Method and system for optimizing file table usage

• US 7,373,647 B2
• Filed: 04/30/2003
• Issued: 05/13/2008
• Est. Priority Date: 04/30/2003
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Xue, Xun, Pereyra, Hebert W., Kalmuk, David C., Lind, Jon A
• Primary Examiner(s): Nguyen; Van H.
• Application Number:
  US10/427,385
• Publication Number:
  US 20040221294A1
• Time in Patent Office: 1,840 Days
• Field of Search: 719310-313, 719/317, 718/100, 718/104, 711/147, 711/170, 711/173, 709213-215
• US Class Current: 719/317
• CPC Class Codes: G06F 9/544 Buffers; Shared memory; Pipes

Abstract

An operating system directed to using special properties of a common inter-process communications mechanism (IPC), namely UNIX domain socket-pairs or stream-pipes alternatively as a storage medium for file-descriptors of UNIX processes. When a file-descriptor is written into a socket-pair, and closed in the UNIX process, the file remains open, but occupies no space in the process'"'"' file-table. The file-descriptor may later be read out of the socket-pair to reestablish it in the file-table, and access it. This property is implemented in an IPC mechanism of UNIX operating system whereby a process such as a dispatcher may manage more connections and processes than its file-table size allow. This provides scalability improvements of the UNIX operating system.

Claims

1. A method for optimizing file table usage comprising:

storing file descriptors which reference a first socket pair within a file table associated with a dispatcher process to reduce a number of file descriptors simultaneously stored within said file table associated with said dispatcher process, wherein said first socket pair stores a plurality of file descriptors associated with an agent process, and each of said plurality of file descriptors references a corresponding closed file within a context of said agent process,

transferring said file descriptors which reference said first socket pair to said agent process via an inter-process communication (IPC) mechanism,

receiving said file descriptors which reference first socket pair from said agent process via the IPC mechanism, wherein said IPC mechanism comprises a second socket pair, wherein said second socket pair comprises a shared socket pair, and

obtaining said shared socket pair from a pool of shared socket pairs prior to a transfer of said file descriptors which reference said first socket pair to said agent process.

2. The method of claim 1 comprising returning said shared socket pair to said pool of shared socket pairs following a receipt of said file descriptors which reference said first socket pair from said agent process.

3. The method of claim 1 comprising:

partitioning the file table associated with said dispatcher process into a plurality of partitions, each partition maintaining a subset of file descriptors;

reserving a partition as a reserved partition to store a plurality of socket pair file descriptors, each corresponding to one of a plurality of socket pairs wherein each of said socket pairs is adapted to store said subset of file descriptors; and

storing file descriptors of a selected one of said plurality of partitions to one of said plurality of socket pairs using an associated one of said socket pair file descriptors;

wherein storing said file descriptors of said selected one of said plurality of partitions to one of said plurality of socket pairs stores said associated socket pair file descriptors to said reserved partition.