File-System Requests Supported in User Space for Enhanced Efficiency

• US 20150074683A1
• Filed: 05/12/2014
• Published: 03/12/2015
• Est. Priority Date: 09/10/2013
• Status: Active Grant

• Current Assignee: Robin Systems, Inc. (Rakuten Group, Inc.)
• Original Assignee: Robin Systems, Inc. (Rakuten Group, Inc.)
• Inventors: Singh, Gurmeet, Yeddanapudi, Krishna Satyasai, Venkatesan, Dhanashankar
• Granted Patent: US 9,455,914 B2
• Time in Patent Office: Days
• US Class Current: 719/312
• CPC Class Codes: G06F 11/34 Recording or statistical evaluation of computer activity, e.g. of down time, of input/output operation ; Recording or statistical evaluation of user activity, e.g. usability assessment
• CPC Class Codes: G06F 11/3409 for performance assessment
• CPC Class Codes: G06F 11/3495 for systems
• CPC Class Codes: G06F 2201/815 Virtual middleware or OS functionality using virtual machines to implement generic software techniques for error detection or fault masking G06F11/1484
• CPC Class Codes: G06F 9/455 Emulation; Interpretation; Software simulation, e.g. virtualisation or emulation of application or operating system execution engines
• CPC Class Codes: G06F 9/5038 considering the execution order of a plurality of tasks, e.g. taking priority or time dependency constraints into consideration scheduling strategies G06F9/4881 and subgroups
• CPC Class Codes: G06F 9/544 Buffers; Shared memory; Pipes
• CPC Class Codes: G06F 9/546 Message passing systems or structures, e.g. queues
• CPC Class Codes: H04L 47/11 Identifying congestion
• CPC Class Codes: H04L 47/2441 relying on flow classification, e.g. using integrated services [IntServ]

Abstract

Systems and methods are disclosed for interacting with a file system. The file system is operable to reside in user space of a computing system. A module, also within user space, may provide a messaging service supporting requests from an application to the file system. By bypassing a System-Call Interface (SCI) of the computing system'"'"'s kernel space, the module may support requests from the application to the file system with enhanced efficiency and/or customizable features not provided by the SCI. In some examples, the module may include a library in an independent layer within user space and below the application, allowing the library to provide an application-independent messaging service for different applications. Furthermore, in some examples, the module may include a segment of memory, within user space, shared between the application and the file system for passing data involved in requests and/or responses to and/or from the file system.

Claims

1. A system for handling file-system requests comprising:

an application residing in user space of a computing system, the computing system comprising processing logic and memory;

a file system residing in the user space of the computing system; and

a customizing-interface module also residing in the user space and operable to provide a messaging service, within the user space, between the application and the file system, the messaging service supporting a file-system request from the application to the file system, the messaging service made customizable to the file-system request by bypassing a System Control Interface (SCI) of the computing system'"'"'s kernel space.

2. The system of claim 1, further comprising:

a library layer within the user space and below the application and containing the customizing-interface module, the customizing-interface module being application agnostic, as enabled by the library layer being separate from the application, the customizing-interface module further comprising;

a library with a set of system-call emulations supported within the messaging service;

the set of system-call emulations comprising at least one of a first subset of emulations of standard system calls and a second subset of emulations of non-standard system calls offering customizable options for the file-system request beyond options offered by the SCI of the computing system'"'"'s kernel space.

3. The system of claim 2, wherein the application is modified to select an emulation of a non-standard call from the second subset of emulations of non-standard system calls for the file-system request to customize the messaging service to the file-system request.

4. The system of claim 2, the library further comprising:

a collection module within the library operable to trap, from the application, system calls used by the application for file-system requests; and

a generation module operable to generate at least a portion of the set of system-call emulations to emulate system calls trapped by the collection module.

5. The system of claim 2, the library further comprising:

an analysis module operable to analyze file-system requests from the application to detect a pattern; and

an anticipation module operable to implement at least one of caching and pre-fetching of data at the library layer, the data anticipated by the pattern.

6. The system of claim 1, wherein:

the computing system supports virtual computing nodes; and

the file system and the customizing-interface module reside within an isolated instance of user space pertaining to a particular virtual computing node supported by the computing system.

7. The system of claim 1, further comprising a shared memory segment within the customizing-interface module, the shared memory segment:

accessible by both the application and the file system; and

operable to support the messaging service by storing data from the application and the file system, customizing the messaging service to avoid copying of the at least one of read data and write data between the kernel space and a buffer maintained by the application.

8. The system of claim 7, the shared memory segment further comprising:

a ring buffer, the ring buffer comprising;

an array of message-request slots, a message-request slot operable to implement a message service between an application and the file system such that multiple message-request slots from the array implement messaging services between the file system and multiple applications concurrently.

9. The system of claim 8, further comprising a coordination module operable to arbitrate between quality of service demands for file-system requests from the multiple applications for which the ring buffer concurrently supports messaging services, thereby customizing the messaging services to the file-system requests.

10. The system of claim 8, further comprising a header section within the shared memory segment, the header operable to mitigate a need to traverse the ring buffer to find an available message-request slot and comprising at least one of:

a read index, indexing individual applications to individual message-request slots in the array providing messaging services for system call emulations related to data retrieval for the individual applications;

a write index, indexing individual applications to individual message-request slots in the array providing messaging services for system call emulations related to data storage for the individual applications; and

a linked list of free message-request slots not currently used to implement a messaging service for an application.

11. A method for providing enhanced file-system services to an application:

receiving, by a messaging module within user space of a computing system, comprising a processor and memory, a request from an application to a file system, the file system also residing in the user space;

providing, by the messaging module, at least one efficiency gain for the request by routing the request through the messaging module in the user space to the file system also residing in the user space and bypassing a system call interface for the computing system'"'"'s kernel space; and

making available by the messaging module, in the user space and for the application, a response to the request from the file system.

12. The method of claim 11, further comprising:

providing, by a library within the messaging module, at least one of;

a standard set of system-call emulations operable to emulate standard system calls;

an enhanced set of system-call emulations operable to respond to application-specific needs;

matching the request to a system-call emulation from at least one of the standard set of system-call emulations and the enhanced set of system-call emulations; and

carrying out the system-call emulation,

the library residing within a messaging layer below the application, the messaging layer remaining within the user space and allowing the messaging module to be independent of an approach to formulating the request to the file system utilized by the application.

13. The method of claim 12, further comprising:

analyzing, by the library, requests from the application to detect a pattern of requests from the application to the file system;

performing at least one of caching and pre-fetching, by the library, to anticipate the pattern of requests.

14. The method of claim 12, further comprising, performing:

where the request to the file system is a retrieval request, reading, by the library, data written by the file system to shared memory shared between the library and the file system; and

where the request to the file system is a storage request, writing, by the library, data to the shared memory for storage by the file system.

15. A system for providing enhanced file-system services to an application in a data-center computing system, further comprising:

a file system operable to function within user space within a data-center comprising multiple computing nodes;

a messaging module also operable to function in user space and to broker requests from an application to the file system and responses to the requests within user space, avoiding constraints on interactions imposed by a kernel-space interface for system calls; and

a library within the messaging module operable to provide at least one service customized to at least one of an application providing a request to the messaging module and to the request, the service providing an efficiency not offered by the kernel-space interface for system calls.

16. The system of claim 15, further comprising an independent layer within user space and below the application, the messaging module and the library separated from the application by the independent layer and operable to service different applications;

an analysis module in the library, the analysis module operable to analyze requests from the application for a pattern among the requests;

a segment of library memory operable to receive data from the file system; and

the library operable to provide at the least one service customized to the application by at least one of caching and pre-fetching data from the file system anticipated by the pattern detected among the requests.

17. The system of claim 15, further comprising a segment of shared memory shared by the library and the file system and operable to receive request parameters from the library and responses from the file system.

18. The system of claim 17, further comprising an array of support slots within the segment of shared memory, each support slot operable to provide services between a distinct application and the file system.

19. The system of claim 18, further comprising a concurrency module operable to provide a customized service by implementing a quality of service parameter for at least one of an application, a request, and a group of requests, the quality of service parameter dictating a priority relative to other demands placed upon the file system by additional requests concurrently directed to the file system.

20. The system of claim 15, wherein:

the computing nodes of the data center include multiple virtual computing nodes supported by a virtual computing environment;

the file system resides in user space for a virtual computing node; and

the messaging module also resides in user space for the virtual computing node.