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>
This commit is contained in:
Matthew Wilcox 2011-03-02 18:37:18 -05:00
Родитель eeee322647
Коммит 1fa6aeadf1
1 изменённых файлов: 67 добавлений и 19 удалений

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@ -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 @@ 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 <willy@linux.intel.com>");