Hardware and operating system support for persistent memory on a memory bus
View Patent ↗Implementations of a file system that is supported by a non-volatile memory that is directly connected to a memory bus, and placed side by side with a dynamic random access memory (DRAM), are described.
1. A system comprising:
one or more processors;
memory, communicatively coupled to the one or more processors, storing instructions that, when executed by the one or more processors, configure the one or more processors to perform acts comprising:
receiving a first write operation to write at least a first set of data to a first portion of a non-volatile memory;
determining whether the first set of data can be written atomically;
in response to determining that the first set of data can be written atomically, atomically writing the first set of data to the first portion of the non-volatile memory; else
in response to determining that the first set of data cannot be written atomically:
copying the first set of data to a second portion of the non-volatile memory,
writing metadata associated with the first set of data to a third portion of the non-volatile memory, and
atomically committing the third portion of the non-volatile memory.
2. The system of claim 1 , wherein atomically committing the third portion of non-volatile memory comprises changing a pointer.
3. The system of claim 1 , wherein the non-volatile memory comprises file data organized as a tree structure.
4. The system of claim 1 , wherein a file system reads and writes data structures directly from and to the non-volatile memory.
5. The system of claim 1 , wherein a state of an application is stored into the non-volatile memory.
6. The system of claim 1 , wherein a first file system for the non-volatile memory operates in conjunction with a second file system for persistent storage such as a hard disk or solid-state disk.
7. The system of claim 1 , wherein upon receiving the first write operation to write at least the first set of data to the first portion of the non-volatile memory, the acts further comprise:
receiving a second write operation to write at least a second set of data to the second portion of the non-volatile memory; and
atomically writing the first set of data and atomically writing the second set of data in a same order as the first write operation and the second write operation were received.
8. A method comprising:
under control of one or more processors configured with executable instructions:
receiving a first write operation to write at least a first set of data to a first portion of a non-volatile memory;
determining whether the first set of data can be written atomically;
in response to determining that the first set of data can be written atomically, atomically writing the first set of data to the first portion of non-volatile memory; else
in response to determining that the first set of data cannot be written atomically:
copying the first set of data to a second portion of the non-volatile memory,
writing metadata associated with the first set of data to a third portion of the non-volatile memory, and
atomically committing the third portion of the non-volatile memory.
9. The method of claim 8 , wherein atomically committing the third portion of non-volatile memory comprises changing a pointer.
10. The method of claim 8 , wherein the non-volatile memory comprises file data organized as a tree structure.
11. The method of claim 8 , wherein a file system reads and writes data structures directly from and to the non-volatile memory.
12. The method of claim 8 , wherein an operating system saves data into non-volatile memory in order to bypass at least a portion of a boot sequence.
13. The method of claim 8 , wherein a state of an application is stored into the non-volatile memory.
14. The method of claim 8 , wherein a first file system for the non-volatile memory operates in conjunction with a second file system for persistent storage.
15. The method of claim 8 , wherein upon receiving the first write operation to write at least the first set of data to the first portion of the non-volatile memory, the method further comprises:
receiving a second write operation to write at least a second set of data to the second portion of the non-volatile memory; and
atomically writing the first set of data and atomically writing the second set of data in a same order as the first write operation and the second write operation were received.
16. A storage device having thereon a data structure, comprising:
a tree that stores file data and metadata associated with the file data in non-volatile memory, wherein at least a portion of the file data in the tree is capable of being atomically updated in the non-volatile memory without making any other modifications to the tree.
17. The storage device of claim 16 , wherein the tree comprises page-sized blocks comprising at least one of pointers, user data, or file system metadata.
18. The storage device of claim 16 , wherein the tree comprises at least one pointer to a data block that is capable of being atomically updated.
19. The storage device of claim 16 , wherein the tree comprises files, wherein each file comprises at least a portion of a data block.
20. The storage device of claim 16 , wherein the tree comprises at least one root pointer that stores a value of a file size, wherein the value is capable of being atomically updated.