diff options
Diffstat (limited to 'drivers/nvme/host/multipath.c')
| -rw-r--r-- | drivers/nvme/host/multipath.c | 96 |
1 files changed, 86 insertions, 10 deletions
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index b9fff3b8ed1b..2839bb70badf 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -1,14 +1,6 @@ +// SPDX-License-Identifier: GPL-2.0 /* * Copyright (c) 2017-2018 Christoph Hellwig. - * - * This program is free software; you can redistribute it and/or modify it - * under the terms and conditions of the GNU General Public License, - * version 2, as published by the Free Software Foundation. - * - * This program is distributed in the hope it will be useful, but WITHOUT - * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or - * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for - * more details. */ #include <linux/moduleparam.h> @@ -141,7 +133,10 @@ static struct nvme_ns *__nvme_find_path(struct nvme_ns_head *head, int node) test_bit(NVME_NS_ANA_PENDING, &ns->flags)) continue; - distance = node_distance(node, ns->ctrl->numa_node); + if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_NUMA) + distance = node_distance(node, ns->ctrl->numa_node); + else + distance = LOCAL_DISTANCE; switch (ns->ana_state) { case NVME_ANA_OPTIMIZED: @@ -168,6 +163,47 @@ static struct nvme_ns *__nvme_find_path(struct nvme_ns_head *head, int node) return found; } +static struct nvme_ns *nvme_next_ns(struct nvme_ns_head *head, + struct nvme_ns *ns) +{ + ns = list_next_or_null_rcu(&head->list, &ns->siblings, struct nvme_ns, + siblings); + if (ns) + return ns; + return list_first_or_null_rcu(&head->list, struct nvme_ns, siblings); +} + +static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head, + int node, struct nvme_ns *old) +{ + struct nvme_ns *ns, *found, *fallback = NULL; + + if (list_is_singular(&head->list)) + return old; + + for (ns = nvme_next_ns(head, old); + ns != old; + ns = nvme_next_ns(head, ns)) { + if (ns->ctrl->state != NVME_CTRL_LIVE || + test_bit(NVME_NS_ANA_PENDING, &ns->flags)) + continue; + + if (ns->ana_state == NVME_ANA_OPTIMIZED) { + found = ns; + goto out; + } + if (ns->ana_state == NVME_ANA_NONOPTIMIZED) + fallback = ns; + } + + if (!fallback) + return NULL; + found = fallback; +out: + rcu_assign_pointer(head->current_path[node], found); + return found; +} + static inline bool nvme_path_is_optimized(struct nvme_ns *ns) { return ns->ctrl->state == NVME_CTRL_LIVE && @@ -180,6 +216,8 @@ inline struct nvme_ns *nvme_find_path(struct nvme_ns_head *head) struct nvme_ns *ns; ns = srcu_dereference(head->current_path[node], &head->srcu); + if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_RR && ns) + ns = nvme_round_robin_path(head, node, ns); if (unlikely(!ns || !nvme_path_is_optimized(ns))) ns = __nvme_find_path(head, node); return ns; @@ -471,6 +509,44 @@ void nvme_mpath_stop(struct nvme_ctrl *ctrl) cancel_work_sync(&ctrl->ana_work); } +#define SUBSYS_ATTR_RW(_name, _mode, _show, _store) \ + struct device_attribute subsys_attr_##_name = \ + __ATTR(_name, _mode, _show, _store) + +static const char *nvme_iopolicy_names[] = { + [NVME_IOPOLICY_NUMA] = "numa", + [NVME_IOPOLICY_RR] = "round-robin", +}; + +static ssize_t nvme_subsys_iopolicy_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct nvme_subsystem *subsys = + container_of(dev, struct nvme_subsystem, dev); + + return sprintf(buf, "%s\n", + nvme_iopolicy_names[READ_ONCE(subsys->iopolicy)]); +} + +static ssize_t nvme_subsys_iopolicy_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct nvme_subsystem *subsys = + container_of(dev, struct nvme_subsystem, dev); + int i; + + for (i = 0; i < ARRAY_SIZE(nvme_iopolicy_names); i++) { + if (sysfs_streq(buf, nvme_iopolicy_names[i])) { + WRITE_ONCE(subsys->iopolicy, i); + return count; + } + } + + return -EINVAL; +} +SUBSYS_ATTR_RW(iopolicy, S_IRUGO | S_IWUSR, + nvme_subsys_iopolicy_show, nvme_subsys_iopolicy_store); + static ssize_t ana_grpid_show(struct device *dev, struct device_attribute *attr, char *buf) { |