Heap Memory Region
A Heap Memory Region is a computer memory region that ...
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- Counter-Example(s):
- See: Secondary Storage, Resource Management (Computing), Computer Memory, Virtual Memory, Virtual Address Space, Random-Access Memory, Paging, Private Memory, Public Memory.
References
2018
- (Wikipedia, 2018) ⇒ https://en.wikipedia.org/wiki/Memory_management#HEAP Retrieved:2018-8-7.
- The task of fulfilling an allocation request consists of locating a block of unused memory of sufficient size. Memory requests are satisfied by allocating portions from a large pool of memory called the heap or free store.Template:Efn At any given time, some parts of the heap are in use, while some are "free" (unused) and thus available for future allocations.
Several issues complicate the implementation, such as external fragmentation, which arises when there are many small gaps between allocated memory blocks, which invalidates their use for an allocation request. The allocator's metadata can also inflate the size of (individually) small allocations. This is often managed by chunking. The memory management system must track outstanding allocations to ensure that they do not overlap and that no memory is ever "lost" (i.e. that there be no “memory leak").
- The task of fulfilling an allocation request consists of locating a block of unused memory of sufficient size. Memory requests are satisfied by allocating portions from a large pool of memory called the heap or free store.Template:Efn At any given time, some parts of the heap are in use, while some are "free" (unused) and thus available for future allocations.
2017
- https://www.gribblelab.org/CBootCamp/7_Memory_Stack_vs_Heap.html
- QUOTE: The heap is a region of your computer's memory that is not managed automatically for you, and is not as tightly managed by the CPU. It is a more free-floating region of memory (and is larger). To allocate memory on the heap, you must use malloc() or calloc(), which are built-in C functions. Once you have allocated memory on the heap, you are responsible for using free() to deallocate that memory once you don't need it any more. If you fail to do this, your program will have what is known as a memory leak. That is, memory on the heap will still be set aside (and won't be available to other processes). As we will see in the debugging section, there is a tool called valgrind that can help you detect memory leaks.
Unlike the stack, the heap does not have size restrictions on variable size (apart from the obvious physical limitations of your computer). Heap memory is slightly slower to be read from and written to, because one has to use pointers to access memory on the heap. We will talk about pointers shortly.
Unlike the stack, variables created on the heap are accessible by any function, anywhere in your program. Heap variables are essentially global in scope.
- QUOTE: The heap is a region of your computer's memory that is not managed automatically for you, and is not as tightly managed by the CPU. It is a more free-floating region of memory (and is larger). To allocate memory on the heap, you must use malloc() or calloc(), which are built-in C functions. Once you have allocated memory on the heap, you are responsible for using free() to deallocate that memory once you don't need it any more. If you fail to do this, your program will have what is known as a memory leak. That is, memory on the heap will still be set aside (and won't be available to other processes). As we will see in the debugging section, there is a tool called valgrind that can help you detect memory leaks.
2016
- https://www.yourkit.com/docs/kb/sizes.jsp
- QUOTE: The JVM memory consists of the following segments:
- Heap Memory, which is the storage for Java objects
- Non-Heap Memory, which is used by Java to store loaded classes and other meta-data
- JVM code itself, JVM internal structures, loaded profiler agent code and data, etc.
- The JVM has a heap that is the runtime data area from which memory for all class instances and arrays are allocated. It is created at the JVM start-up.
- QUOTE: The JVM memory consists of the following segments:
2015
- (Cantalupo et al., 2015) ⇒ Christopher Cantalupo, Vishwanath Venkatesan, Jeff Hammond, Krzysztof Czurlyo, and Simon David Hammond. (2015). “memkind: An Extensible Heap Memory Manager for Heterogeneous Memory Platforms and Mixed Memory Policies.” No. SAND2015-1862C. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States),
- ABSTRACT: Additional sophistication in memory management software is required for the array of new hardware technologies coming to market: on package addressable memory, stacked DRAM, non-volatile high capacity DIMM's, and low-latency on-package fabric. As a complement to these hardware improvements there are many policy features that can be applied to virtual memory within the framework of the Linux system calls mmap (2), mbind (2), madvise (2), mprotect (2), and mlock (2). These policy features can support a wide range of future hardware capabilities including bandwidth control, latency control, inter-process sharing, inter-node sharing, accelerator sharing, persistence, checkpointing, and encryption. The combinatorial range implied by a platform with heterogeneous memory hardware, and many options for operating system policies applied to that hardware is enormous, so it is intractable to have a separate custom allocator addressing each of them. Each layer of the application software stack