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authorJana Saout <jana@saout.de>2012-05-15 12:34:46 +0200
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2012-05-21 10:52:53 -0400
commitd79d5959a023fd637e90ed1ff6547ff09d19396b (patch)
treeac84685e07eb11ff45891d992103207cc14f261a /drivers/xen
parentd2fb4c51c7471a23f0a95526b624c14cec62603d (diff)
downloadlinux-linaro-stable-d79d5959a023fd637e90ed1ff6547ff09d19396b.tar.gz
xen: Add selfballoning memory reservation tunable.
Currently, the memory target in the Xen selfballooning driver is mainly driven by the value of "Committed_AS". However, there are cases in which it is desirable to assign additional memory to be available for the kernel, e.g. for local caches (which are not covered by cleancache), e.g. dcache and inode caches. This adds an additional tunable in the selfballooning driver (accessible via sysfs) which allows the user to specify an additional constant amount of memory to be reserved by the selfballoning driver for the local domain. Signed-off-by: Jana Saout <jana@saout.de> Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/xen-selfballoon.c34
1 files changed, 33 insertions, 1 deletions
diff --git a/drivers/xen/xen-selfballoon.c b/drivers/xen/xen-selfballoon.c
index 146c94897016..7d041cb6da26 100644
--- 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,