Batched Memory Page Hinting for Hypervisor Reuse
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Solution Overview
Problem
Virtualized computer systems face inefficiencies in memory management due to the need for individual notifications for each released memory page, which can lead to security vulnerabilities and increased overhead, especially when relying on shared memory between guest operating systems and hypervisors.
Innovation Solution
Implementing batched memory page hinting, where a guest operating system collects and notifies the hypervisor of released memory pages only when a predetermined threshold is reached, reducing the need for individual notifications and eliminating reliance on shared memory, thereby enhancing memory management and security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individual notifications are sent for each released memory page, then the hypervisor can promptly update memory status, but communication overhead increases and security vulnerabilities arise from shared memory reliance
Solution Approach 1:
The patent combines multiple individual memory page release notifications into a single batched notification mechanism. Instead of sending separate notifications for each released page, the system accumulates release information and transmits it in batches, reducing communication overhead while maintaining accurate memory status updates.
Solution Approach 2:
The patent introduces a batch buffer as an intermediary data structure between the guest operating system and hypervisor. This buffer serves as a mediator that accumulates memory page release information before transmission, eliminating the need for shared memory and reducing security vulnerabilities while maintaining communication efficiency.
2Ease of operation
If shared memory is used for memory page identification, then communication between guest OS and hypervisor is simplified, but security vulnerabilities increase
Solution Approach 1:
The patent replaces shared memory with a batch buffer mechanism that acts as an intermediary. This buffer is managed through controlled interfaces rather than direct shared access, maintaining communication simplicity while eliminating security vulnerabilities associated with shared memory exposure.
Solution Approach 2:
The patent extracts the security vulnerability by removing the shared memory component entirely from the architecture. Memory page release information is now transmitted through controlled batch notification interfaces rather than through shared memory, separating the communication function from the security risk.
3Quantity of substance
If memory pages are paged out to secondary storage, then physical memory is freed for other virtual machines, but I/O operations cause significant delay
Solution Approach 1:
The patent implements preliminary action by having the guest operating system proactively identify and notify released memory pages before the hypervisor needs to reclaim them. This advance notification allows the hypervisor to plan memory reclamation more efficiently, reducing urgent paging operations and associated delays.
Solution Approach 2:
The patent establishes a feedback mechanism where the guest operating system provides information about released memory pages back to the hypervisor. This feedback loop enables the hypervisor to make informed decisions about memory management, optimizing when to page out pages to secondary storage and reducing unnecessary I/O operations.
Data Source
AI summary
Systems and methods for batching memory page hints that may enable a hypervisor to reuse a particular memory page without copying the particular memory page to and from swap space. An example method may comprise: releasing, by a processing device executing a virtual machine, memory pages in use by the virtual machine; adding the memory pages to a set of memory pages; determining, by the virtual machine, that the set of memory pages satisfies a threshold quantity; and responsive to the determining, notifying a hypervisor that the memory pages released by the virtual machine are available for reuse by the hypervisor without being copied to persistent storage.