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path: root/drivers/xen/xenbus/xenbus_probe_backend.c
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Diffstat (limited to 'drivers/xen/xenbus/xenbus_probe_backend.c')
-rw-r--r--drivers/xen/xenbus/xenbus_probe_backend.c39
1 files changed, 38 insertions, 1 deletions
diff --git a/drivers/xen/xenbus/xenbus_probe_backend.c b/drivers/xen/xenbus/xenbus_probe_backend.c
index b0bed4faf44c..791f6fe01e91 100644
--- a/drivers/xen/xenbus/xenbus_probe_backend.c
+++ b/drivers/xen/xenbus/xenbus_probe_backend.c
@@ -198,7 +198,6 @@ static struct xen_bus_type xenbus_backend = {
.uevent = xenbus_uevent_backend,
.probe = xenbus_dev_probe,
.remove = xenbus_dev_remove,
- .shutdown = xenbus_dev_shutdown,
.dev_groups = xenbus_dev_groups,
},
};
@@ -248,6 +247,41 @@ static int backend_probe_and_watch(struct notifier_block *notifier,
return NOTIFY_DONE;
}
+static int backend_reclaim_memory(struct device *dev, void *data)
+{
+ const struct xenbus_driver *drv;
+ struct xenbus_device *xdev;
+
+ if (!dev->driver)
+ return 0;
+ drv = to_xenbus_driver(dev->driver);
+ if (drv && drv->reclaim_memory) {
+ xdev = to_xenbus_device(dev);
+ if (!spin_trylock(&xdev->reclaim_lock))
+ return 0;
+ drv->reclaim_memory(xdev);
+ spin_unlock(&xdev->reclaim_lock);
+ }
+ return 0;
+}
+
+/*
+ * Returns 0 always because we are using shrinker to only detect memory
+ * pressure.
+ */
+static unsigned long backend_shrink_memory_count(struct shrinker *shrinker,
+ struct shrink_control *sc)
+{
+ bus_for_each_dev(&xenbus_backend.bus, NULL, NULL,
+ backend_reclaim_memory);
+ return 0;
+}
+
+static struct shrinker backend_memory_shrinker = {
+ .count_objects = backend_shrink_memory_count,
+ .seeks = DEFAULT_SEEKS,
+};
+
static int __init xenbus_probe_backend_init(void)
{
static struct notifier_block xenstore_notifier = {
@@ -264,6 +298,9 @@ static int __init xenbus_probe_backend_init(void)
register_xenstore_notifier(&xenstore_notifier);
+ if (register_shrinker(&backend_memory_shrinker))
+ pr_warn("shrinker registration failed\n");
+
return 0;
}
subsys_initcall(xenbus_probe_backend_init);