linux-kernel - Re: [PATCHv3, RESEND 6/8] khugepaged: Allow to collapse PTE-mapped compound pages

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Date:   Thu, 16 Apr 2020 00:52:05 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Zi Yan <ziy@...dia.com>, Yang Shi <yang.shi@...ux.alibaba.com>,
        Ralph Campbell <rcampbell@...dia.com>,
        John Hubbard <jhubbard@...dia.com>,
        William Kucharski <william.kucharski@...cle.com>,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCHv3, RESEND 6/8] khugepaged: Allow to collapse PTE-mapped
 compound pages

On Wed, Apr 15, 2020 at 02:44:26PM -0700, Andrew Morton wrote:
> On Mon, 13 Apr 2020 15:52:18 +0300 "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com> wrote:
> 
> > We can collapse PTE-mapped compound pages. We only need to avoid
> > handling them more than once: lock/unlock page only once if it's present
> > in the PMD range multiple times as it handled on compound level. The
> > same goes for LRU isolation and putback.
> > 
> > ...
> >
> > --- a/mm/khugepaged.c
> > +++ b/mm/khugepaged.c
> > @@ -515,17 +515,30 @@ void __khugepaged_exit(struct mm_struct *mm)
> >  
> >  static void release_pte_page(struct page *page)
> >  {
> > -	dec_node_page_state(page, NR_ISOLATED_ANON + page_is_file_cache(page));
> 
> I have
> 
> 	dec_node_page_state(page, NR_ISOLATED_ANON + page_is_file_lru(page));
> 
> here.  Is there some prerequisite which I wasn't able to find?

The patchset is on top of v5.6. It has been changed since. See
9de4f22a60f7 ("mm: code cleanup for MADV_FREE").

Look like a trivial fixup is required.

-- 
 Kirill A. Shutemov