aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/xen/balloon.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/xen/balloon.c')
-rw-r--r--drivers/xen/balloon.c149
1 files changed, 113 insertions, 36 deletions
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index b23edf64c2b2..4f4a47ae72b1 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -43,6 +43,8 @@
#include <linux/sched.h>
#include <linux/cred.h>
#include <linux/errno.h>
+#include <linux/freezer.h>
+#include <linux/kthread.h>
#include <linux/mm.h>
#include <linux/bootmem.h>
#include <linux/pagemap.h>
@@ -56,6 +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/pgalloc.h>
@@ -73,6 +76,12 @@
#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
@@ -120,7 +129,7 @@ static struct ctl_table xen_root[] = {
#define EXTENT_ORDER (fls(XEN_PFN_PER_PAGE) - 1)
/*
- * balloon_process() state:
+ * balloon_thread() state:
*
* BP_DONE: done or nothing to do,
* BP_WAIT: wait to be rescheduled,
@@ -128,13 +137,15 @@ 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);
static DEFINE_MUTEX(balloon_mutex);
@@ -149,10 +160,6 @@ static xen_pfn_t frame_list[PAGE_SIZE / sizeof(xen_pfn_t)];
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);
-static DECLARE_DELAYED_WORK(balloon_worker, balloon_process);
-
/* When ballooning out (allocating memory to return to Xen) we don't really
want the kernel to try too hard since that can trigger the oom killer. */
#define GFP_BALLOON \
@@ -206,18 +213,15 @@ 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 (state == BP_ECANCELED)
- return BP_ECANCELED;
+ if (balloon_state == BP_WAIT || balloon_state == BP_ECANCELED)
+ return;
- 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;
@@ -226,7 +230,8 @@ 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;
@@ -234,7 +239,7 @@ 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
@@ -383,7 +388,7 @@ static void xen_online_page(struct page *page)
static int xen_memory_notifier(struct notifier_block *nb, unsigned long val, void *v)
{
if (val == MEM_ONLINE)
- schedule_delayed_work(&balloon_worker, 0);
+ wake_up(&balloon_thread_wq);
return NOTIFY_OK;
}
@@ -508,50 +513,79 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
}
/*
- * As this is a work item it is guaranteed to run as a single instance only.
+ * 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(long credit)
+{
+ if (balloon_state == BP_DONE)
+ credit = 0;
+
+ return current_credit() != credit || kthread_should_stop();
+}
+
+/*
+ * As this is a kthread it is guaranteed to run as a single instance only.
* We may of course race updates of the target counts (which are protected
* by the balloon lock), or with changes to the Xen hard limit, but we will
* recover from these in time.
*/
-static void balloon_process(struct work_struct *work)
+static int balloon_thread(void *unused)
{
- enum bp_state state = BP_DONE;
long credit;
+ unsigned long timeout;
+
+ set_freezable();
+ for (;;) {
+ switch (balloon_state) {
+ case BP_DONE:
+ case BP_ECANCELED:
+ timeout = 3600 * HZ;
+ break;
+ case BP_EAGAIN:
+ timeout = balloon_stats.schedule_delay * HZ;
+ break;
+ case BP_WAIT:
+ timeout = HZ;
+ break;
+ }
+
+ credit = current_credit();
+
+ wait_event_freezable_timeout(balloon_thread_wq,
+ balloon_thread_cond(credit), timeout);
+ if (kthread_should_stop())
+ return 0;
- do {
mutex_lock(&balloon_mutex);
credit = current_credit();
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);
cond_resched();
-
- } while (credit && state == BP_DONE);
-
- /* Schedule more work if there is some still to be done. */
- if (state == BP_EAGAIN)
- schedule_delayed_work(&balloon_worker, balloon_stats.schedule_delay * HZ);
+ }
}
/* Resets the Xen limit, sets new target, and kicks off processing. */
@@ -559,7 +593,7 @@ void balloon_set_new_target(unsigned long target)
{
/* No need for lock. Not read-modify-write updates. */
balloon_stats.target_pages = target;
- schedule_delayed_work(&balloon_worker, 0);
+ wake_up(&balloon_thread_wq);
}
EXPORT_SYMBOL_GPL(balloon_set_new_target);
@@ -664,7 +698,7 @@ void free_xenballooned_pages(int nr_pages, struct page **pages)
/* The balloon may be too large now. Shrink it if needed. */
if (current_credit())
- schedule_delayed_work(&balloon_worker, 0);
+ wake_up(&balloon_thread_wq);
mutex_unlock(&balloon_mutex);
}
@@ -698,6 +732,8 @@ static void __init balloon_add_region(unsigned long start_pfn,
static int __init balloon_init(void)
{
+ struct task_struct *task;
+
if (!xen_domain())
return -ENODEV;
@@ -741,9 +777,50 @@ static int __init balloon_init(void)
}
#endif
+ task = kthread_run(balloon_thread, NULL, "xen-balloon");
+ if (IS_ERR(task)) {
+ pr_err("xen-balloon thread could not be started, ballooning will not work!\n");
+ return PTR_ERR(task);
+ }
+
/* Init the xen-balloon driver. */
xen_balloon_init();
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);
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-05-23 04:45:15 +0000