Re: [PATCH 1/3] mm: Allow anon exclusive check over hugetlb tail pages

[Matthew Wilcox]

On Thu, Apr 04, 2024 at 09:45:58AM -0400, Peter Xu wrote:
> On Thu, Apr 04, 2024 at 01:05:57AM +0100, Matthew Wilcox wrote:
> > 	if (PageHuge(page))
> > 		page = compound_head(page);
> 
> I would think PageHead() check would help us to avoid compound_head() on
> heads, which should still be the majority cases iiuc (assuming page->flags
> is already around in the cache anyway).  I've no strong opinion though, as
> I can hardly tell a difference in reality.

compound_head() includes a check for PageHead().  Adding the check just
makes things slower.