[nvdimm PATCH 0/6] Label initialization time optimizations

[nvdimm PATCH 0/6] Label initialization time optimizations

[Alexander Duyck]

This patch set is intended to improve NVDIMM label read times by first
increasing the upper limit on the label read/write size, and then
reducing the number of reads by making use of the free label bitmap in
the index to determine what labels are actually populated and only read
those labels. In my testing on a system populated with 24 NVDIMM modules
I see the total label init time drop from about 24 seconds down to 2 to
3 seconds. 

In the process of coding this up I came across a few minor issues that
I felt should be addressed so I have added a few patches for those fixes
along the way.

---

Alexander Duyck (5):
      nvdimm: Sanity check labeloff
      nvdimm: Clarify comment in sizeof_namespace_index
      nvdimm: Remove empty if statement
      nvdimm: Split label init out from the logic for getting config data
      nvdimm: Use namespace index data to reduce number of label reads needed

Dan Williams (1):
      libnvdimm, dimm: Maximize label transfer size


 drivers/nvdimm/dimm.c      |    6 --
 drivers/nvdimm/dimm_devs.c |   60 +++++++------------
 drivers/nvdimm/label.c     |  142 ++++++++++++++++++++++++++++++++++++++++++--
 drivers/nvdimm/label.h     |    4 -
 drivers/nvdimm/nd.h        |    2 +
 5 files changed, 163 insertions(+), 51 deletions(-)

--
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[nvdimm PATCH 1/6] libnvdimm, dimm: Maximize label transfer size

[Alexander Duyck]

From: Dan Williams <dan.j.williams@intel.com>

Use kvzalloc() to bypass the arbitrary PAGE_SIZE limit of label transfer
operations. Given the expense of calling into firmware, maximize the
amount of label data we transfer per call to be up to the total label
space if allowed by the firmware.

Instead of limiting based on PAGE_SIZE we can instead simply limit the
maximum size based on either the config_size int he case of the get
operation, or the length of the write based on the set operation.

On a system with 24 NVDIMM modules each with a config_size of 128K and a
maximum transfer size of 64K - 4, this patch reduces the init time for the
label data from around 24 seconds down to between 4-5 seconds.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
---

I think I only did a few minor tweaks on this so I thought I would leave
Dan as the author and just add my Signed-off-by.

 drivers/nvdimm/dimm_devs.c |   13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index 863cabc35215..75ac78017b15 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -111,8 +111,8 @@ int nvdimm_init_config_data(struct nvdimm_drvdata *ndd)
 	if (!ndd->data)
 		return -ENOMEM;
 
-	max_cmd_size = min_t(u32, PAGE_SIZE, ndd->nsarea.max_xfer);
-	cmd = kzalloc(max_cmd_size + sizeof(*cmd), GFP_KERNEL);
+	max_cmd_size = min_t(u32, ndd->nsarea.config_size, ndd->nsarea.max_xfer);
+	cmd = kvzalloc(max_cmd_size + sizeof(*cmd), GFP_KERNEL);
 	if (!cmd)
 		return -ENOMEM;
 
@@ -134,7 +134,7 @@ int nvdimm_init_config_data(struct nvdimm_drvdata *ndd)
 		memcpy(ndd->data + offset, cmd->out_buf, cmd->in_length);
 	}
 	dev_dbg(ndd->dev, "len: %zu rc: %d\n", offset, rc);
-	kfree(cmd);
+	kvfree(cmd);
 
 	return rc;
 }
@@ -157,9 +157,8 @@ int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,
 	if (offset + len > ndd->nsarea.config_size)
 		return -ENXIO;
 
-	max_cmd_size = min_t(u32, PAGE_SIZE, len);
-	max_cmd_size = min_t(u32, max_cmd_size, ndd->nsarea.max_xfer);
-	cmd = kzalloc(max_cmd_size + sizeof(*cmd) + sizeof(u32), GFP_KERNEL);
+	max_cmd_size = min_t(u32, len, ndd->nsarea.max_xfer);
+	cmd = kvzalloc(max_cmd_size + sizeof(*cmd) + sizeof(u32), GFP_KERNEL);
 	if (!cmd)
 		return -ENOMEM;
 
@@ -183,7 +182,7 @@ int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,
 			break;
 		}
 	}
-	kfree(cmd);
+	kvfree(cmd);
 
 	return rc;
 }

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[nvdimm PATCH 2/6] nvdimm: Sanity check labeloff

[Alexander Duyck]

This patch adds validation for the labeloff field in the indexes.

Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
---
 drivers/nvdimm/label.c |    7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
index 1d28cd656536..1f5842509dbc 100644
--- a/drivers/nvdimm/label.c
+++ b/drivers/nvdimm/label.c
@@ -183,6 +183,13 @@ static int __nd_label_validate(struct nvdimm_drvdata *ndd)
 					__le64_to_cpu(nsindex[i]->otheroff));
 			continue;
 		}
+		if (__le64_to_cpu(nsindex[i]->labeloff)
+				!= 2 * sizeof_namespace_index(ndd)) {
+			dev_dbg(dev, "nsindex%d labeloff: %#llx invalid\n",
+					i, (unsigned long long)
+					__le64_to_cpu(nsindex[i]->labeloff));
+			continue;
+		}
 
 		size = __le64_to_cpu(nsindex[i]->mysize);
 		if (size > sizeof_namespace_index(ndd)

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[nvdimm PATCH 3/6] nvdimm: Clarify comment in sizeof_namespace_index

[Alexander Duyck]

When working on the label code I found it rather confusing to see several
spots that reference a minimum label size of 256 while working with labels
that are 128 bytes in size.

This patch is meant to provide a clarification on one of the comments that
was at the heart of the issue. Specifically for version 1.2 and later of
the namespace specification the minimum label size is 256, prior to that
the minimum label size was 128. So we should state that as such to avoid
confusion.

Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
---
 drivers/nvdimm/label.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
index 1f5842509dbc..bb813b8e8ace 100644
--- a/drivers/nvdimm/label.c
+++ b/drivers/nvdimm/label.c
@@ -75,7 +75,8 @@ size_t sizeof_namespace_index(struct nvdimm_drvdata *ndd)
 	/*
 	 * Per UEFI 2.7, the minimum size of the Label Storage Area is large
 	 * enough to hold 2 index blocks and 2 labels.  The minimum index
-	 * block size is 256 bytes, and the minimum label size is 256 bytes.
+	 * block size is 256 bytes. The label size is 128 for namespaces
+	 * prior to version 1.2 and at minimum 256 for version 1.2 and later.
 	 */
 	nslot = nvdimm_num_label_slots(ndd);
 	space = ndd->nsarea.config_size - nslot * sizeof_namespace_label(ndd);

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[nvdimm PATCH 4/6] nvdimm: Remove empty if statement

[Alexander Duyck]

This patch removes an empty statement from an if expression and promotes
the else statement to the if expression with the expression logic reversed.

I feel this is more readable as the empty statement can lead to issues if
any additional logic was ever added.

Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
---
 drivers/nvdimm/label.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
index bb813b8e8ace..43bad0d5bdb6 100644
--- a/drivers/nvdimm/label.c
+++ b/drivers/nvdimm/label.c
@@ -261,9 +261,8 @@ int nd_label_validate(struct nvdimm_drvdata *ndd)
 void nd_label_copy(struct nvdimm_drvdata *ndd, struct nd_namespace_index *dst,
 		struct nd_namespace_index *src)
 {
-	if (dst && src)
-		/* pass */;
-	else
+	/* just exit if either destination or source is NULL */
+	if (!dst || !src)
 		return;
 
 	memcpy(dst, src, sizeof_namespace_index(ndd));

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[nvdimm PATCH 5/6] nvdimm: Split label init out from the logic for getting config data

[Alexander Duyck]

This patch splits the initialization of the label data into two functions.
One for doing the init, and another for reading the actual configuration
data. The idea behind this is that by doing this we create a symmetry
between the getting and setting of config data in that we have a function
for both. In addition it will make it easier for us to identify the bits
that are related to init versus the pieces that are a wrapper for reading
data from the ACPI interface.

So for example by splitting things out like this it becomes much more
obvious that we were performing checks that weren't necessarily related to
the set/get operations such as relying on ndd->data being present when the
set and get ops should not care about a locally cached copy of the label
area.

Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
---
 drivers/nvdimm/dimm.c      |    2 +-
 drivers/nvdimm/dimm_devs.c |   49 +++++++++++++++++---------------------------
 drivers/nvdimm/label.c     |   38 ++++++++++++++++++++++++++++++++++
 drivers/nvdimm/label.h     |    1 +
 drivers/nvdimm/nd.h        |    2 ++
 5 files changed, 61 insertions(+), 31 deletions(-)

diff --git a/drivers/nvdimm/dimm.c b/drivers/nvdimm/dimm.c
index 6c8fb7590838..07bf96948553 100644
--- a/drivers/nvdimm/dimm.c
+++ b/drivers/nvdimm/dimm.c
@@ -75,7 +75,7 @@ static int nvdimm_probe(struct device *dev)
 	 * DIMM capacity. We fail the dimm probe to prevent regions from
 	 * attempting to parse the label area.
 	 */
-	rc = nvdimm_init_config_data(ndd);
+	rc = nd_label_data_init(ndd);
 	if (rc == -EACCES)
 		nvdimm_set_locked(dev);
 	if (rc)
diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index 75ac78017b15..6c3de2317390 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -85,55 +85,47 @@ int nvdimm_init_nsarea(struct nvdimm_drvdata *ndd)
 	return cmd_rc;
 }
 
-int nvdimm_init_config_data(struct nvdimm_drvdata *ndd)
+int nvdimm_get_config_data(struct nvdimm_drvdata *ndd, void *buf,
+			   size_t offset, size_t len)
 {
 	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
+	struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
 	int rc = validate_dimm(ndd), cmd_rc = 0;
 	struct nd_cmd_get_config_data_hdr *cmd;
-	struct nvdimm_bus_descriptor *nd_desc;
-	u32 max_cmd_size, config_size;
-	size_t offset;
+	size_t max_cmd_size, buf_offset;
 
 	if (rc)
 		return rc;
 
-	if (ndd->data)
-		return 0;
-
-	if (ndd->nsarea.status || ndd->nsarea.max_xfer == 0
-			|| ndd->nsarea.config_size < ND_LABEL_MIN_SIZE) {
-		dev_dbg(ndd->dev, "failed to init config data area: (%d:%d)\n",
-				ndd->nsarea.max_xfer, ndd->nsarea.config_size);
+	if (offset + len > ndd->nsarea.config_size)
 		return -ENXIO;
-	}
 
-	ndd->data = kvmalloc(ndd->nsarea.config_size, GFP_KERNEL);
-	if (!ndd->data)
-		return -ENOMEM;
-
-	max_cmd_size = min_t(u32, ndd->nsarea.config_size, ndd->nsarea.max_xfer);
+	max_cmd_size = min_t(u32, len, ndd->nsarea.max_xfer);
 	cmd = kvzalloc(max_cmd_size + sizeof(*cmd), GFP_KERNEL);
 	if (!cmd)
 		return -ENOMEM;
 
-	nd_desc = nvdimm_bus->nd_desc;
-	for (config_size = ndd->nsarea.config_size, offset = 0;
-			config_size; config_size -= cmd->in_length,
-			offset += cmd->in_length) {
-		cmd->in_length = min(config_size, max_cmd_size);
-		cmd->in_offset = offset;
+	for (buf_offset = 0; len;
+	     len -= cmd->in_length, buf_offset += cmd->in_length) {
+		size_t cmd_size;
+
+		cmd->in_offset = offset + buf_offset;
+		cmd->in_length = min(max_cmd_size, len);
+
+		cmd_size = sizeof(*cmd) + cmd->in_length;
+
 		rc = nd_desc->ndctl(nd_desc, to_nvdimm(ndd->dev),
-				ND_CMD_GET_CONFIG_DATA, cmd,
-				cmd->in_length + sizeof(*cmd), &cmd_rc);
+				ND_CMD_GET_CONFIG_DATA, cmd, cmd_size, &cmd_rc);
 		if (rc < 0)
 			break;
 		if (cmd_rc < 0) {
 			rc = cmd_rc;
 			break;
 		}
-		memcpy(ndd->data + offset, cmd->out_buf, cmd->in_length);
+
+		/* out_buf should be valid, copy it into our output buffer */
+		memcpy(buf + buf_offset, cmd->out_buf, cmd->in_length);
 	}
-	dev_dbg(ndd->dev, "len: %zu rc: %d\n", offset, rc);
 	kvfree(cmd);
 
 	return rc;
@@ -151,9 +143,6 @@ int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,
 	if (rc)
 		return rc;
 
-	if (!ndd->data)
-		return -ENXIO;
-
 	if (offset + len > ndd->nsarea.config_size)
 		return -ENXIO;
 
diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
index 43bad0d5bdb6..563f24af01b5 100644
--- a/drivers/nvdimm/label.c
+++ b/drivers/nvdimm/label.c
@@ -417,6 +417,44 @@ int nd_label_reserve_dpa(struct nvdimm_drvdata *ndd)
 	return 0;
 }
 
+int nd_label_data_init(struct nvdimm_drvdata *ndd)
+{
+	size_t config_size, read_size;
+	int rc = 0;
+
+	if (ndd->data)
+		return 0;
+
+	if (ndd->nsarea.status || ndd->nsarea.max_xfer == 0) {
+		dev_dbg(ndd->dev, "failed to init config data area: (%u:%u)\n",
+			ndd->nsarea.max_xfer, ndd->nsarea.config_size);
+		return -ENXIO;
+	}
+
+	/*
+	 * We need to determine the maximum index area as this is the section
+	 * we must read and validate before we can start processing labels.
+	 *
+	 * If the area is too small to contain the two indexes and 2 labels
+	 * then we abort.
+	 *
+	 * Start at a label size of 128 as this should result in the largest
+	 * possible namespace index size.
+	 */
+	ndd->nslabel_size = 128;
+	read_size = sizeof_namespace_index(ndd) * 2;
+	if (!read_size)
+		return -ENXIO;
+
+	/* Allocate config data */
+	config_size = ndd->nsarea.config_size;
+	ndd->data = kvzalloc(config_size, GFP_KERNEL);
+	if (!ndd->data)
+		return -ENOMEM;
+
+	return nvdimm_get_config_data(ndd, ndd->data, 0, config_size);
+}
+
 int nd_label_active_count(struct nvdimm_drvdata *ndd)
 {
 	struct nd_namespace_index *nsindex;
diff --git a/drivers/nvdimm/label.h b/drivers/nvdimm/label.h
index 18bbe183b3a9..685afb3de0fe 100644
--- a/drivers/nvdimm/label.h
+++ b/drivers/nvdimm/label.h
@@ -141,6 +141,7 @@ static inline int nd_label_next_nsindex(int index)
 int nd_label_validate(struct nvdimm_drvdata *ndd);
 void nd_label_copy(struct nvdimm_drvdata *ndd, struct nd_namespace_index *dst,
 		struct nd_namespace_index *src);
+int nd_label_data_init(struct nvdimm_drvdata *ndd);
 size_t sizeof_namespace_index(struct nvdimm_drvdata *ndd);
 int nd_label_active_count(struct nvdimm_drvdata *ndd);
 struct nd_namespace_label *nd_label_active(struct nvdimm_drvdata *ndd, int n);
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index 98317e7ce5b5..e79cc8e5c114 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -241,6 +241,8 @@ ssize_t nd_size_select_store(struct device *dev, const char *buf,
 int nvdimm_check_config_data(struct device *dev);
 int nvdimm_init_nsarea(struct nvdimm_drvdata *ndd);
 int nvdimm_init_config_data(struct nvdimm_drvdata *ndd);
+int nvdimm_get_config_data(struct nvdimm_drvdata *ndd, void *buf,
+			   size_t offset, size_t len);
 int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,
 		void *buf, size_t len);
 long nvdimm_clear_poison(struct device *dev, phys_addr_t phys,

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[nvdimm PATCH 6/6] nvdimm: Use namespace index data to reduce number of label reads needed

[Alexander Duyck]

This patch adds logic that is meant to make use of the namespace index data
to reduce the number of reads that are needed to initialize a given
namespace. The general idea is that once we have enough data to validate
the namespace index we do so and then proceed to fetch only those labels
that are not listed as being "free". By doing this I am seeing a total time
reduction from about 4-5 seconds to 2-3 seconds for 24 NVDIMM modules each
with 128K of label config area.

Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
---
 drivers/nvdimm/dimm.c  |    4 --
 drivers/nvdimm/label.c |   93 +++++++++++++++++++++++++++++++++++++++++++++---
 drivers/nvdimm/label.h |    3 --
 3 files changed, 88 insertions(+), 12 deletions(-)

diff --git a/drivers/nvdimm/dimm.c b/drivers/nvdimm/dimm.c
index 07bf96948553..9899c97138a3 100644
--- a/drivers/nvdimm/dimm.c
+++ b/drivers/nvdimm/dimm.c
@@ -84,10 +84,6 @@ static int nvdimm_probe(struct device *dev)
 	dev_dbg(dev, "config data size: %d\n", ndd->nsarea.config_size);
 
 	nvdimm_bus_lock(dev);
-	ndd->ns_current = nd_label_validate(ndd);
-	ndd->ns_next = nd_label_next_nsindex(ndd->ns_current);
-	nd_label_copy(ndd, to_next_namespace_index(ndd),
-			to_current_namespace_index(ndd));
 	if (ndd->ns_current >= 0) {
 		rc = nd_label_reserve_dpa(ndd);
 		if (rc == 0)
diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
index 563f24af01b5..7f03d117824f 100644
--- a/drivers/nvdimm/label.c
+++ b/drivers/nvdimm/label.c
@@ -235,7 +235,7 @@ static int __nd_label_validate(struct nvdimm_drvdata *ndd)
 	return -1;
 }
 
-int nd_label_validate(struct nvdimm_drvdata *ndd)
+static int nd_label_validate(struct nvdimm_drvdata *ndd)
 {
 	/*
 	 * In order to probe for and validate namespace index blocks we
@@ -258,8 +258,9 @@ int nd_label_validate(struct nvdimm_drvdata *ndd)
 	return -1;
 }
 
-void nd_label_copy(struct nvdimm_drvdata *ndd, struct nd_namespace_index *dst,
-		struct nd_namespace_index *src)
+static void nd_label_copy(struct nvdimm_drvdata *ndd,
+			  struct nd_namespace_index *dst,
+			  struct nd_namespace_index *src)
 {
 	/* just exit if either destination or source is NULL */
 	if (!dst || !src)
@@ -419,7 +420,9 @@ int nd_label_reserve_dpa(struct nvdimm_drvdata *ndd)
 
 int nd_label_data_init(struct nvdimm_drvdata *ndd)
 {
-	size_t config_size, read_size;
+	size_t config_size, read_size, max_xfer, offset;
+	struct nd_namespace_index *nsindex;
+	unsigned int i;
 	int rc = 0;
 
 	if (ndd->data)
@@ -452,7 +455,87 @@ int nd_label_data_init(struct nvdimm_drvdata *ndd)
 	if (!ndd->data)
 		return -ENOMEM;
 
-	return nvdimm_get_config_data(ndd, ndd->data, 0, config_size);
+	/*
+	 * We want to guarantee as few reads as possible while conserving
+	 * memory. To do that we figure out how much unused space will be left
+	 * in the last read, divide that by the total number of reads it is
+	 * going to take given our maximum transfer size, and then reduce our
+	 * maximum transfer size based on that result.
+	 */
+	max_xfer = min_t(size_t, ndd->nsarea.max_xfer, config_size);
+	if (read_size < max_xfer) {
+		/* trim waste */
+		max_xfer -= ((max_xfer - 1) - (config_size - 1) % max_xfer) /
+			    DIV_ROUND_UP(config_size, max_xfer);
+		/* make certain we read indexes in exactly 1 read */
+		if (max_xfer < read_size)
+			max_xfer = read_size;
+	}
+
+	/* Make our initial read size a multiple of max_xfer size */
+	read_size = min(DIV_ROUND_UP(read_size, max_xfer) * max_xfer,
+			config_size);
+
+	/* Read the index data */
+	rc = nvdimm_get_config_data(ndd, ndd->data, 0, read_size);
+	if (rc)
+		goto out_err;
+
+	/* Validate index data, if not valid assume all labels are invalid */
+	ndd->ns_current = nd_label_validate(ndd);
+	if (ndd->ns_current < 0)
+		return 0;
+
+	/* Record our index values */
+	ndd->ns_next = nd_label_next_nsindex(ndd->ns_current);
+
+	/* Copy "current" index on top of the "next" index */
+	nsindex = to_current_namespace_index(ndd);
+	nd_label_copy(ndd, to_next_namespace_index(ndd), nsindex);
+
+	/* Determine starting offset for label data */
+	offset = __le64_to_cpu(nsindex->labeloff);
+
+	/* Loop through the free list pulling in any active labels */
+	for (i = 0; i < nsindex->nslot; i++, offset += ndd->nslabel_size) {
+		size_t label_read_size;
+
+		/* zero out the unused labels */
+		if (test_bit_le(i, nsindex->free)) {
+			memset(ndd->data + offset, 0, ndd->nslabel_size);
+			continue;
+		}
+
+		/* if we already read past here then just continue */
+		if (offset + ndd->nslabel_size <= read_size)
+			continue;
+
+		/* if we haven't read in a while reset our read_size offset */
+		if (read_size < offset)
+			read_size = offset;
+
+		/* determine how much more will be read after this next call. */
+		label_read_size = offset + ndd->nslabel_size - read_size;
+		label_read_size = DIV_ROUND_UP(label_read_size, max_xfer) *
+				  max_xfer;
+
+		/* truncate last read if needed */
+		if (read_size + label_read_size > config_size)
+			label_read_size = config_size - read_size;
+
+		/* Read the label data */
+		rc = nvdimm_get_config_data(ndd, ndd->data + read_size,
+					    read_size, label_read_size);
+		if (rc)
+			goto out_err;
+
+		/* push read_size to next read offset */
+		read_size += label_read_size;
+	}
+
+	dev_dbg(ndd->dev, "len: %zu rc: %d\n", offset, rc);
+out_err:
+	return rc;
 }
 
 int nd_label_active_count(struct nvdimm_drvdata *ndd)
diff --git a/drivers/nvdimm/label.h b/drivers/nvdimm/label.h
index 685afb3de0fe..e9a2ad3c2150 100644
--- a/drivers/nvdimm/label.h
+++ b/drivers/nvdimm/label.h
@@ -138,9 +138,6 @@ static inline int nd_label_next_nsindex(int index)
 }
 
 struct nvdimm_drvdata;
-int nd_label_validate(struct nvdimm_drvdata *ndd);
-void nd_label_copy(struct nvdimm_drvdata *ndd, struct nd_namespace_index *dst,
-		struct nd_namespace_index *src);
 int nd_label_data_init(struct nvdimm_drvdata *ndd);
 size_t sizeof_namespace_index(struct nvdimm_drvdata *ndd);
 int nd_label_active_count(struct nvdimm_drvdata *ndd);

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Re: [nvdimm PATCH 6/6] nvdimm: Use namespace index data to reduce number of label reads needed

[Dan Williams]

On Wed, Oct 10, 2018 at 4:51 PM Alexander Duyck
<alexander.h.duyck@linux.intel.com> wrote:
>
> This patch adds logic that is meant to make use of the namespace index data
> to reduce the number of reads that are needed to initialize a given
> namespace. The general idea is that once we have enough data to validate
> the namespace index we do so and then proceed to fetch only those labels
> that are not listed as being "free". By doing this I am seeing a total time
> reduction from about 4-5 seconds to 2-3 seconds for 24 NVDIMM modules each
> with 128K of label config area.
>
> Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
> ---
>  drivers/nvdimm/dimm.c  |    4 --
>  drivers/nvdimm/label.c |   93 +++++++++++++++++++++++++++++++++++++++++++++---
>  drivers/nvdimm/label.h |    3 --
>  3 files changed, 88 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/nvdimm/dimm.c b/drivers/nvdimm/dimm.c
> index 07bf96948553..9899c97138a3 100644
> --- a/drivers/nvdimm/dimm.c
> +++ b/drivers/nvdimm/dimm.c
> @@ -452,7 +455,87 @@ int nd_label_data_init(struct nvdimm_drvdata *ndd)
[..]
> +       /* Loop through the free list pulling in any active labels */
> +       for (i = 0; i < nsindex->nslot; i++, offset += ndd->nslabel_size) {

0day points out a sparse warning on that usage of nslot which is an
__le32. I'll append a fixup.
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Re: [nvdimm PATCH 0/6] Label initialization time optimizations

[Dan Williams]

On Wed, Oct 10, 2018 at 4:36 PM Alexander Duyck
<alexander.h.duyck@linux.intel.com> wrote:
>
> This patch set is intended to improve NVDIMM label read times by first
> increasing the upper limit on the label read/write size, and then
> reducing the number of reads by making use of the free label bitmap in
> the index to determine what labels are actually populated and only read
> those labels. In my testing on a system populated with 24 NVDIMM modules
> I see the total label init time drop from about 24 seconds down to 2 to
> 3 seconds.
>
> In the process of coding this up I came across a few minor issues that
> I felt should be addressed so I have added a few patches for those fixes
> along the way.

Thanks, this all looks good to me, the split looks good, and the
commentary in patch6 made it easy to review.

I quibble with "Remove empty if statement" because I find positive
logic easier to read than negative logic, but removing more lines than
it adds made me reserve that quibble for another time.
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Re: [nvdimm PATCH 0/6] Label initialization time optimizations

[Kani, Toshi]

On Wed, 2018-10-10 at 16:36 -0700, Alexander Duyck wrote:
> This patch set is intended to improve NVDIMM label read times by first
> increasing the upper limit on the label read/write size, and then
> reducing the number of reads by making use of the free label bitmap in
> the index to determine what labels are actually populated and only read
> those labels. In my testing on a system populated with 24 NVDIMM modules
> I see the total label init time drop from about 24 seconds down to 2 to
> 3 seconds. 
> 
> In the process of coding this up I came across a few minor issues that
> I felt should be addressed so I have added a few patches for those fixes
> along the way.
> 
> ---
> 
> Alexander Duyck (5):
>       nvdimm: Sanity check labeloff
>       nvdimm: Clarify comment in sizeof_namespace_index
>       nvdimm: Remove empty if statement
>       nvdimm: Split label init out from the logic for getting config data
>       nvdimm: Use namespace index data to reduce number of label reads needed
> 
> Dan Williams (1):
>       libnvdimm, dimm: Maximize label transfer size
> 

This series really helps us a lot!! The change looks good to me.

Reviewed-by: Toshi Kani <toshi.kani@hpe.com>

Thanks!
-Toshi
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