diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 43dc35fe5bc0..1396fd2d9031 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -6349,6 +6349,13 @@
improve timer resolution at the expense of processing
more timer interrupts.
+ xen.balloon_boot_timeout= [XEN]
+ The time (in seconds) to wait before giving up to boot
+ in case initial ballooning fails to free enough memory.
+ Applies only when running as HVM or PVH guest and
+ started with less memory configured than allowed at
+ max. Default is 180.
+
xen.event_eoi_delay= [XEN]
How long to delay EOI handling in case of event
storms (jiffies). Default is 10.
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 3a50f097ed3e..8db96b5e7253 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -58,6 +58,7 @@
#include <linux/percpu-defs.h>
#include <linux/slab.h>
#include <linux/sysctl.h>
+#include <linux/moduleparam.h>
#include <asm/page.h>
#include <asm/tlb.h>
@@ -73,6 +74,12 @@
#include <xen/page.h>
#include <xen/mem-reservation.h>
+#undef MODULE_PARAM_PREFIX
+#define MODULE_PARAM_PREFIX "xen."
+
+static uint __read_mostly balloon_boot_timeout = 180;
+module_param(balloon_boot_timeout, uint, 0444);
+
static int xen_hotplug_unpopulated;
#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
@@ -125,12 +132,12 @@ static struct ctl_table xen_root[] = {
* BP_ECANCELED: error, balloon operation canceled.
*/
-enum bp_state {
+static enum bp_state {
BP_DONE,
BP_WAIT,
BP_EAGAIN,
BP_ECANCELED
-};
+} balloon_state = BP_DONE;
/* Main waiting point for xen-balloon thread. */
static DECLARE_WAIT_QUEUE_HEAD(balloon_thread_wq);
@@ -199,18 +206,15 @@ static struct page *balloon_next_page(struct page *page)
return list_entry(next, struct page, lru);
}
-static enum bp_state update_schedule(enum bp_state state)
+static void update_schedule(void)
{
- if (state == BP_WAIT)
- return BP_WAIT;
+ if (balloon_state == BP_WAIT || balloon_state == BP_ECANCELED)
+ return;
- if (state == BP_ECANCELED)
- return BP_ECANCELED;
-
- if (state == BP_DONE) {
+ if (balloon_state == BP_DONE) {
balloon_stats.schedule_delay = 1;
balloon_stats.retry_count = 1;
- return BP_DONE;
+ return;
}
++balloon_stats.retry_count;
@@ -219,7 +223,8 @@ static enum bp_state update_schedule(enum bp_state state)
balloon_stats.retry_count > balloon_stats.max_retry_count) {
balloon_stats.schedule_delay = 1;
balloon_stats.retry_count = 1;
- return BP_ECANCELED;
+ balloon_state = BP_ECANCELED;
+ return;
}
balloon_stats.schedule_delay <<= 1;
@@ -227,7 +232,7 @@ static enum bp_state update_schedule(enum bp_state state)
if (balloon_stats.schedule_delay > balloon_stats.max_schedule_delay)
balloon_stats.schedule_delay = balloon_stats.max_schedule_delay;
- return BP_EAGAIN;
+ balloon_state = BP_EAGAIN;
}
#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
@@ -494,9 +499,9 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
* Stop waiting if either state is BP_DONE and ballooning action is
* needed, or if the credit has changed while state is not BP_DONE.
*/
-static bool balloon_thread_cond(enum bp_state state, long credit)
+static bool balloon_thread_cond(long credit)
{
- if (state == BP_DONE)
+ if (balloon_state == BP_DONE)
credit = 0;
return current_credit() != credit || kthread_should_stop();
@@ -510,13 +515,12 @@ static bool balloon_thread_cond(enum bp_state state, long credit)
*/
static int balloon_thread(void *unused)
{
- enum bp_state state = BP_DONE;
long credit;
unsigned long timeout;
set_freezable();
for (;;) {
- switch (state) {
+ switch (balloon_state) {
case BP_DONE:
case BP_ECANCELED:
timeout = 3600 * HZ;
@@ -532,7 +536,7 @@ static int balloon_thread(void *unused)
credit = current_credit();
wait_event_freezable_timeout(balloon_thread_wq,
- balloon_thread_cond(state, credit), timeout);
+ balloon_thread_cond(credit), timeout);
if (kthread_should_stop())
return 0;
@@ -543,22 +547,23 @@ static int balloon_thread(void *unused)
if (credit > 0) {
if (balloon_is_inflated())
- state = increase_reservation(credit);
+ balloon_state = increase_reservation(credit);
else
- state = reserve_additional_memory();
+ balloon_state = reserve_additional_memory();
}
if (credit < 0) {
long n_pages;
n_pages = min(-credit, si_mem_available());
- state = decrease_reservation(n_pages, GFP_BALLOON);
- if (state == BP_DONE && n_pages != -credit &&
+ balloon_state = decrease_reservation(n_pages,
+ GFP_BALLOON);
+ if (balloon_state == BP_DONE && n_pages != -credit &&
n_pages < totalreserve_pages)
- state = BP_EAGAIN;
+ balloon_state = BP_EAGAIN;
}
- state = update_schedule(state);
+ update_schedule();
mutex_unlock(&balloon_mutex);
@@ -765,3 +770,38 @@ static int __init balloon_init(void)
return 0;
}
subsys_initcall(balloon_init);
+
+static int __init balloon_wait_finish(void)
+{
+ long credit, last_credit = 0;
+ unsigned long last_changed = 0;
+
+ if (!xen_domain())
+ return -ENODEV;
+
+ /* PV guests don't need to wait. */
+ if (xen_pv_domain() || !current_credit())
+ return 0;
+
+ pr_notice("Waiting for initial ballooning down having finished.\n");
+
+ while ((credit = current_credit()) < 0) {
+ if (credit != last_credit) {
+ last_changed = jiffies;
+ last_credit = credit;
+ }
+ if (balloon_state == BP_ECANCELED) {
+ pr_warn_once("Initial ballooning failed, %ld pages need to be freed.\n",
+ -credit);
+ if (jiffies - last_changed >= HZ * balloon_boot_timeout)
+ panic("Initial ballooning failed!\n");
+ }
+
+ schedule_timeout_interruptible(HZ / 10);
+ }
+
+ pr_notice("Initial ballooning down finished.\n");
+
+ return 0;
+}
+late_initcall_sync(balloon_wait_finish);