Re: [PATCH 3/7] mm: Add an 'end' parameter to find_get_entries

From: Matthew Wilcox
Date: Fri Aug 21 2020 - 12:34:52 EST


On Fri, Aug 21, 2020 at 06:07:59PM +0200, Jan Kara wrote:
> On Wed 19-08-20 16:05:51, Matthew Wilcox (Oracle) wrote:
> > This simplifies the callers and leads to a more efficient implementation
> > since the XArray has this functionality already.
> >
> > Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
>
> The patch looks good to me. Just I'd note that you could drop some:
>
> if (index >= end)
> break;
>
> checks in shmem_undo_range() as well.

Oh yes, missed a couple ;-) Thanks, I'll add.

> In the past I was considering moving find_get_entries() to the same API as
> find_get_pages_range() has (which is essentially what you do now, but I
> also had 'start' to be a pgoff_t * so that we can return there where the
> iteration ended in the range). But in the end I've decided the churn is not
> worth the few removed lines and didn't push the patch in the end. What you
> did in this patch seems to be a reasonable middle-ground :)

I did look at that, but since we're returning the indices, we don't _need_
to update the index here.

I have some other ideas for this family of interfaces, but I'm trying
to get the THP work off my plate before getting distracted by that ;-)