcu_idx = srcu_read_lock(&head->srcu);
ns = srcu_dereference(head->current_path, &head->srcu);
ns = srcu_dereference(head->current_path[numa_node_id()], &head->srcu);
if (likely(ns && nvme_path_is_optimized(ns)))
found = ns->queue->poll_fn(q, qc);
srcu_read_unlock(&head->srcu, srcu_idx);

25
drivers/nvme/host/nvme.h
View file

@ -277,14 +277,6 @@ struct nvme_ns_ids {
* only ever has a single entry for private namespaces.
*/
struct nvme_ns_head {
#ifdef CONFIG_NVME_MULTIPATH
struct gendisk *disk;
struct nvme_ns __rcu *current_path;
struct bio_list requeue_list;
spinlock_t requeue_lock;
struct work_struct requeue_work;
struct mutex lock;
#endif
struct list_head list;
struct srcu_struct srcu;
struct nvme_subsystem *subsys;
@ -293,6 +285,14 @@ struct nvme_ns_head {
struct list_head entry;
struct kref ref;
int instance;
#ifdef CONFIG_NVME_MULTIPATH
struct gendisk *disk;
struct bio_list requeue_list;
spinlock_t requeue_lock;
struct work_struct requeue_work;
struct mutex lock;
struct nvme_ns __rcu *current_path[];
#endif
};
#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
@ -474,14 +474,7 @@ void nvme_mpath_remove_disk(struct nvme_ns_head *head);
int nvme_mpath_init(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id);
void nvme_mpath_uninit(struct nvme_ctrl *ctrl);
void nvme_mpath_stop(struct nvme_ctrl *ctrl);
static inline void nvme_mpath_clear_current_path(struct nvme_ns *ns)
{
struct nvme_ns_head *head = ns->head;
if (head && ns == rcu_access_pointer(head->current_path))
rcu_assign_pointer(head->current_path, NULL);
}
void nvme_mpath_clear_current_path(struct nvme_ns *ns);
struct nvme_ns *nvme_find_path(struct nvme_ns_head *head);
static inline void nvme_mpath_check_last_path(struct nvme_ns *ns)