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authorLinus Torvalds <torvalds@linux-foundation.org>2018-04-10 20:25:57 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-10 20:25:57 +0300
commit9f3a0941fb5efaa4d27911e251dc595034d58baa (patch)
tree7212d9872b41b73a0b3c4f8c991039b639add212 /Documentation
parentfbe173e3ffbd897b5a859020d714c0eaf4af2a1a (diff)
parente13e75b86ef2f88e3a47d672dd4c52a293efb95b (diff)
downloadlinux-9f3a0941fb5efaa4d27911e251dc595034d58baa.tar.xz
Merge tag 'libnvdimm-for-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm updates from Dan Williams: "This cycle was was not something I ever want to repeat as there were several late changes that have only now just settled. Half of the branch up to commit d2c997c0f145 ("fs, dax: use page->mapping to warn...") have been in -next for several releases. The of_pmem driver and the address range scrub rework were late arrivals, and the dax work was scaled back at the last moment. The of_pmem driver missed a previous merge window due to an oversight. A sense of obligation to rectify that miss is why it is included for 4.17. It has acks from PowerPC folks. Stephen reported a build failure that only occurs when merging it with your latest tree, for now I have fixed that up by disabling modular builds of of_pmem. A test merge with your tree has received a build success report from the 0day robot over 156 configs. An initial version of the ARS rework was submitted before the merge window. It is self contained to libnvdimm, a net code reduction, and passing all unit tests. The filesystem-dax changes are based on the wait_var_event() functionality from tip/sched/core. However, late review feedback showed that those changes regressed truncate performance to a large degree. The branch was rewound to drop the truncate behavior change and now only includes preparation patches and cleanups (with full acks and reviews). The finalization of this dax-dma-vs-trnucate work will need to wait for 4.18. Summary: - A rework of the filesytem-dax implementation provides for detection of unmap operations (truncate / hole punch) colliding with in-progress device-DMA. A fix for these collisions remains a work-in-progress pending resolution of truncate latency and starvation regressions. - The of_pmem driver expands the users of libnvdimm outside of x86 and ACPI to describe an implementation of persistent memory on PowerPC with Open Firmware / Device tree. - Address Range Scrub (ARS) handling is completely rewritten to account for the fact that ARS may run for 100s of seconds and there is no platform defined way to cancel it. ARS will now no longer block namespace initialization. - The NVDIMM Namespace Label implementation is updated to handle label areas as small as 1K, down from 128K. - Miscellaneous cleanups and updates to unit test infrastructure" * tag 'libnvdimm-for-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (39 commits) libnvdimm, of_pmem: workaround OF_NUMA=n build error nfit, address-range-scrub: add module option to skip initial ars nfit, address-range-scrub: rework and simplify ARS state machine nfit, address-range-scrub: determine one platform max_ars value powerpc/powernv: Create platform devs for nvdimm buses doc/devicetree: Persistent memory region bindings libnvdimm: Add device-tree based driver libnvdimm: Add of_node to region and bus descriptors libnvdimm, region: quiet region probe libnvdimm, namespace: use a safe lookup for dimm device name libnvdimm, dimm: fix dpa reservation vs uninitialized label area libnvdimm, testing: update the default smart ctrl_temperature libnvdimm, testing: Add emulation for smart injection commands nfit, address-range-scrub: introduce nfit_spa->ars_state libnvdimm: add an api to cast a 'struct nd_region' to its 'struct device' nfit, address-range-scrub: fix scrub in-progress reporting dax, dm: allow device-mapper to operate without dax support dax: introduce CONFIG_DAX_DRIVER fs, dax: use page->mapping to warn if truncate collides with a busy page ext2, dax: introduce ext2_dax_aops ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/pmem/pmem-region.txt65
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diff --git a/Documentation/devicetree/bindings/pmem/pmem-region.txt b/Documentation/devicetree/bindings/pmem/pmem-region.txt
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+Device-tree bindings for persistent memory regions
+-----------------------------------------------------
+
+Persistent memory refers to a class of memory devices that are:
+
+ a) Usable as main system memory (i.e. cacheable), and
+ b) Retain their contents across power failure.
+
+Given b) it is best to think of persistent memory as a kind of memory mapped
+storage device. To ensure data integrity the operating system needs to manage
+persistent regions separately to the normal memory pool. To aid with that this
+binding provides a standardised interface for discovering where persistent
+memory regions exist inside the physical address space.
+
+Bindings for the region nodes:
+-----------------------------
+
+Required properties:
+ - compatible = "pmem-region"
+
+ - reg = <base, size>;
+ The reg property should specificy an address range that is
+ translatable to a system physical address range. This address
+ range should be mappable as normal system memory would be
+ (i.e cacheable).
+
+ If the reg property contains multiple address ranges
+ each address range will be treated as though it was specified
+ in a separate device node. Having multiple address ranges in a
+ node implies no special relationship between the two ranges.
+
+Optional properties:
+ - Any relevant NUMA assocativity properties for the target platform.
+
+ - volatile; This property indicates that this region is actually
+ backed by non-persistent memory. This lets the OS know that it
+ may skip the cache flushes required to ensure data is made
+ persistent after a write.
+
+ If this property is absent then the OS must assume that the region
+ is backed by non-volatile memory.
+
+Examples:
+--------------------
+
+ /*
+ * This node specifies one 4KB region spanning from
+ * 0x5000 to 0x5fff that is backed by non-volatile memory.
+ */
+ pmem@5000 {
+ compatible = "pmem-region";
+ reg = <0x00005000 0x00001000>;
+ };
+
+ /*
+ * This node specifies two 4KB regions that are backed by
+ * volatile (normal) memory.
+ */
+ pmem@6000 {
+ compatible = "pmem-region";
+ reg = < 0x00006000 0x00001000
+ 0x00008000 0x00001000 >;
+ volatile;
+ };
+