Re: Memory hotplug softlock issue

[Baoquan He]

On 11/20/18 at 03:05pm, Michal Hocko wrote:
> > Yes, I applied Hugh's patch 8 hours ago, then our QE Ping operated on
> > that machine, after many times of hot removing/adding, the endless
> > looping during mirgrating is not seen any more. The test result for
> > Hugh's patch is positive. I even suggested Ping increasing the memory
> > pressure to "stress -m 250", it still succeeded to offline and remove.
> > 
> > So I think this patch works to solve the issue. Thanks a lot for your
> > help, all of you. 
> 
> This is a great news! Thanks for your swift feedback. I will go and try
> to review Hugh's patch soon.

Yeah. Thanks a lot for your help on debugging and narrowing down
to position the cause of the issue, Michal, really appreciated!

> > Meanwhile we found sometime onlining page may not add back all memory
> > blocks on one memory board, then hot removing/adding them will cause
> > kernel panic. I will investigate further and collect information, see if
> > it's a kernel issue or udev issue.
> 
> It would be great to get a report in a new email thread.

Sure, will do after reproducing and inforamtion arranging.

Thanks
Baoquan