memtest86 can be configured to display address bit patterns that can then be consumed by the Linux kernel as a command line argument: https://lwn.net/Articles/440319/
But in other cases, this can be managed entirely by the BIOS. I know (or rather, think -- didn't boot Linux on a machine with memory problems recently) that some Dell machines will mark bad locations/ranges as reserved in the ACPI memory map if you run the built-in diagnostic tool from the boot menu.
I've heard rumors of low prices on high-capacity "bad RAM", but never been able to find anywhere to buy it. Have you investigated this possibility before?
Never heard that one before; I don't know much about how problem spots usually develop, so I would be wary about the "stability" of any known faults when using a module like that.
But in other cases, this can be managed entirely by the BIOS. I know (or rather, think -- didn't boot Linux on a machine with memory problems recently) that some Dell machines will mark bad locations/ranges as reserved in the ACPI memory map if you run the built-in diagnostic tool from the boot menu.