Re: [PATCH 1/2] mm/memory: remove redundant pte_devmap case for copy_one_pte()

[Michal Hocko <mhocko@suse.com>]

On Sun 19-04-20 03:26:13, Matthew Wilcox wrote:
> On Sun, Apr 19, 2020 at 11:30:16AM +0800, qiwuchen55@gmail.com wrote:
> > From: chenqiwu <chenqiwu@xiaomi.com>
> > 
> > As discussed in patch[1], special mapping ptes such as device
> > mapping ptes don't need to operate on their corresponding pages,
> > so the redundant pte_devmap case can be removed.
> > 
> > [1] https://patchwork.kernel.org/patch/11494691/
> 
> This is a terrible changelog.  What it should say is something like:
> 
> Since commit 25b2995a35b6 ("mm: remove MEMORY_DEVICE_PUBLIC support"),
> the assignment to 'page' has been unnecessary.  Remove it.
> 
> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>

With this changelog, feel free to tadd
Acked-by: Michal Hocko <mhocko@suse.com>

> 
> > Signed-off-by: chenqiwu <chenqiwu@xiaomi.com>
> > ---
> >  mm/memory.c | 2 --
> >  1 file changed, 2 deletions(-)
> > 
> > diff --git a/mm/memory.c b/mm/memory.c
> > index f703fe8..2143827 100644
> > --- a/mm/memory.c
> > +++ b/mm/memory.c
> > @@ -802,8 +802,6 @@ struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
> >  		get_page(page);
> >  		page_dup_rmap(page, false);
> >  		rss[mm_counter(page)]++;
> > -	} else if (pte_devmap(pte)) {
> > -		page = pte_page(pte);
> >  	}
> >  
> >  out_set_pte:
> > -- 
> > 1.9.1
> > 
> > 

-- 
Michal Hocko
SUSE Labs