Re: [PATCH 1/4] mm/ksm: refactor out try_to_merge_with_zero_page()

[David Hildenbrand]

Am 27.05.24 um 06:36 schrieb Chengming Zhou:
> On 2024/5/24 23:12, David Hildenbrand wrote:
> > On 24.05.24 10:56, Chengming Zhou wrote:
> > > In preparation for later changes, refactor out a new function called
> > > try_to_merge_with_zero_page(), which tries to merge with zero page.
> > >
> > > Signed-off-by: Chengming Zhou <chengming.zhou@xxxxxxxxx>
> > > ---
> > >    mm/ksm.c | 67 +++++++++++++++++++++++++++++++++++-----------------------------
> > >    1 file changed, 37 insertions(+), 30 deletions(-)
> > >
> > > diff --git a/mm/ksm.c b/mm/ksm.c
> > > index 4dc707d175fa..cbd4ba7ea974 100644
> > > --- a/mm/ksm.c
> > > +++ b/mm/ksm.c
> > > @@ -1531,6 +1531,41 @@ static int try_to_merge_one_page(struct vm_area_struct *vma,
> > >        return err;
> > >    }
> > >    +/* This function returns 0 if the pages were merged, -EFAULT otherwise. */
> >
> > No it doesn't. Check the "err = 0" case.
>
> Right, how about this: This function returns 0 if the page were merged or the vma
> is out of date, which means we don't need to continue, -EFAULT otherwise.

Maybe slightly adjusted:

This function returns 0 if the pages were merged or if they are no longer 
merging candidates (e.g., VMA stale), -EFAULT otherwise.

--
Thanks,

David / dhildenb