From 1cf6a6c82918c9aad4bb73a7e7379a649e4d8e50 Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Thu, 25 Jun 2015 16:29:18 +0100 Subject: 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 Reviewed-by: Daniel Kiper --- v3: - Add xen.balloon.hotplug_unpopulated sysctl to enable use of hotplug for unpopulated pages. --- include/xen/balloon.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/xen') diff --git a/include/xen/balloon.h b/include/xen/balloon.h index 83efdeb243bf..d1767dfb0d95 100644 --- a/include/xen/balloon.h +++ b/include/xen/balloon.h @@ -8,6 +8,7 @@ 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; -- cgit v1.2.1