From 1fa6aeadf18aeebd7a217d7a3a933856448375b6 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Wed, 2 Mar 2011 18:37:18 -0500 Subject: [PATCH] NVMe: Add a kthread to handle the congestion list Instead of trying to resubmit I/Os in the I/O completion path (in interrupt context), wake up a kthread which will resubmit I/O from user context. This allows mke2fs to run to completion. Signed-off-by: Matthew Wilcox --- drivers/block/nvme.c | 86 ++++++++++++++++++++++++++++++++++---------- 1 file changed, 67 insertions(+), 19 deletions(-) diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c index 61a241741ca6..606371e62905 100644 --- a/drivers/block/nvme.c +++ b/drivers/block/nvme.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #include #include @@ -50,10 +51,15 @@ module_param(nvme_major, int, 0); static int use_threaded_interrupts; module_param(use_threaded_interrupts, int, 0); +static DEFINE_SPINLOCK(dev_list_lock); +static LIST_HEAD(dev_list); +static struct task_struct *nvme_thread; + /* * Represents an NVM Express device. Each nvme_dev is a PCI function. */ struct nvme_dev { + struct list_head node; struct nvme_queue **queues; u32 __iomem *dbs; struct pci_dev *pci_dev; @@ -97,6 +103,7 @@ struct nvme_queue { dma_addr_t sq_dma_addr; dma_addr_t cq_dma_addr; wait_queue_head_t sq_full; + wait_queue_t sq_cong_wait; struct bio_list sq_cong; u32 __iomem *q_db; u16 q_depth; @@ -108,8 +115,6 @@ struct nvme_queue { unsigned long cmdid_data[]; }; -static void nvme_resubmit_bio(struct nvme_queue *nvmeq, struct bio *bio); - /* * Check we didin't inadvertently grow the command struct */ @@ -309,9 +314,6 @@ static void bio_completion(struct nvme_queue *nvmeq, void *ctx, bio_data_dir(bio) ? DMA_TO_DEVICE : DMA_FROM_DEVICE); free_nbio(nvmeq, nbio); bio_endio(bio, status ? -EIO : 0); - bio = bio_list_pop(&nvmeq->sq_cong); - if (bio) - nvme_resubmit_bio(nvmeq, bio); } /* length is in bytes */ @@ -482,16 +484,6 @@ static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns, return result; } -static void nvme_resubmit_bio(struct nvme_queue *nvmeq, struct bio *bio) -{ - struct nvme_ns *ns = bio->bi_bdev->bd_disk->private_data; - if (nvme_submit_bio_queue(nvmeq, ns, bio)) - bio_list_add_head(&nvmeq->sq_cong, bio); - else if (bio_list_empty(&nvmeq->sq_cong)) - blk_clear_queue_congested(ns->queue, rw_is_sync(bio->bi_rw)); - /* XXX: Need to duplicate the logic from __freed_request here */ -} - /* * NB: return value of non-zero would mean that we were a stacking driver. * make_request must always succeed. @@ -774,6 +766,7 @@ static struct nvme_queue *nvme_alloc_queue(struct nvme_dev *dev, int qid, nvmeq->cq_head = 0; nvmeq->cq_phase = 1; init_waitqueue_head(&nvmeq->sq_full); + init_waitqueue_entry(&nvmeq->sq_cong_wait, nvme_thread); bio_list_init(&nvmeq->sq_cong); nvmeq->q_db = &dev->dbs[qid * 2]; nvmeq->q_depth = depth; @@ -1097,6 +1090,43 @@ static const struct block_device_operations nvme_fops = { .ioctl = nvme_ioctl, }; +static void nvme_resubmit_bios(struct nvme_queue *nvmeq) +{ + while (bio_list_peek(&nvmeq->sq_cong)) { + struct bio *bio = bio_list_pop(&nvmeq->sq_cong); + struct nvme_ns *ns = bio->bi_bdev->bd_disk->private_data; + if (nvme_submit_bio_queue(nvmeq, ns, bio)) { + bio_list_add_head(&nvmeq->sq_cong, bio); + break; + } + } +} + +static int nvme_kthread(void *data) +{ + struct nvme_dev *dev; + + while (!kthread_should_stop()) { + __set_current_state(TASK_RUNNING); + spin_lock(&dev_list_lock); + list_for_each_entry(dev, &dev_list, node) { + int i; + for (i = 0; i < dev->queue_count; i++) { + struct nvme_queue *nvmeq = dev->queues[i]; + spin_lock_irq(&nvmeq->q_lock); + if (nvme_process_cq(nvmeq)) + printk("process_cq did something\n"); + nvme_resubmit_bios(nvmeq); + spin_unlock_irq(&nvmeq->q_lock); + } + } + spin_unlock(&dev_list_lock); + set_current_state(TASK_INTERRUPTIBLE); + schedule_timeout(HZ); + } + return 0; +} + static struct nvme_ns *nvme_alloc_ns(struct nvme_dev *dev, int index, struct nvme_id_ns *id, struct nvme_lba_range_type *rt) { @@ -1307,6 +1337,10 @@ static int nvme_dev_remove(struct nvme_dev *dev) { struct nvme_ns *ns, *next; + spin_lock(&dev_list_lock); + list_del(&dev->node); + spin_unlock(&dev_list_lock); + /* TODO: wait all I/O finished or cancel them */ list_for_each_entry_safe(ns, next, &dev->namespaces, list) { @@ -1406,6 +1440,11 @@ static int __devinit nvme_probe(struct pci_dev *pdev, result = nvme_dev_add(dev); if (result) goto delete; + + spin_lock(&dev_list_lock); + list_add(&dev->node, &dev_list); + spin_unlock(&dev_list_lock); + return 0; delete: @@ -1479,17 +1518,25 @@ static struct pci_driver nvme_driver = { static int __init nvme_init(void) { - int result; + int result = -EBUSY; + + nvme_thread = kthread_run(nvme_kthread, NULL, "nvme"); + if (IS_ERR(nvme_thread)) + return PTR_ERR(nvme_thread); nvme_major = register_blkdev(nvme_major, "nvme"); if (nvme_major <= 0) - return -EBUSY; + goto kill_kthread; result = pci_register_driver(&nvme_driver); - if (!result) - return 0; + if (result) + goto unregister_blkdev; + return 0; + unregister_blkdev: unregister_blkdev(nvme_major, "nvme"); + kill_kthread: + kthread_stop(nvme_thread); return result; } @@ -1497,6 +1544,7 @@ static void __exit nvme_exit(void) { pci_unregister_driver(&nvme_driver); unregister_blkdev(nvme_major, "nvme"); + kthread_stop(nvme_thread); } MODULE_AUTHOR("Matthew Wilcox "); -- 2.20.1