> On Mar 1, 2021, at 11:02 AM, Luck, Tony <[email protected]> wrote:
>
>
>>
>> Some programs may use read(2), write(2), etc as ways to check if
>> memory is valid without getting a signal. They might not want
>> signals, which means that this feature might need to be configurable.
>
> That sounds like an appalling hack. If users need such a mechanism
> we should create some better way to do that.
>
Appalling hack or not, it works. So, if we’re going to send a signal to user
code that looks like it originated from a bina fide architectural recoverable
fault, it needs to be recoverable. A load from a failed NVDIMM page is such a
fault. A *kernel* load is not. So we need to distinguish it somehow.
> An aeon ago ACPI created the RASF table as a way for the OS to
> ask the platform to scan a block of physical memory using the patrol
> scrubber in the memory controller. I never did anything with it in Linux
> because it was just too complex and didn't know of any use cases.
>
> Users would want to check virtual addresses. Perhaps some new
> option MADV_CHECKFORPOISON to madvise(2) ?
>
> -Tony
