[deliverable/linux.git] / drivers / xen / tmem.c

/*
 * Xen implementation for transcendent memory (tmem)
 *
 * Copyright (C) 2009-2011 Oracle Corp.  All rights reserved.
 * Author: Dan Magenheimer
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/pagemap.h>
#include <linux/cleancache.h>
#include <linux/frontswap.h>

#include <xen/xen.h>
#include <xen/interface/xen.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/page.h>
#include <asm/xen/hypervisor.h>
#include <xen/tmem.h>

#define TMEM_CONTROL               0
#define TMEM_NEW_POOL              1
#define TMEM_DESTROY_POOL          2
#define TMEM_NEW_PAGE              3
#define TMEM_PUT_PAGE              4
#define TMEM_GET_PAGE              5
#define TMEM_FLUSH_PAGE            6
#define TMEM_FLUSH_OBJECT          7
#define TMEM_READ                  8
#define TMEM_WRITE                 9
#define TMEM_XCHG                 10

/* Bits for HYPERVISOR_tmem_op(TMEM_NEW_POOL) */
#define TMEM_POOL_PERSIST          1
#define TMEM_POOL_SHARED           2
#define TMEM_POOL_PAGESIZE_SHIFT   4
#define TMEM_VERSION_SHIFT        24


struct tmem_pool_uuid {
	u64 uuid_lo;
	u64 uuid_hi;
};

struct tmem_oid {
	u64 oid[3];
};

#define TMEM_POOL_PRIVATE_UUID	{ 0, 0 }

/* flags for tmem_ops.new_pool */
#define TMEM_POOL_PERSIST          1
#define TMEM_POOL_SHARED           2

/* xen tmem foundation ops/hypercalls */

static inline int xen_tmem_op(u32 tmem_cmd, u32 tmem_pool, struct tmem_oid oid,
	u32 index, unsigned long gmfn, u32 tmem_offset, u32 pfn_offset, u32 len)
{
	struct tmem_op op;
	int rc = 0;

	op.cmd = tmem_cmd;
	op.pool_id = tmem_pool;
	op.u.gen.oid[0] = oid.oid[0];
	op.u.gen.oid[1] = oid.oid[1];
	op.u.gen.oid[2] = oid.oid[2];
	op.u.gen.index = index;
	op.u.gen.tmem_offset = tmem_offset;
	op.u.gen.pfn_offset = pfn_offset;
	op.u.gen.len = len;
	set_xen_guest_handle(op.u.gen.gmfn, (void *)gmfn);
	rc = HYPERVISOR_tmem_op(&op);
	return rc;
}

static int xen_tmem_new_pool(struct tmem_pool_uuid uuid,
				u32 flags, unsigned long pagesize)
{
	struct tmem_op op;
	int rc = 0, pageshift;

	for (pageshift = 0; pagesize != 1; pageshift++)
		pagesize >>= 1;
	flags |= (pageshift - 12) << TMEM_POOL_PAGESIZE_SHIFT;
	flags |= TMEM_SPEC_VERSION << TMEM_VERSION_SHIFT;
	op.cmd = TMEM_NEW_POOL;
	op.u.new.uuid[0] = uuid.uuid_lo;
	op.u.new.uuid[1] = uuid.uuid_hi;
	op.u.new.flags = flags;
	rc = HYPERVISOR_tmem_op(&op);
	return rc;
}

/* xen generic tmem ops */

static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid,
			     u32 index, unsigned long pfn)
{
	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;

	return xen_tmem_op(TMEM_PUT_PAGE, pool_id, oid, index,
		gmfn, 0, 0, 0);
}

static int xen_tmem_get_page(u32 pool_id, struct tmem_oid oid,
			     u32 index, unsigned long pfn)
{
	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;

	return xen_tmem_op(TMEM_GET_PAGE, pool_id, oid, index,
		gmfn, 0, 0, 0);
}

static int xen_tmem_flush_page(u32 pool_id, struct tmem_oid oid, u32 index)
{
	return xen_tmem_op(TMEM_FLUSH_PAGE, pool_id, oid, index,
		0, 0, 0, 0);
}

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)
{
	struct tmem_oid oid = { { 0 } };

	return xen_tmem_op(TMEM_DESTROY_POOL, pool_id, oid, 0, 0, 0, 0, 0);
}

/* cleancache ops */

static void tmem_cleancache_put_page(int pool, struct cleancache_filekey key,
				     pgoff_t index, struct page *page)
{
	u32 ind = (u32) index;
	struct tmem_oid oid = *(struct tmem_oid *)&key;
	unsigned long pfn = page_to_pfn(page);

	if (pool < 0)
		return;
	if (ind != index)
		return;
	mb(); /* ensure page is quiescent; tmem may address it with an alias */
	(void)xen_tmem_put_page((u32)pool, oid, ind, pfn);
}

static int tmem_cleancache_get_page(int pool, struct cleancache_filekey key,
				    pgoff_t index, struct page *page)
{
	u32 ind = (u32) index;
	struct tmem_oid oid = *(struct tmem_oid *)&key;
	unsigned long pfn = page_to_pfn(page);
	int ret;

	/* translate return values to linux semantics */
	if (pool < 0)
		return -1;
	if (ind != index)
		return -1;
	ret = xen_tmem_get_page((u32)pool, oid, ind, pfn);
	if (ret == 1)
		return 0;
	else
		return -1;
}

static void tmem_cleancache_flush_page(int pool, struct cleancache_filekey key,
				       pgoff_t index)
{
	u32 ind = (u32) index;
	struct tmem_oid oid = *(struct tmem_oid *)&key;

	if (pool < 0)
		return;
	if (ind != index)
		return;
	(void)xen_tmem_flush_page((u32)pool, oid, ind);
}

static void tmem_cleancache_flush_inode(int pool, struct cleancache_filekey key)
{
	struct tmem_oid oid = *(struct tmem_oid *)&key;

	if (pool < 0)
		return;
	(void)xen_tmem_flush_object((u32)pool, oid);
}

static void tmem_cleancache_flush_fs(int pool)
{
	if (pool < 0)
		return;
	(void)xen_tmem_destroy_pool((u32)pool);
}

static int tmem_cleancache_init_fs(size_t pagesize)
{
	struct tmem_pool_uuid uuid_private = TMEM_POOL_PRIVATE_UUID;

	return xen_tmem_new_pool(uuid_private, 0, pagesize);
}

static int tmem_cleancache_init_shared_fs(char *uuid, size_t pagesize)
{
	struct tmem_pool_uuid shared_uuid;

	shared_uuid.uuid_lo = *(u64 *)uuid;
	shared_uuid.uuid_hi = *(u64 *)(&uuid[8]);
	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,
	.invalidate_page = tmem_cleancache_flush_page,
	.invalidate_inode = tmem_cleancache_flush_inode,
	.invalidate_fs = tmem_cleancache_flush_fs,
	.init_shared_fs = tmem_cleancache_init_shared_fs,
	.init_fs = tmem_cleancache_init_fs
};
#endif

#ifdef CONFIG_FRONTSWAP
/* frontswap tmem operations */

/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
static int tmem_frontswap_poolid;

/*
 * Swizzling increases objects per swaptype, increasing tmem concurrency
 * for heavy swaploads.  Later, larger nr_cpus -> larger SWIZ_BITS
 */
#define SWIZ_BITS		4
#define SWIZ_MASK		((1 << SWIZ_BITS) - 1)
#define _oswiz(_type, _ind)	((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
#define iswiz(_ind)		(_ind >> SWIZ_BITS)

static inline struct tmem_oid oswiz(unsigned type, u32 ind)
{
	struct tmem_oid oid = { .oid = { 0 } };
	oid.oid[0] = _oswiz(type, ind);
	return oid;
}

/* returns 0 if the page was successfully put into frontswap, -1 if not */
static int tmem_frontswap_store(unsigned type, pgoff_t offset,
				   struct page *page)
{
	u64 ind64 = (u64)offset;
	u32 ind = (u32)offset;
	unsigned long pfn = page_to_pfn(page);
	int pool = tmem_frontswap_poolid;
	int ret;

	if (pool < 0)
		return -1;
	if (ind64 != ind)
		return -1;
	mb(); /* ensure page is quiescent; tmem may address it with an alias */
	ret = xen_tmem_put_page(pool, oswiz(type, ind), iswiz(ind), pfn);
	/* translate Xen tmem return values to linux semantics */
	if (ret == 1)
		return 0;
	else
		return -1;
}

/*
 * returns 0 if the page was successfully gotten from frontswap, -1 if
 * was not present (should never happen!)
 */
static int tmem_frontswap_load(unsigned type, pgoff_t offset,
				   struct page *page)
{
	u64 ind64 = (u64)offset;
	u32 ind = (u32)offset;
	unsigned long pfn = page_to_pfn(page);
	int pool = tmem_frontswap_poolid;
	int ret;

	if (pool < 0)
		return -1;
	if (ind64 != ind)
		return -1;
	ret = xen_tmem_get_page(pool, oswiz(type, ind), iswiz(ind), pfn);
	/* translate Xen tmem return values to linux semantics */
	if (ret == 1)
		return 0;
	else
		return -1;
}

/* flush a single page from frontswap */
static void tmem_frontswap_flush_page(unsigned type, pgoff_t offset)
{
	u64 ind64 = (u64)offset;
	u32 ind = (u32)offset;
	int pool = tmem_frontswap_poolid;

	if (pool < 0)
		return;
	if (ind64 != ind)
		return;
	(void) xen_tmem_flush_page(pool, oswiz(type, ind), iswiz(ind));
}

/* flush all pages from the passed swaptype */
static void tmem_frontswap_flush_area(unsigned type)
{
	int pool = tmem_frontswap_poolid;
	int ind;

	if (pool < 0)
		return;
	for (ind = SWIZ_MASK; ind >= 0; ind--)
		(void)xen_tmem_flush_object(pool, oswiz(type, ind));
}

static void tmem_frontswap_init(unsigned ignored)
{
	struct tmem_pool_uuid private = TMEM_POOL_PRIVATE_UUID;

	/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
	if (tmem_frontswap_poolid < 0)
		tmem_frontswap_poolid =
		    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,
	.invalidate_page = tmem_frontswap_flush_page,
	.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)
{
	if (!xen_domain())
		return 0;
#ifdef CONFIG_FRONTSWAP
	if (tmem_enabled && !disable_frontswap) {
		char *s = "";
		struct frontswap_ops *old_ops =
			frontswap_register_ops(&tmem_frontswap_ops);

		tmem_frontswap_poolid = -1;
		if (IS_ERR(old_ops) || old_ops) {
			if (IS_ERR(old_ops))
				return PTR_ERR(old_ops);
			s = " (WARNING: frontswap_ops overridden)";
		}
		printk(KERN_INFO "frontswap enabled, RAM provided by "
				 "Xen Transcendent Memory%s\n", s);
	}
#endif
#ifdef CONFIG_CLEANCACHE
	BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
	if (tmem_enabled && !disable_cleancache) {
		char *s = "";
		struct cleancache_ops *old_ops =
			cleancache_register_ops(&tmem_cleancache_ops);
		if (old_ops)
			s = " (WARNING: cleancache_ops overridden)";
		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");
Commit	Line	Data
5bc20fc5 DM	1	/*
	2	* Xen implementation for transcendent memory (tmem)
	3	*
afec6e04	4	* Copyright (C) 2009-2011 Oracle Corp. All rights reserved.
5bc20fc5 DM	5	* Author: Dan Magenheimer
	6	*/
	7
10a7a077	8	#include <linux/module.h>
5bc20fc5 DM	9	#include <linux/kernel.h>
	10	#include <linux/types.h>
	11	#include <linux/init.h>
	12	#include <linux/pagemap.h>
	13	#include <linux/cleancache.h>
afec6e04	14	#include <linux/frontswap.h>
afec6e04	15
5bc20fc5 DM	16	#include <xen/xen.h>
	17	#include <xen/interface/xen.h>
	18	#include <asm/xen/hypercall.h>
	19	#include <asm/xen/page.h>
	20	#include <asm/xen/hypervisor.h>
b8b0f559	21	#include <xen/tmem.h>
5bc20fc5 DM	22
	23	#define TMEM_CONTROL 0
	24	#define TMEM_NEW_POOL 1
	25	#define TMEM_DESTROY_POOL 2
	26	#define TMEM_NEW_PAGE 3
	27	#define TMEM_PUT_PAGE 4
	28	#define TMEM_GET_PAGE 5
	29	#define TMEM_FLUSH_PAGE 6
	30	#define TMEM_FLUSH_OBJECT 7
	31	#define TMEM_READ 8
	32	#define TMEM_WRITE 9
	33	#define TMEM_XCHG 10
	34
	35	/* Bits for HYPERVISOR_tmem_op(TMEM_NEW_POOL) */
	36	#define TMEM_POOL_PERSIST 1
	37	#define TMEM_POOL_SHARED 2
	38	#define TMEM_POOL_PAGESIZE_SHIFT 4
	39	#define TMEM_VERSION_SHIFT 24
	40
	41
	42	struct tmem_pool_uuid {
	43	u64 uuid_lo;
	44	u64 uuid_hi;
	45	};
	46
	47	struct tmem_oid {
	48	u64 oid[3];
	49	};
	50
	51	#define TMEM_POOL_PRIVATE_UUID { 0, 0 }
	52
	53	/* flags for tmem_ops.new_pool */
	54	#define TMEM_POOL_PERSIST 1
	55	#define TMEM_POOL_SHARED 2
	56
	57	/* xen tmem foundation ops/hypercalls */
	58
	59	static inline int xen_tmem_op(u32 tmem_cmd, u32 tmem_pool, struct tmem_oid oid,
	60	u32 index, unsigned long gmfn, u32 tmem_offset, u32 pfn_offset, u32 len)
	61	{
	62	struct tmem_op op;
	63	int rc = 0;
	64
	65	op.cmd = tmem_cmd;
	66	op.pool_id = tmem_pool;
	67	op.u.gen.oid[0] = oid.oid[0];
	68	op.u.gen.oid[1] = oid.oid[1];
	69	op.u.gen.oid[2] = oid.oid[2];
	70	op.u.gen.index = index;
	71	op.u.gen.tmem_offset = tmem_offset;
	72	op.u.gen.pfn_offset = pfn_offset;
	73	op.u.gen.len = len;
	74	set_xen_guest_handle(op.u.gen.gmfn, (void *)gmfn);
	75	rc = HYPERVISOR_tmem_op(&op);
	76	return rc;
	77	}
	78
	79	static int xen_tmem_new_pool(struct tmem_pool_uuid uuid,
	80	u32 flags, unsigned long pagesize)
	81	{
	82	struct tmem_op op;
	83	int rc = 0, pageshift;
	84
	85	for (pageshift = 0; pagesize != 1; pageshift++)
86	pagesize >>= 1;
87	flags \|= (pageshift - 12) << TMEM_POOL_PAGESIZE_SHIFT;
88	flags \|= TMEM_SPEC_VERSION << TMEM_VERSION_SHIFT;
89	op.cmd = TMEM_NEW_POOL;
90	op.u.new.uuid[0] = uuid.uuid_lo;
91	op.u.new.uuid[1] = uuid.uuid_hi;
92	op.u.new.flags = flags;
93	rc = HYPERVISOR_tmem_op(&op);
94	return rc;
95	}
96
97	/* xen generic tmem ops */
98
99	static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid,
100	u32 index, unsigned long pfn)
101	{
102	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
103
104	return xen_tmem_op(TMEM_PUT_PAGE, pool_id, oid, index,
105	gmfn, 0, 0, 0);
106	}
107
108	static int xen_tmem_get_page(u32 pool_id, struct tmem_oid oid,
109	u32 index, unsigned long pfn)
110	{
111	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
112
113	return xen_tmem_op(TMEM_GET_PAGE, pool_id, oid, index,
114	gmfn, 0, 0, 0);
115	}
116
117	static int xen_tmem_flush_page(u32 pool_id, struct tmem_oid oid, u32 index)
118	{
119	return xen_tmem_op(TMEM_FLUSH_PAGE, pool_id, oid, index,
120	0, 0, 0, 0);
121	}
122
123	static int xen_tmem_flush_object(u32 pool_id, struct tmem_oid oid)
124	{
125	return xen_tmem_op(TMEM_FLUSH_OBJECT, pool_id, oid, 0, 0, 0, 0, 0);
126	}
127
10a7a077	128	#ifndef CONFIG_XEN_TMEM_MODULE
8e6f7c23	129	bool __read_mostly tmem_enabled = false;
5bc20fc5 DM	130
	131	static int __init enable_tmem(char *s)
	132	{
8e6f7c23	133	tmem_enabled = true;
5bc20fc5 DM	134	return 1;
5bc20fc5 DM	135	}
5bc20fc5	136	__setup("tmem", enable_tmem);
10a7a077	137	#endif
5bc20fc5	138
afec6e04 DM	139	#ifdef CONFIG_CLEANCACHE
	140	static int xen_tmem_destroy_pool(u32 pool_id)
	141	{
	142	struct tmem_oid oid = { { 0 } };
	143
	144	return xen_tmem_op(TMEM_DESTROY_POOL, pool_id, oid, 0, 0, 0, 0, 0);
	145	}
	146
5bc20fc5 DM	147	/* cleancache ops */
	148
	149	static void tmem_cleancache_put_page(int pool, struct cleancache_filekey key,
	150	pgoff_t index, struct page *page)
	151	{
	152	u32 ind = (u32) index;
	153	struct tmem_oid oid = (struct tmem_oid )&key;
	154	unsigned long pfn = page_to_pfn(page);
	155
	156	if (pool < 0)
	157	return;
	158	if (ind != index)
	159	return;
	160	mb(); /* ensure page is quiescent; tmem may address it with an alias */
	161	(void)xen_tmem_put_page((u32)pool, oid, ind, pfn);
	162	}
	163
	164	static int tmem_cleancache_get_page(int pool, struct cleancache_filekey key,
	165	pgoff_t index, struct page *page)
	166	{
	167	u32 ind = (u32) index;
	168	struct tmem_oid oid = (struct tmem_oid )&key;
	169	unsigned long pfn = page_to_pfn(page);
	170	int ret;
	171
	172	/* translate return values to linux semantics */
	173	if (pool < 0)
	174	return -1;
	175	if (ind != index)
	176	return -1;
	177	ret = xen_tmem_get_page((u32)pool, oid, ind, pfn);
	178	if (ret == 1)
	179	return 0;
	180	else
	181	return -1;
	182	}
	183
	184	static void tmem_cleancache_flush_page(int pool, struct cleancache_filekey key,
	185	pgoff_t index)
	186	{
	187	u32 ind = (u32) index;
	188	struct tmem_oid oid = (struct tmem_oid )&key;
	189
	190	if (pool < 0)
	191	return;
	192	if (ind != index)
	193	return;
	194	(void)xen_tmem_flush_page((u32)pool, oid, ind);
	195	}
	196
	197	static void tmem_cleancache_flush_inode(int pool, struct cleancache_filekey key)
	198	{
	199	struct tmem_oid oid = (struct tmem_oid )&key;
	200
	201	if (pool < 0)
	202	return;
	203	(void)xen_tmem_flush_object((u32)pool, oid);
	204	}
	205
	206	static void tmem_cleancache_flush_fs(int pool)
	207	{
	208	if (pool < 0)
	209	return;
	210	(void)xen_tmem_destroy_pool((u32)pool);
211	}
212
213	static int tmem_cleancache_init_fs(size_t pagesize)
214	{
215	struct tmem_pool_uuid uuid_private = TMEM_POOL_PRIVATE_UUID;
216
217	return xen_tmem_new_pool(uuid_private, 0, pagesize);
218	}
219
220	static int tmem_cleancache_init_shared_fs(char *uuid, size_t pagesize)
221	{
222	struct tmem_pool_uuid shared_uuid;
223
224	shared_uuid.uuid_lo = (u64 )uuid;
225	shared_uuid.uuid_hi = (u64 )(&uuid[8]);
226	return xen_tmem_new_pool(shared_uuid, TMEM_POOL_SHARED, pagesize);
227	}
228
10a7a077 DM	229	static bool disable_cleancache __read_mostly;
	230	static bool disable_selfballooning __read_mostly;
	231	#ifdef CONFIG_XEN_TMEM_MODULE
	232	module_param(disable_cleancache, bool, S_IRUGO);
	233	module_param(disable_selfballooning, bool, S_IRUGO);
	234	#else
5bc20fc5 DM	235	static int __init no_cleancache(char *s)
5bc20fc5 DM	236	{
10a7a077	237	disable_cleancache = true;
5bc20fc5 DM	238	return 1;
5bc20fc5 DM	239	}
5bc20fc5	240	__setup("nocleancache", no_cleancache);
10a7a077	241	#endif
5bc20fc5	242
833f8662	243	static struct cleancache_ops tmem_cleancache_ops = {
5bc20fc5 DM	244	.put_page = tmem_cleancache_put_page,
5bc20fc5 DM	245	.get_page = tmem_cleancache_get_page,
91c6cc9b DM	246	.invalidate_page = tmem_cleancache_flush_page,
	247	.invalidate_inode = tmem_cleancache_flush_inode,
	248	.invalidate_fs = tmem_cleancache_flush_fs,
5bc20fc5 DM	249	.init_shared_fs = tmem_cleancache_init_shared_fs,
	250	.init_fs = tmem_cleancache_init_fs
	251	};
afec6e04	252	#endif
5bc20fc5	253
afec6e04 DM	254	#ifdef CONFIG_FRONTSWAP
	255	/* frontswap tmem operations */
	256
	257	/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
	258	static int tmem_frontswap_poolid;
	259
	260	/*
	261	* Swizzling increases objects per swaptype, increasing tmem concurrency
	262	* for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
	263	*/
	264	#define SWIZ_BITS 4
	265	#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
	266	#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) \| (_ind & SWIZ_MASK))
	267	#define iswiz(_ind) (_ind >> SWIZ_BITS)
	268
	269	static inline struct tmem_oid oswiz(unsigned type, u32 ind)
5bc20fc5	270	{
afec6e04 DM	271	struct tmem_oid oid = { .oid = { 0 } };
	272	oid.oid[0] = _oswiz(type, ind);
	273	return oid;
	274	}
5bc20fc5	275
afec6e04	276	/* returns 0 if the page was successfully put into frontswap, -1 if not */
165c8aed	277	static int tmem_frontswap_store(unsigned type, pgoff_t offset,
afec6e04 DM	278	struct page *page)
	279	{
	280	u64 ind64 = (u64)offset;
	281	u32 ind = (u32)offset;
	282	unsigned long pfn = page_to_pfn(page);
	283	int pool = tmem_frontswap_poolid;
	284	int ret;
	285
	286	if (pool < 0)
	287	return -1;
	288	if (ind64 != ind)
	289	return -1;
	290	mb(); /* ensure page is quiescent; tmem may address it with an alias */
	291	ret = xen_tmem_put_page(pool, oswiz(type, ind), iswiz(ind), pfn);
	292	/* translate Xen tmem return values to linux semantics */
	293	if (ret == 1)
	294	return 0;
	295	else
	296	return -1;
	297	}
	298
	299	/*
	300	* returns 0 if the page was successfully gotten from frontswap, -1 if
	301	* was not present (should never happen!)
	302	*/
165c8aed	303	static int tmem_frontswap_load(unsigned type, pgoff_t offset,
afec6e04 DM	304	struct page *page)
	305	{
	306	u64 ind64 = (u64)offset;
	307	u32 ind = (u32)offset;
	308	unsigned long pfn = page_to_pfn(page);
	309	int pool = tmem_frontswap_poolid;
	310	int ret;
	311
	312	if (pool < 0)
	313	return -1;
	314	if (ind64 != ind)
	315	return -1;
	316	ret = xen_tmem_get_page(pool, oswiz(type, ind), iswiz(ind), pfn);
	317	/* translate Xen tmem return values to linux semantics */
	318	if (ret == 1)
	319	return 0;
	320	else
	321	return -1;
	322	}
	323
	324	/* flush a single page from frontswap */
	325	static void tmem_frontswap_flush_page(unsigned type, pgoff_t offset)
	326	{
	327	u64 ind64 = (u64)offset;
	328	u32 ind = (u32)offset;
	329	int pool = tmem_frontswap_poolid;
	330
	331	if (pool < 0)
	332	return;
	333	if (ind64 != ind)
	334	return;
	335	(void) xen_tmem_flush_page(pool, oswiz(type, ind), iswiz(ind));
	336	}
	337
	338	/* flush all pages from the passed swaptype */
	339	static void tmem_frontswap_flush_area(unsigned type)
	340	{
	341	int pool = tmem_frontswap_poolid;
	342	int ind;
	343
	344	if (pool < 0)
	345	return;
	346	for (ind = SWIZ_MASK; ind >= 0; ind--)
	347	(void)xen_tmem_flush_object(pool, oswiz(type, ind));
	348	}
	349
	350	static void tmem_frontswap_init(unsigned ignored)
	351	{
	352	struct tmem_pool_uuid private = TMEM_POOL_PRIVATE_UUID;
	353
	354	/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
	355	if (tmem_frontswap_poolid < 0)
	356	tmem_frontswap_poolid =
	357	xen_tmem_new_pool(private, TMEM_POOL_PERSIST, PAGE_SIZE);
	358	}
	359
10a7a077 DM	360	static bool disable_frontswap __read_mostly;
	361	static bool disable_frontswap_selfshrinking __read_mostly;
	362	#ifdef CONFIG_XEN_TMEM_MODULE
	363	module_param(disable_frontswap, bool, S_IRUGO);
	364	module_param(disable_frontswap_selfshrinking, bool, S_IRUGO);
	365	#else
afec6e04 DM	366	static int __init no_frontswap(char *s)
afec6e04 DM	367	{
10a7a077	368	disable_frontswap = true;
afec6e04 DM	369	return 1;
afec6e04 DM	370	}
afec6e04	371	__setup("nofrontswap", no_frontswap);
10a7a077	372	#endif
afec6e04	373
1e01c968	374	static struct frontswap_ops tmem_frontswap_ops = {
165c8aed KRW	375	.store = tmem_frontswap_store,
165c8aed KRW	376	.load = tmem_frontswap_load,
91c6cc9b DM	377	.invalidate_page = tmem_frontswap_flush_page,
91c6cc9b DM	378	.invalidate_area = tmem_frontswap_flush_area,
afec6e04 DM	379	.init = tmem_frontswap_init
afec6e04 DM	380	};
10a7a077 DM	381	#else /* CONFIG_FRONTSWAP */
10a7a077 DM	382	#define disable_frontswap_selfshrinking 1
afec6e04 DM	383	#endif
afec6e04 DM	384
10a7a077	385	static int xen_tmem_init(void)
afec6e04	386	{
5bc20fc5 DM	387	if (!xen_domain())
5bc20fc5 DM	388	return 0;
afec6e04	389	#ifdef CONFIG_FRONTSWAP
10a7a077	390	if (tmem_enabled && !disable_frontswap) {
afec6e04	391	char *s = "";
1e01c968	392	struct frontswap_ops *old_ops =
afec6e04 DM	393	frontswap_register_ops(&tmem_frontswap_ops);
	394
	395	tmem_frontswap_poolid = -1;
f42158fe KRW	396	if (IS_ERR(old_ops) \|\| old_ops) {
	397	if (IS_ERR(old_ops))
	398	return PTR_ERR(old_ops);
afec6e04	399	s = " (WARNING: frontswap_ops overridden)";
f42158fe	400	}
afec6e04	401	printk(KERN_INFO "frontswap enabled, RAM provided by "
22230c18	402	"Xen Transcendent Memory%s\n", s);
afec6e04 DM	403	}
afec6e04 DM	404	#endif
5bc20fc5 DM	405	#ifdef CONFIG_CLEANCACHE
5bc20fc5 DM	406	BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
10a7a077	407	if (tmem_enabled && !disable_cleancache) {
5bc20fc5	408	char *s = "";
833f8662	409	struct cleancache_ops *old_ops =
afec6e04	410	cleancache_register_ops(&tmem_cleancache_ops);
833f8662	411	if (old_ops)
5bc20fc5 DM	412	s = " (WARNING: cleancache_ops overridden)";
	413	printk(KERN_INFO "cleancache enabled, RAM provided by "
	414	"Xen Transcendent Memory%s\n", s);
	415	}
10a7a077 DM	416	#endif
	417	#ifdef CONFIG_XEN_SELFBALLOONING
	418	xen_selfballoon_init(!disable_selfballooning,
	419	!disable_frontswap_selfshrinking);
5bc20fc5 DM	420	#endif
	421	return 0;
	422	}
	423
	424	module_init(xen_tmem_init)
10a7a077 DM	425	MODULE_LICENSE("GPL");
	426	MODULE_AUTHOR("Dan Magenheimer <dan.magenheimer@oracle.com>");
	427	MODULE_DESCRIPTION("Shim to Xen transcendent memory");