On 9/10/20 3:20 AM, David Hildenbrand wrote: > While I'd love to rip it out completely, I think it would break old > lsmem/chmem completely - and I assume that's not acceptable. I was > wondering what would be considered safe to do now/in the future: > > 1. Make it always return 0 (just as if "sclp.rzm" would be set to 0 on > s390x). This will make old lsmem/chmem behave differently after > switching to a new kernel, like if sclp.rzm would not be set by HW - > AFAIU, it will assume all memory is in a single memory increment. Do we > care? > 2. Restrict it to s390x only. It always returned 0 on other > architectures, I was not able to find any user.
By "restrict it", do you mean just remove the sysfs file on everything other than s390x? That seems like a good idea, especially if we don't have any users. That, plus boot option or something to reenable it would be nice if someone trips over it disappearing. If there is a user, we stand a chance of finding them because they'll hopefully get a good error message. Worst case, an strace will show an -ENOENT and should be pretty easy to track down.