公开(公告)号：US20050165837A1

公开(公告)日：2005-07-28

申请号：US10763090

申请日：2004-01-22

Applicant: Janet Dmitrovich ,  Philip Langdale ,  James Robbins ,  William Tracey

Inventor： Janet Dmitrovich ,  Philip Langdale ,  James Robbins ,  William Tracey

IPC: G06F7/00 ,  G06F9/45 ,  G06F12/08

CPC classification number: G06F12/0866 ,  G06F9/45516 ,  G06F2212/2022

Abstract: A system and method are provided to allow demand loading and discarding of Java executable image (JXE) files. The virtual machine allocates an address space for a requested JXE program. The read-only portion of the JXE file is memory mapped from its nonvolatile location to the allocated memory space using read-only mapping and the read/write section of the JXE file are loaded into memory. When a page of the JXE program is needed, a page fault occurs if the read-only portion has not been loaded into memory. The operating system's page fault handler retrieves the needed page(s) from the nonvolatile storage location based upon the mapping data that resulted from the previously performed memory mapping. Because the read-only section of the JXE file is memory mapped using read-only mapping, the operating system's paging process is free to discard previously loaded memory pages that contain read-only portions of the JXE file.

Abstract translation: 提供了一种系统和方法来允许需求加载和丢弃Java可执行映像（JXE）文件。 虚拟机为所请求的JXE程序分配一个地址空间。 使用只读映射将JXE文件的只读部分从其非易失性位置映射到分配的存储空间，并将JXE文件的读/写部分加载到内存中。 当需要JXE程序的页面时，如果只读部分尚未加载到内存中，则会发生页面错误。 操作系统的页面错误处理器基于从先前执行的存储器映射产生的映射数据，从非易失性存储位置检索所需的页面。 由于JXE文件的只读部分是使用只读映射进行内存映射，因此操作系统的分页过程可以放弃先前加载的包含JXE文件只读部分的内存页。