Notify a host about a guest memory size limit. Idea of this patch was discussed with Ian Campbell and Ian Jackson.
Signed-off-by: Daniel Kiper <[email protected]> --- drivers/xen/balloon.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index a56776d..856661f 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -65,6 +65,7 @@ #include <xen/balloon.h> #include <xen/features.h> #include <xen/page.h> +#include <xen/xenbus.h> /* * balloon_process() state: @@ -586,6 +587,9 @@ static void __init balloon_add_region(unsigned long start_pfn, static int __init balloon_init(void) { int i; +#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG + int rc; +#endif if (!xen_domain()) return -ENODEV; @@ -621,6 +625,27 @@ static int __init balloon_init(void) balloon_add_region(PFN_UP(xen_extra_mem[i].start), PFN_DOWN(xen_extra_mem[i].size)); +#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG + /* + * Notify a host about our memory size limit. + * + * The guest-max value is in KiB, so MAX_DOMAIN_PAGES should + * be converted respectively. PAGE_SHIFT converts pages to bytes, + * hence PAGE_SHIFT - 10. + */ + rc = xenbus_printf(XBT_NIL, "memory", "guest-max", "%lu", + MAX_DOMAIN_PAGES << (PAGE_SHIFT - 10)); + + if (rc < 0) + pr_info("xen/balloon: Memory hotplug may not be supported " + "in some environments: %i\n", rc); +#else + xenbus_printf(XBT_NIL, "memory", "guest-max", "%lu", + (balloon_stats.current_pages + + balloon_stats.balloon_low + + balloon_stats.balloon_high) << (PAGE_SHIFT - 10)); +#endif + return 0; } -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
