On Mon, Jun 24, 2019 at 1:32 PM Pingfan Liu <kernelf...@gmail.com> wrote:
>
> On Mon, Jun 24, 2019 at 12:43 PM Ira Weiny <ira.we...@intel.com> wrote:
> >
> > On Mon, Jun 24, 2019 at 12:12:41PM +0800, Pingfan Liu wrote:
> > > Both hugetlb and thp locate on the same migration type of pageblock, since
> > > they are allocated from a free_list[]. Based on this fact, it is enough to
> > > check on a single subpage to decide the migration type of the whole huge
> > > page. By this way, it saves (2M/4K - 1) times loop for pmd_huge on x86,
> > > similar on other archs.
> > >
> > > Furthermore, when executing isolate_huge_page(), it avoid taking global
> > > hugetlb_lock many times, and meanless remove/add to the local link list
> > > cma_page_list.
> > >
> > > Signed-off-by: Pingfan Liu <kernelf...@gmail.com>
> > > Cc: Andrew Morton <a...@linux-foundation.org>
> > > Cc: Ira Weiny <ira.we...@intel.com>
> > > Cc: Mike Rapoport <r...@linux.ibm.com>
> > > Cc: "Kirill A. Shutemov" <kirill.shute...@linux.intel.com>
> > > Cc: Thomas Gleixner <t...@linutronix.de>
> > > Cc: John Hubbard <jhubb...@nvidia.com>
> > > Cc: "Aneesh Kumar K.V" <aneesh.ku...@linux.ibm.com>
> > > Cc: Christoph Hellwig <h...@lst.de>
> > > Cc: Keith Busch <keith.bu...@intel.com>
> > > Cc: Mike Kravetz <mike.krav...@oracle.com>
> > > Cc: Linux-kernel@vger.kernel.org
> > > ---
> > > mm/gup.c | 19 ++++++++++++-------
> > > 1 file changed, 12 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/mm/gup.c b/mm/gup.c
> > > index ddde097..544f5de 100644
> > > --- a/mm/gup.c
> > > +++ b/mm/gup.c
> > > @@ -1342,19 +1342,22 @@ static long check_and_migrate_cma_pages(struct
> > > task_struct *tsk,
> > > LIST_HEAD(cma_page_list);
> > >
> > > check_again:
> > > - for (i = 0; i < nr_pages; i++) {
> > > + for (i = 0; i < nr_pages;) {
> > > +
> > > + struct page *head = compound_head(pages[i]);
> > > + long step = 1;
> > > +
> > > + if (PageCompound(head))
> > > + step = compound_order(head) - (pages[i] - head);
> >
> > Sorry if I missed this last time. compound_order() is not correct here.
> For thp, prep_transhuge_page()->prep_compound_page()->set_compound_order().
> For smaller hugetlb,
> prep_new_huge_page()->prep_compound_page()->set_compound_order().
> For gigantic page, prep_compound_gigantic_page()->set_compound_order().
>
> Do I miss anything?
>
Oh, got it. It should be 1<<compound_order(head)
> Thanks,
> Pingfan
> [...]
