linux-kernel - [PATCH v1 6/8] vmw_balloon: mark inflated pages PG

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Date:   Mon, 19 Nov 2018 11:16:14 +0100
From:   David Hildenbrand <david@...hat.com>
To:     linux-mm@...ck.org
Cc:     linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
        devel@...uxdriverproject.org, linux-fsdevel@...r.kernel.org,
        linux-pm@...r.kernel.org, xen-devel@...ts.xenproject.org,
        kexec-ml <kexec@...ts.infradead.org>, pv-drivers@...are.com,
        David Hildenbrand <david@...hat.com>,
        Xavier Deguillard <xdeguillard@...are.com>,
        Nadav Amit <namit@...are.com>, Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Julien Freche <jfreche@...are.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Matthew Wilcox <willy@...radead.org>,
        Michal Hocko <mhocko@...e.com>,
        "Michael S. Tsirkin" <mst@...hat.com>
Subject: [PATCH v1 6/8] vmw_balloon: mark inflated pages PG_offline

Mark inflated and never onlined pages PG_offline, to tell the world that
the content is stale and should not be dumped.

Cc: Xavier Deguillard <xdeguillard@...are.com>
Cc: Nadav Amit <namit@...are.com>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Julien Freche <jfreche@...are.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Matthew Wilcox <willy@...radead.org>
Cc: Michal Hocko <mhocko@...e.com>
Cc: "Michael S. Tsirkin" <mst@...hat.com>
Signed-off-by: David Hildenbrand <david@...hat.com>
---
 drivers/misc/vmw_balloon.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index e6126a4b95d3..8cc8bd9a4e32 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -544,6 +544,36 @@ unsigned int vmballoon_page_order(enum vmballoon_page_size_type page_size)
 	return page_size == VMW_BALLOON_2M_PAGE ? VMW_BALLOON_2M_ORDER : 0;
 }
 
+/**
+ * vmballoon_mark_page_offline() - mark a page as offline
+ * @page: pointer for the page
+ * @page_size: the size of the page.
+ */
+static void
+vmballoon_mark_page_offline(struct page *page,
+			    enum vmballoon_page_size_type page_size)
+{
+	int i;
+
+	for (i = 0; i < 1ULL << vmballoon_page_order(page_size); i++)
+		__SetPageOffline(page + i);
+}
+
+/**
+ * vmballoon_mark_page_online() - mark a page as online
+ * @page: pointer for the page
+ * @page_size: the size of the page.
+ */
+static void
+vmballoon_mark_page_online(struct page *page,
+			   enum vmballoon_page_size_type page_size)
+{
+	int i;
+
+	for (i = 0; i < 1ULL << vmballoon_page_order(page_size); i++)
+		__ClearPageOffline(page + i);
+}
+
 /**
  * vmballoon_page_in_frames() - returns the number of frames in a page.
  * @page_size: the size of the page.
@@ -612,6 +642,7 @@ static int vmballoon_alloc_page_list(struct vmballoon *b,
 					 ctl->page_size);
 
 		if (page) {
+			vmballoon_mark_page_offline(page, ctl->page_size);
 			/* Success. Add the page to the list and continue. */
 			list_add(&page->lru, &ctl->pages);
 			continue;
@@ -850,6 +881,7 @@ static void vmballoon_release_page_list(struct list_head *page_list,
 
 	list_for_each_entry_safe(page, tmp, page_list, lru) {
 		list_del(&page->lru);
+		vmballoon_mark_page_online(page, page_size);
 		__free_pages(page, vmballoon_page_order(page_size));
 	}
 
-- 
2.17.2