This patch enables asynchronous flush for virtio pmem using work queue. Also, it coalesce the flush requests when a flush is already in process.
Signed-off-by: Pankaj Gupta <[email protected]> --- drivers/nvdimm/nd_virtio.c | 62 ++++++++++++++++++++++++++---------- drivers/nvdimm/virtio_pmem.c | 9 ++++++ drivers/nvdimm/virtio_pmem.h | 14 ++++++++ 3 files changed, 68 insertions(+), 17 deletions(-) diff --git a/drivers/nvdimm/nd_virtio.c b/drivers/nvdimm/nd_virtio.c index 10351d5b49fa..ef53d0a0d134 100644 --- a/drivers/nvdimm/nd_virtio.c +++ b/drivers/nvdimm/nd_virtio.c @@ -97,29 +97,57 @@ static int virtio_pmem_flush(struct nd_region *nd_region) return err; }; +static void submit_async_flush(struct work_struct *ws); + /* The asynchronous flush callback function */ int async_pmem_flush(struct nd_region *nd_region, struct bio *bio) { - /* - * Create child bio for asynchronous flush and chain with - * parent bio. Otherwise directly call nd_region flush. - */ - if (bio && bio->bi_iter.bi_sector != -1) { - struct bio *child = bio_alloc(GFP_ATOMIC, 0); - - if (!child) - return -ENOMEM; - bio_copy_dev(child, bio); - child->bi_opf = REQ_PREFLUSH; - child->bi_iter.bi_sector = -1; - bio_chain(child, bio); - submit_bio(child); - return 0; + struct virtio_device *vdev = nd_region->provider_data; + struct virtio_pmem *vpmem = vdev->priv; + ktime_t start = ktime_get_boottime(); + + spin_lock_irq(&vpmem->lock); + wait_event_lock_irq(vpmem->sb_wait, + !vpmem->flush_bio || + ktime_after(vpmem->last_flush, start), + vpmem->lock); + + if (!ktime_after(vpmem->last_flush, start)) { + WARN_ON(vpmem->flush_bio); + vpmem->flush_bio = bio; + bio = NULL; } - if (virtio_pmem_flush(nd_region)) - return -EIO; + spin_unlock_irq(&vpmem->lock); + if (!bio) { + INIT_WORK(&vpmem->flush_work, submit_async_flush); + queue_work(vpmem->pmem_wq, &vpmem->flush_work); + return 1; + } + + bio->bi_opf &= ~REQ_PREFLUSH; return 0; }; EXPORT_SYMBOL_GPL(async_pmem_flush); + +static void submit_async_flush(struct work_struct *ws) +{ + struct virtio_pmem *vpmem = container_of(ws, struct virtio_pmem, flush_work); + struct bio *bio = vpmem->flush_bio; + + vpmem->start_flush = ktime_get_boottime(); + bio->bi_status = errno_to_blk_status(virtio_pmem_flush(vpmem->nd_region)); + vpmem->last_flush = vpmem->start_flush; + vpmem->flush_bio = NULL; + wake_up(&vpmem->sb_wait); + + /* Submit parent bio only for PREFLUSH */ + if (bio && (bio->bi_opf & REQ_PREFLUSH)) { + bio->bi_opf &= ~REQ_PREFLUSH; + submit_bio(bio); + } else if (bio && (bio->bi_opf & REQ_FUA)) { + bio->bi_opf &= ~REQ_FUA; + bio_endio(bio); + } +} MODULE_LICENSE("GPL"); diff --git a/drivers/nvdimm/virtio_pmem.c b/drivers/nvdimm/virtio_pmem.c index 5e3d07b47e0c..4ab135d820fd 100644 --- a/drivers/nvdimm/virtio_pmem.c +++ b/drivers/nvdimm/virtio_pmem.c @@ -24,6 +24,7 @@ static int init_vq(struct virtio_pmem *vpmem) return PTR_ERR(vpmem->req_vq); spin_lock_init(&vpmem->pmem_lock); + spin_lock_init(&vpmem->lock); INIT_LIST_HEAD(&vpmem->req_list); return 0; @@ -58,6 +59,12 @@ static int virtio_pmem_probe(struct virtio_device *vdev) goto out_err; } + vpmem->pmem_wq = alloc_workqueue("vpmem_wq", WQ_MEM_RECLAIM, 0); + if (!vpmem->pmem_wq) { + err = -ENOMEM; + goto out_err; + } + init_waitqueue_head(&vpmem->sb_wait); virtio_cread(vpmem->vdev, struct virtio_pmem_config, start, &vpmem->start); virtio_cread(vpmem->vdev, struct virtio_pmem_config, @@ -90,10 +97,12 @@ static int virtio_pmem_probe(struct virtio_device *vdev) goto out_nd; } nd_region->provider_data = dev_to_virtio(nd_region->dev.parent->parent); + vpmem->nd_region = nd_region; return 0; out_nd: nvdimm_bus_unregister(vpmem->nvdimm_bus); out_vq: + destroy_workqueue(vpmem->pmem_wq); vdev->config->del_vqs(vdev); out_err: return err; diff --git a/drivers/nvdimm/virtio_pmem.h b/drivers/nvdimm/virtio_pmem.h index 0dddefe594c4..9d3615a324bf 100644 --- a/drivers/nvdimm/virtio_pmem.h +++ b/drivers/nvdimm/virtio_pmem.h @@ -35,9 +35,23 @@ struct virtio_pmem { /* Virtio pmem request queue */ struct virtqueue *req_vq; + struct bio *flush_bio; + /* last_flush is when the last completed flush was started */ + ktime_t last_flush, start_flush; + + /* work queue for deferred flush */ + struct work_struct flush_work; + struct workqueue_struct *pmem_wq; + + /* Synchronize flush wait queue data */ + spinlock_t lock; + /* for waiting for previous flush to complete */ + wait_queue_head_t sb_wait; + /* nvdimm bus registers virtio pmem device */ struct nvdimm_bus *nvdimm_bus; struct nvdimm_bus_descriptor nd_desc; + struct nd_region *nd_region; /* List to store deferred work if virtqueue is full */ struct list_head req_list; -- 2.20.1 _______________________________________________ Linux-nvdimm mailing list -- [email protected] To unsubscribe send an email to [email protected]
