NVMe: Device specific stripe size handling
We have an nvme device that has a concept of a stripe size. IO requests
that do not transfer data crossing a stripe boundary has greater
performance compared to IO that does cross it. This patch sets the
stripe size for the device if the device and vendor ids match one with
this feature and splits IO requests that cross the stripe boundary.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index f812806..4151a3d 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -519,7 +519,11 @@
{
struct bio_vec *bvec, *bvprv = NULL;
struct scatterlist *sg = NULL;
- int i, length = 0, nsegs = 0;
+ int i, length = 0, nsegs = 0, split_len = bio->bi_size;
+
+ if (nvmeq->dev->stripe_size)
+ split_len = nvmeq->dev->stripe_size -
+ ((bio->bi_sector << 9) & (nvmeq->dev->stripe_size - 1));
sg_init_table(iod->sg, psegs);
bio_for_each_segment(bvec, bio, i) {
@@ -535,6 +539,10 @@
bvec->bv_offset);
nsegs++;
}
+
+ if (split_len - length < bvec->bv_len)
+ return nvme_split_and_submit(bio, nvmeq, i, split_len,
+ split_len - length);
length += bvec->bv_len;
bvprv = bvec;
}
@@ -543,6 +551,7 @@
if (dma_map_sg(nvmeq->q_dmadev, iod->sg, iod->nents, dma_dir) == 0)
return -ENOMEM;
+ BUG_ON(length != bio->bi_size);
return length;
}
@@ -1612,6 +1621,7 @@
struct nvme_id_ns *id_ns;
void *mem;
dma_addr_t dma_addr;
+ int shift = NVME_CAP_MPSMIN(readq(&dev->bar->cap)) + 12;
res = nvme_setup_io_queues(dev);
if (res)
@@ -1634,10 +1644,11 @@
memcpy(dev->serial, ctrl->sn, sizeof(ctrl->sn));
memcpy(dev->model, ctrl->mn, sizeof(ctrl->mn));
memcpy(dev->firmware_rev, ctrl->fr, sizeof(ctrl->fr));
- if (ctrl->mdts) {
- int shift = NVME_CAP_MPSMIN(readq(&dev->bar->cap)) + 12;
+ if (ctrl->mdts)
dev->max_hw_sectors = 1 << (ctrl->mdts + shift - 9);
- }
+ if ((dev->pci_dev->vendor == PCI_VENDOR_ID_INTEL) &&
+ (dev->pci_dev->device == 0x0953) && ctrl->vs[3])
+ dev->stripe_size = 1 << (ctrl->vs[3] + shift);
id_ns = mem;
for (i = 1; i <= nn; i++) {
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 9b6fba8..af29b0e 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -536,6 +536,7 @@
char model[40];
char firmware_rev[8];
u32 max_hw_sectors;
+ u32 stripe_size;
u16 oncs;
};