Is there a way to automatically reserve bad page frames?

English Hardware
1

I am getting a lot of single bit ECC failures at the same address. Is there a way to set a threshold for the number of failures, such that when the hits pass the threshold Linux will automatically move the page to a different page frame, or page it out, and then mark the bad page frame as permanently reserved?

2

Hi
If you know the exact address you could look at the memmap kernel option to reserve/block it from use.

https://www.kernel.org/doc/Documentation/admin-guide/kernel-parameters.txt

Replace the RAM module, if you move to a different slot does the error move…?

3

Is memmap=1$ss legitimate?

Editing /etc/sysctl.conf takes care of the one occurrence, but I was really hoping for a way to make it automatic for future occurrences.

4

Hi
Alas my last and very limited experience with ECC memory was in the early 2000’s on Solaris… check via dmesg | grep e820.

5

What is the full parameter name in /etc/sysctl.conf and do I use memmap=1$0x000000002a7cb510, memmap=16$0x000000002a7cb510 or memmap=4K$x000000002a7cb000?

Thanks.

6

Hi
The last iteration so that would exclude 4K of memory starting at address 0x000000002a7cb000 (it is 0x too).

7

Thanks. What name do I use for /proc or sysctl -w if I want to do it before a reboot?

8

Hi
It should be down in /proc/sys/vm/.

Have a read here: https://www.kernel.org/doc/Documentation/sysctl/vm.txt

9

That doesn’t list memmap.

10

I don’t see any subdirectory there relevant to reserving physical memory. I see /proc/sys/vm/mmap/foo, but those are something different.