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From:   David Hildenbrand <david@redhat.com>
To:     linux-mm@kvack.org
Cc:     linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
        devel@linuxdriverproject.org, linux-fsdevel@vger.kernel.org,
        linux-pm@vger.kernel.org, xen-devel@lists.xenproject.org,
        David Hildenbrand <david@redhat.com>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Juergen Gross <jgross@suse.com>,
        Stefano Stabellini <sstabellini@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Matthew Wilcox <willy@infradead.org>,
        Michal Hocko <mhocko@suse.com>,
        "Michael S. Tsirkin" <mst@redhat.com>
Subject: [PATCH RFC 4/6] xen/balloon: mark inflated pages PG_offline
Date:   Wed, 14 Nov 2018 22:17:02 +0100
Message-Id: <20181114211704.6381-5-david@redhat.com>
In-Reply-To: <20181114211704.6381-1-david@redhat.com>
References: <20181114211704.6381-1-david@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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

Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 drivers/xen/balloon.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 12148289debd..14dd6b814db3 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -425,6 +425,7 @@ static int xen_bring_pgs_online(struct page *pg, unsigned int order)
 	for (i = 0; i < size; i++) {
 		p = pfn_to_page(start_pfn + i);
 		__online_page_set_limits(p);
+		__SetPageOffline(p);
 		__balloon_append(p);
 	}
 	mutex_unlock(&balloon_mutex);
@@ -493,6 +494,7 @@ static enum bp_state increase_reservation(unsigned long nr_pages)
 		xenmem_reservation_va_mapping_update(1, &page, &frame_list[i]);
 
 		/* Relinquish the page back to the allocator. */
+		__ClearPageOffline(page);
 		free_reserved_page(page);
 	}
 
@@ -519,6 +521,7 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
 			state = BP_EAGAIN;
 			break;
 		}
+		__SetPageOffline(page);
 		adjust_managed_page_count(page, -1);
 		xenmem_reservation_scrub_page(page);
 		list_add(&page->lru, &pages);
-- 
2.17.2