Pre-registering memory regions for remote direct memory access in a distributed file system

Patent metadata

Field	Value
Publication number	US-2020341940-A1
Application number	US-202016927795-A
Country	US
Kind code	A1
Filing date	Jul 13, 2020
Priority date	Jan 13, 2016
Publication date	Oct 29, 2020
Grant date	—

Abstract

The subject matter of this specification can be implemented in, among other things, a method that includes pre-registering, at a client device, one or more input/output (IO) buffers for a remote direct memory access (RDMA) interface at the client device. In response to pre-registering the one or more IO buffers at the client device, an application executed by the client device is provided with access to a distributed file system through the RDMA interface. In response to determining that data of a requested file in the distributed file system has been designated for caching, a first IO buffer among the IO buffers is designated as a cache for the data of the file. The data for the file is received via the RDMA interface and from the distributed file system, for the first IO buffer.

First claim

What is claimed is:

1 . A method comprising:
pre-registering, at a client device, one or more input/output (IO) buffers for a remote direct memory access (RDMA) interface at the client device; responsive to pre-registering the one or more TO buffers at the client device, providing an application executed by the client device with access to a distributed file system through the RDMA interface; responsive to determining that data of a requested file in the distributed file system has been designated for caching, designating a first TO buffer among the TO buffers as a cache for the data of the file; and receiving, via the RDMA interface and from the distributed file system, the data of the file for the first IO buffer.

2 . The method of claim 1 , wherein the one or more TO buffers are pre-registered during initialization of the RDMA interface.

3 . The method of claim 1 , wherein the one or more TO buffers comprise a plurality of TO buffers that comprise a first set of TO buffers designated for caching data received from the distributed file system and a second set of TO buffers that are not designated for caching the data received from the distributed file system, and wherein the first set of TO buffers comprises the first TO buffer.

4 . The method of claim 3 , wherein the data of the file received for the first IO buffer is used for a subsequent request to access the file from the client device, and wherein the method further comprises determining that the data of the file in the first IO buffer relative to the data of the file in the distributed file system has not changed prior to using the data of the file in the first IO buffer.

5 . The method of claim 3 , further comprising:
responsive to determining that the data of the requested file in the distributed file system has not been designated for caching, causing the data of the file to be stored in a second IO buffer of the second set of IO buffers that are not designated for caching data received from the distributed file system.

6 . The method of claim 1 , wherein pre-registering comprises specifying multiple levels of access for the one or more IO buffers due to a level of access for the IO buffers, wherein the level of access for the IO buffers is determined in view of a level of access subsequently used by the application not yet being known at a time the IO buffers are pre-registered.

7 . The method of claim 1 , further comprising:
receiving a request to access the file in the distributed file system from the application at the client device, wherein the request to access the file comprises a system call or a file operation of an operating system, and wherein the system call or the file operation accesses a virtual file system.

8 . A system comprising:
a remote direct memory access (RDMA) interface at a client device; a memory, at the client device, comprising multiple memory regions; and a processing device, at the client device, to communicate with the RDMA interface and the memory, the processing device to:
pre-register one or more input/output (IO) buffers for the RDMA interface at the client device;
responsive to pre-registering the one or more IO buffers at the client device, provide an application executed by the client device with access to a distributed file system through the RDMA interface;
responsive to determining that data of a requested file in the distributed file system has been designated for caching, designating a first IO buffer among the IO buffers as a cache for the data of the file; and
receive, via the RDMA interface and from the distributed file system, the data of the file for the first IO buffer.

9 . The system of claim 8 , wherein the one or more IO buffers are pre-registered during initialization of the RDMA interface.

10 . The system of claim 8 , wherein the one or more IO buffers comprise a plurality of IO buffers that comprise a first set of IO buffers designated for caching data received from the distributed file system and a second set of IO buffers that are not designated for caching the data received from the distributed file system, and wherein the first set of IO buffers comprises the first IO buffer.

11 . The system of claim 10 , wherein the data of the file received for the first IO buffer is used for a subsequent request to access the file from the client device, and wherein the processing device is further to:
determine that the data of the file in the first IO buffer relative to the data of the file in the distributed file system has not changed prior to using the data of the file in the first IO buffer.

12 . The system of claim 10 , wherein the processing device is further to:
responsive to determining that the data of the requested file in the distributed file system has not been designated for caching, cause the data of the file to be stored in a second IO buffer of the second set of IO buffers that are not designated for caching data received from the distributed file system.

13 . The system of claim 8 , wherein pre-registering comprises specifying multiple levels of access for the one or more IO buffers due to a level of access for the IO buffers, wherein the level of access for the IO buffers is determined in view of a level of access subsequently used by the application not yet being known at a time the IO buffers are pre-registered.

14 . A non-transitory, computer readable medium having instructions that, when executed by a processing device, cause the processing device to:
pre-register, at a client device, one or more input/output (IO) buffers for a remote direct memory access (RDMA) interface at the client device; responsive to pre-registering the one or more IO buffers at the client device, provide an application executed by the client device with access to a distributed file system through the RDMA interface; responsive to determining that data of a requested file in the distributed file system has been designated for caching, designate a first IO buffer among the IO buffers as a cache for the data of the file; and receive, via the RDMA interface and from the distributed file system, the data of the file for the first IO buffer.

15 . The non-transitory, computer readable medium of claim 14 , wherein the one or more IO buffers are pre-registered during initialization of the RDMA interface.

16 . The non-transitory, computer readable medium of claim 14 , wherein the one or more IO buffers that comprise a first set of IO buffers designated for caching data received from the distributed file system and a second set of IO buffers that are not designated for caching the data received from the distributed file system, and wherein the first set of IO buffers comprises the first IO buffer.

17 . The non-transitory, computer readable medium of claim 16 , wherein the data of the file received for the first IO buffer is used for a subsequent request to access the file from the client device, and wherein the processing device is further to:
determine that the data of the file in the first IO buffer relative to the data of the file in the distributed file system has not changed prior to using the data of the file in the first IO buffer.

18 . The non-transitory, computer readable medium of claim 16 , wherein the processing device is further to:
responsive to determining that the data of the requested file in the distributed file system has not been designated for caching, cause the data of the file to be stored in a second IO buffer of the second set of IO buffers that are not designated for caching data rec

Assignees

• Red Hat Inc

Inventors

• Parambil Mohammed Rafi Kavungal Chundattu
• Talur Raghavendra

Classifications

• H04L67/1097 Primary

  for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS] · CPC title

• H04L49/9005

  using dynamic buffer space allocation · CPC title

• G06F15/17331 Primary

  Distributed shared memory [DSM], e.g. remote direct memory access [RDMA] · CPC title

• G06F9/54

  Interprogram communication · CPC title