29 Aug, 2015
3 commits
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The expectation is that the legacy / non-standard pmem discovery method
(e820 type-12) will only ever be used to describe small quantities of
persistent memory. Larger capacities will be described via the ACPI
NFIT. When "allocate struct page from pmem" support is added this default
policy can be overridden by assigning a legacy pmem namespace to a pfn
device, however this would be only be necessary if a platform used the
legacy mechanism to define a very large range.Cc: Christoph Hellwig
Signed-off-by: Dan Williams -
Enable the pmem driver to handle PFN device instances. Attaching a pmem
namespace to a pfn device triggers the driver to allocate and initialize
struct page entries for pmem. Memory capacity for this allocation comes
exclusively from RAM for now which is suitable for low PMEM to RAM
ratios. This mechanism will be expanded later for setting an "allocate
from PMEM" policy.Cc: Boaz Harrosh
Cc: Ross Zwisler
Cc: Christoph Hellwig
Signed-off-by: Dan Williams -
Implement the base infrastructure for libnvdimm PFN devices. Similar to
BTT devices they take a namespace as a backing device and layer
functionality on top. In this case the functionality is reserving space
for an array of 'struct page' entries to be handed out through
pfn_to_page(). For now this is just the basic libnvdimm-device-model for
configuring the base PFN device.As the namespace claiming mechanism for PFN devices is mostly identical
to BTT devices drivers/nvdimm/claim.c is created to house the common
bits.Cc: Ross Zwisler
Signed-off-by: Dan Williams
15 Aug, 2015
1 commit
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When a BTT is instantiated on a namespace it must validate the namespace
uuid matches the 'parent_uuid' stored in the btt superblock. This
property enforces that changing the namespace UUID invalidates all
former BTT instances on that storage. For "IO namespaces" that don't
have a label or UUID, the parent_uuid is set to zero, and this
validation is skipped. For such cases, old BTTs have to be invalidated
by forcing the namespace to raw mode, and overwriting the BTT info
blocks.Based on a patch by Dan Williams
Signed-off-by: Vishal Verma
Signed-off-by: Dan Williams
01 Aug, 2015
1 commit
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Fix multiple build warnings when CONFIG_BTT is not enabled:
In file included from ../drivers/nvdimm/bus.c:29:0:
../drivers/nvdimm/nd.h:169:15: warning: return type defaults to 'int' [-Wreturn-type]
static inline nd_btt_probe(struct nd_namespace_common *ndns, void *drvdata)
^Signed-off-by: Randy Dunlap
Cc: Dan Williams
Cc: linux-nvdimm@lists.01.org
Signed-off-by: Dan Williams
26 Jun, 2015
7 commits
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ACPI NFIT table has System Physical Address Range Structure entries that
describe a proximity ID of each range when ACPI_NFIT_PROXIMITY_VALID is
set in the flags.Change acpi_nfit_register_region() to map a proximity ID to its node ID,
and set it to a new numa_node field of nd_region_desc, which is then
conveyed to the nd_region device.The device core arranges for btt and namespace devices to inherit their
node from their parent region.Signed-off-by: Toshi Kani
[djbw: move set_dev_node() from region.c to bus.c]
Signed-off-by: Dan Williams -
Upon detection of an unarmed dimm in a region, arrange for descendant
BTT, PMEM, or BLK instances to be read-only. A dimm is primarily marked
"unarmed" via flags passed by platform firmware (NFIT).The flags in the NFIT memory device sub-structure indicate the state of
the data on the nvdimm relative to its energy source or last "flush to
persistence". For the most part there is nothing the driver can do but
advertise the state of these flags in sysfs and emit a message if
firmware indicates that the contents of the device may be corrupted.
However, for the case of ACPI_NFIT_MEM_ARMED, the driver can arrange for
the block devices incorporating that nvdimm to be marked read-only.
This is a safe default as the data is still available and new writes are
held off until the administrator either forces read-write mode, or the
energy source becomes armed.A 'read_only' attribute is added to REGION devices to allow for
overriding the default read-only policy of all descendant block devices.Signed-off-by: Dan Williams
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This is disabled by default as the overhead is prohibitive, but if the
user takes the action to turn it on we'll oblige.Reviewed-by: Vishal Verma
Signed-off-by: Dan Williams -
Support multiple block sizes (sector + metadata) for nd_blk in the
same way as done for the BTT. Add the idea of an 'internal' lbasize,
which is properly aligned and padded, and store metadata in this space.Signed-off-by: Vishal Verma
Signed-off-by: Dan Williams -
Support multiple block sizes (sector + metadata) using the blk integrity
framework. This registers a new integrity template that defines the
protection information tuple size based on the configured metadata size,
and simply acts as a passthrough for protection information generated by
another layer. The metadata is written to the storage as-is, and read back
with each sector.Signed-off-by: Vishal Verma
Signed-off-by: Dan Williams -
The libnvdimm implementation handles allocating dimm address space (DPA)
between PMEM and BLK mode interfaces. After DPA has been allocated from
a BLK-region to a BLK-namespace the nd_blk driver attaches to handle I/O
as a struct bio based block device. Unlike PMEM, BLK is required to
handle platform specific details like mmio register formats and memory
controller interleave. For this reason the libnvdimm generic nd_blk
driver calls back into the bus provider to carry out the I/O.This initial implementation handles the BLK interface defined by the
ACPI 6 NFIT [1] and the NVDIMM DSM Interface Example [2] composed from
DCR (dimm control region), BDW (block data window), IDT (interleave
descriptor) NFIT structures and the hardware register format.
[1]: http://www.uefi.org/sites/default/files/resources/ACPI_6.0.pdf
[2]: http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdfCc: Andy Lutomirski
Cc: Boaz Harrosh
Cc: H. Peter Anvin
Cc: Jens Axboe
Cc: Ingo Molnar
Cc: Christoph Hellwig
Signed-off-by: Ross Zwisler
Acked-by: Rafael J. Wysocki
Signed-off-by: Dan Williams -
BTT stands for Block Translation Table, and is a way to provide power
fail sector atomicity semantics for block devices that have the ability
to perform byte granularity IO. It relies on the capability of libnvdimm
namespace devices to do byte aligned IO.The BTT works as a stacked blocked device, and reserves a chunk of space
from the backing device for its accounting metadata. It is a bio-based
driver because all IO is done synchronously, and there is no queuing or
asynchronous completions at either the device or the driver level.The BTT uses 'lanes' to index into various 'on-disk' data structures,
and lanes also act as a synchronization mechanism in case there are more
CPUs than available lanes. We did a comparison between two lane lock
strategies - first where we kept an atomic counter around that tracked
which was the last lane that was used, and 'our' lane was determined by
atomically incrementing that. That way, for the nr_cpus > nr_lanes case,
theoretically, no CPU would be blocked waiting for a lane. The other
strategy was to use the cpu number we're scheduled on to and hash it to
a lane number. Theoretically, this could block an IO that could've
otherwise run using a different, free lane. But some fio workloads
showed that the direct cpu -> lane hash performed faster than tracking
'last lane' - my reasoning is the cache thrash caused by moving the
atomic variable made that approach slower than simply waiting out the
in-progress IO. This supports the conclusion that the driver can be a
very simple bio-based one that does synchronous IOs instead of queuing.Cc: Andy Lutomirski
Cc: Boaz Harrosh
Cc: H. Peter Anvin
Cc: Jens Axboe
Cc: Ingo Molnar
Cc: Christoph Hellwig
Cc: Neil Brown
Cc: Jeff Moyer
Cc: Dave Chinner
Cc: Greg KH
[jmoyer: fix nmi watchdog timeout in btt_map_init]
[jmoyer: move btt initialization to module load path]
[jmoyer: fix memory leak in the btt initialization path]
[jmoyer: Don't overwrite corrupted arenas]
Signed-off-by: Vishal Verma
Signed-off-by: Dan Williams
25 Jun, 2015
9 commits
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NVDIMM namespaces, in addition to accepting "struct bio" based requests,
also have the capability to perform byte-aligned accesses. By default
only the bio/block interface is used. However, if another driver can
make effective use of the byte-aligned capability it can claim namespace
interface and use the byte-aligned ->rw_bytes() interface.The BTT driver is the initial first consumer of this mechanism to allow
adding atomic sector update semantics to a pmem or blk namespace. This
patch is the sysfs infrastructure to allow configuring a BTT instance
for a namespace. Enabling that BTT and performing i/o is in a
subsequent patch.Cc: Greg KH
Cc: Neil Brown
Signed-off-by: Dan Williams -
After 'uuid', 'size', and optionally 'alt_name' have been set to valid
values the labels on the dimms can be updated.Write procedure is:
1/ Allocate and write new labels in the "next" index
2/ Free the old labels in the working copy
3/ Write the bitmap and the label space on the dimm
4/ Write the index to make the update validLabel ranges directly mirror the dpa resource values for the given
label_id of the namespace.Cc: Greg KH
Cc: Neil Brown
Acked-by: Christoph Hellwig
Signed-off-by: Dan Williams -
A blk label set describes a namespace comprised of one or more
discontiguous dpa ranges on a single dimm. They may alias with one or
more pmem interleave sets that include the given dimm.This is the runtime/volatile configuration infrastructure for sysfs
manipulation of 'alt_name', 'uuid', 'size', and 'sector_size'. A later
patch will make these settings persistent by writing back the label(s).Unlike pmem namespaces, multiple blk namespaces can be created per
region. Once a blk namespace has been created a new seed device
(unconfigured child of a parent blk region) is instantiated. As long as
a region has 'available_size' != 0 new child namespaces may be created.Cc: Greg KH
Cc: Neil Brown
Acked-by: Christoph Hellwig
Signed-off-by: Dan Williams -
A complete label set is a PMEM-label per-dimm per-interleave-set where
all the UUIDs match and the interleave set cookie matches the hosting
interleave set.Present sysfs attributes for manipulation of a PMEM-namespace's
'alt_name', 'uuid', and 'size' attributes. A later patch will make
these settings persistent by writing back the label.Note that PMEM allocations grow forwards from the start of an interleave
set (lowest dimm-physical-address (DPA)). BLK-namespaces that alias
with a PMEM interleave set will grow allocations backward from the
highest DPA.Cc: Greg KH
Cc: Neil Brown
Acked-by: Christoph Hellwig
Signed-off-by: Dan Williams -
This on media label format [1] consists of two index blocks followed by
an array of labels. None of these structures are ever updated in place.
A sequence number tracks the current active index and the next one to
write, while labels are written to free slots.+------------+
| |
| nsindex0 |
| |
+------------+
| |
| nsindex1 |
| |
+------------+
| label0 |
+------------+
| label1 |
+------------+
| |
....nslot...
| |
+------------+
| labelN |
+------------+After reading valid labels, store the dpa ranges they claim into
per-dimm resource trees.[1]: http://pmem.io/documents/NVDIMM_Namespace_Spec.pdf
Cc: Neil Brown
Acked-by: Christoph Hellwig
Signed-off-by: Dan Williams -
On platforms that have firmware support for reading/writing per-dimm
label space, a portion of the dimm may be accessible via an interleave
set PMEM mapping in addition to the dimm's BLK (block-data-window
aperture(s)) interface. A label, stored in a "configuration data
region" on the dimm, disambiguates which dimm addresses are accessed
through which exclusive interface.Add infrastructure that allows the kernel to block modifications to a
label in the set while any member dimm is active. Note that this is
meant only for enforcing "no modifications of active labels" via the
coarse ioctl command. Adding/deleting namespaces from an active
interleave set is always possible via sysfs.Another aspect of tracking interleave sets is tracking their integrity
when DIMMs in a set are physically re-ordered. For this purpose we
generate an "interleave-set cookie" that can be recorded in a label and
validated against the current configuration. It is the bus provider
implementation's responsibility to calculate the interleave set cookie
and attach it to a given region.Cc: Neil Brown
Cc:
Cc: Greg KH
Cc: Robert Moore
Cc: Rafael J. Wysocki
Acked-by: Christoph Hellwig
Acked-by: Rafael J. Wysocki
Signed-off-by: Dan Williams -
The libnvdimm region driver is an intermediary driver that translates
non-volatile "region"s into "namespace" sub-devices that are surfaced by
persistent memory block-device drivers (PMEM and BLK).ACPI 6 introduces the concept that a given nvdimm may simultaneously
offer multiple access modes to its media through direct PMEM load/store
access, or windowed BLK mode. Existing nvdimms mostly implement a PMEM
interface, some offer a BLK-like mode, but never both as ACPI 6 defines.
If an nvdimm is single interfaced, then there is no need for dimm
metadata labels. For these devices we can take the region boundaries
directly to create a child namespace device (nd_namespace_io).Acked-by: Christoph Hellwig
Tested-by: Toshi Kani
Signed-off-by: Dan Williams -
A "region" device represents the maximum capacity of a BLK range (mmio
block-data-window(s)), or a PMEM range (DAX-capable persistent memory or
volatile memory), without regard for aliasing. Aliasing, in the
dimm-local address space (DPA), is resolved by metadata on a dimm to
designate which exclusive interface will access the aliased DPA ranges.
Support for the per-dimm metadata/label arrvies is in a subsequent
patch.The name format of "region" devices is "regionN" where, like dimms, N is
a global ida index assigned at discovery time. This id is not reliable
across reboots nor in the presence of hotplug. Look to attributes of
the region or static id-data of the sub-namespace to generate a
persistent name. However, if the platform configuration does not change
it is reasonable to expect the same region id to be assigned at the next
boot."region"s have 2 generic attributes "size", and "mapping"s where:
- size: the BLK accessible capacity or the span of the
system physical address range in the case of PMEM.- mappingN: a tuple describing a dimm's contribution to the region's
capacity in the format (,,). For a PMEM-region
there will be at least one mapping per dimm in the interleave set. For
a BLK-region there is only "mapping0" listing the starting DPA of the
BLK-region and the available DPA capacity of that space (matches "size"
above).The max number of mappings per "region" is hard coded per the
constraints of sysfs attribute groups. That said the number of mappings
per region should never exceed the maximum number of possible dimms in
the system. If the current number turns out to not be enough then the
"mappings" attribute clarifies how many there are supposed to be. "32
should be enough for anybody...".Cc: Neil Brown
Cc:
Cc: Greg KH
Cc: Robert Moore
Cc: Rafael J. Wysocki
Acked-by: Christoph Hellwig
Acked-by: Rafael J. Wysocki
Tested-by: Toshi Kani
Signed-off-by: Dan Williams -
* Implement the device-model infrastructure for loading modules and
attaching drivers to nvdimm devices. This is a simple association of a
nd-device-type number with a driver that has a bitmask of supported
device types. To facilitate userspace bind/unbind operations 'modalias'
and 'devtype', that also appear in the uevent, are added as generic
sysfs attributes for all nvdimm devices. The reason for the device-type
number is to support sub-types within a given parent devtype, be it a
vendor-specific sub-type or otherwise.* The first consumer of this infrastructure is the driver
for dimm devices. It simply uses control messages to retrieve and
store the configuration-data image (label set) from each dimm.Note: nd_device_register() arranges for asynchronous registration of
nvdimm bus devices by default.Cc: Greg KH
Cc: Neil Brown
Acked-by: Christoph Hellwig
Tested-by: Toshi Kani
Signed-off-by: Dan Williams