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authorPingfan Liu <kernelfans@gmail.com>2019-07-11 20:57:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-12 11:05:45 -0700
commitaa712399c1e8245c375a5c44760de684ec2ebefb (patch)
tree10c9359a002db7e0f01ff327ab1fbeda3da7b2fe /mm
parent520b4a4496f12b117b94f3ac7c493651881c5fe3 (diff)
downloadlinux-aa712399c1e8245c375a5c44760de684ec2ebefb.tar.bz2
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. [akpm@linux-foundation.org: make `i' and `step' unsigned] Link: http://lkml.kernel.org/r/1561612545-28997-1-git-send-email-kernelfans@gmail.com Signed-off-by: Pingfan Liu <kernelfans@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Hubbard <jhubbard@nvidia.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Keith Busch <keith.busch@intel.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/gup.c24
1 files changed, 16 insertions, 8 deletions
diff --git a/mm/gup.c b/mm/gup.c
index 83d480e9b05f..f411bab037f5 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1449,25 +1449,31 @@ static long check_and_migrate_cma_pages(struct task_struct *tsk,
struct vm_area_struct **vmas,
unsigned int gup_flags)
{
- long i;
+ unsigned long i;
+ unsigned long 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 +1488,8 @@ check_again:
}
}
}
+
+ i += step;
}
if (!list_empty(&cma_page_list)) {