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 | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index ddde097..2eecb16 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1342,16 +1342,19 @@ 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);
/*
* If we get a page from the CMA zone, since we are going to
* be pinning these entries, we might as well move them out
* of the CMA zone if possible.
*/
if (is_migrate_cma_page(pages[i])) {
-
- struct page *head = compound_head(pages[i]);
-
if (PageHuge(head)) {
isolate_huge_page(head, &cma_page_list);
} else {
@@ -1369,6 +1372,8 @@ static long check_and_migrate_cma_pages(struct
task_struct *tsk,
}
}
}
+
+ i += step;
}
if (!list_empty(&cma_page_list)) {
--
2.7.5
