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 <matthew.r.wilcox@intel.com>
diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c
index 61a2417..606371e 100644
--- a/drivers/block/nvme.c
+++ b/drivers/block/nvme.c
@@ -26,6 +26,7 @@
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kdev_t.h>
+#include <linux/kthread.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
@@ -50,10 +51,15 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
.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 @@
{
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 @@
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 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 @@
{
pci_unregister_driver(&nvme_driver);
unregister_blkdev(nvme_major, "nvme");
+ kthread_stop(nvme_thread);
}
MODULE_AUTHOR("Matthew Wilcox <willy@linux.intel.com>");