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path: root/drivers/block/xen-blkback/xenbus.c
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Diffstat (limited to 'drivers/block/xen-blkback/xenbus.c')
-rw-r--r--drivers/block/xen-blkback/xenbus.c26
1 files changed, 22 insertions, 4 deletions
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 4c5d99f87813..42944d41aea0 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -467,7 +467,6 @@ static void xenvbd_sysfs_delif(struct xenbus_device *dev)
device_remove_file(&dev->dev, &dev_attr_physical_device);
}
-
static void xen_vbd_free(struct xen_vbd *vbd)
{
if (vbd->bdev)
@@ -524,6 +523,7 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
handle, blkif->domid);
return 0;
}
+
static int xen_blkbk_remove(struct xenbus_device *dev)
{
struct backend_info *be = dev_get_drvdata(&dev->dev);
@@ -607,6 +607,7 @@ static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info
if (err)
dev_warn(&dev->dev, "writing feature-discard (%d)", err);
}
+
int xen_blkbk_barrier(struct xenbus_transaction xbt,
struct backend_info *be, int state)
{
@@ -691,7 +692,6 @@ fail:
return err;
}
-
/*
* Callback received when the hotplug scripts have placed the physical-device
* node. Read it and the mode node, and create a vbd. If the frontend is
@@ -783,7 +783,6 @@ static void backend_changed(struct xenbus_watch *watch,
}
}
-
/*
* Callback received when the frontend's state changes.
*/
@@ -858,9 +857,27 @@ static void frontend_changed(struct xenbus_device *dev,
}
}
+/* Once a memory pressure is detected, squeeze free page pools for a while. */
+static unsigned int buffer_squeeze_duration_ms = 10;
+module_param_named(buffer_squeeze_duration_ms,
+ buffer_squeeze_duration_ms, int, 0644);
+MODULE_PARM_DESC(buffer_squeeze_duration_ms,
+"Duration in ms to squeeze pages buffer when a memory pressure is detected");
-/* ** Connection ** */
+/*
+ * Callback received when the memory pressure is detected.
+ */
+static void reclaim_memory(struct xenbus_device *dev)
+{
+ struct backend_info *be = dev_get_drvdata(&dev->dev);
+ if (!be)
+ return;
+ be->blkif->buffer_squeeze_end = jiffies +
+ msecs_to_jiffies(buffer_squeeze_duration_ms);
+}
+
+/* ** Connection ** */
/*
* Write the physical details regarding the block device to the store, and
@@ -1152,6 +1169,7 @@ static struct xenbus_driver xen_blkbk_driver = {
.remove = xen_blkbk_remove,
.otherend_changed = frontend_changed,
.allow_rebind = true,
+ .reclaim_memory = reclaim_memory,
};
int xen_blkif_xenbus_init(void)