Re: [PATCH v3 5/5] hugetlb: Do early cow when page pinned on src mm

[Mike Kravetz <mike.kravetz@oracle.com>]

On 2/5/21 8:54 AM, Peter Xu wrote:
> This is the last missing piece of the COW-during-fork effort when there're
> pinned pages found.  One can reference 70e806e4e645 ("mm: Do early cow for
> pinned pages during fork() for ptes", 2020-09-27) for more information, since
> we do similar things here rather than pte this time, but just for hugetlb.

Thanks for all the changes, the patch looks much better.

I did not look at 70e806e4e645 in detail until now.  That commit had the
'write protect trick' which was removed in subsequent commits.  It took me
a bit of git history tracking to figure out the state of that code today and
the reasons for the subsequent changes.  I guess that was a good way to
educate me. :) 

> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  mm/hugetlb.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++----
>  1 file changed, 62 insertions(+), 4 deletions(-)

Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
-- 
Mike Kravetz