BMC/Intel-BMC/linux.git/drivers/nvdimm/namespace_devs.c, branch dev-4.3

libnvdimm, pmem: direct map legacy pmem by default

2015-08-29T03:40:05+00:00

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

libnvdimm, pfn: 'struct page' provider infrastructure

2015-08-29T03:39:36+00:00

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

libnvdimm, btt: write and validate parent_uuid

2015-08-14T17:43:04+00:00

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

libnvdimm: Add sysfs numa_node to NVDIMM devices

2015-06-26T15:23:38+00:00

Add support of sysfs 'numa_node' to I/O-related NVDIMM devices under /sys/bus/nd/devices, regionN, namespaceN.0, and bttN.x. An example of numa_node values on a 2-socket system with a single NVDIMM range on each socket is shown below. /sys/bus/nd/devices |-- btt0.0/numa_node:0 |-- btt1.0/numa_node:1 |-- btt1.1/numa_node:1 |-- namespace0.0/numa_node:0 |-- namespace1.0/numa_node:1 |-- region0/numa_node:0 |-- region1/numa_node:1 These numa_node files are then linked under the block class of their device names. /sys/class/block/pmem0/device/numa_node:0 /sys/class/block/pmem1s/device/numa_node:1 This enables numactl(8) to accept 'block:' and 'file:' paths of pmem and btt devices as shown in the examples below. numactl --preferred block:pmem0 --show numactl --preferred file:/dev/pmem1s --show Signed-off-by: Toshi Kani Signed-off-by: Dan Williams

libnvdimm, blk: add support for blk integrity

2015-06-26T15:23:38+00:00

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

libnvdimm, nfit, nd_blk: driver for BLK-mode access persistent memory

2015-06-26T15:23:38+00:00

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.pdf Cc: 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

nd_btt: atomic sector updates

2015-06-26T15:23:38+00:00

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

libnvdimm: infrastructure for btt devices

2015-06-25T08:20:04+00:00

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

libnvdimm: write blk label set

2015-06-25T01:24:10+00:00

After 'uuid', 'size', 'sector_size', and optionally 'alt_name' have been set to valid values the labels on the dimm can be updated. The difference with the pmem case is that blk namespaces are limited to one dimm and can cover discontiguous ranges in dpa space. Also, after allocating label slots, it is useful for userspace to know how many slots are left. Export this information in sysfs. Cc: Greg KH Cc: Neil Brown Acked-by: Christoph Hellwig Signed-off-by: Dan Williams

libnvdimm: write pmem label set

2015-06-25T01:24:10+00:00

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 valid Label 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