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

[Liang Li]

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.du...@linux.intel.com>
Cc: Mel Gorman <mgor...@techsingularity.net>
Cc: Andrea Arcangeli <aarca...@redhat.com>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: Dave Hansen <dave.han...@intel.com>
Cc: David Hildenbrand <da...@redhat.com>  
Cc: Michal Hocko <mho...@suse.com> 
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Alex Williamson <alex.william...@redhat.com>
Cc: Michael S. Tsirkin <m...@redhat.com>
Cc: Jason Wang <jasow...@redhat.com>
Cc: Mike Kravetz <mike.krav...@oracle.com>
Cc: Liang Li <liliang...@gmail.com>
Signed-off-by: Liang Li <liliang...@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