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From: Lance Yang <ioworker0@gmail.com>
Date: Wed, 17 Apr 2024 17:01:18 +0800
Message-ID: <CAK1f24mFfwXky9Patwmcq-VQ8y1hxcRm8K4B4o0RO+dsr-7Q=A@mail.gmail.com>
Subject: Re: [PATCH v7 1/3] mm/madvise: introduce clear_young_dirty_ptes()
 batch helper
To: David Hildenbrand <david@redhat.com>
Cc: 21cnbao@gmail.com, akpm@linux-foundation.org, fengwei.yin@intel.com, 
	linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.com, 
	minchan@kernel.org, peterx@redhat.com, ryan.roberts@arm.com, 
	shy828301@gmail.com, songmuchun@bytedance.com, wangkefeng.wang@huawei.com, 
	xiehuan09@gmail.com, zokeefe@google.com
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On Wed, Apr 17, 2024 at 4:19=E2=80=AFPM David Hildenbrand <david@redhat.com=
> wrote:
>
> On 17.04.24 07:04, Lance Yang wrote:
> > Hey David, Ryan,
> >
> > How about this change?
> >
> > static inline void clear_young_dirty_ptes(struct vm_area_struct *vma,
> >                                         unsigned long addr, pte_t *ptep=
,
> >                                         unsigned int nr, cydp_t flags)
> > {
> >       if (flags =3D=3D CYDP_CLEAR_YOUNG) {
> >               for (;;) {
> >                       ptep_test_and_clear_young(vma, addr, ptep);
> >                       if (--nr =3D=3D 0)
> >                               break;
> >                       ptep++;
> >                       addr +=3D PAGE_SIZE;
> >               }
> >               return;
> >       }
> >
> >       pte_t pte;
> >
> >       for (;;) {
> >               pte =3D ptep_get_and_clear(vma->vm_mm, addr, ptep);
> >
> >               if (flags & CYDP_CLEAR_YOUNG)
> >                       pte =3D pte_mkold(pte);
> >               if (flags & CYDP_CLEAR_DIRTY)
> >                       pte =3D pte_mkclean(pte);
> >
> >               if (--nr =3D=3D 0)
> >                       break;
> >               ptep++;
> >               addr +=3D PAGE_SIZE;
> >       }
> > }
>
> Likely it might be best to just KIS for now and leave it as is. The
> compiler should optimize out based on flags already, that's what I ignore=
d.

Got it. Let's keep it as is for now :)

Thanks,
Lance

>
> --
> Cheers,
>
> David / dhildenb
>