linux/include/xen/balloon.h
David Vrabel 1cf6a6c829 xen/balloon: use hotplugged pages for foreign mappings etc.
alloc_xenballooned_pages() is used to get ballooned pages to back
foreign mappings etc.  Instead of having to balloon out real pages,
use (if supported) hotplugged memory.

This makes more memory available to the guest and reduces
fragmentation in the p2m.

This is only enabled if the xen.balloon.hotplug_unpopulated sysctl is
set to 1.  This sysctl defaults to 0 in case the udev rules to
automatically online hotplugged memory do not exist.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
v3:
- Add xen.balloon.hotplug_unpopulated sysctl to enable use of hotplug
  for unpopulated pages.
2015-10-23 14:20:05 +01:00

38 lines
1.0 KiB
C

/******************************************************************************
* Xen balloon functionality
*/
#define RETRY_UNLIMITED 0
struct balloon_stats {
/* We aim for 'current allocation' == 'target allocation'. */
unsigned long current_pages;
unsigned long target_pages;
unsigned long target_unpopulated;
/* Number of pages in high- and low-memory balloons. */
unsigned long balloon_low;
unsigned long balloon_high;
unsigned long total_pages;
unsigned long schedule_delay;
unsigned long max_schedule_delay;
unsigned long retry_count;
unsigned long max_retry_count;
};
extern struct balloon_stats balloon_stats;
void balloon_set_new_target(unsigned long target);
int alloc_xenballooned_pages(int nr_pages, struct page **pages);
void free_xenballooned_pages(int nr_pages, struct page **pages);
struct device;
#ifdef CONFIG_XEN_SELFBALLOONING
extern int register_xen_selfballooning(struct device *dev);
#else
static inline int register_xen_selfballooning(struct device *dev)
{
return -ENOSYS;
}
#endif