The patch titled
Subject: mm/gup: speed up check_and_migrate_cma_pages() on huge page
has been added to the -mm tree. Its filename is
mm-gup-speed-up-check_and_migrate_cma_pages-on-huge-page.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-gup-speed-up-check_and_migrate_cma_pages-on-huge-page.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-gup-speed-up-check_and_migrate_cma_pages-on-huge-page.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Pingfan Liu <kernelfans@xxxxxxxxx>
Subject: mm/gup: speed up check_and_migrate_cma_pages() on huge page
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.
Link: http://lkml.kernel.org/r/1561612545-28997-1-git-send-email-kernelfans@xxxxxxxxx
Signed-off-by: Pingfan Liu <kernelfans@xxxxxxxxx>
Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Keith Busch <keith.busch@xxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/gup.c | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)
--- a/mm/gup.c~mm-gup-speed-up-check_and_migrate_cma_pages-on-huge-page
+++ a/mm/gup.c
@@ -1449,25 +1449,30 @@ static long check_and_migrate_cma_pages(
struct vm_area_struct **vmas,
unsigned int gup_flags)
{
- long i;
+ long i, step;
bool drain_allow = true;
bool migrate_allow = true;
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]);
+
+ /*
+ * gup may start from a tail page. Advance step by the left
+ * part.
+ */
+ step = (1 << 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)) {
+ if (is_migrate_cma_page(head)) {
+ if (PageHuge(head))
isolate_huge_page(head, &cma_page_list);
- } else {
+ else {
if (!PageLRU(head) && drain_allow) {
lru_add_drain_all();
drain_allow = false;
@@ -1482,6 +1487,8 @@ check_again:
}
}
}
+
+ i += step;
}
if (!list_empty(&cma_page_list)) {
_
Patches currently in -mm which might be from kernelfans@xxxxxxxxx are
mm-gup-speed-up-check_and_migrate_cma_pages-on-huge-page.patch
