xen: tmem: enable Xen tmem shim to be built/loaded as a module
Allow Xen tmem shim to be built/loaded as a module. Xen self-ballooning
and frontswap-selfshrinking are now also "lazily" initialized when the
Xen tmem shim is loaded as a module, unless explicitly disabled by
module parameters.
Note runtime dependency disallows loading if cleancache/frontswap lazy
initialization patches are not present.
If built-in (not built as a module), the original mechanism of enabling
via a kernel boot parameter is retained, but this should be considered
deprecated.
Note that module unload is explicitly not yet supported.
[v1: Removed the [CLEANCACHE|FRONTSWAP]_HAS_LAZY_INIT ifdef]
[v2: Squashed the xen/tmem: Remove the subsys call patch in]
[akpm@linux-foundation.org: fix build (disable_frontswap_selfshrinking undeclared)]
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Andor Daam <andor.daam@googlemail.com>
Cc: Florian Schmaus <fschmaus@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Stefan Hengelein <ilendir@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 67af155..dd4d9cb 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -145,9 +145,9 @@
select SWIOTLB
config XEN_TMEM
- bool
+ tristate
depends on !ARM
- default y if (CLEANCACHE || FRONTSWAP)
+ default m if (CLEANCACHE || FRONTSWAP)
help
Shim to interface in-kernel Transcendent Memory hooks
(e.g. cleancache and frontswap) to Xen tmem hypercalls.
diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
index fd79eab..8adde8e 100644
--- a/drivers/xen/tmem.c
+++ b/drivers/xen/tmem.c
@@ -5,6 +5,7 @@
* Author: Dan Magenheimer
*/
+#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
@@ -128,6 +129,7 @@
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)
@@ -136,6 +138,7 @@
return 1;
}
__setup("tmem", enable_tmem);
+#endif
#ifdef CONFIG_CLEANCACHE
static int xen_tmem_destroy_pool(u32 pool_id)
@@ -227,14 +230,19 @@
return xen_tmem_new_pool(shared_uuid, TMEM_POOL_SHARED, pagesize);
}
-static bool __initdata use_cleancache = true;
-
+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)
{
- use_cleancache = false;
+ disable_cleancache = true;
return 1;
}
__setup("nocleancache", no_cleancache);
+#endif
static struct cleancache_ops tmem_cleancache_ops = {
.put_page = tmem_cleancache_put_page,
@@ -353,14 +361,19 @@
xen_tmem_new_pool(private, TMEM_POOL_PERSIST, PAGE_SIZE);
}
-static bool __initdata use_frontswap = true;
-
+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)
{
- use_frontswap = false;
+ disable_frontswap = true;
return 1;
}
__setup("nofrontswap", no_frontswap);
+#endif
static struct frontswap_ops tmem_frontswap_ops = {
.store = tmem_frontswap_store,
@@ -369,14 +382,16 @@
.invalidate_area = tmem_frontswap_flush_area,
.init = tmem_frontswap_init
};
+#else /* CONFIG_FRONTSWAP */
+#define disable_frontswap_selfshrinking 1
#endif
-static int __init xen_tmem_init(void)
+static int xen_tmem_init(void)
{
if (!xen_domain())
return 0;
#ifdef CONFIG_FRONTSWAP
- if (tmem_enabled && use_frontswap) {
+ if (tmem_enabled && !disable_frontswap) {
char *s = "";
struct frontswap_ops *old_ops =
frontswap_register_ops(&tmem_frontswap_ops);
@@ -390,7 +405,7 @@
#endif
#ifdef CONFIG_CLEANCACHE
BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
- if (tmem_enabled && use_cleancache) {
+ if (tmem_enabled && !disable_cleancache) {
char *s = "";
struct cleancache_ops *old_ops =
cleancache_register_ops(&tmem_cleancache_ops);
@@ -400,7 +415,14 @@
"Xen Transcendent Memory%s\n", s);
}
#endif
+#ifdef CONFIG_XEN_SELFBALLOONING
+ xen_selfballoon_init(!disable_selfballooning,
+ !disable_frontswap_selfshrinking);
+#endif
return 0;
}
module_init(xen_tmem_init)
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Dan Magenheimer <dan.magenheimer@oracle.com>");
+MODULE_DESCRIPTION("Shim to Xen transcendent memory");
diff --git a/drivers/xen/xen-selfballoon.c b/drivers/xen/xen-selfballoon.c
index 2552d3e..f2ef569 100644
--- a/drivers/xen/xen-selfballoon.c
+++ b/drivers/xen/xen-selfballoon.c
@@ -121,7 +121,7 @@
static bool frontswap_selfshrinking __read_mostly;
/* Enable/disable with kernel boot option. */
-static bool use_frontswap_selfshrink __initdata = true;
+static bool use_frontswap_selfshrink = true;
/*
* The default values for the following parameters were deemed reasonable
@@ -185,7 +185,7 @@
__setup("noselfshrink", xen_nofrontswap_selfshrink_setup);
/* Disable with kernel boot option. */
-static bool use_selfballooning __initdata = true;
+static bool use_selfballooning = true;
static int __init xen_noselfballooning_setup(char *s)
{
@@ -196,7 +196,7 @@
__setup("noselfballooning", xen_noselfballooning_setup);
#else /* !CONFIG_FRONTSWAP */
/* Enable with kernel boot option. */
-static bool use_selfballooning __initdata = false;
+static bool use_selfballooning;
static int __init xen_selfballooning_setup(char *s)
{
@@ -537,7 +537,7 @@
}
EXPORT_SYMBOL(register_xen_selfballooning);
-static int __init xen_selfballoon_init(void)
+int xen_selfballoon_init(bool use_selfballooning, bool use_frontswap_selfshrink)
{
bool enable = false;
@@ -571,7 +571,4 @@
return 0;
}
-
-subsys_initcall(xen_selfballoon_init);
-
-MODULE_LICENSE("GPL");
+EXPORT_SYMBOL(xen_selfballoon_init);
diff --git a/include/xen/tmem.h b/include/xen/tmem.h
index 591550a..3930a90 100644
--- a/include/xen/tmem.h
+++ b/include/xen/tmem.h
@@ -3,7 +3,15 @@
#include <linux/types.h>
+#ifdef CONFIG_XEN_TMEM_MODULE
+#define tmem_enabled true
+#else
/* defined in drivers/xen/tmem.c */
extern bool tmem_enabled;
+#endif
+
+#ifdef CONFIG_XEN_SELFBALLOONING
+extern int xen_selfballoon_init(bool, bool);
+#endif
#endif /* _XEN_TMEM_H */