[Xen-devel] [PATCH] xen/balloon: Only mark a page as managed when it is released

[Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>]

Only mark a page as managed when it is released back to the allocator.
This ensures that the managed page count does not get falsely increased
when a VM is running. Correspondingly change it so that pages are
marked as unmanaged after getting them from the allocator.

Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
---
 drivers/xen/balloon.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index e4db19e..db107fa 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -180,7 +180,6 @@ static void __balloon_append(struct page *page)
 static void balloon_append(struct page *page)
 {
        __balloon_append(page);
-       adjust_managed_page_count(page, -1);
 }
 
 /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */
@@ -201,8 +200,6 @@ static struct page *balloon_retrieve(bool require_lowmem)
        else
                balloon_stats.balloon_low--;
 
-       adjust_managed_page_count(page, 1);
-
        return page;
 }
 
@@ -478,7 +475,7 @@ static enum bp_state increase_reservation(unsigned long 
nr_pages)
 #endif
 
                /* Relinquish the page back to the allocator. */
-               __free_reserved_page(page);
+               free_reserved_page(page);
        }
 
        balloon_stats.current_pages += rc;
@@ -509,6 +506,7 @@ static enum bp_state decrease_reservation(unsigned long 
nr_pages, gfp_t gfp)
                        state = BP_EAGAIN;
                        break;
                }
+               adjust_managed_page_count(page, -1);
                scrub_page(page);
                list_add(&page->lru, &pages);
        }
-- 
2.7.4


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