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Commit 10a7a077 authored by Dan Magenheimer's avatar Dan Magenheimer Committed by Linus Torvalds
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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: default avatarDan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: default avatarBob 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ff610a1d

drivers/xen/Kconfig

+2 −2
Original line number Diff line number Diff line
@@ -145,9 +145,9 @@ config SWIOTLB_XEN 
	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.

drivers/xen/tmem.c

+31 −9
Original line number Diff line number Diff line
@@ -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 @@ 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)
@@ -136,6 +138,7 @@ static int __init enable_tmem(char *s) 
	return 1;

}

__setup("tmem", enable_tmem);

#endif



#ifdef CONFIG_CLEANCACHE

static int xen_tmem_destroy_pool(u32 pool_id)
@@ -227,14 +230,19 @@ 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 __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 @@ static void tmem_frontswap_init(unsigned ignored) 
		    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 @@ 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 __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 @@ static int __init xen_tmem_init(void) 
#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);
@@ -399,8 +414,15 @@ static int __init xen_tmem_init(void) 
		printk(KERN_INFO "cleancache enabled, RAM provided by "

				 "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");

drivers/xen/xen-selfballoon.c

+5 −8
Original line number Diff line number Diff line
@@ -121,7 +121,7 @@ static DECLARE_DELAYED_WORK(selfballoon_worker, selfballoon_process); 
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 @@ static int __init xen_nofrontswap_selfshrink_setup(char *s) 
__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 @@ static int __init xen_noselfballooning_setup(char *s) 
__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 @@ int register_xen_selfballooning(struct device *dev) 
}

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 @@ static int __init xen_selfballoon_init(void) 


	return 0;

}



subsys_initcall(xen_selfballoon_init);



MODULE_LICENSE("GPL");
 
EXPORT_SYMBOL(xen_selfballoon_init);

include/xen/tmem.h

+8 −0
Original line number Diff line number Diff line
@@ -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 */