Lines Matching full:memory
19 Increasing DRAM size and cost have made memory subsystem reliability an
21 could cause expensive or fatal issues. Memory errors are among the top
24 Memory scrubbing is a feature where an ECC (Error-Correcting Code) engine
25 reads data from each memory media location, corrects if necessary and writes
26 the corrected data back to the same memory media location.
28 DIMMs can be scrubbed at a configurable rate to detect uncorrected memory
35 2. When detected, uncorrected errors caught in unallocated memory pages are
39 memory errors.
41 4. The additional data on failures in memory may be used to build up
42 statistics that are later used to decide whether to use memory repair
45 There are 2 types of memory scrubbing:
49 2. On-demand scrubbing for a specific address range or region of memory.
51 Several types of interfaces to hardware memory scrubbers have been
52 identified, such as CXL memory device patrol scrub, CXL DDR5 ECS, ACPI
53 RAS2 memory scrubbing, and ACPI NVDIMM ARS (Address Range Scrub).
55 The control mechanisms vary across different memory scrubbers. To enable
59 A generic memory EDAC scrub control allows users to manage underlying
67 1. Several types of interfaces for hardware memory scrubbers have been
68 identified, including the CXL memory device patrol scrub, CXL DDR5 ECS,
69 ACPI RAS2 memory scrubbing features, ACPI NVDIMM ARS (Address Range Scrub),
70 and software-based memory scrubbers.
72 Of the identified interfaces to hardware memory scrubbers some support
75 interfaces vary between memory scrubbers, highlighting the need for
87 4. User-space tools can also control memory DIMM scrubbing at a configurable
90 4.1. Detects uncorrectable memory errors early, before user access to affected
91 memory, helping facilitate recovery.
96 5. Policy control for hotplugged memory is necessary because there may not
107 CXL Memory Scrubbing features
110 CXL spec r3.1 [1]_ section 8.2.9.9.11.1 describes the memory device patrol
135 The DDR5 device contains number of memory media Field Replaceable Units (FRU)
139 ACPI RAS2 Hardware-based Memory Scrubbing
147 Memory RAS features apply to RAS capabilities, controls and operations that
148 are specific to memory. RAS2 PCC sub-spaces for memory-specific RAS features
149 have a Feature Type of 0x00 (Memory).
151 The platform can use the hardware-based memory scrubbing feature to expose
152 controls and capabilities associated with hardware-based memory scrub
153 engines. The RAS2 memory scrubbing feature supports as per spec,
155 1. Independent memory scrubbing controls for each NUMA domain, identified
158 2. Provision for background (patrol) scrubbing of the entire memory system,
159 as well as on-demand scrubbing for a specific region of memory.
165 ARS allows the platform to communicate memory errors to system software.
167 uncorrectable errors in memory. ARS functions manage all NVDIMMs present in
175 2. Start ARS triggers an Address Range Scrub for the given memory range.
176 Address scrubbing can be done for volatile or persistent memory, or both.
212 | Mode of | Scrub ctrl| per device| per memory| Unknown |
273 1. CXL memory Patrol Scrub
280 - Scrubbing may apply to memory that isn't online at all yet. Likely this
289 CXL memory is exposed to memory management subsystem and ultimately userspace
291 described in "Section 1 CXL Memory Patrol Scrub".
301 CXL memory is exposed to memory management subsystem and ultimately userspace
302 via CXL regions. CXL Regions represent mapped memory capacity in system
304 memory devices with traffic interleaved across them. The user may want to control
312 "Section 1 CXL Memory Patrol Scrub".
329 2. CXL memory Error Check Scrub (ECS)
331 The Error Check Scrub (ECS) feature enables a memory device to perform error
333 memory controller sets the ECS mode with a trigger sent to the memory
338 initiating Error Check Scrub on a memory device may lie with the memory