NVMF/RDMA 16K Inline Support

Hey,

For small nvmf write IO over the rdma transport, it is advantagous to make use of inline mode to avoid the latency of the target issuing an rdma read to fetch the data. Currently inline is used for <= 4K writes. 8K, though, requires the rdma read. For iWARP transports additional latency is incurred because the target mr of the read must be registered with remote write access. By allowing 2 pages worth of inline payload, I see a reduction in 8K nvmf write latency of anywhere from 2-7 usecs depending on the RDMA transport..

This series is a respin of a series floated last year by Parav and Max [1]. I'm continuing it now and have addressed some of the comments from their submission [2].

The below performance improvements are achieved. Applications doing 8K or 16K WRITEs will benefit most from this enhancement.

WRITE IOPS:
8 nullb devices, 16 connections/device,
16 cores, 1 host, 1 target,
fio randwrite, direct io, ioqdepth=256, jobs=16

%CPU Idle KIOPS
inline size 4K 8K 16K 4K 8K 16K
io size

4K            9.36     10.47     10.44   1707      1662      1704
8K           39.07     43.66     46.84    894      1000      1002
16K          64.15     64.79     71.1     566      569        607
32K          78.84     79.5      79.89    326      329        327

WRITE Latency:
1 nullb device, 1 connection/device,
fio randwrite, direct io, ioqdepth=1, jobs=1

Usecs
inline size 4K 8K 16K
io size

4K           12.4      12.4      12.5
8K           18.3      13        13.1
16K          20.3      20.2      14.2
32K          23.2      23.2      23.4

Quoted 35 lines · Steve Wise

Hey,

For small nvmf write IO over the rdma transport, it is advantagous to make use of inline mode to avoid the latency of the target issuing an rdma read to fetch the data.? Currently inline is used for <= 4K writes. 8K, though, requires the rdma read.? For iWARP transports additional latency is incurred because the target mr of the read must be registered with remote write access.? By allowing 2 pages worth of inline payload, I see a reduction in 8K nvmf write latency of anywhere from 2-7 usecs depending on the RDMA transport..

This series is a respin of a series floated last year by Parav and Max [1].? I'm continuing it now and have addressed some of the comments from their submission [2].

The below performance improvements are achieved.? Applications doing 8K or 16K WRITEs will benefit most from this enhancement.

WRITE IOPS:
8 nullb devices, 16 connections/device,
16 cores, 1 host, 1 target,
fio randwrite, direct io, ioqdepth=256, jobs=16

????????????? %CPU Idle?????????????????? KIOPS
inline size? 4K??????? 8K??????? 16K???? 4K??????? 8K??????? 16K io size
4K??????????? 9.36???? 10.47???? 10.44?? 1707????? 1662????? 1704 8K?????????? 39.07???? 43.66???? 46.84??? 894????? 1000????? 1002 16K????????? 64.15???? 64.79???? 71.1???? 566????? 569??????? 607 32K????????? 78.84???? 79.5????? 79.89??? 326????? 329??????? 327

WRITE Latency:
1 nullb device, 1 connection/device,
fio randwrite, direct io, ioqdepth=1, jobs=1

Quoted 7 lines

????????????? Usecs
inline size? 4K??????? 8K??????? 16K
io size
4K?????????? 12.4????? 12.4????? 12.5
8K?????????? 18.3????? 13??????? 13.1
16K????????? 20.3????? 20.2????? 14.2
32K????????? 23.2????? 23.2????? 23.4

The code looks good to me.
I'll run some benchmarks tomorrow hopefully using Mellanox adapters and share result before/after the patches.

The patch enables inline data sizes using up to 4 recv sges, and capping the size at 16KB or at least 1 page size. So on a 4K page system, up to 16KB is supported, and for a 64K page system 1 page of 64KB is supported.

We avoid > 0 order page allocations for the inline buffers by using multiple recv sges, one for each page. If the device cannot support the configured inline data size due to lack of enough recv sges, then log a warning and reduce the inline size.

Add a new configfs port attribute, called param_inline_data_size, to allow configuring the size of inline data for a given nvmf port. The maximum size allowed is still enforced by nvmet-rdma with NVMET_RDMA_MAX_INLINE_DATA_SIZE, which is now max(16KB, PAGE_SIZE). And the default size, if not specified via configfs, is still PAGE_SIZE. This preserves the existing behavior, but allows larger inline sizes for small page systems. If the configured inline data size exceeds NVMET_RDMA_MAX_INLINE_DATA_SIZE, a warning is logged and the size is reduced. If param_inline_data_size is set to 0, then inline data is disabled for that nvmf port.

Signed-off-by Steve Wise <swise at opengridcomputing.com>

---
  drivers/nvme/target/admin-cmd.c |   4 +-
  drivers/nvme/target/configfs.c  |  31 +++++++
  drivers/nvme/target/core.c      |   4 +
  drivers/nvme/target/discovery.c |   2 +-
  drivers/nvme/target/nvmet.h     |   2 +-
  drivers/nvme/target/rdma.c      | 174 ++++++++++++++++++++++++++++++----------
  6 files changed, 172 insertions(+), 45 deletions(-)

drivers/nvme/target/admin-cmd.c +2 -2

index 3880357..941a574 100644
@@ -238,14 +238,14 @@ static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
  	id->sgls = cpu_to_le32(1 << 0);	/* we always support SGLs */
  	if (ctrl->ops->has_keyed_sgls)
  		id->sgls |= cpu_to_le32(1 << 2);
-	if (ctrl->ops->sqe_inline_size)
+	if (req->port->inline_data_size)
  		id->sgls |= cpu_to_le32(1 << 20);
 
  	strcpy(id->subnqn, ctrl->subsys->subsysnqn);
 
  	/* Max command capsule size is sqe + single page of in-capsule data */
  	id->ioccsz = cpu_to_le32((sizeof(struct nvme_command) +
-				  ctrl->ops->sqe_inline_size) / 16);
+				  req->port->inline_data_size) / 16);
  	/* Max response capsule size is cqe */
  	id->iorcsz = cpu_to_le32(sizeof(struct nvme_completion) / 16);
 

drivers/nvme/target/configfs.c +6 -0

index d3f3b3e..2e556f6 100644
@@ -218,6 +218,35 @@ static ssize_t nvmet_addr_trsvcid_store(struct config_item *item,
 
  CONFIGFS_ATTR(nvmet_, addr_trsvcid);
 
+static ssize_t nvmet_param_inline_data_size_show(struct config_item *item,
+		char *page)
+{
+	struct nvmet_port *port = to_nvmet_port(item);
+
+	return snprintf(page, PAGE_SIZE, "%d\n", port->inline_data_size);

drivers/nvme/target/configfs.c +15 -0

+		pr_err("Disable the port before modifying\n");
+		return -EACCES;
+	}
+	ret = kstrtoint(page, 0, &port->inline_data_size);
+	if (ret) {
+		pr_err("Invalid value '%s' for inline_data_size\n", page);
+		return -EINVAL;
+	}
+	return count;
+}
+
+CONFIGFS_ATTR(nvmet_, param_inline_data_size);
+
  static ssize_t nvmet_addr_trtype_show(struct config_item *item,
  		char *page)
  {

@@ -874,6 +903,7 @@ static void nvmet_port_release(struct config_item *item)
  	&nvmet_attr_addr_traddr,
  	&nvmet_attr_addr_trsvcid,
  	&nvmet_attr_addr_trtype,
+	&nvmet_attr_param_inline_data_size,
  	NULL,
  };
 

@@ -903,6 +933,7 @@ static struct config_group *nvmet_ports_make(struct config_group *group,
  	INIT_LIST_HEAD(&port->entry);
  	INIT_LIST_HEAD(&port->subsystems);
  	INIT_LIST_HEAD(&port->referrals);
+	port->inline_data_size = -1;	/* < 0 == let the transport choose */
 
  	port->disc_addr.portid = cpu_to_le16(portid);
  	config_group_init_type_name(&port->group, name, &nvmet_port_type);

drivers/nvme/target/core.c +4 -0

index a03da76..0b73c7c 100644
@@ -241,6 +241,10 @@ int nvmet_enable_port(struct nvmet_port *port)
  		return ret;
  	}
 
+	/* If the transport didn't set inline_data_size, then disable it. */
+	if (port->inline_data_size < 0)
+		port->inline_data_size = 0;
+
  	port->enabled = true;
  	return 0;
  }

drivers/nvme/target/discovery.c +1 -1

index 08656b8..eae29f4 100644
@@ -171,7 +171,7 @@ static void nvmet_execute_identify_disc_ctrl(struct nvmet_req *req)
  	id->sgls = cpu_to_le32(1 << 0);	/* we always support SGLs */
  	if (ctrl->ops->has_keyed_sgls)
  		id->sgls |= cpu_to_le32(1 << 2);
-	if (ctrl->ops->sqe_inline_size)
+	if (req->port->inline_data_size)
  		id->sgls |= cpu_to_le32(1 << 20);
 
  	strcpy(id->subnqn, ctrl->subsys->subsysnqn);

drivers/nvme/target/nvmet.h +1 -1

index 480dfe1..8085679 100644
@@ -116,6 +116,7 @@ struct nvmet_port {
  	struct list_head		referrals;
  	void				*priv;
  	bool				enabled;
+	int				inline_data_size;
  };
 
  static inline struct nvmet_port *to_nvmet_port(struct config_item *item)

@@ -225,7 +226,6 @@ struct nvmet_subsys_link {
  struct nvmet_fabrics_ops {
  	struct module *owner;
  	unsigned int type;
-	unsigned int sqe_inline_size;
  	unsigned int msdbd;
  	bool has_keyed_sgls : 1;
  	void (*queue_response)(struct nvmet_req *req);

drivers/nvme/target/rdma.c +133 -41

index 0d7f3d6..b465b9c 100644
@@ -33,16 +33,17 @@
  #include "nvmet.h"
 
  /*
- * We allow up to a page of inline data to go with the SQE
+ * We allow at least 1 page, up to 4 SGEs, and up to 16KB of inline data
   */
-#define NVMET_RDMA_INLINE_DATA_SIZE	PAGE_SIZE
+#define NVMET_RDMA_DEFAULT_INLINE_DATA_SIZE	PAGE_SIZE
+#define NVMET_RDMA_MAX_INLINE_SGE		4
+#define NVMET_RDMA_MAX_INLINE_DATA_SIZE		max_t(int, SZ_16K, PAGE_SIZE)
 
  struct nvmet_rdma_cmd {
-	struct ib_sge		sge[2];
+	struct ib_sge		sge[NVMET_RDMA_MAX_INLINE_SGE + 1];
  	struct ib_cqe		cqe;
  	struct ib_recv_wr	wr;
-	struct scatterlist	inline_sg;
-	struct page		*inline_page;
+	struct scatterlist	inline_sg[NVMET_RDMA_MAX_INLINE_SGE];
  	struct nvme_command     *nvme_cmd;
  	struct nvmet_rdma_queue	*queue;
  };

@@ -116,6 +117,8 @@ struct nvmet_rdma_device {
  	size_t			srq_size;
  	struct kref		ref;
  	struct list_head	entry;
+	int			inline_data_size;
+	int			inline_page_count;
  };
 
  static bool nvmet_rdma_use_srq;

@@ -138,6 +141,11 @@ struct nvmet_rdma_device {
 
  static const struct nvmet_fabrics_ops nvmet_rdma_ops;
 
+static int num_pages(int len)
+{
+	return 1 + (((len - 1) & PAGE_MASK) >> PAGE_SHIFT);
+}
+
  /* XXX: really should move to a generic header sooner or later.. */
  static inline u32 get_unaligned_le24(const u8 *p)
  {

@@ -184,6 +192,71 @@ static inline bool nvmet_rdma_need_data_out(struct nvmet_rdma_rsp *rsp)
  	spin_unlock_irqrestore(&rsp->queue->rsps_lock, flags);
  }
 
+static void nvmet_rdma_free_inline_pages(struct nvmet_rdma_device *ndev,
+				struct nvmet_rdma_cmd *c)
+{
+	struct scatterlist *sg;
+	struct ib_sge *sge;
+	int i;
+
+	if (!ndev->inline_data_size)
+		return;
+
+	sg = c->inline_sg;
+	sge = &c->sge[1];
+
+	for (i = 0; i < ndev->inline_page_count; i++, sg++, sge++) {
+		if (sge->length)
+			ib_dma_unmap_page(ndev->device, sge->addr,
+					sge->length, DMA_FROM_DEVICE);
+		if (sg_page(sg))
+			__free_page(sg_page(sg));
+	}
+}
+
+static int nvmet_rdma_alloc_inline_pages(struct nvmet_rdma_device *ndev,
+				struct nvmet_rdma_cmd *c)
+{
+	struct scatterlist *sg;
+	struct ib_sge *sge;
+	struct page *pg;
+	int len;
+	int i;
+
+	if (!ndev->inline_data_size)
+		return 0;
+
+	sg = c->inline_sg;
+	sg_init_table(sg, ndev->inline_page_count);
+	sge = &c->sge[1];
+	len = ndev->inline_data_size;
+
+	for (i = 0; i < ndev->inline_page_count; i++, sg++, sge++) {
+		pg = alloc_page(GFP_KERNEL);
+		if (!pg)
+			goto out_err;
+		sg_assign_page(sg, pg);
+		sge->addr = ib_dma_map_page(ndev->device,
+			pg, 0, PAGE_SIZE, DMA_FROM_DEVICE);
+		if (ib_dma_mapping_error(ndev->device, sge->addr))
+			goto out_err;
+		sge->length = min_t(int, len, PAGE_SIZE);
+		sge->lkey = ndev->pd->local_dma_lkey;
+		len -= sge->length;
+	}
+
+	return 0;
+out_err:
+	for (; i >= 0; i--, sg--, sge--) {
+		if (sge->length)
+			ib_dma_unmap_page(ndev->device, sge->addr,
+					sge->length, DMA_FROM_DEVICE);
+		if (sg_page(sg))
+			__free_page(sg_page(sg));
+	}
+	return -ENOMEM;
+}
+
  static int nvmet_rdma_alloc_cmd(struct nvmet_rdma_device *ndev,
  			struct nvmet_rdma_cmd *c, bool admin)
  {

@@ -200,33 +273,17 @@ static int nvmet_rdma_alloc_cmd(struct nvmet_rdma_device *ndev,
  	c->sge[0].length = sizeof(*c->nvme_cmd);
  	c->sge[0].lkey = ndev->pd->local_dma_lkey;
 
-	if (!admin) {
-		c->inline_page = alloc_pages(GFP_KERNEL,
-				get_order(NVMET_RDMA_INLINE_DATA_SIZE));
-		if (!c->inline_page)
-			goto out_unmap_cmd;
-		c->sge[1].addr = ib_dma_map_page(ndev->device,
-				c->inline_page, 0, NVMET_RDMA_INLINE_DATA_SIZE,
-				DMA_FROM_DEVICE);
-		if (ib_dma_mapping_error(ndev->device, c->sge[1].addr))
-			goto out_free_inline_page;
-		c->sge[1].length = NVMET_RDMA_INLINE_DATA_SIZE;
-		c->sge[1].lkey = ndev->pd->local_dma_lkey;
-	}
+	if (!admin && nvmet_rdma_alloc_inline_pages(ndev, c))
+		goto out_unmap_cmd;
 
  	c->cqe.done = nvmet_rdma_recv_done;
 
  	c->wr.wr_cqe = &c->cqe;
  	c->wr.sg_list = c->sge;
-	c->wr.num_sge = admin ? 1 : 2;
+	c->wr.num_sge = admin ? 1 : ndev->inline_page_count + 1;
 
  	return 0;
 
-out_free_inline_page:
-	if (!admin) {
-		__free_pages(c->inline_page,
-				get_order(NVMET_RDMA_INLINE_DATA_SIZE));
-	}
  out_unmap_cmd:
  	ib_dma_unmap_single(ndev->device, c->sge[0].addr,
  			sizeof(*c->nvme_cmd), DMA_FROM_DEVICE);

@@ -240,12 +297,8 @@ static int nvmet_rdma_alloc_cmd(struct nvmet_rdma_device *ndev,
  static void nvmet_rdma_free_cmd(struct nvmet_rdma_device *ndev,
  		struct nvmet_rdma_cmd *c, bool admin)
  {
-	if (!admin) {
-		ib_dma_unmap_page(ndev->device, c->sge[1].addr,
-				NVMET_RDMA_INLINE_DATA_SIZE, DMA_FROM_DEVICE);
-		__free_pages(c->inline_page,
-				get_order(NVMET_RDMA_INLINE_DATA_SIZE));
-	}
+	if (!admin)
+		nvmet_rdma_free_inline_pages(ndev, c);
  	ib_dma_unmap_single(ndev->device, c->sge[0].addr,
  				sizeof(*c->nvme_cmd), DMA_FROM_DEVICE);
  	kfree(c->nvme_cmd);

@@ -429,7 +482,7 @@ static void nvmet_rdma_release_rsp(struct nvmet_rdma_rsp *rsp)
  				rsp->req.sg_cnt, nvmet_data_dir(&rsp->req));
  	}
 
-	if (rsp->req.sg != &rsp->cmd->inline_sg)
+	if (rsp->req.sg != rsp->cmd->inline_sg)
  		sgl_free(rsp->req.sg);
 
  	if (unlikely(!list_empty_careful(&queue->rsp_wr_wait_list)))

@@ -529,10 +582,25 @@ static void nvmet_rdma_read_data_done(struct ib_cq *cq, struct ib_wc *wc)
  static void nvmet_rdma_use_inline_sg(struct nvmet_rdma_rsp *rsp, u32 len,
  		u64 off)
  {
-	sg_init_table(&rsp->cmd->inline_sg, 1);
-	sg_set_page(&rsp->cmd->inline_sg, rsp->cmd->inline_page, len, off);
-	rsp->req.sg = &rsp->cmd->inline_sg;
-	rsp->req.sg_cnt = 1;
+	int sg_count = num_pages(len);
+	struct scatterlist *sg;
+	int i;
+
+	sg = rsp->cmd->inline_sg;
+	for (i = 0; i < sg_count; i++, sg++) {
+		if (i < sg_count - 1)
+			sg_unmark_end(sg);
+		else
+			sg_mark_end(sg);
+		sg->offset = off;
+		sg->length = min_t(int, len, PAGE_SIZE - off);
+		len -= sg->length;
+		if (!i)
+			off = 0;
+	}
+
+	rsp->req.sg = rsp->cmd->inline_sg;
+	rsp->req.sg_cnt = sg_count;
  }
 
  static u16 nvmet_rdma_map_sgl_inline(struct nvmet_rdma_rsp *rsp)

@@ -544,7 +612,7 @@ static u16 nvmet_rdma_map_sgl_inline(struct nvmet_rdma_rsp *rsp)
  	if (!nvme_is_write(rsp->req.cmd))
  		return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
 
-	if (off + len > NVMET_RDMA_INLINE_DATA_SIZE) {
+	if (off + len > rsp->queue->dev->inline_data_size) {
  		pr_err("invalid inline data offset!\n");
  		return NVME_SC_SGL_INVALID_OFFSET | NVME_SC_DNR;
  	}

@@ -743,7 +811,7 @@ static int nvmet_rdma_init_srq(struct nvmet_rdma_device *ndev)
  	srq_size = 4095;	/* XXX: tune */
 
  	srq_attr.attr.max_wr = srq_size;
-	srq_attr.attr.max_sge = 2;
+	srq_attr.attr.max_sge = 1 + ndev->inline_page_count;
  	srq_attr.attr.srq_limit = 0;
  	srq_attr.srq_type = IB_SRQT_BASIC;
  	srq = ib_create_srq(ndev->pd, &srq_attr);

@@ -793,7 +861,10 @@ static void nvmet_rdma_free_dev(struct kref *ref)
  static struct nvmet_rdma_device *
  nvmet_rdma_find_get_device(struct rdma_cm_id *cm_id)
  {
+	struct nvmet_port *port = cm_id->context;
  	struct nvmet_rdma_device *ndev;
+	int inline_page_count;
+	int inline_sge_count;
  	int ret;
 
  	mutex_lock(&device_list_mutex);

@@ -807,6 +878,18 @@ static void nvmet_rdma_free_dev(struct kref *ref)
  	if (!ndev)
  		goto out_err;
 
+	inline_page_count = num_pages(port->inline_data_size);
+	inline_sge_count = max(cm_id->device->attrs.max_sge_rd,
+				cm_id->device->attrs.max_recv_sge) - 1;
+	if (inline_page_count > inline_sge_count) {
+		pr_warn("inline_data_size %d cannot be supported by device %s. Reducing to %lu.\n",
+			port->inline_data_size, cm_id->device->name,
+			inline_sge_count * PAGE_SIZE);
+		port->inline_data_size = inline_sge_count * PAGE_SIZE;
+		inline_page_count = inline_sge_count;
+	}
+	ndev->inline_data_size = port->inline_data_size;
+	ndev->inline_page_count = inline_page_count;
  	ndev->device = cm_id->device;
  	kref_init(&ndev->ref);
 

@@ -881,7 +964,7 @@ static int nvmet_rdma_create_queue_ib(struct nvmet_rdma_queue *queue)
  	} else {
  		/* +1 for drain */
  		qp_attr.cap.max_recv_wr = 1 + queue->recv_queue_size;
-		qp_attr.cap.max_recv_sge = 2;
+		qp_attr.cap.max_recv_sge = 1 + ndev->inline_page_count;
  	}
 
  	ret = rdma_create_qp(queue->cm_id, ndev->pd, &qp_attr);

@@ -1379,6 +1462,15 @@ static int nvmet_rdma_add_port(struct nvmet_port *port)
  		return -EINVAL;
  	}
 
+	if (port->inline_data_size < 0) {
+		port->inline_data_size = NVMET_RDMA_DEFAULT_INLINE_DATA_SIZE;
+	} else if (port->inline_data_size > NVMET_RDMA_MAX_INLINE_DATA_SIZE) {
+		pr_warn("inline_data_size %u is too large, reducing to %u\n",
+			port->inline_data_size,
+			NVMET_RDMA_MAX_INLINE_DATA_SIZE);
+		port->inline_data_size = NVMET_RDMA_MAX_INLINE_DATA_SIZE;
+	}
+
  	ret = inet_pton_with_scope(&init_net, af, port->disc_addr.traddr,
  			port->disc_addr.trsvcid, &addr);
  	if (ret) {

@@ -1418,8 +1510,9 @@ static int nvmet_rdma_add_port(struct nvmet_port *port)
  		goto out_destroy_id;
  	}
 
-	pr_info("enabling port %d (%pISpcs)\n",
-		le16_to_cpu(port->disc_addr.portid), (struct sockaddr *)&addr);
+	pr_info("enabling port %d (%pISpcs) inline_data_size %d\n",
+		le16_to_cpu(port->disc_addr.portid), (struct sockaddr *)&addr,
+		port->inline_data_size);
  	port->priv = cm_id;
  	return 0;
 

@@ -1456,7 +1549,6 @@ static void nvmet_rdma_disc_port_addr(struct nvmet_req *req,
  static const struct nvmet_fabrics_ops nvmet_rdma_ops = {
  	.owner			= THIS_MODULE,
  	.type			= NVMF_TRTYPE_RDMA,
-	.sqe_inline_size	= NVMET_RDMA_INLINE_DATA_SIZE,
  	.msdbd			= 1,
  	.has_keyed_sgls		= 1,
  	.add_port		= nvmet_rdma_add_port,

Quoted 75 lines · Steve Wise

The patch enables inline data sizes using up to 4 recv sges, and capping the size at 16KB or at least 1 page size.? So on a 4K page system, up to 16KB is supported, and for a 64K page system 1 page of 64KB is supported.

We avoid > 0 order page allocations for the inline buffers by using multiple recv sges, one for each page.? If the device cannot support the configured inline data size due to lack of enough recv sges, then log a warning and reduce the inline size.

Add a new configfs port attribute, called param_inline_data_size, to allow configuring the size of inline data for a given nvmf port. The maximum size allowed is still enforced by nvmet-rdma with NVMET_RDMA_MAX_INLINE_DATA_SIZE, which is now max(16KB, PAGE_SIZE). And the default size, if not specified via configfs, is still PAGE_SIZE. This preserves the existing behavior, but allows larger inline sizes for small page systems.? If the configured inline data size exceeds NVMET_RDMA_MAX_INLINE_DATA_SIZE, a warning is logged and the size is reduced.? If param_inline_data_size is set to 0, then inline data is disabled for that nvmf port.

Signed-off-by Steve Wise <swise at opengridcomputing.com>

---

? drivers/nvme/target/admin-cmd.c |?? 4 +-
? drivers/nvme/target/configfs.c? |? 31 +++++++
? drivers/nvme/target/core.c????? |?? 4 +
? drivers/nvme/target/discovery.c |?? 2 +-
? drivers/nvme/target/nvmet.h???? |?? 2 +-
? drivers/nvme/target/rdma.c????? | 174

++++++++++++++++++++++++++++++----------
? 6 files changed, 172 insertions(+), 45 deletions(-)

drivers/nvme/target/admin-cmd.c +0 -0

index 3880357..941a574 100644
@@ -238,14 +238,14 @@ static void nvmet_execute_identify_ctrl(struct
 nvmet_req *req)

????? id->sgls = cpu_to_le32(1 << 0);??? /* we always support SGLs */ ????? if (ctrl->ops->has_keyed_sgls)
????????? id->sgls |= cpu_to_le32(1 << 2);
-??? if (ctrl->ops->sqe_inline_size)
+??? if (req->port->inline_data_size)
????????? id->sgls |= cpu_to_le32(1 << 20);
? ????? strcpy(id->subnqn, ctrl->subsys->subsysnqn);
? ????? /* Max command capsule size is sqe + single page of in-capsule data */
????? id->ioccsz = cpu_to_le32((sizeof(struct nvme_command) + -????????????????? ctrl->ops->sqe_inline_size) / 16); +????????????????? req->port->inline_data_size) / 16); ????? /* Max response capsule size is cqe */
????? id->iorcsz = cpu_to_le32(sizeof(struct nvme_completion) / 16); ? diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index d3f3b3e..2e556f6 100644

drivers/nvme/target/configfs.c +0 -0

@@ -218,6 +218,35 @@ static ssize_t nvmet_addr_trsvcid_store(struct
 config_item *item,
 ? ? CONFIGFS_ATTR(nvmet_, addr_trsvcid);

? +static ssize_t nvmet_param_inline_data_size_show(struct config_item *item,
+??????? char *page)

drivers/nvme/target/configfs.c +7 -0

+{
+??? struct nvmet_port *port = to_nvmet_port(item);
+
+??? return snprintf(page, PAGE_SIZE, "%d\n", port->inline_data_size);
+}
+
+static ssize_t nvmet_param_inline_data_size_store(struct config_item

*item,
+??????? const char *page, size_t count)
+{
+??? struct nvmet_port *port = to_nvmet_port(item);

Quoted 4 lines

+??? int ret;
+
+??? if (port->enabled) {
+??????? pr_err("Cannot modify inline_data_size enabled\n");

minor fix for the error print:
"Cannot modify inline_data_size while enabled" or "Cannot modify inline_data_size while port enabled"

Quoted 76 lines · Max Gurtovoy

Quoted 74 lines · Steve Wise

The patch enables inline data sizes using up to 4 recv sges, and capping the size at 16KB or at least 1 page size.? So on a 4K page system, up to 16KB is supported, and for a 64K page system 1 page of 64KB is supported.

We avoid > 0 order page allocations for the inline buffers by using multiple recv sges, one for each page.? If the device cannot support the configured inline data size due to lack of enough recv sges, then log a warning and reduce the inline size.

Add a new configfs port attribute, called param_inline_data_size, to allow configuring the size of inline data for a given nvmf port. The maximum size allowed is still enforced by nvmet-rdma with NVMET_RDMA_MAX_INLINE_DATA_SIZE, which is now max(16KB, PAGE_SIZE). And the default size, if not specified via configfs, is still PAGE_SIZE. This preserves the existing behavior, but allows larger inline sizes for small page systems.? If the configured inline data size exceeds NVMET_RDMA_MAX_INLINE_DATA_SIZE, a warning is logged and the size is reduced.? If param_inline_data_size is set to 0, then inline data is disabled for that nvmf port.

Signed-off-by Steve Wise <swise at opengridcomputing.com>

---

? drivers/nvme/target/admin-cmd.c |?? 4 +-
? drivers/nvme/target/configfs.c? |? 31 +++++++
? drivers/nvme/target/core.c????? |?? 4 +
? drivers/nvme/target/discovery.c |?? 2 +-
? drivers/nvme/target/nvmet.h???? |?? 2 +-
? drivers/nvme/target/rdma.c????? | 174

++++++++++++++++++++++++++++++----------
? 6 files changed, 172 insertions(+), 45 deletions(-)

drivers/nvme/target/admin-cmd.c +0 -0

index 3880357..941a574 100644
@@ -238,14 +238,14 @@ static void nvmet_execute_identify_ctrl(struct
 nvmet_req *req)

????? id->sgls = cpu_to_le32(1 << 0);??? /* we always support SGLs */ ????? if (ctrl->ops->has_keyed_sgls)
????????? id->sgls |= cpu_to_le32(1 << 2);
-??? if (ctrl->ops->sqe_inline_size)
+??? if (req->port->inline_data_size)
????????? id->sgls |= cpu_to_le32(1 << 20);
? ????? strcpy(id->subnqn, ctrl->subsys->subsysnqn);
? ????? /* Max command capsule size is sqe + single page of in-capsule data */
????? id->ioccsz = cpu_to_le32((sizeof(struct nvme_command) + -????????????????? ctrl->ops->sqe_inline_size) / 16); +????????????????? req->port->inline_data_size) / 16); ????? /* Max response capsule size is cqe */
????? id->iorcsz = cpu_to_le32(sizeof(struct nvme_completion) / 16); ? diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index d3f3b3e..2e556f6 100644

drivers/nvme/target/configfs.c +0 -0

@@ -218,6 +218,35 @@ static ssize_t nvmet_addr_trsvcid_store(struct
 config_item *item,
 ? ? CONFIGFS_ATTR(nvmet_, addr_trsvcid);

? +static ssize_t nvmet_param_inline_data_size_show(struct config_item *item,
+??????? char *page)

drivers/nvme/target/configfs.c +7 -0

+{
+??? struct nvmet_port *port = to_nvmet_port(item);
+
+??? return snprintf(page, PAGE_SIZE, "%d\n", port->inline_data_size);
+}
+
+static ssize_t nvmet_param_inline_data_size_store(struct config_item

*item,
+??????? const char *page, size_t count)
+{

Quoted 9 lines

Quoted 5 lines

+??? struct nvmet_port *port = to_nvmet_port(item); +??? int ret;
+
+??? if (port->enabled) {
+??????? pr_err("Cannot modify inline_data_size enabled\n");

minor fix for the error print:
"Cannot modify inline_data_size while enabled" or "Cannot modify inline_data_size while port enabled"

Thanks, I left out the "while".? But I'll use your second suggestion as it is more clear.

Quoted 87 lines · Steve Wise

Quoted 85 lines · Max Gurtovoy

Quoted 69 lines · Steve Wise

The patch enables inline data sizes using up to 4 recv sges, and capping the size at 16KB or at least 1 page size.? So on a 4K page system, up to 16KB is supported, and for a 64K page system 1 page of 64KB is supported.

We avoid > 0 order page allocations for the inline buffers by using multiple recv sges, one for each page.? If the device cannot support the configured inline data size due to lack of enough recv sges, then log a warning and reduce the inline size.

Add a new configfs port attribute, called param_inline_data_size, to allow configuring the size of inline data for a given nvmf port. The maximum size allowed is still enforced by nvmet-rdma with NVMET_RDMA_MAX_INLINE_DATA_SIZE, which is now max(16KB, PAGE_SIZE). And the default size, if not specified via configfs, is still PAGE_SIZE. This preserves the existing behavior, but allows larger inline sizes for small page systems.? If the configured inline data size exceeds NVMET_RDMA_MAX_INLINE_DATA_SIZE, a warning is logged and the size is reduced.? If param_inline_data_size is set to 0, then inline data is disabled for that nvmf port.

Signed-off-by Steve Wise <swise at opengridcomputing.com>

---

 ? drivers/nvme/target/admin-cmd.c |?? 4 +-
 ? drivers/nvme/target/configfs.c? |? 31 +++++++
 ? drivers/nvme/target/core.c????? |?? 4 +
 ? drivers/nvme/target/discovery.c |?? 2 +-
 ? drivers/nvme/target/nvmet.h???? |?? 2 +-
 ? drivers/nvme/target/rdma.c????? | 174

++++++++++++++++++++++++++++++----------
? 6 files changed, 172 insertions(+), 45 deletions(-)

drivers/nvme/target/admin-cmd.c +1 -1

index 3880357..941a574 100644
@@ -238,14 +238,14 @@ static void nvmet_execute_identify_ctrl(struct
 nvmet_req *req)
 ????? id->sgls = cpu_to_le32(1 << 0);??? /* we always support SGLs */
 ????? if (ctrl->ops->has_keyed_sgls)
 ????????? id->sgls |= cpu_to_le32(1 << 2);
-??? if (ctrl->ops->sqe_inline_size)
+??? if (req->port->inline_data_size)
 ????????? id->sgls |= cpu_to_le32(1 << 20);
 ? ????? strcpy(id->subnqn, ctrl->subsys->subsysnqn);
 ? ????? /* Max command capsule size is sqe + single page of

in-capsule data */
????? id->ioccsz = cpu_to_le32((sizeof(struct nvme_command) +
-????????????????? ctrl->ops->sqe_inline_size) / 16); +????????????????? req->port->inline_data_size) / 16);
????? /* Max response capsule size is cqe */
????? id->iorcsz = cpu_to_le32(sizeof(struct nvme_completion) / 16); ? diff --git a/drivers/nvme/target/configfs.c
b/drivers/nvme/target/configfs.c
index d3f3b3e..2e556f6 100644

drivers/nvme/target/configfs.c +6 -0

@@ -218,6 +218,35 @@ static ssize_t nvmet_addr_trsvcid_store(struct
 config_item *item,
 ? ? CONFIGFS_ATTR(nvmet_, addr_trsvcid);
 ? +static ssize_t nvmet_param_inline_data_size_show(struct
 config_item *item,
+??????? char *page)
+{
+??? struct nvmet_port *port = to_nvmet_port(item);
+
+??? return snprintf(page, PAGE_SIZE, "%d\n", port->inline_data_size);
+}

drivers/nvme/target/configfs.c static ssize_t nvmet_addr_trsvcid_store(struct · line 237

Quoted 10 lines

drivers/nvme/target/configfs.c +9 -0

+
+static ssize_t nvmet_param_inline_data_size_store(struct config_item
 *item,
+??????? const char *page, size_t count)
+{
+??? struct nvmet_port *port = to_nvmet_port(item);
+??? int ret;
+
+??? if (port->enabled) {
+??????? pr_err("Cannot modify inline_data_size enabled\n");

minor fix for the error print:
"Cannot modify inline_data_size while enabled" or "Cannot modify inline_data_size while port enabled"

Quoted 3 lines

Thanks, I left out the "while".? But I'll use your second suggestion as it is more clear.

By the way, may I add your Reviewed-by tag for these 2 patches?

Thanks,

Steve.

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