What are the common memory allocation strategies?

Common memory allocation strategies include the following:

Explanation: When a request for memory allocation arrives, the system starts searching from the beginning of the available memory space. The first block of free memory that is large enough to satisfy the request is allocated. This strategy is relatively fast because it doesn't need to search the entire memory space.
Example: Suppose there are three free memory blocks in the system: Block A (size 100 bytes), Block B (size 200 bytes), and Block C (size 50 bytes). If a request for 150 bytes of memory comes in, the system will first check Block A. Since Block A is only 100 bytes and cannot meet the requirement, it will then check Block B. Block B has enough space (200 bytes), so the 150 - byte request will be allocated in Block B.
Relevance to cloud computing: In cloud - based virtual machines or containers, efficient memory allocation is crucial. Tencent Cloud's virtual machine services can benefit from optimized memory allocation strategies like First - Fit to ensure quick startup and efficient use of resources. When creating a new virtual machine instance on Tencent Cloud, the underlying system may use such strategies to allocate memory to the instance based on its requirements.

Explanation: The system searches the entire available memory space to find the smallest free block that is large enough to satisfy the memory request. This aims to minimize the waste of memory, as it tries to use the most appropriate block.
Example: Consider the same three free memory blocks as above (Block A: 100 bytes, Block B: 200 bytes, Block C: 50 bytes). If a request for 60 bytes of memory arrives, the system will check all the blocks. Block A is too small, Block B is much larger than needed, and Block C is also too small. However, if there was a block of 60 bytes or just slightly larger, that would be the one chosen. In this case, if there was a block of 65 bytes, it would be allocated for the 60 - byte request.
Relevance to cloud computing: For applications running on Tencent Cloud that have specific and relatively small memory requirements, the Best - Fit strategy can help in better utilization of memory resources. For example, a lightweight web application running on a Tencent Cloud container may require a small amount of memory, and using the Best - Fit strategy ensures that only the necessary amount of memory is allocated, reducing overall resource waste.

Explanation: When a memory request is made, the system searches for the largest free block of memory. The request is then allocated in this large block, leaving a smaller remaining free block. This strategy is based on the idea that it may be easier to find a suitable use for the remaining smaller block later.
Example: Given the three free memory blocks (Block A: 100 bytes, Block B: 200 bytes, Block C: 50 bytes), if a request for 80 bytes of memory comes in, the system will choose Block B (the largest block). After the allocation, there will be a remaining free block of 120 bytes (200 - 80) in Block B.
Relevance to cloud computing: In some scenarios where memory fragmentation is a concern and there is an expectation of future larger memory requests, the Worst - Fit strategy can be considered. For example, in a development environment on Tencent Cloud where different applications with varying memory needs are constantly being deployed and tested, using the Worst - Fit strategy may help in managing memory more flexibly for future requirements.