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-rw-r--r--drivers/xen/balloon.c90
-rw-r--r--include/xen/balloon.h1
2 files changed, 81 insertions, 10 deletions
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 7ec933d505d2..25fd1bd949d8 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -55,6 +55,7 @@
#include <linux/memory_hotplug.h>
#include <linux/percpu-defs.h>
#include <linux/slab.h>
+#include <linux/sysctl.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
@@ -71,6 +72,46 @@
#include <xen/features.h>
#include <xen/page.h>
+static int xen_hotplug_unpopulated;
+
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+
+static int zero;
+static int one = 1;
+
+static struct ctl_table balloon_table[] = {
+ {
+ .procname = "hotplug_unpopulated",
+ .data = &xen_hotplug_unpopulated,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &one,
+ },
+ { }
+};
+
+static struct ctl_table balloon_root[] = {
+ {
+ .procname = "balloon",
+ .mode = 0555,
+ .child = balloon_table,
+ },
+ { }
+};
+
+static struct ctl_table xen_root[] = {
+ {
+ .procname = "xen",
+ .mode = 0555,
+ .child = balloon_root,
+ },
+ { }
+};
+
+#endif
+
/*
* balloon_process() state:
*
@@ -99,6 +140,7 @@ static xen_pfn_t frame_list[PAGE_SIZE / sizeof(unsigned long)];
/* List of ballooned pages, threaded through the mem_map array. */
static LIST_HEAD(ballooned_pages);
+static DECLARE_WAIT_QUEUE_HEAD(balloon_wq);
/* Main work function, always executed in process context. */
static void balloon_process(struct work_struct *work);
@@ -127,6 +169,7 @@ static void __balloon_append(struct page *page)
list_add(&page->lru, &ballooned_pages);
balloon_stats.balloon_low++;
}
+ wake_up(&balloon_wq);
}
static void balloon_append(struct page *page)
@@ -242,7 +285,8 @@ static enum bp_state reserve_additional_memory(void)
int nid, rc;
unsigned long balloon_hotplug;
- credit = balloon_stats.target_pages - balloon_stats.total_pages;
+ credit = balloon_stats.target_pages + balloon_stats.target_unpopulated
+ - balloon_stats.total_pages;
/*
* Already hotplugged enough pages? Wait for them to be
@@ -323,7 +367,7 @@ static struct notifier_block xen_memory_nb = {
static enum bp_state reserve_additional_memory(void)
{
balloon_stats.target_pages = balloon_stats.current_pages;
- return BP_DONE;
+ return BP_ECANCELED;
}
#endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */
@@ -516,6 +560,28 @@ void balloon_set_new_target(unsigned long target)
}
EXPORT_SYMBOL_GPL(balloon_set_new_target);
+static int add_ballooned_pages(int nr_pages)
+{
+ enum bp_state st;
+
+ if (xen_hotplug_unpopulated) {
+ st = reserve_additional_memory();
+ if (st != BP_ECANCELED) {
+ mutex_unlock(&balloon_mutex);
+ wait_event(balloon_wq,
+ !list_empty(&ballooned_pages));
+ mutex_lock(&balloon_mutex);
+ return 0;
+ }
+ }
+
+ st = decrease_reservation(nr_pages, GFP_USER);
+ if (st != BP_DONE)
+ return -ENOMEM;
+
+ return 0;
+}
+
/**
* alloc_xenballooned_pages - get pages that have been ballooned out
* @nr_pages: Number of pages to get
@@ -526,27 +592,28 @@ int alloc_xenballooned_pages(int nr_pages, struct page **pages)
{
int pgno = 0;
struct page *page;
+ int ret;
+
mutex_lock(&balloon_mutex);
+
+ balloon_stats.target_unpopulated += nr_pages;
+
while (pgno < nr_pages) {
page = balloon_retrieve(true);
if (page) {
pages[pgno++] = page;
} else {
- enum bp_state st;
- st = decrease_reservation(nr_pages - pgno, GFP_USER);
- if (st != BP_DONE)
+ ret = add_ballooned_pages(nr_pages - pgno);
+ if (ret < 0)
goto out_undo;
}
}
mutex_unlock(&balloon_mutex);
return 0;
out_undo:
- while (pgno)
- balloon_append(pages[--pgno]);
- /* Free the memory back to the kernel soon */
- schedule_delayed_work(&balloon_worker, 0);
mutex_unlock(&balloon_mutex);
- return -ENOMEM;
+ free_xenballooned_pages(pgno, pages);
+ return ret;
}
EXPORT_SYMBOL(alloc_xenballooned_pages);
@@ -566,6 +633,8 @@ void free_xenballooned_pages(int nr_pages, struct page **pages)
balloon_append(pages[i]);
}
+ balloon_stats.target_unpopulated -= nr_pages;
+
/* The balloon may be too large now. Shrink it if needed. */
if (current_credit())
schedule_delayed_work(&balloon_worker, 0);
@@ -623,6 +692,7 @@ static int __init balloon_init(void)
#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
set_online_page_callback(&xen_online_page);
register_memory_notifier(&xen_memory_nb);
+ register_sysctl_table(xen_root);
#endif
/*
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;