Memory management

About: Memory management is a research topic. Over the lifetime, 16743 publications have been published within this topic receiving 312028 citations. The topic is also known as: memory allocation.

IBM memory expansion technology (MXT)

Abstract: Several technologies are leveraged to establish an architecture for a low-cost, high-performance memory controller and memory system that more than double the effective size of the installed main memory without significant added cost. This architecture is the first of its kind to employ real-time main-memory content compression at a performance competitive with the best the market has to offer. A large low-latency shared cache exists between the processor bus and a content-compressed main memory. Highspeed, low-latency hardware performs realtime compression and decompression of data traffic between the shared cache and the main memory. Sophisticated memory management hardware dynamically allocates main-memory storage in small sectors to accommodate storing the variable-sized compressed data without the need for "garbage" collection or significant wasted space due to fragmentation. Though the main-memory compression ratio is limited to the range 1:1-64:1, typical ratios range between 2:1 and 6:1, as measured in "real-world" system applications.

Memory management and protection system for virtual memory in computer system

Abstract: A memory management and protection system for realizing a high speed execution and a proper and flexible memory access control for multiple programs sharing an identical logical address space. In the system, the memory access is permitted according to a segment identifier identifying a segment in the logical address space, and a memory protection information for a region in each segment including a target right permission to indicate assigned rights to make a memory access from the region to each of the segments, and an execution permission to indicate a type of the memory access permitted by the right permission. Alternatively, a memory access can be permitted by using an access control list to be attached to each address table entry, which stores a plurality of program numbers identifying programs which are permitted to make accesses to the logical address stored in each address table entry, among which one that matches with the current program number is to be searched. Also, it is preferable to allocate a plurality of programs within a limit of available memory protection capacity to an identical logical address space, without any overlap between adjacently allocated address regions.

Packet Classification Algorithms: From Theory to Practice

Abstract: During the past decade, the packet classification problem has been widely studied to accelerate network applications such as access control, traffic engineering and intrusion detection. In our research, we found that although a great number of packet classification algorithms have been proposed in recent years, unfortunately most of them stagnate in mathematical analysis or software simulation stages and few of them have been implemented in commercial products as a generic solution. To fill the gap between theory and practice, in this paper, we propose a novel packet classification algorithm named HyperSplit. Compared to the well-known HiCuts and HSM algorithms, HyperSplit achieves superior performance in terms of classification speed, memory usage and preprocessing time. The practicability of the proposed algorithm is manifested by two facts in our test: HyperSplit is the only algorithm that can successfully handle all the rule sets; HyperSplit is also the only algorithm that reaches more than 6Gbps throughput on the Octeon3860 multi-core platform when tested with 64-byte Ethernet packets against 10K ACL rules.

Reconsidering custom memory allocation

Abstract: Programmers hoping to achieve performance improvements often use custom memory allocators This in-depth study examines eight applications that use custom allocators Surprisingly, for six of these applications, a state-of-the-art general-purpose allocator (the Lea allocator) performs as well as or better than the custom allocators The two exceptions use regions, which deliver higher performance (improvements of up to 44%) Regions also reduce programmer burden and eliminate a source of memory leaks However, we show that the inability of programmers to free individual objects within regions can lead to a substantial increase in memory consumption Worse, this limitation precludes the use of regions for common programming idioms, reducing their usefulnessWe present a generalization of general-purpose and region-based allocators that we call reaps Reaps are a combination of regions and heaps, providing a full range of region semantics with the addition of individual object deletion We show that our implementation of reaps provides high performance, outperforming other allocators with region-like semantics We then use a case study to demonstrate the space advantages and software engineering benefits of reaps in practice Our results indicate that programmers needing fast regions should use reaps, and that most programmers considering custom allocators should instead use the Lea allocator

Write-erase endurance lifetime of memory storage devices

Abstract: A memory management system and method for managing memory blocks of a memory device of a computer. The system includes a free block data structure including free memory blocks for writing, and sorting the free memory blocks in a predetermined order based on block write-erase endurance cycle count and receiving new user-write requests to update existing data and relocation write requests to relocate existing data separately, a user-write block pool for receiving youngest blocks holding user-write data (i.e., any page being updated frequently) from the free block data structure, a relocation block pool for receiving oldest blocks holding relocation data (i.e., any page being updated infrequently) from the free block data structure, and a garbage collection pool structure for selecting at least one of user-write blocks and relocation blocks for garbage collection, wherein the selected block is moved back to the free block data structure upon being relocated and erased.