2020-04-12 09:15:33

by Liang Li

[permalink] [raw]
Subject: [RFC PATCH 2/4] mm: Add batch size for free page reporting

Use the page order as the only threshold for page reporting
is not flexible, add a batch size as another threshold, so
the reporting will be triggered only when the amount of free
page is bigger than the batch size.

Cc: Alexander Duyck <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Alex Williamson <[email protected]>

Signed-off-by: liliangleo <[email protected]>
---
mm/page_reporting.c | 2 ++
mm/page_reporting.h | 12 ++++++++++--
2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/mm/page_reporting.c b/mm/page_reporting.c
index 3a7084e508e1..dc7a22a4b752 100644
--- a/mm/page_reporting.c
+++ b/mm/page_reporting.c
@@ -14,6 +14,8 @@
#define PAGE_REPORTING_DELAY (2 * HZ)
#define MAX_SCAN_NUM 1024

+unsigned long page_report_batch_size __read_mostly = 4 * 1024 * 1024UL;
+
static struct page_reporting_dev_info __rcu *pr_dev_info __read_mostly;

enum {
diff --git a/mm/page_reporting.h b/mm/page_reporting.h
index aa6d37f4dc22..f18c85ecdfe0 100644
--- a/mm/page_reporting.h
+++ b/mm/page_reporting.h
@@ -12,6 +12,8 @@

#define PAGE_REPORTING_MIN_ORDER pageblock_order

+extern unsigned long page_report_batch_size;
+
#ifdef CONFIG_PAGE_REPORTING
DECLARE_STATIC_KEY_FALSE(page_reporting_enabled);
void __page_reporting_notify(void);
@@ -33,6 +35,8 @@ static inline bool page_reported(struct page *page)
*/
static inline void page_reporting_notify_free(unsigned int order)
{
+ static long batch_size;
+
/* Called from hot path in __free_one_page() */
if (!static_branch_unlikely(&page_reporting_enabled))
return;
@@ -41,8 +45,12 @@ static inline void page_reporting_notify_free(unsigned int order)
if (order < PAGE_REPORTING_MIN_ORDER)
return;

- /* This will add a few cycles, but should be called infrequently */
- __page_reporting_notify();
+ batch_size += (1 << order) << PAGE_SHIFT;
+ if (batch_size >= page_report_batch_size) {
+ batch_size = 0;
+ /* This add a few cycles, but should be called infrequently */
+ __page_reporting_notify();
+ }
}
#else /* CONFIG_PAGE_REPORTING */
#define page_reported(_page) false
--
2.14.1