Oracle America, Inc.

Oracle International Corporation

Sun Microsystems, Inc.

Vmware, Inc.

Eric E Lowe

Blake Alan Jones

George R Cameron

Daniel J Scales

Michael Nelson

Andrew G Tucker

Wesley M Shao

Jonathan William Adams

In general, in one aspect, the invention relates to a system that includes memory and a prediction subsystem. The memory includes a first memgroup and a second memgroup, wherein the first memgroup comprises a first physical page and a second physical page, wherein the first physical page is a first subtype, and wherein the second physical page is a second subtype. The prediction subsystem is configured to obtain a status value indicating an amount of freed physical pages on the memory, store the status value in a sample buffer comprising a plurality of previous status values, determine, using the status value and the plurality of previous status values, a deficiency subtype state for the first subtype based on an anticipated need for the first subtype on the memory, and instruct, based on the determination, an allocation subsystem to coalesce the second physical page to the first subtype.

Physical memory usage prediction

A device, system, and method are directed towards managing limited resources in a computer system with multiple processing units. Each processing unit has a corresponding bucket. Each thread executing on a processing unit has a corresponding wallet. Buckets and wallets contain credits corresponding to units of the limited resource. When a request for the resource is made, mechanisms of the invention attempt to fulfill the request by looking in a local wallet, a local bucket, or non-local buckets. In a resource shortage situation, credits may be moved to a primary bucket. A load balancing mechanism may distribute credits among buckets, or move credits from wallets to buckets.

Scalable resource allocation

Managing physical memory for one or more processes with both a minimum and a maximum amount of physical memory. Memory sets are created, each specifying a number of credits. The total number of credits specified by all memory sets are equal to the total number of pages in physical memory. One or more processes are bound to a memory set. All of the processes bound to a memory set are collectively referred to as the workload of the memory set. Each physical page is accounted for to ensure that each workload can utilize at least the number of physical pages equaling the number of credits in its memory set. Additionally, a workload is permitted to use physical pages that are being explicitly shared by workloads of other memory sets. Accordingly, a workload with both a minimum and a maximum amount of physical memory is specified by its memory set.

Partitionable accounting of memory utilization

A fault-tolerant virtualized computer system comprises a primary host executing a primary virtual machine (VM) and a backup host executing a backup VM. In one embodiment, each VM includes a virtual disk mapped to a shared disk image on physical disk accessible to both hosts. A virtual disk IO request is received by virtualization software executing on the backup host from a backup VM. When the virtual disk IO request is a read request, the virtual disk IO request is mapped to a physical read IO request of a virtual disk image stored on a physical disk, the physical read IO request is issued to the physical disk. However, when the virtual disk IO request is a write request, it is assumed to be completed without mapping the virtual disk IO request or issuing a mapped physical IO request to the physical disk.

Storage handling for fault tolerance in virtual machines

According to one embodiment of the invention, a technique is provided for facilitating the relocation of data from a source page to a destination page in a computing system in which I/O devices may conduct DVMA transactions via an IOMMU. Before the relocation, it is determined whether any devices potentially are accessing the source page. If it is determined that a device potentially is accessing the source page, then the IOMMU's device driver ('bus nexus') 'suspends' the bus. The bus nexus allows any pending memory transactions to finish. While the bus is suspended, the kernel moves the contents of the source page to the destination page. After the kernel has moved the contents, the IOMMU's TLB is updated so that the virtual address that was mapped to the source page's physical address is mapped to the destination page's physical address. The bus nexus &#x201c;unsuspends&#x201d; the bus.

Relocation of active DMA pages

Improved techniques and systems for accommodating TLB shootdown events in multi-processor computer systems are disclosed. A memory management unit (MMU) having a TLB miss handler and miss exception handler is provided. The MMU receives instructions relative to a virtual address. A TLB is searched for the virtual address, if the virtual address is not found in the TLB, secondary memory assets are searched for a TTE that corresponds to the virtual address and its associated context identifier. The context identifier is tested to determine if the TTE is available. Where the TTE is available, the TLB and secondary memory assets are updated as necessary and the method initiates memory access instructions. Where the TTE is unavailable, the method either resolves the unavailability or waits until the unavailability is resolved and then initiates memory access instructions, thereby enabling the desired virtual address information to be accessed.

Growing community of inventors

Pflugerville, TX, United States of America

Eric E Lowe