[RFC PATCH] Fixes and cleanups to the tmem driver. (v1)

[RFC PATCH] Fixes and cleanups to the tmem driver. (v1)

[Konrad Rzeszutek Wilk]

These patches are RFC - I hadn't yet completly tested them. But they
fix the annoying:
 drivers/xen/tmem.c:365:13: warning: 'disable_frontswap_selfshrinking' defined but not used [-Wunused-variable]

(patch #4: [PATCH 4/8] xen/tmem: Fix compile warning. does it).

The rest are cleanups and removes some of the #ifdef machinary.

I hadn't yet the full testing and I am sure I am missing some
other documentation I should update.

 Documentation/kernel-parameters.txt | 20 ++++++++++
 drivers/xen/Kconfig                 |  7 ++--
 drivers/xen/tmem.c                  | 79 +++++++++++++++----------------------
 drivers/xen/xen-selfballoon.c       | 36 +----------------
 4 files changed, 56 insertions(+), 86 deletions(-)

(Yeey! More deletions!)

Konrad Rzeszutek Wilk (8):
      xen/tmem: Cleanup. Remove the parts that say temporary.
      xen/tmem: Move all of the boot and module parameters to the top of the file.
      xen/tmem: Split out the different module/boot options.
      xen/tmem: Fix compile warning.
      xen/tmem: s/disable_// and change the logic.
      xen/tmem: Remove the boot options and fold them in the tmem.X parameters.
      xen/tmem: Remove the usage of 'noselfshrink' and use 'tmem.selfshrink' bool instead.
      xen/tmem: Remove the usage of 'noselfballoon','selfballoon' and use 'tmem.selfballon' bool instead.

[PATCH 1/8] xen/tmem: Cleanup. Remove the parts that say temporary.

[Konrad Rzeszutek Wilk]

Frontswap is upstream, no need for this #ifdef.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/tmem.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
index e3600be..5686d6d 100644
--- a/drivers/xen/tmem.c
+++ b/drivers/xen/tmem.c
@@ -11,11 +11,7 @@
 #include <linux/init.h>
 #include <linux/pagemap.h>
 #include <linux/cleancache.h>
-
-/* temporary ifdef until include/linux/frontswap.h is upstream */
-#ifdef CONFIG_FRONTSWAP
 #include <linux/frontswap.h>
-#endif
 
 #include <xen/xen.h>
 #include <xen/interface/xen.h>
-- 
1.8.1.4

[PATCH 2/8] xen/tmem: Move all of the boot and module parameters to the top of the file.

[Konrad Rzeszutek Wilk]

Just code movement to see the different boot or module parameters.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/tmem.c | 85 +++++++++++++++++++++++++++++-------------------------
 1 file changed, 45 insertions(+), 40 deletions(-)

diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
index 5686d6d..edf7e18 100644
--- a/drivers/xen/tmem.c
+++ b/drivers/xen/tmem.c
@@ -20,6 +20,51 @@
 #include <asm/xen/hypervisor.h>
 #include <xen/tmem.h>
 
+#ifndef CONFIG_XEN_TMEM_MODULE
+bool __read_mostly tmem_enabled = false;
+
+static int __init enable_tmem(char *s)
+{
+	tmem_enabled = true;
+	return 1;
+}
+__setup("tmem", enable_tmem);
+#endif
+
+#ifdef CONFIG_CLEANCACHE
+static bool disable_cleancache __read_mostly;
+static bool disable_selfballooning __read_mostly;
+#ifdef CONFIG_XEN_TMEM_MODULE
+module_param(disable_cleancache, bool, S_IRUGO);
+module_param(disable_selfballooning, bool, S_IRUGO);
+#else
+static int __init no_cleancache(char *s)
+{
+	disable_cleancache = true;
+	return 1;
+}
+__setup("nocleancache", no_cleancache);
+#endif
+#endif /* CONFIG_CLEANCACHE */
+
+#ifdef CONFIG_FRONTSWAP
+static bool disable_frontswap __read_mostly;
+static bool disable_frontswap_selfshrinking __read_mostly;
+#ifdef CONFIG_XEN_TMEM_MODULE
+module_param(disable_frontswap, bool, S_IRUGO);
+module_param(disable_frontswap_selfshrinking, bool, S_IRUGO);
+#else
+static int __init no_frontswap(char *s)
+{
+	disable_frontswap = true;
+	return 1;
+}
+__setup("nofrontswap", no_frontswap);
+#endif
+#else /* CONFIG_FRONTSWAP */
+#define disable_frontswap_selfshrinking 1
+#endif /* CONFIG_FRONTSWAP */
+
 #define TMEM_CONTROL               0
 #define TMEM_NEW_POOL              1
 #define TMEM_DESTROY_POOL          2
@@ -125,16 +170,6 @@ static int xen_tmem_flush_object(u32 pool_id, struct tmem_oid oid)
 	return xen_tmem_op(TMEM_FLUSH_OBJECT, pool_id, oid, 0, 0, 0, 0, 0);
 }
 
-#ifndef CONFIG_XEN_TMEM_MODULE
-bool __read_mostly tmem_enabled = false;
-
-static int __init enable_tmem(char *s)
-{
-	tmem_enabled = true;
-	return 1;
-}
-__setup("tmem", enable_tmem);
-#endif
 
 #ifdef CONFIG_CLEANCACHE
 static int xen_tmem_destroy_pool(u32 pool_id)
@@ -226,20 +261,6 @@ static int tmem_cleancache_init_shared_fs(char *uuid, size_t pagesize)
 	return xen_tmem_new_pool(shared_uuid, TMEM_POOL_SHARED, pagesize);
 }
 
-static bool disable_cleancache __read_mostly;
-static bool disable_selfballooning __read_mostly;
-#ifdef CONFIG_XEN_TMEM_MODULE
-module_param(disable_cleancache, bool, S_IRUGO);
-module_param(disable_selfballooning, bool, S_IRUGO);
-#else
-static int __init no_cleancache(char *s)
-{
-	disable_cleancache = true;
-	return 1;
-}
-__setup("nocleancache", no_cleancache);
-#endif
-
 static struct cleancache_ops tmem_cleancache_ops = {
 	.put_page = tmem_cleancache_put_page,
 	.get_page = tmem_cleancache_get_page,
@@ -357,20 +378,6 @@ static void tmem_frontswap_init(unsigned ignored)
 		    xen_tmem_new_pool(private, TMEM_POOL_PERSIST, PAGE_SIZE);
 }
 
-static bool disable_frontswap __read_mostly;
-static bool disable_frontswap_selfshrinking __read_mostly;
-#ifdef CONFIG_XEN_TMEM_MODULE
-module_param(disable_frontswap, bool, S_IRUGO);
-module_param(disable_frontswap_selfshrinking, bool, S_IRUGO);
-#else
-static int __init no_frontswap(char *s)
-{
-	disable_frontswap = true;
-	return 1;
-}
-__setup("nofrontswap", no_frontswap);
-#endif
-
 static struct frontswap_ops tmem_frontswap_ops = {
 	.store = tmem_frontswap_store,
 	.load = tmem_frontswap_load,
@@ -378,8 +385,6 @@ static struct frontswap_ops tmem_frontswap_ops = {
 	.invalidate_area = tmem_frontswap_flush_area,
 	.init = tmem_frontswap_init
 };
-#else	/* CONFIG_FRONTSWAP */
-#define disable_frontswap_selfshrinking 1
 #endif
 
 static int xen_tmem_init(void)
-- 
1.8.1.4

[PATCH 3/8] xen/tmem: Split out the different module/boot options.

[Konrad Rzeszutek Wilk]

There are three options - depending on what combination of
CONFIG_FRONTSWAP, CONFIG_CLEANCACHE and CONFIG_XEN_SELFBALLOONING
is used. Lets split them out nicely out in three groups to
make it easier to clean up.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/tmem.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
index edf7e18..c2ee188 100644
--- a/drivers/xen/tmem.c
+++ b/drivers/xen/tmem.c
@@ -49,10 +49,8 @@ __setup("nocleancache", no_cleancache);
 
 #ifdef CONFIG_FRONTSWAP
 static bool disable_frontswap __read_mostly;
-static bool disable_frontswap_selfshrinking __read_mostly;
 #ifdef CONFIG_XEN_TMEM_MODULE
 module_param(disable_frontswap, bool, S_IRUGO);
-module_param(disable_frontswap_selfshrinking, bool, S_IRUGO);
 #else
 static int __init no_frontswap(char *s)
 {
@@ -61,8 +59,15 @@ static int __init no_frontswap(char *s)
 }
 __setup("nofrontswap", no_frontswap);
 #endif
-#else /* CONFIG_FRONTSWAP */
+#endif /* CONFIG_FRONTSWAP */
+
+#ifdef CONFIG_FRONTSWAP
+static bool disable_frontswap_selfshrinking __read_mostly;
+#ifdef CONFIG_XEN_TMEM_MODULE
+module_param(disable_frontswap_selfshrinking, bool, S_IRUGO);
+#else
 #define disable_frontswap_selfshrinking 1
+#endif
 #endif /* CONFIG_FRONTSWAP */
 
 #define TMEM_CONTROL               0
-- 
1.8.1.4

[PATCH 4/8] xen/tmem: Fix compile warning.

[Konrad Rzeszutek Wilk]

We keep on getting:
drivers/xen/tmem.c:65:13: warning: ‘disable_frontswap_selfshrinking’ defined but not used [-Wunused-variable]

if CONFIG_FRONTSWAP=y and # CONFIG_CLEANCACHE is not set

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/tmem.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
index c2ee188..30bf974 100644
--- a/drivers/xen/tmem.c
+++ b/drivers/xen/tmem.c
@@ -61,14 +61,12 @@ __setup("nofrontswap", no_frontswap);
 #endif
 #endif /* CONFIG_FRONTSWAP */
 
-#ifdef CONFIG_FRONTSWAP
+#ifdef CONFIG_XEN_SELFBALLOONING
 static bool disable_frontswap_selfshrinking __read_mostly;
 #ifdef CONFIG_XEN_TMEM_MODULE
 module_param(disable_frontswap_selfshrinking, bool, S_IRUGO);
-#else
-#define disable_frontswap_selfshrinking 1
 #endif
-#endif /* CONFIG_FRONTSWAP */
+#endif /* CONFIG_XEN_SELFBALLOONING */
 
 #define TMEM_CONTROL               0
 #define TMEM_NEW_POOL              1
-- 
1.8.1.4

[PATCH 5/8] xen/tmem: s/disable_// and change the logic.

[Konrad Rzeszutek Wilk]

The variety of disable_[cleancache|frontswap|selfshrinking] are
making this a bit complex. Just remove the "disable_" part and
change the logic around for the "nofrontswap" and "nocleancache"
parameters.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/tmem.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
index 30bf974..411c7e3 100644
--- a/drivers/xen/tmem.c
+++ b/drivers/xen/tmem.c
@@ -32,15 +32,15 @@ __setup("tmem", enable_tmem);
 #endif
 
 #ifdef CONFIG_CLEANCACHE
-static bool disable_cleancache __read_mostly;
-static bool disable_selfballooning __read_mostly;
+static bool cleancache __read_mostly = true;
+static bool selfballooning __read_mostly = true;
 #ifdef CONFIG_XEN_TMEM_MODULE
-module_param(disable_cleancache, bool, S_IRUGO);
-module_param(disable_selfballooning, bool, S_IRUGO);
+module_param(cleancache, bool, S_IRUGO);
+module_param(selfballooning, bool, S_IRUGO);
 #else
 static int __init no_cleancache(char *s)
 {
-	disable_cleancache = true;
+	cleancache = false;
 	return 1;
 }
 __setup("nocleancache", no_cleancache);
@@ -48,13 +48,13 @@ __setup("nocleancache", no_cleancache);
 #endif /* CONFIG_CLEANCACHE */
 
 #ifdef CONFIG_FRONTSWAP
-static bool disable_frontswap __read_mostly;
+static bool frontswap __read_mostly = true;
 #ifdef CONFIG_XEN_TMEM_MODULE
-module_param(disable_frontswap, bool, S_IRUGO);
+module_param(frontswap, bool, S_IRUGO);
 #else
 static int __init no_frontswap(char *s)
 {
-	disable_frontswap = true;
+	frontswap = false;
 	return 1;
 }
 __setup("nofrontswap", no_frontswap);
@@ -62,9 +62,9 @@ __setup("nofrontswap", no_frontswap);
 #endif /* CONFIG_FRONTSWAP */
 
 #ifdef CONFIG_XEN_SELFBALLOONING
-static bool disable_frontswap_selfshrinking __read_mostly;
+static bool frontswap_selfshrinking __read_mostly = true;
 #ifdef CONFIG_XEN_TMEM_MODULE
-module_param(disable_frontswap_selfshrinking, bool, S_IRUGO);
+module_param(frontswap_selfshrinking, bool, S_IRUGO);
 #endif
 #endif /* CONFIG_XEN_SELFBALLOONING */
 
@@ -395,7 +395,7 @@ static int xen_tmem_init(void)
 	if (!xen_domain())
 		return 0;
 #ifdef CONFIG_FRONTSWAP
-	if (tmem_enabled && !disable_frontswap) {
+	if (tmem_enabled && frontswap) {
 		char *s = "";
 		struct frontswap_ops *old_ops =
 			frontswap_register_ops(&tmem_frontswap_ops);
@@ -412,7 +412,7 @@ static int xen_tmem_init(void)
 #endif
 #ifdef CONFIG_CLEANCACHE
 	BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
-	if (tmem_enabled && !disable_cleancache) {
+	if (tmem_enabled && cleancache) {
 		char *s = "";
 		struct cleancache_ops *old_ops =
 			cleancache_register_ops(&tmem_cleancache_ops);
@@ -423,8 +423,7 @@ static int xen_tmem_init(void)
 	}
 #endif
 #ifdef CONFIG_XEN_SELFBALLOONING
-	xen_selfballoon_init(!disable_selfballooning,
-				!disable_frontswap_selfshrinking);
+	xen_selfballoon_init(selfballooning, frontswap_selfshrinking);
 #endif
 	return 0;
 }
-- 
1.8.1.4

[PATCH 6/8] xen/tmem: Remove the boot options and fold them in the tmem.X parameters.

[Konrad Rzeszutek Wilk]

If tmem is built-in or a module, the user has the option on
the command line to influence it by doing: tmem.<some option>
instead of having a variety of "nocleancache", and
"nofrontswap". The others: "noselfballooning" and "selfballooning";
and "noselfshrink" are in a different driver xen-selfballoon.c
and the patches:

 xen/tmem: Remove the usage of 'noselfshrink' and use 'tmem.selfshrink' bool instead.
 xen/tmem: Remove the usage of 'noselfballoon','selfballoon' and use 'tmem.selfballon' bool instead.

removes them.

Also add documentation.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 Documentation/kernel-parameters.txt | 20 ++++++++++++++++++++
 drivers/xen/tmem.c                  | 28 ++++------------------------
 2 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index c3bfacb..3de01ed 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3005,6 +3005,26 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			Force threading of all interrupt handlers except those
 			marked explicitly IRQF_NO_THREAD.
 
+	tmem		[KNL,XEN]
+			Enable the Transcendent memory driver if built-in.
+
+	tmem.cleancache=0|1 [KNL, XEN]
+			Default is on (1). Disable the usage of the cleancache
+			API to send anonymous pages to the hypervisor.
+
+	tmem.frontswap=0|1 [KNL, XEN]
+			Default is on (1). Disable the usage of the frontswap
+			API to send swap pages to the hypervisor.
+
+	tmem.selfballooning=0|1 [KNL, XEN]
+			Default is on (1). Disable the driving of swap pages
+			to the hypervisor.
+
+	tmem.selfshrinking=0|1 [KNL, XEN]
+			Default is on (1). Partial swapoff that immediately
+			transfers pages from Xen hypervisor back to the
+			kernel based on different criteria.
+
 	topology=	[S390]
 			Format: {off | on}
 			Specify if the kernel should make use of the cpu
diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
index 411c7e3..c1df0ff 100644
--- a/drivers/xen/tmem.c
+++ b/drivers/xen/tmem.c
@@ -33,39 +33,19 @@ __setup("tmem", enable_tmem);
 
 #ifdef CONFIG_CLEANCACHE
 static bool cleancache __read_mostly = true;
-static bool selfballooning __read_mostly = true;
-#ifdef CONFIG_XEN_TMEM_MODULE
 module_param(cleancache, bool, S_IRUGO);
+static bool selfballooning __read_mostly = true;
 module_param(selfballooning, bool, S_IRUGO);
-#else
-static int __init no_cleancache(char *s)
-{
-	cleancache = false;
-	return 1;
-}
-__setup("nocleancache", no_cleancache);
-#endif
 #endif /* CONFIG_CLEANCACHE */
 
 #ifdef CONFIG_FRONTSWAP
 static bool frontswap __read_mostly = true;
-#ifdef CONFIG_XEN_TMEM_MODULE
 module_param(frontswap, bool, S_IRUGO);
-#else
-static int __init no_frontswap(char *s)
-{
-	frontswap = false;
-	return 1;
-}
-__setup("nofrontswap", no_frontswap);
-#endif
 #endif /* CONFIG_FRONTSWAP */
 
 #ifdef CONFIG_XEN_SELFBALLOONING
-static bool frontswap_selfshrinking __read_mostly = true;
-#ifdef CONFIG_XEN_TMEM_MODULE
-module_param(frontswap_selfshrinking, bool, S_IRUGO);
-#endif
+static bool selfshrinking __read_mostly = true;
+module_param(selfshrinking, bool, S_IRUGO);
 #endif /* CONFIG_XEN_SELFBALLOONING */
 
 #define TMEM_CONTROL               0
@@ -423,7 +403,7 @@ static int xen_tmem_init(void)
 	}
 #endif
 #ifdef CONFIG_XEN_SELFBALLOONING
-	xen_selfballoon_init(selfballooning, frontswap_selfshrinking);
+	xen_selfballoon_init(selfballooning, selfshrinking);
 #endif
 	return 0;
 }
-- 
1.8.1.4

[PATCH 7/8] xen/tmem: Remove the usage of 'noselfshrink' and use 'tmem.selfshrink' bool instead.

[Konrad Rzeszutek Wilk]

As the 'tmem' driver is the one that actually sets whether
it will use it or not so might as well make tmem responsible
for this knob.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/Kconfig           |  2 +-
 drivers/xen/xen-selfballoon.c | 15 ++-------------
 2 files changed, 3 insertions(+), 14 deletions(-)

diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index dd4d9cb..b0337a6 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -22,7 +22,7 @@ config XEN_SELFBALLOONING
 	  ballooning is disabled by default but can be enabled with the
 	  'selfballooning' kernel boot parameter.  If FRONTSWAP is configured,
 	  frontswap-selfshrinking is enabled by default but can be disabled
-	  with the 'noselfshrink' kernel boot parameter; and self-ballooning
+	  with the 'tmem.selfshrink=0' kernel boot parameter; and self-ballooning
 	  is enabled by default but can be disabled with the 'noselfballooning'
 	  kernel boot parameter.  Note that systems without a sufficiently
 	  large swap device should not enable self-ballooning.
diff --git a/drivers/xen/xen-selfballoon.c b/drivers/xen/xen-selfballoon.c
index f2ef569..012f9d9 100644
--- a/drivers/xen/xen-selfballoon.c
+++ b/drivers/xen/xen-selfballoon.c
@@ -60,8 +60,8 @@
  * be enabled with the "selfballooning" kernel boot option; similarly
  * selfballooning is enabled by default if frontswap is configured and
  * can be disabled with the "noselfballooning" kernel boot option.  Finally,
- * when frontswap is configured, frontswap-selfshrinking can be disabled
- * with the "noselfshrink" kernel boot option.
+ * when frontswap is configured,frontswap-selfshrinking can be disabled
+ * with the "tmem.selfshrink=0" kernel boot option.
  *
  * Selfballooning is disallowed in domain0 and force-disabled.
  *
@@ -120,9 +120,6 @@ static DECLARE_DELAYED_WORK(selfballoon_worker, selfballoon_process);
 /* Enable/disable with sysfs. */
 static bool frontswap_selfshrinking __read_mostly;
 
-/* Enable/disable with kernel boot option. */
-static bool use_frontswap_selfshrink = true;
-
 /*
  * The default values for the following parameters were deemed reasonable
  * by experimentation, may be workload-dependent, and can all be
@@ -176,14 +173,6 @@ static void frontswap_selfshrink(void)
 	frontswap_shrink(tgt_frontswap_pages);
 }
 
-static int __init xen_nofrontswap_selfshrink_setup(char *s)
-{
-	use_frontswap_selfshrink = false;
-	return 1;
-}
-
-__setup("noselfshrink", xen_nofrontswap_selfshrink_setup);
-
 /* Disable with kernel boot option. */
 static bool use_selfballooning = true;
 
-- 
1.8.1.4

[PATCH 8/8] xen/tmem: Remove the usage of 'noselfballoon','selfballoon' and use 'tmem.selfballon' bool instead.

[Konrad Rzeszutek Wilk]

As the 'tmem' driver is the one that actually sets whether
it will use it or not so might as well make tmem responsible
for this knob.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/Kconfig           |  5 ++---
 drivers/xen/xen-selfballoon.c | 21 ---------------------
 2 files changed, 2 insertions(+), 24 deletions(-)

diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index b0337a6..221b3a6 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -19,11 +19,10 @@ config XEN_SELFBALLOONING
 	  by the current usage of anonymous memory ("committed AS") and
 	  controlled by various sysfs-settable parameters.  Configuring
 	  FRONTSWAP is highly recommended; if it is not configured, self-
-	  ballooning is disabled by default but can be enabled with the
-	  'selfballooning' kernel boot parameter.  If FRONTSWAP is configured,
+	  ballooning is disabled by default. If FRONTSWAP is configured,
 	  frontswap-selfshrinking is enabled by default but can be disabled
 	  with the 'tmem.selfshrink=0' kernel boot parameter; and self-ballooning
-	  is enabled by default but can be disabled with the 'noselfballooning'
+	  is enabled by default but can be disabled with the 'tmem.selfballooning=0'
 	  kernel boot parameter.  Note that systems without a sufficiently
 	  large swap device should not enable self-ballooning.
 
diff --git a/drivers/xen/xen-selfballoon.c b/drivers/xen/xen-selfballoon.c
index 012f9d9..ee49367 100644
--- a/drivers/xen/xen-selfballoon.c
+++ b/drivers/xen/xen-selfballoon.c
@@ -173,27 +173,6 @@ static void frontswap_selfshrink(void)
 	frontswap_shrink(tgt_frontswap_pages);
 }
 
-/* Disable with kernel boot option. */
-static bool use_selfballooning = true;
-
-static int __init xen_noselfballooning_setup(char *s)
-{
-	use_selfballooning = false;
-	return 1;
-}
-
-__setup("noselfballooning", xen_noselfballooning_setup);
-#else /* !CONFIG_FRONTSWAP */
-/* Enable with kernel boot option. */
-static bool use_selfballooning;
-
-static int __init xen_selfballooning_setup(char *s)
-{
-	use_selfballooning = true;
-	return 1;
-}
-
-__setup("selfballooning", xen_selfballooning_setup);
 #endif /* CONFIG_FRONTSWAP */
 
 #define MB2PAGES(mb)	((mb) << (20 - PAGE_SHIFT))
-- 
1.8.1.4