Re: [PATCH v35 1/5] mm: support to get hints of free page blocks

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Jul 11, 2018 at 07:00:37AM +0300, Michael S. Tsirkin wrote:
> On Tue, Jul 10, 2018 at 10:33:08AM -0700, Linus Torvalds wrote:
> > NAK.
> > 
> > On Tue, Jul 10, 2018 at 2:56 AM Wei Wang <wei.w.wang@intel.com> wrote:
> > >
> > > +
> > > +       buf_page = list_first_entry_or_null(pages, struct page, lru);
> > > +       if (!buf_page)
> > > +               return -EINVAL;
> > > +       buf = (__le64 *)page_address(buf_page);
> > 
> > Stop this garbage.
> > 
> > Why the hell would you pass in some crazy "liost of pages" that uses
> > that lru list?
> > 
> > That's just insane shit.
> > 
> > Just pass in a an array to fill in.
> > No idiotic games like this with
> > odd list entries (what's the locking?) and crazy casting to
> > 
> > So if you want an array of page addresses, pass that in as such. If
> > you want to do it in a page, do it with
> > 
> >     u64 *array = page_address(page);
> >     int nr = PAGE_SIZE / sizeof(u64);
> > 
> > and now you pass that array in to the thing. None of this completely
> > insane crazy crap interfaces.
> 
> Question was raised what to do if there are so many free
> MAX_ORDER pages that their addresses don't fit in a single MAX_ORDER
> page.

Oh you answered already, I spoke too soon. Nevermind, pls ignore me.