Re: [PATCH] mm/hugetlb: Remove redundant VM_BUG_ON_PAGE on putback_active_hugepage()

[Miaohe Lin]

Hi:
On 2021/2/9 9:26, Mike Kravetz wrote:
> On 2/8/21 12:37 AM, Miaohe Lin wrote:
>> PageHead(page) is implicitly checked in set_page_huge_active() via the
>> PageHeadHuge(page) check. So remove this explicit one.
> 
> I do not disagree with the code change.  However, this commit message
> is not accurate.  set_page_huge_active() no longer exists in the tree
> you are changing.  It was replaced with SetHPageMigratable.  Also, the
> VM_BUG_ON_PAGE(!PageHeadHuge(page), page) was removed in the process.
> So, there is no redundant check.
> 
> However, a quick audit of calling code reveals that all callers know they
> are operating on a hugetlb head page.
> 

So I should change the commit log like:

	All callers know they are operating on a hugetlb head page. So this VM_BUG_ON_PAGE
	can't catch anything useful.

and send a v2. Right?