[54] PROCESSING METHOD, APPARATUS AND SYSTEM FOR MEMORY MANAGEMENT USING SHARED MEMORIES WITH COMMON DATA AREAS
[75] Inventor: Shigeo Suzuki, Yokohama, Japan
[73] Assignee: Canon Kabushiki Kaisha, Tokyo, Japan
[ * ] Notice: This patent issued on a continued prosecution application filed under 37 CFR 1.53(d), and is subject to the twenty year patent term provisions ol 35 U.S.C. 154(a)(2).
[21] Appl. No.: 08/675,414
[22] Filed: Jul. 2, 1996
[30] Foreign Application Priority Data
Jul. 11, 1995 [JP] Japan 7-174784
[51] Int. C I. G06F 13/00
[52] U.S. CI 711/147; 709/216; 711/148;
711/209
[58] Field of Search 711/147, 148,
711/119, 209; 395/200.42, 200.43, 200.44, 200.46; 709/212, 213, 214, 216
[56] References Cited
U.S. PATENT DOCUMENTS
5,136,500 8/1992 Lemay et al 709/216
An information processing system using a plurality of nodes is disclosed, in which each of the nodes is capable of accessing its own internal memory, as well as memory of the other nodes. In certain situations it becomes necessary to acquire a work area, such as a physical page, for the purpose of executing processing, in the storage area of a physical memory in one of a plurality of information processing apparatuses. If the work area is a common data area, used jointly (shared) by a plurality of processes, and cannot be acquired (e.g., if the number of free physical pages is below some threshold value), then an area which is not such a common data area, stored in that storage area, is exported (copied) to the storage area of the physical memory of another of the information processing apparatuses. As a result, the work area is obtained in the storage area newly produced by the exporting of the information previously stored there. When a local storage area or page cannot be acquired, and therefore a page must be exported, then preferably a physical page which has a low rate of use, and is not a common data area, is selected for export. In this way, a remote page may be used for areas for which the amount of cache coherence of maintenance information is small.
14 Claims, 3 Drawing Sheets
