nvme: replace the kthread with a per-device watchdog timer
The only work left in the kthread is the periodic health check for each controller. There is no need to run this from process context or keep a thread context around for it, so replace it with a simpler timer. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Christoph Hellwig
Jens Axboe
Родитель
79f2b358c9
Коммит
2d55cd5f51
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@ -27,7 +27,6 @@
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#include <linux/interrupt.h>
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#include <linux/io.h>
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#include <linux/kdev_t.h>
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#include <linux/kthread.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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@ -39,6 +38,7 @@
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/t10-pi.h>
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#include <linux/timer.h>
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#include <linux/types.h>
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#include <linux/io-64-nonatomic-lo-hi.h>
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#include <asm/unaligned.h>
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@ -64,11 +64,7 @@ static bool use_cmb_sqes = true;
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module_param(use_cmb_sqes, bool, 0644);
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MODULE_PARM_DESC(use_cmb_sqes, "use controller's memory buffer for I/O SQes");
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static LIST_HEAD(dev_list);
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static DEFINE_SPINLOCK(dev_list_lock);
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static struct task_struct *nvme_thread;
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static struct workqueue_struct *nvme_workq;
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static wait_queue_head_t nvme_kthread_wait;
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struct nvme_dev;
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struct nvme_queue;
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@ -82,7 +78,6 @@ static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown);
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* Represents an NVM Express device. Each nvme_dev is a PCI function.
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*/
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struct nvme_dev {
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struct list_head node;
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struct nvme_queue **queues;
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struct blk_mq_tag_set tagset;
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struct blk_mq_tag_set admin_tagset;
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@ -101,6 +96,7 @@ struct nvme_dev {
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struct work_struct scan_work;
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struct work_struct remove_work;
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struct work_struct async_work;
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struct timer_list watchdog_timer;
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struct mutex shutdown_lock;
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bool subsystem;
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void __iomem *cmb;
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@ -1334,36 +1330,26 @@ static int nvme_configure_admin_queue(struct nvme_dev *dev)
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return result;
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}
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static int nvme_kthread(void *data)
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static void nvme_watchdog_timer(unsigned long data)
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{
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struct nvme_dev *dev, *next;
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struct nvme_dev *dev = (struct nvme_dev *)data;
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u32 csts = readl(dev->bar + NVME_REG_CSTS);
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while (!kthread_should_stop()) {
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set_current_state(TASK_INTERRUPTIBLE);
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spin_lock(&dev_list_lock);
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list_for_each_entry_safe(dev, next, &dev_list, node) {
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u32 csts = readl(dev->bar + NVME_REG_CSTS);
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/*
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* Skip controllers currently under reset.
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*/
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if (work_pending(&dev->reset_work) || work_busy(&dev->reset_work))
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continue;
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if ((dev->subsystem && (csts & NVME_CSTS_NSSRO)) ||
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csts & NVME_CSTS_CFS) {
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if (queue_work(nvme_workq, &dev->reset_work)) {
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dev_warn(dev->ctrl.device,
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"Failed status: %x, reset controller\n",
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readl(dev->bar + NVME_REG_CSTS));
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}
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continue;
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}
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/*
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* Skip controllers currently under reset.
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*/
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if (!work_pending(&dev->reset_work) && !work_busy(&dev->reset_work) &&
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((csts & NVME_CSTS_CFS) ||
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(dev->subsystem && (csts & NVME_CSTS_NSSRO)))) {
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if (queue_work(nvme_workq, &dev->reset_work)) {
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dev_warn(dev->dev,
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"Failed status: 0x%x, reset controller.\n",
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csts);
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}
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spin_unlock(&dev_list_lock);
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schedule_timeout(round_jiffies_relative(HZ));
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return;
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}
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return 0;
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mod_timer(&dev->watchdog_timer, round_jiffies(jiffies + HZ));
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}
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static int nvme_create_io_queues(struct nvme_dev *dev)
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@ -1777,56 +1763,12 @@ static void nvme_dev_unmap(struct nvme_dev *dev)
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}
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}
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static int nvme_dev_list_add(struct nvme_dev *dev)
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{
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bool start_thread = false;
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spin_lock(&dev_list_lock);
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if (list_empty(&dev_list) && IS_ERR_OR_NULL(nvme_thread)) {
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start_thread = true;
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nvme_thread = NULL;
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}
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list_add(&dev->node, &dev_list);
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spin_unlock(&dev_list_lock);
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if (start_thread) {
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nvme_thread = kthread_run(nvme_kthread, NULL, "nvme");
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wake_up_all(&nvme_kthread_wait);
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} else
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wait_event_killable(nvme_kthread_wait, nvme_thread);
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if (IS_ERR_OR_NULL(nvme_thread))
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return nvme_thread ? PTR_ERR(nvme_thread) : -EINTR;
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return 0;
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}
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/*
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* Remove the node from the device list and check
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* for whether or not we need to stop the nvme_thread.
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*/
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static void nvme_dev_list_remove(struct nvme_dev *dev)
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{
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struct task_struct *tmp = NULL;
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spin_lock(&dev_list_lock);
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list_del_init(&dev->node);
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if (list_empty(&dev_list) && !IS_ERR_OR_NULL(nvme_thread)) {
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tmp = nvme_thread;
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nvme_thread = NULL;
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}
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spin_unlock(&dev_list_lock);
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if (tmp)
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kthread_stop(tmp);
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}
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static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
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{
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int i;
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u32 csts = -1;
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nvme_dev_list_remove(dev);
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del_timer_sync(&dev->watchdog_timer);
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mutex_lock(&dev->shutdown_lock);
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if (dev->bar) {
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@ -1927,9 +1869,7 @@ static void nvme_reset_work(struct work_struct *work)
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dev->ctrl.event_limit = NVME_NR_AEN_COMMANDS;
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queue_work(nvme_workq, &dev->async_work);
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result = nvme_dev_list_add(dev);
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if (result)
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goto remove;
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mod_timer(&dev->watchdog_timer, round_jiffies(jiffies + HZ));
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/*
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* Keep the controller around but remove all namespaces if we don't have
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@ -1946,8 +1886,6 @@ static void nvme_reset_work(struct work_struct *work)
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clear_bit(NVME_CTRL_RESETTING, &dev->flags);
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return;
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remove:
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nvme_dev_list_remove(dev);
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free_tags:
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nvme_dev_remove_admin(dev);
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blk_put_queue(dev->ctrl.admin_q);
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@ -2055,11 +1993,12 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
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dev->dev = get_device(&pdev->dev);
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pci_set_drvdata(pdev, dev);
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INIT_LIST_HEAD(&dev->node);
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INIT_WORK(&dev->scan_work, nvme_dev_scan);
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INIT_WORK(&dev->reset_work, nvme_reset_work);
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INIT_WORK(&dev->remove_work, nvme_remove_dead_ctrl_work);
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INIT_WORK(&dev->async_work, nvme_async_event_work);
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setup_timer(&dev->watchdog_timer, nvme_watchdog_timer,
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(unsigned long)dev);
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mutex_init(&dev->shutdown_lock);
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init_completion(&dev->ioq_wait);
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@ -2108,9 +2047,7 @@ static void nvme_remove(struct pci_dev *pdev)
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{
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struct nvme_dev *dev = pci_get_drvdata(pdev);
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spin_lock(&dev_list_lock);
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list_del_init(&dev->node);
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spin_unlock(&dev_list_lock);
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del_timer_sync(&dev->watchdog_timer);
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pci_set_drvdata(pdev, NULL);
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flush_work(&dev->async_work);
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@ -2223,8 +2160,6 @@ static int __init nvme_init(void)
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{
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int result;
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init_waitqueue_head(&nvme_kthread_wait);
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nvme_workq = alloc_workqueue("nvme", WQ_UNBOUND | WQ_MEM_RECLAIM, 0);
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if (!nvme_workq)
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return -ENOMEM;
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@ -2239,7 +2174,6 @@ static void __exit nvme_exit(void)
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{
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pci_unregister_driver(&nvme_driver);
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destroy_workqueue(nvme_workq);
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BUG_ON(nvme_thread && !IS_ERR(nvme_thread));
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_nvme_check_size();
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}
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