Vmware, Inc.

Hewlett-packard Development Company, L.p.

Anil Rao

Xiaoxin Chen

Carl Alan Waldspurger

Ajay Gulati

Osten Kit Colbert

Abhishek Chaturvedi

Gregory T Harmon

Gregory T Harm

Carl A Waldspruger

Systems and methods are disclosed that allow for transparently recovering from an uncorrected multi-bit error of arbitrary length located at a memory address. Storing one or more parity pages, for a set of pages in system memory, such that a page in the set of pages may be reconstructed using one of the parity pages is disclosed. Storing an indication of one or more page'disk location such that the one or more pages may be reconstructed by refilling the page from disk is also disclosed.

Transparent and lightweight recovery from hardware memory errors

Virtualization software can improve the effectiveness of a guest application running inside a virtual machine (VM) by providing information to the guest application indicative of a memory condition of the VM. The memory condition is indicative of an availability of memory resources to the guest application. When guest physical memory can be reserved by a balloon application running in the (VM), providing memory condition data indicative of the memory condition provides more accurate information regarding the availability of memory resources to the guest application than could be provided by the guest operating system of the VM.

Providing memory condition information to guest applications

A method of managing host physical memory using a balloon application executing within a guest virtual machine (GVM) running on a host platform is described. The balloon application receives allocation parameters from an entity outside the GVM, the allocation parameters identifying an amount of memory for the balloon application to allocate. The balloon application adjusts the allocated amount of memory according to the allocated amount. Physical memory backing up the allocated memory can then be assigned by virtualization software for use by another virtual machine running on the host platform.

Controlling memory conditions in a virtual machine

A resource scheduler for managing a distribution of host physical memory (HPM) among a plurality of virtual machines (VMs) monitors usage by each of the VMs of respective guest physical memories (GPM) to determine how much of the HPM should be allocated to each of the VMs. On determining that an amount of HPM allocated to a source VM should be reallocated to a target VM, the scheduler sends allocation parameters to a balloon application executing in the source VM causing it to reserve and write a value to a guest virtual memory (GVM) location in the source VM. The scheduler identifies the HPM location that corresponds to the reserved GVM and allocates it to the target VM by mapping a guest physical memory location of the target VM to the HPM location.

System and method for cooperative virtual machine memory scheduling

Systems and methods are disclosed that allow for transparently recovering from an uncorrected multi-bit error of arbitrary length located at a memory address. Storing one or more parity pages, for a set of pages in system memory, such that a page in the set of pages may be reconstructed using one of the parity pages is disclosed. Storing an indication of one or more page's disk location such that the one or more pages may be reconstructed by refilling the page from disk is also disclosed.

Methods and systems for managing distribution of host physical memory (HPM) among virtual machines (VMs) executing on a host via a hypervisor are presented, where each VM has guest system software including an operating system. A method includes an operation for reserving, by a balloon application executing in a first VM, a guest virtual memory (GVM) location in the first VM. The GVM location is mapped to a guest physical memory (GPM) location, which is mapped to a host physical memory (HPM) location. The balloon application is responsive to the hypervisor for reserving memory. Further, the method includes operations for writing a value to the reserved GVM location and for remapping a plurality of GPM locations containing the value to a single HPM location. The remapping is performed by a content-based page sharing component of the hypervisor. Additionally, the method reclaims the HPM location when the HPM location is freed due to the remapping, and assigns the reclaimed HPM location to a different VM or to a pool of available HPM locations.

Management of host physical memory allocation to virtual machines with a balloon application

A memory management sub-system includes code executable by a processor fir performing selecting a plurality of contexts, and selecting a sample of the separately allocable portions of an address space for each of the contexts. For each of the selected allocable portions, a corresponding portion of the host memory to which the selected allocable portion is mapped is determined, and a count corresponding to a number of separately allocable portions of any context that are commonly mapped to the corresponding portion of the host memory. For each context, a metric is computed that is a function of the counts for that context. Host memory is allocated among the contexts at least in part based on their respective metrics.

Memory management system in a computer system with shared memory mappings

A swap space is provided for a host computer system, where the swap space includes a plurality of swap files with each individual swap file for swapping data only for a single corresponding virtual machine (VM). The per-VM swap space is used solely by the single, corresponding VM, such that only that particular VM's memory is allowed to be swapped out to the swap file.

Separate swap files corresponding to different virtual machines in a host computer system

Memory assigned to a virtual machine is reclaimed. A resource reservation application running as a guest application on the virtual machine reserves a location in guest virtual memory. The corresponding physical memory can be reclaimed and allocated to another virtual machine. The resource reservation application allows detection of guest virtual memory page-out by the guest operating system. Measuring guest virtual memory page-out is useful for determining memory conditions inside the guest operating system. Given determined memory conditions, memory allocation and reclaiming can be used control memory conditions. Memory conditions in the virtual machine can be controlled with the objective of achieving some target memory conditions.

Described herein are approaches to managing expandable resource reservations. In one approach, a method is described in which an attempt is made to change a resource reservation from a first amount to a second amount. The second amount is examined to determine whether it exceeds a reservation limit. The second amount is compared with available resources, and reserved.

System for managing and providing expandable resource reservations in a tree hierarchy

A host computer system is configured to present each of multiple resident contexts with an address space that may be mapped, at least in part, to corresponding portions of a host memory. The address space of a selected context is sampled, and, for each of a plurality of sampled portions of the address space of the selected context that are backed by a corresponding portion of host memory, a count of the number of portions of address spaces of any contexts that are backed by the same portion of the host memory is obtained. A metric is then computed as a function of the count. A decision about swapping out or reclaiming the allocation of the memory of the contexts is based on the metric. The metric is preferably a function of a mean (such as harmonic, geometric or arithmetic) or median of the counts for each context.

Memory management methods in a computer system with shared memory mappings

A method for allocating memory associated with a local shared memory segment to facilitate execution of a first process. The method includes automatically allocating memory associated with a first MRG to the local shared memory segment if the local shared memory segment is created by the first process. The first MRG is associated with a first local shared affiliation that involves the first process. The method also includes automatically allocating memory associated with a second MRG to the local shared memory segment if the local shared memory is created by a second process different from the first process. The second MRG is associated with a second local shared affiliation that involves a second process.

Managing shared memory usage within a memory resource group infrastructure

A method for allocating memory in a computer system is disclosed. The method includes creating a kernel memory class, the kernel memory class acting as a logical container for at least a first kernel memory resource group. The method further includes processing a kernel client's request for additional memory by ascertaining whether there is sufficient free memory in the first kernel memory resource group to accommodate the kernel client's request. The method additionally includes denying the kernel client's request if there is insufficient free memory in the first kernel memory resource group to accommodate the kernel client's request.

Growing community of inventors

San Jose, CA, United States of America

Anil Rao