Re: Re: [PATCH] mm: hugetlbfs: add hwcrp_hugepages to record memory failure on hugetlbfs

["HORIGUCHI NAOYA(堀口 直也)" <naoya.horiguchi@nec.com>]

On Tue, Jun 08, 2021 at 10:24:50AM +0800, wangbin wrote:
> > What specific problem are you trying to solve?  Are trying to see how
> > many huge pages were hit by memory errors?
> 
> Yes, I'd like to know how many huge pages are not available because of
> the memory errors. Just like HardwareCorrupted in the /proc/meminfo.
> But the HardwareCorrupted only adds one page size when a huge page is
> hit by memory errors, and mixes with normal pages. So I think we should
> add a new counts to track the memory errors on hugetlbfs. 

If you can use root privilege in your use-case, an easy way to get the
number of corrupted hugepages is to use page-types.c (which reads
/proc/kpageflags) like below:

    $ page-types -b huge,hwpoison=huge,hwpoison
                 flags      page-count       MB  symbolic-flags                     long-symbolic-flags
    0x00000000000a8000               1        0  _______________H_G_X_______________________        compound_head,huge,hwpoison
                 total               1        0


But I guess that many usecases do not permit access to this interface,
where some new accounting interface for corrupted hugepages could be
helpful as you suggest.

Thanks,
Naoya Horiguchi