Hybrid In-Heap Out-of-Heap Ballooning for JVM Memory Reclamation
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Solution Overview
Problem
Java Virtual Machines (JVMs) face challenges with conventional memory over-commitment in virtual computing environments, leading to performance issues due to exclusive memory management and inability to effectively reuse freed memory, resulting in host swapping and efficiency losses.
Innovation Solution
A balloon agent within the JVM runtime environment coordinates with the guest operating system and hypervisor to implement an out-of-heap memory balloon mechanism, dynamically reallocating memory pages to address external and internal memory pressure, allowing for flexible memory management and avoiding costly host swapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory over-commitment is implemented using traditional ballooning techniques, then more virtual machines can run simultaneously on a host, but Java Virtual Machines experience performance degradation due to exclusive memory management and inability to reuse freed memory
Solution Approach 1:
The patent segments memory management into two distinct mechanisms: in-heap ballooning for managing JVM heap memory and out-of-heap ballooning for managing non-heap memory. This segmentation allows each mechanism to operate independently with appropriate strategies, preventing the performance degradation that occurs when a single memory management approach is applied to all JVM memory
Solution Approach 2:
The patent introduces a memory management intermediary layer that coordinates between the JVM's garbage collection mechanisms and the hypervisor's memory allocation. This intermediary manages balloon objects that can be inserted into heap memory and coordinates memory page sharing with the guest operating system, enabling seamless memory reuse without impacting JVM performance
2Reliability
If JVM uses its own memory management mechanisms with exclusive control over heap memory, then garbage collection can effectively recycle dead objects, but freed memory cannot be used by other applications or virtualized infrastructure
Solution Approach 1:
The patent implements dynamic memory management where balloon objects can be inserted into or removed from heap memory based on system conditions. The memory management system dynamically adjusts the balance between exclusive JVM control and system-wide reuse by inserting balloon objects when system memory is needed and removing them when JVM needs memory, enabling both reliability and adaptability
3Quantity of substance
If hypervisor resorts to host swapping of memory pages to disk when JVM cannot give up memory, then memory over-commitment can be maintained, but performance and efficiency are heavily impacted
Solution Approach 1:
The patent applies preliminary action by proactively inserting balloon objects into JVM heap memory before the JVM needs to reclaim memory. This allows the system to reserve memory pages for potential reuse by the hypervisor while maintaining JVM functionality, avoiding the need for emergency host swapping operations that incur heavy performance costs
Data Source
AI summary
A mechanism is provided for managing memory of a runtime environment executing on a virtual machine. A balloon agent that is part of a runtime environment is configured to coordinate inflations of a memory balloon within a heap of” the runtime environment and an out-of-heap overflow balloon, particularly in situations where a hypervisor needs to reclaim more memory from the runtime environment than the runtime environment is able to give up. The balloon agent may slowly free out-of-heap balloon memory, which may cause an increase of a target size for the balloon agent, which in turn inflates the memory balloon inside the heap of the runtime environment.