A system and a method of managing storage of cached data objects on a non-volatile memory (NVM) computer storage media including at least one NVM storage device, by at least one processor, may include: receiving one or more data objects having respective Time to Live (TTL) values; storing the one or more data objects and respective TTL values at one or more physical block addresses (PBAs) of the storage media; and performing a garbage collection (GC) process on one or more PBAs of the storage media based on at least one TTL value stored at a PBA of the storage media.

Garbage collection (GC) to reclaim memory in computing systems sometimes suspends applications, web services, and other mutator programs in order to scan their execution stacks, which reduces their responsiveness. But suspension times are decreased by behavior-driven stack scan optimization (BDSSO) functionality that increases the concurrency of mutator execution with GC stack scanning. BDSSO obtains execution stack frame occurrence data, determines frame execution likelihoods, selects a stack scan depth based on the likelihoods, and installs a scan return barrier at the selected depth. Then the GC scans the execution stack below the barrier while the mutator runs, thus increasing concurrency and improving mutator responsiveness. Selected barrier locations vary according to actual stack activity to provide optimized concurrency instead of using an inflexible approach to barrier placement. Existing profiler samples or virtual machine interfaces can be reused by BDSSO. Skinny samples that lack profiler performance data may also be used.

A method and a system for garbage collection on a system. The method includes initiating a garbage collection process on a system by a garbage collector. The garbage collector includes one or more garbage collector threads. The method also includes marking a plurality of referenced objects using the garbage collector threads and one or more application threads during a preemption point. The method includes replicating the referenced objects using the garbage collector threads and marking for replication any newly discovered referenced objects found by scanning the application thread stack from a low-water mark. The method also includes replicating the newly discovered referenced objects and overwriting any reference to the old memory location.

Dynamically selecting a protection duration for locking objects in a storage. A garbage collection deletes objects over time. The objects may not be removed from storage until associated locks have expired. The length of the lock may impact the cost. A new lock extension value is selected each time a lock extension operation is performed. The lock extension value selection process accounts for a garbage collection operation cycle, an amount of deleted objects that are stored because of being locked, and a garbage collection churn. This allows an optimum lock extension value to be selected dynamically and repeatedly to control costs automatically.

Managing secondary objects efficiently increases garbage collection concurrency and reduces object storage requirements. Aliveness marking of secondary objects is integrated with aliveness marking of referenced objects. Allocation of reference-sized secondary object identifier fields in objects which are not primary objects is avoided; a dedicated bit specifies primary objects, together with an object relationship table. A primary object is one with at least one secondary object which is deemed alive by garbage collection if the primary object is alive, without being a referenced object of the primary object. Any referenced objects of the alive primary object will also still be deemed alive. Code paths for marking referenced objects can be shared to allow more efficient secondary object marking. Primary-secondary object relationships may be represented in dependent handles, and may be specified in a hash table or other data structure.

A scheduling system for a memory controller is provided. The system includes operation queues and a scheduler. The scheduler receives operation requests, prioritizes each operation request according to one or more policies, and inserts each operation request into an operation queue.

A method of manual memory management is described which comprises enabling one or more threads to access an object created in a manual heap by storing a reference to the object in thread-local state and subsequently deleting the stored reference after accessing the object. In response to abandonment of the object, an identifier for the object and a current value of either a local counter of a thread or a global counter are stored in a delete queue and all threads are prevented from storing any further references to the object in thread-local state. Deallocation of the object only occurs when all references to the object stored in thread-local state for any threads have been deleted and a current value of the local counter for the thread or the global counter has incremented to a value that is at least a pre-defined amount more than the stored value, wherein the global counter is updated using one or more local counters.

A guarded storage facility sets up a boundary indicating a range of addresses to be guarded or protected. When a program attempts to access an address in a guarded section defined by the boundary, a guarded storage event occurs. Use of this facility facilitates performance of certain tasks within a computing environment, including storage reclamation.

Parallel mark processing is disclosed including traversing first objects in a virtual machine heap based on correspondences between memory blocks in the virtual machine heap and N marking threads, pushing a first pointer of a first object into a private stack of a marking thread corresponding to a memory block, the first object being located in the memory block, performing first mark processing of the first object based on a push-in condition of the first pointer, and after traversal of the first objects has been completed, launching the N marking threads to cause the N marking threads to synchronously perform mark processing used in garbage collection based on push-in conditions of first pointers in respective private stacks of the first pointers.

A RAID-enabled solid state drive (SSD) including: a controller connected to a plurality of channels; a plurality of flash chip groups, each including a plurality of flash chips coupled to the plurality of channels, the plurality of flash chips including: a plurality of non-parity flash chips; and i parity flash chips, wherein the controller is configured to write data to the plurality of flash chip groups such that within each of the plurality of flash chip groups only i or less flash chips of the plurality of flash chips are allowed to be written to at the same time, where i is an integer equal to 1 or more.