From f333444708f82c4a4d3ccac004da0bfd9cfdfa42 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 11 Sep 2018 09:51:29 +0200 Subject: [PATCH] nvme: take node locality into account when selecting a path 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 Reviewed-by: Keith Busch Reviewed-by: Hannes Reinecke --- drivers/nvme/host/core.c | 7 +++++- drivers/nvme/host/multipath.c | 50 +++++++++++++++++++++++++++++++++---------- drivers/nvme/host/nvme.h | 25 ++++++++-------------- 3 files changed, 54 insertions(+), 28 deletions(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 089d744..2db33a7 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -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); diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index ac16093..5298705 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -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: - fallback = ns; + 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); diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index 2503f8f..9fefba0 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -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) -- 2.7.4