G06F2212/655

Handling effective address synonyms in a load-store unit that operates without address translation

Technical solutions are described for issuing, by a load-store unit (LSU), a plurality of instructions from an out-of-order (OoO) window. The issuing includes, in response to determining a first effective address (EA) being used by a first instruction, the first EA corresponding to a first real address (RA), creating a first effective real translation (ERT) table entry in an ERT table, the ERT entry mapping the first EA to the first RA. Further, in response to determining an EA synonym used by a second instruction, the execution includes replacing the first ERT entry with a second ERT entry, wherein the second ERT entry maps the second EA with the first RA, and creating an ERT eviction (ERTE) table entry in an ERTE table, wherein the ERTE entry maps the first RA to the first EA, the ERTE table entry maintains the relationship between the first EA and the first RA.

Handling effective address synonyms in a load-store unit that operates without address translation

Technical solutions are described for issuing, by a load-store unit (LSU), a plurality of instructions from an out-of-order (OoO) window. The issuing includes, in response to determining a first effective address (EA) being used by a first instruction, the first EA corresponding to a first real address (RA), creating a first effective real translation (ERT) table entry in an ERT table, the ERT entry mapping the first EA to the first RA. Further, in response to determining an EA synonym used by a second instruction, the execution includes replacing the first ERT entry with a second ERT entry, wherein the second ERT entry maps the second EA with the first RA, and creating an ERT eviction (ERTE) table entry in an ERTE table, wherein the ERTE entry maps the first RA to the first EA, the ERTE table entry maintains the relationship between the first EA and the first RA.

PROCESS ISOLATION FOR OUT OF PROCESS PAGE FAULT HANDLING

A system and method relates to detecting a hardware event, determining a first virtual memory address associated with the hardware event, wherein the first virtual memory address is associated with a first processing thread, identifying, using the first virtual memory address, an entry of a logical address table, the entry comprising a file descriptor and a file offset associated with a file, identifying a memory address table associated with the file descriptor, translating, using the memory address table, the file offset into a second virtual memory address associated with a second processing thread, and transmitting, to the second processing thread, a notification comprising the second virtual memory address.

Apparatus and method for handling access requests

An apparatus and method are provided for handling access requests. The apparatus has processing circuitry for processing a plurality of program threads to perform data processing operations on data, where the operations identify the data using virtual addresses, and the virtual addresses are mapped to physical addresses within a memory system. The cache storage has a plurality of cache entries to store data, an aliasing condition existing when multiple virtual addresses map to the same physical address, and allocation of data into the cache storage being constrained to prevent multiple cache entries of the cache storage simultaneously storing data for the same physical address. Cache access circuitry is then responsive to an access request specifying a virtual address, to utilise a cache index at least partially determined from the specified virtual address to identify at least one cache entry within the cache storage, and to detect whether a hit is present within the at least one cache entry by comparing a physical address portion associated with that cache entry with a tag portion of the physical address corresponding to the specified virtual address. Remap handling circuitry is then arranged whilst a first program thread is in the process of performing an exclusive operation using a first virtual address to identify a specified physical address whose data is stored in the cache storage, to detect a remap condition when a second program thread issues a second program thread access request of at least one type that specifies a second virtual address that exhibits the aliasing condition with the first virtual address. In the presence of the remap condition, the remap handling circuitry remaps the cache index at least partially determined from the second virtual address, so that the remapped cache index as then used by the cache access circuitry matches the cache index at least partially determined from the first virtual address. This provides an effective mechanism for avoiding potential live-lock scenarios that can otherwise arise.

Hypervisor deduplication page comparison speedup
10545673 · 2020-01-28 · ·

A hypervisor deduplcation system includes a memory, a processor in communication with the memory, and a hypervisor executing on the processor. The hypervisor is configured to scan a first page, detect that the first page is an unchanged page, check a first free page hint, and insert the unchanged page into a tree. Responsive to inserting the unchanged page into the tree, the hypervisor compares the unchanged page to other pages in the tree and determine a status of the unchanged page as matching one of the other pages or mismatching the other pages in the tree. Responsive to determining the status of the page as matching another page, the hypervisor deduplicates the unchanged page. Additionally, the hypervisor is configured to scan a second page of the memory, check a second free page hint, deduplicate the second page if the free page hint indicates the page is unused.

Pseudo-invalidating dynamic address translation (DAT) tables of a DAT structure associated with a workload

A computer-implemented method includes pseudo-invalidating a first Dynamic Address Translation (DAT) table of a DAT structure associated with a workload. A page fault occurring during translation of a virtual memory address of data required by the workload is detected. Responsive to the page fault, the DAT structure is traversed. The DAT structure includes one or more DAT tables, and each DAT entry in each of the one or more DAT tables is associated with an in-use bit indicating whether the DAT entry is in use. Traversing the DAT structure includes pseudo-invalidating each of one or more DAT entries in the DAT structure that are involved in translating the virtual memory address for which the page fault occurred; and identifying a first page frame referenced by the virtual memory address for which the page fault occurred. The data in the first page frame is processed responsive to the page fault.

ENHANCED MEMORY MANAGEMENT FOR VIRTUAL MACHINES
20190370044 · 2019-12-05 ·

Aspects of the disclosure provide for mechanisms for memory management of virtual machines in a computer system. A method of the disclosure includes: releasing a memory page of a guest memory of a virtual machine; sending, by the virtual machine, a first notification to a hypervisor, the first notification comprising an indication that a memory page associated with the virtual machine is to be rendered inaccessible; and receiving, by the virtual machine, a second notification indicative of detection of an attempt to access the memory page.

Host performance booster L2P handoff

Methods that may be performed by a host controller of a computing device for synchronizing logical-to-physical (L2P) tables before entering a hibernate mode are disclosed. Embodiment methods may include determining whether a first L2P table stored in a dynamic random-access memory (DRAM) communicatively connected to the host controller is out of synchronization with a second L2P table stored in a static random-access memory (SRAM) of a universal flash storage (UFS) device communicatively connected to the host controller via a link. If the first and second L2P tables are out of synch, the host controller may retrieve at least one modified L2P map entry from the second L2P table when the UFS device is configured to enter a hibernate mode from the UFS device, and update the first L2P tabled with the at least one modified L2P map entry before the link and the UFS device enter the hibernate mode.

EXECUTING LOAD-STORE OPERATIONS WITHOUT ADDRESS TRANSLATION HARDWARE PER LOAD-STORE UNIT PORT
20190310849 · 2019-10-10 ·

Technical solutions are described for out-of-order (OoO) execution of one or more instructions by a processing unit includes receiving, by a load-store unit (LSU) of the processing unit, an OoO window of instructions including a plurality of instructions to be executed OoO, and issuing, by the LSU, instructions from the OoO window. The issuing includes selecting an instruction from the OoO window, the instruction using an effective address. Further, in response to the instruction being a load instruction, it is determined whether the effective address is present in an effective address directory (EAD). In response to the effective address being present in the EAD, the load instruction is issued using the effective address. Further, in response to the instruction being a store instruction, a real address mapped to the effective address is determined from an effective-real translation (ERT) table, and the store instruction is issued using the real address.

Process isolation for out of process page fault handling

A system and method relates to detecting a hardware event, determining a first virtual memory address associated with the hardware event, wherein the first virtual memory address is associated with a first processing thread, identifying, using the first virtual memory address, an entry of a logical address table, the entry comprising a file descriptor and a file offset associated with a file, identifying a memory address table associated with the file descriptor, translating, using the memory address table, the file offset into a second virtual memory address associated with a second processing thread, and transmitting, to the second processing thread, a notification comprising the second virtual memory address.