Emc Corporation

Emc IP Holding Company LLC

Christopher M Gould

Peter John McCann

Jeffrey Alan Brown

Robert J Bell, Iv

Vitaly Mayatskikh

Joseph B Caisse

Mikhail Y Simonov

Described are techniques that map virtual to physical memory. A first module may be loaded into a first physical memory location mapped, using a first page size, to a first virtual address space. A virtual memory portion of the first virtual address space may be identified that is a virtual address range mapped to at least a portion of the first physical memory location including the first module. First data of the first physical memory location may be copied to a second physical memory location. A set of pages of physical memory may be identified. Each such page may be a second page size. The virtual memory portion may be remapped to the set of pages using a page size that is the second page size. The first data may be copied from the second physical memory location to the set of one or more pages of physical memory.

Virtual memory management techniques

Described are techniques for building a code entity. A plurality of configuration files are selected in accordance with a target and target variant. The target identifies hardware and software platform information about an environment in which the code entity is to be configured for execution. The target variant identifies a software build variation for a particular target. One or more build phases are performed using the plurality of configuration files selected in said selecting. The code entity is generated as an output of performing the one or more build phases where the code entity varies with the target and target variant.

Techniques for building code entities

Described are techniques for providing a logical device model. In one embodiment, a a method for providing a logical device model includes providing a plurality of logical devices, at least one of said plurality of logical devices being provided by a first provider executing in kernel space and at least one of said plurality of logical devices being provided by a second provider executing in user space, and establishing a relationship between the first provider and the second provider wherein the first provider is a consumer of a logical device provided by the second provider, said logical device model including said relationship.

Logical device model

Described are techniques for creating a thread. A first plurality of calls are issued to create the thread. The first plurality of calls are executed in the context of an executing first thread and form a call chain traversing a plurality of code layers in a first order. A data area including thread-specific context information is created and initialized at each of the plurality of code layers when code of each code layer is invoked in accordance with the interface of each code layer to create the thread. Each of the plurality of code layers is included in a registered set. Executing the thread includes issuing a second plurality of calls traversing said plurality of code layers in an order that is a reverse of the first order. The second plurality of calls result in transferring control to a first body of code for the thread.

Providing hierarchical thread storage

Techniques are provided for routinely enqueuing events onto event queues by direct operation of an interrupt service routine (ISR) in kernel space when possible. Only when the event queue is unavailable does the ISR resort to offloading the enqueuing process to another kernel space thread. Unavailability can further be made uncommon by using separate event cores for different processing cores.

Efficient communication of interrupts from kernel space to user space using event queues

Described are techniques for executing code performing one or more operations corresponding to scheduling and synchronization primitives. During execution of the code, a call is performed using an application programming interface requesting a first of the operations corresponding to one of said scheduling and synchronization primitives. During runtime in response to said call, it is determined whether to perform the first operation. The determining step uses a set of one or more criteria indicating conditions as to when the scheduling and synchronization primitives are allowed to be performed. The one or more criteria are determined in accordance with a plurality of different platforms. If it is determined that the first operation is allowable and the first operation is to be performed, then the code can be executed on each of the different platforms in a privileged execution mode and a non-privileged execution mode.

Common scheduling and synchronization primitives

Described are techniques for performing remote procedure calls (RPCs). An RPC API is described which provides for using an optimized technique and an unoptimized technique for performing RPCs. The optimized technique includes a client container performing a call to obtain RPC configuration information which is then stored by the client container and may be used by the client container in connection with multiple RPC invocations. Techniques are also described for communicating parameter information between containers executing in different address spaces by forming parameter information on the client side using embedded lists, encoding the parameter information on the client side prior to transmission to the server, and transmitting the encoded parameter information to the server which determines output parameters and returns the output parameters to the client.

Techniques for performing a remote procedure call using remote procedure call configuration information

Described are techniques for communicating between one or more producers and one or more consumers. A first consumer of an event queue registers for notification regarding occurrences of one or more events. A producer of the event queue posts one or more notifications to one or more consumers of the event queue regarding one or more occurrences of one or more events. Each of the consumers receive notification regarding occurrences of events for which said each consumer is registered. The first consumer retrieves posted event notifications regarding events for which said first consumer is registered. If the first consumer is executing in user space and an event notification list to which said event notifications for said first consumer are posted is located in shared memory, said first consumer retrieves said posted event notifications without proxying into kernel space.

Event queues

Described are techniques synchronizing processing of at least two code threads. A first thread executing in user space is provided. A second thread executing in kernel space is provided. A global mutex lock is provided for synchronizing processing between said first thread and said second thread. One of said first thread and said second thread holds the global mutex lock and is identified as a current owner of the global mutex lock. The other of said first thread and said second thread requests the global mutex lock and is blocked until the current owner of the global mutex lock releases the global mutex lock. The global mutex lock is held by at most one thread at a point in time and is identified as the current owner.

Techniques for synchronizing processing of at least two code threads

Described are techniques for processing a module. A module is generated for execution on a target operating system. The module includes four entry points and code portions associated with each of said four entry points. The four entry points correspond to four handlers invoked at different processing points in connection with a state associated with said module. The four handlers include a load handler, an unload handler, a start handler, and a quiesce handler. First processing is performed in connection with the module. The first processing including at least one of dynamically loading the module, dynamically unloading the module, starting module-specific processing performed by the module, and issuing a request to commence preparation for unloading the module. An appropriate one or more of the four handlers are invoked in accordance with the first processing performed.

Universal module model

Described are techniques for intermodule communication between a first code module and a second code module each executing in user space. A shared memory portion includes storage for one or more commands and is accessible to the first and the second code modules. A first first-in-first-out (FIFO) structure is used for sending a location in the shared memory portion from the first code module to the second code module. A second FIFO structure is used for sending a location in the shared memory portion from the second code module to the first code module. The first code module stores command data for a command at a first location in the shared memory portion. A command is issued from the first code module to the second code module by sending the first location from the first code module to the second code module using the first FIFO structure.

Techniques for inter-user-space communication

Described are techniques for communicating between one or more producers and one or more consumers. A first consumer of an event queue registers for notification regarding occurrences of one or more events. A producer of the event queue posts one or more notifications to one or more consumers of the event queue regarding one or more occurrences of one or more events. Each of the consumers receive notification regarding occurrences of events for which the consumer is registered. The first consumer retrieves posted event notifications regarding events for which the first consumer is registered. If the first consumer is executing in user space and an event notification list to which the event notifications for the first consumer are posted is located in shared memory, the first consumer retrieves the posted event notifications without proxying into kernel space.

Described are techniques for intermodule communication between a first code module and a second code module wherein one of the first and second code modules executing in user space and the other of the first and second code modules executing in kernel space. A shared memory portion includes storage for one or more commands. A first first-in-first-out (FIFO) structure is used to send a location in the shared memory portion from the first to the second code module. A second FIFO structure is used for sending a location in the shared memory portion from the second to the first code module. The first code module stores command data for a command at a first location in the shared memory portion. A command is issued from the first to the second code module by sending the first location using the first FIFO structure.

Growing community of inventors

Leominster, MA, United States of America

Christopher M Gould