[RFC PATCH 3/3] mm: support free hugepage pre zero out

[Liang Li <liliang.opensource@gmail.com>]

This patch add support of pre zero out free hugepage, we can use
this feature to speed up page population and page fault handing.

Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Hildenbrand <david@redhat.com>  
Cc: Michal Hocko <mhocko@suse.com> 
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Liang Li <liliang324@gmail.com>
Signed-off-by: Liang Li <liliangleo@didiglobal.com>
---
 mm/page_prezero.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/mm/page_prezero.c b/mm/page_prezero.c
index c8ce720bfc54..dff4e0adf402 100644
--- a/mm/page_prezero.c
+++ b/mm/page_prezero.c
@@ -26,6 +26,7 @@ static unsigned long delay_millisecs = 1000;
 static unsigned long zeropage_enable __read_mostly;
 static DEFINE_MUTEX(kzeropaged_mutex);
 static struct page_reporting_dev_info zero_page_dev_info;
+static struct page_reporting_dev_info zero_hugepage_dev_info;
 
 inline void clear_zero_page_flag(struct page *page, int order)
 {
@@ -69,9 +70,17 @@ static int start_kzeropaged(void)
 		zero_page_dev_info.delay_jiffies = msecs_to_jiffies(delay_millisecs);
 
 		err = page_reporting_register(&zero_page_dev_info);
+
+		zero_hugepage_dev_info.report = zero_free_pages;
+		zero_hugepage_dev_info.mini_order = mini_page_order;
+		zero_hugepage_dev_info.batch_size = batch_size;
+		zero_hugepage_dev_info.delay_jiffies = msecs_to_jiffies(delay_millisecs);
+
+		err |= hugepage_reporting_register(&zero_hugepage_dev_info);
 		pr_info("Zero page enabled\n");
 	} else {
 		page_reporting_unregister(&zero_page_dev_info);
+		hugepage_reporting_unregister(&zero_hugepage_dev_info);
 		pr_info("Zero page disabled\n");
 	}
 
@@ -90,7 +99,15 @@ static int restart_kzeropaged(void)
 		zero_page_dev_info.batch_size = batch_size;
 		zero_page_dev_info.delay_jiffies = msecs_to_jiffies(delay_millisecs);
 
+		hugepage_reporting_unregister(&zero_hugepage_dev_info);
+
+		zero_hugepage_dev_info.report = zero_free_pages;
+		zero_hugepage_dev_info.mini_order = mini_page_order;
+		zero_hugepage_dev_info.batch_size = batch_size;
+		zero_hugepage_dev_info.delay_jiffies = msecs_to_jiffies(delay_millisecs);
+
 		err = page_reporting_register(&zero_page_dev_info);
+		err |= hugepage_reporting_register(&zero_hugepage_dev_info);
 		pr_info("Zero page enabled\n");
 	}
 
-- 
2.18.2