Merge tag 'mfd-3.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/sameo/mfd-2.6

[deliverable/linux.git] / drivers / xen / xen-selfballoon.c

diff --git a/drivers/xen/xen-selfballoon.c b/drivers/xen/xen-selfballoon.c
index 146c948970160147142e22b511439346f6602cf1..7d041cb6da2662fada88101835b94d1aed63b9bc 100644 (file)
--- a/drivers/xen/xen-selfballoon.c
+++ b/drivers/xen/xen-selfballoon.c
@@ -105,6 +105,12 @@ static unsigned int selfballoon_interval __read_mostly = 5;
  */
 static unsigned int selfballoon_min_usable_mb;
 
+/*
+ * Amount of RAM in MB to add to the target number of pages.
+ * Can be used to reserve some more room for caches and the like.
+ */
+static unsigned int selfballoon_reserved_mb;
+
 static void selfballoon_process(struct work_struct *work);
 static DECLARE_DELAYED_WORK(selfballoon_worker, selfballoon_process);
 
@@ -217,7 +223,8 @@ static void selfballoon_process(struct work_struct *work)
                cur_pages = totalram_pages;
                tgt_pages = cur_pages; /* default is no change */
                goal_pages = percpu_counter_read_positive(&vm_committed_as) +
-                               totalreserve_pages;
+                               totalreserve_pages +
+                               MB2PAGES(selfballoon_reserved_mb);
 #ifdef CONFIG_FRONTSWAP
                /* allow space for frontswap pages to be repatriated */
                if (frontswap_selfshrinking && frontswap_enabled)
@@ -397,6 +404,30 @@ static DEVICE_ATTR(selfballoon_min_usable_mb, S_IRUGO | S_IWUSR,
                   show_selfballoon_min_usable_mb,
                   store_selfballoon_min_usable_mb);
 
+SELFBALLOON_SHOW(selfballoon_reserved_mb, "%d\n",
+                               selfballoon_reserved_mb);
+
+static ssize_t store_selfballoon_reserved_mb(struct device *dev,
+                                            struct device_attribute *attr,
+                                            const char *buf,
+                                            size_t count)
+{
+       unsigned long val;
+       int err;
+
+       if (!capable(CAP_SYS_ADMIN))
+               return -EPERM;
+       err = strict_strtoul(buf, 10, &val);
+       if (err || val == 0)
+               return -EINVAL;
+       selfballoon_reserved_mb = val;
+       return count;
+}
+
+static DEVICE_ATTR(selfballoon_reserved_mb, S_IRUGO | S_IWUSR,
+                  show_selfballoon_reserved_mb,
+                  store_selfballoon_reserved_mb);
+
 
 #ifdef CONFIG_FRONTSWAP
 SELFBALLOON_SHOW(frontswap_selfshrinking, "%d\n", frontswap_selfshrinking);
@@ -480,6 +511,7 @@ static struct attribute *selfballoon_attrs[] = {
        &dev_attr_selfballoon_downhysteresis.attr,
        &dev_attr_selfballoon_uphysteresis.attr,
        &dev_attr_selfballoon_min_usable_mb.attr,
+       &dev_attr_selfballoon_reserved_mb.attr,
 #ifdef CONFIG_FRONTSWAP
        &dev_attr_frontswap_selfshrinking.attr,
        &dev_attr_frontswap_hysteresis.attr,