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-rw-r--r--drivers/xen/balloon.c29
1 files changed, 19 insertions, 10 deletions
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index e7f1d4ca6d75..e7f74ea7cd5e 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -679,7 +679,7 @@ void xen_free_ballooned_pages(unsigned int nr_pages, struct page **pages)
}
EXPORT_SYMBOL(xen_free_ballooned_pages);
-static int __init balloon_add_regions(void)
+static int __init balloon_add_regions(bool append)
{
unsigned long start_pfn, pages;
unsigned long pfn, extra_pfn_end;
@@ -703,19 +703,26 @@ static int __init balloon_add_regions(void)
balloon_append(pfn_to_page(pfn));
/*
- * Extra regions are accounted for in the physmap, but need
- * decreasing from current_pages and target_pages to balloon
- * down the initial allocation, because they are already
- * accounted for in total_pages.
+ * There are two different use-cases depending on how the
+ * initial memory target is fetched. For PVH dom0 and PV the
+ * target is usually set to reflect the domain assigned memory,
+ * and hence extra regions need adding.
+ *
+ * OTOH for HVM and PVH domU the target is set to the amount of
+ * RAM reported in the memory map, and hence extra regions need
+ * subtracting to reflect the real memory usage.
*/
pages = extra_pfn_end - start_pfn;
- if (pages >= balloon_stats.current_pages ||
- pages >= balloon_stats.target_pages) {
+ if (append) {
+ balloon_stats.total_pages += pages;
+ } else if (pages >= balloon_stats.current_pages ||
+ pages >= balloon_stats.target_pages) {
WARN(1, "Extra pages underflow current target");
return -ERANGE;
+ } else {
+ balloon_stats.current_pages -= pages;
+ balloon_stats.target_pages -= pages;
}
- balloon_stats.current_pages -= pages;
- balloon_stats.target_pages -= pages;
}
return 0;
@@ -726,6 +733,7 @@ static int __init balloon_init(void)
struct task_struct *task;
long current_pages = 0;
domid_t domid = DOMID_SELF;
+ bool append = true;
int rc;
if (!xen_domain())
@@ -745,6 +753,7 @@ static int __init balloon_init(void)
} else {
if (xen_unpopulated_pages >= get_num_physpages())
goto underflow;
+ append = false;
current_pages = get_num_physpages() -
xen_unpopulated_pages;
}
@@ -767,7 +776,7 @@ static int __init balloon_init(void)
register_sysctl_init("xen/balloon", balloon_table);
#endif
- rc = balloon_add_regions();
+ rc = balloon_add_regions(append);
if (rc)
return rc;