Does Linux have a mechanism to "scrub" memory? e.g. testing the memory and marking areas as dirty if they fail so that the system can continue to operate "safely" even with bad ram chips installed?!
This is actually a bad idea. Memory cannot be reliably tested in a quick sweep. This is why software like memtest86 uses multiple passes with different bit patters to test memory. Solution:
memmap=nn[KMG]$ss[KMG] [KNL,ACPI] Mark specific memory as reserved. Region of memory to be used, from ss to ss+nn. Example: Exclude memory from 0x18690000-0x1869ffff memmap=64K$0x18690000 or memmap=0x10000$0x18690000
In addition, you can use ECC memory which will correct 1-bit errors and detect 2-bit errors in your memory automatically (and you'll get log messages from kernel about uncorrectable memory problems if they happen)
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The post and answer misunderstand the issue. Memory scrubbing is intended to keep correctible single bit errors from turning into uncorrectible double errors. The scrubber merely all physical memory (forcing cache misses to do so) occasionally. If there are any single bit errors, they will be corrected (and the correction must rewrite the correct value using a compare-and-swap), thus clearing the error.
Otherwise, if a second error occurs in a word which already has one error, the entire word will be uncorrectible and the OS will have to do something drastic.
Scrubbing is important because without it, memory which is read but not written (like code pages) may accumulate errors over time.