On Wed, Jun 26, 2019 at 1:51 AM Ira Weiny <[email protected]> wrote: > > On Tue, Jun 25, 2019 at 10:13:19PM +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 <[email protected]> > > Cc: Andrew Morton <[email protected]> > > Cc: Ira Weiny <[email protected]> > > Cc: Mike Rapoport <[email protected]> > > Cc: "Kirill A. Shutemov" <[email protected]> > > Cc: Thomas Gleixner <[email protected]> > > Cc: John Hubbard <[email protected]> > > Cc: "Aneesh Kumar K.V" <[email protected]> > > Cc: Christoph Hellwig <[email protected]> > > Cc: Keith Busch <[email protected]> > > Cc: Mike Kravetz <[email protected]> > > Cc: [email protected] > > --- > > v2 -> v3: fix page order to size convertion > > > > mm/gup.c | 19 ++++++++++++------- > > 1 file changed, 12 insertions(+), 7 deletions(-) > > > > diff --git a/mm/gup.c b/mm/gup.c > > index ddde097..03cc1f4 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 = 1 << compound_order(head) - (pages[i] - head); > > Check your precedence here. > > step = (1 << compound_order(head)) - (pages[i] - head); OK.
Thanks, Pingfan
