[mirror_ubuntu-bionic-kernel.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>

/* 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>
#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>
	14
afec6e04 DM	15	/* temporary ifdef until include/linux/frontswap.h is upstream */
	16	#ifdef CONFIG_FRONTSWAP
	17	#include <linux/frontswap.h>
	18	#endif
	19
5bc20fc5 DM	20	#include <xen/xen.h>
	21	#include <xen/interface/xen.h>
	22	#include <asm/xen/hypercall.h>
	23	#include <asm/xen/page.h>
	24	#include <asm/xen/hypervisor.h>
b8b0f559	25	#include <xen/tmem.h>
5bc20fc5 DM	26
	27	#define TMEM_CONTROL 0
	28	#define TMEM_NEW_POOL 1
	29	#define TMEM_DESTROY_POOL 2
	30	#define TMEM_NEW_PAGE 3
	31	#define TMEM_PUT_PAGE 4
	32	#define TMEM_GET_PAGE 5
	33	#define TMEM_FLUSH_PAGE 6
	34	#define TMEM_FLUSH_OBJECT 7
	35	#define TMEM_READ 8
	36	#define TMEM_WRITE 9
	37	#define TMEM_XCHG 10
	38
	39	/* Bits for HYPERVISOR_tmem_op(TMEM_NEW_POOL) */
	40	#define TMEM_POOL_PERSIST 1
	41	#define TMEM_POOL_SHARED 2
	42	#define TMEM_POOL_PAGESIZE_SHIFT 4
	43	#define TMEM_VERSION_SHIFT 24
	44
	45
	46	struct tmem_pool_uuid {
	47	u64 uuid_lo;
	48	u64 uuid_hi;
	49	};
	50
	51	struct tmem_oid {
	52	u64 oid[3];
	53	};
	54
	55	#define TMEM_POOL_PRIVATE_UUID { 0, 0 }
	56
	57	/* flags for tmem_ops.new_pool */
	58	#define TMEM_POOL_PERSIST 1
	59	#define TMEM_POOL_SHARED 2
	60
	61	/* xen tmem foundation ops/hypercalls */
	62
	63	static inline int xen_tmem_op(u32 tmem_cmd, u32 tmem_pool, struct tmem_oid oid,
	64	u32 index, unsigned long gmfn, u32 tmem_offset, u32 pfn_offset, u32 len)
	65	{
	66	struct tmem_op op;
	67	int rc = 0;
	68
	69	op.cmd = tmem_cmd;
	70	op.pool_id = tmem_pool;
	71	op.u.gen.oid[0] = oid.oid[0];
	72	op.u.gen.oid[1] = oid.oid[1];
	73	op.u.gen.oid[2] = oid.oid[2];
	74	op.u.gen.index = index;
	75	op.u.gen.tmem_offset = tmem_offset;
	76	op.u.gen.pfn_offset = pfn_offset;
	77	op.u.gen.len = len;
	78	set_xen_guest_handle(op.u.gen.gmfn, (void *)gmfn);
	79	rc = HYPERVISOR_tmem_op(&op);
	80	return rc;
	81	}
	82
	83	static int xen_tmem_new_pool(struct tmem_pool_uuid uuid,
	84	u32 flags, unsigned long pagesize)
	85	{
	86	struct tmem_op op;
	87	int rc = 0, pageshift;
	88
	89	for (pageshift = 0; pagesize != 1; pageshift++)
90	pagesize >>= 1;
91	flags \|= (pageshift - 12) << TMEM_POOL_PAGESIZE_SHIFT;
92	flags \|= TMEM_SPEC_VERSION << TMEM_VERSION_SHIFT;
93	op.cmd = TMEM_NEW_POOL;
94	op.u.new.uuid[0] = uuid.uuid_lo;
95	op.u.new.uuid[1] = uuid.uuid_hi;
96	op.u.new.flags = flags;
97	rc = HYPERVISOR_tmem_op(&op);
98	return rc;
99	}
100
101	/* xen generic tmem ops */
102
103	static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid,
104	u32 index, unsigned long pfn)
105	{
106	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
107
108	return xen_tmem_op(TMEM_PUT_PAGE, pool_id, oid, index,
109	gmfn, 0, 0, 0);
110	}
111
112	static int xen_tmem_get_page(u32 pool_id, struct tmem_oid oid,
113	u32 index, unsigned long pfn)
114	{
115	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
116
117	return xen_tmem_op(TMEM_GET_PAGE, pool_id, oid, index,
118	gmfn, 0, 0, 0);
119	}
120
121	static int xen_tmem_flush_page(u32 pool_id, struct tmem_oid oid, u32 index)
122	{
123	return xen_tmem_op(TMEM_FLUSH_PAGE, pool_id, oid, index,
124	0, 0, 0, 0);
125	}
126
127	static int xen_tmem_flush_object(u32 pool_id, struct tmem_oid oid)
128	{
129	return xen_tmem_op(TMEM_FLUSH_OBJECT, pool_id, oid, 0, 0, 0, 0, 0);
130	}
131
10a7a077	132	#ifndef CONFIG_XEN_TMEM_MODULE
8e6f7c23	133	bool __read_mostly tmem_enabled = false;
5bc20fc5 DM	134
	135	static int __init enable_tmem(char *s)
	136	{
8e6f7c23	137	tmem_enabled = true;
5bc20fc5 DM	138	return 1;
5bc20fc5 DM	139	}
5bc20fc5	140	__setup("tmem", enable_tmem);
10a7a077	141	#endif
5bc20fc5	142
afec6e04 DM	143	#ifdef CONFIG_CLEANCACHE
	144	static int xen_tmem_destroy_pool(u32 pool_id)
	145	{
	146	struct tmem_oid oid = { { 0 } };
	147
	148	return xen_tmem_op(TMEM_DESTROY_POOL, pool_id, oid, 0, 0, 0, 0, 0);
	149	}
	150
5bc20fc5 DM	151	/* cleancache ops */
	152
	153	static void tmem_cleancache_put_page(int pool, struct cleancache_filekey key,
	154	pgoff_t index, struct page *page)
	155	{
	156	u32 ind = (u32) index;
	157	struct tmem_oid oid = (struct tmem_oid )&key;
	158	unsigned long pfn = page_to_pfn(page);
	159
	160	if (pool < 0)
	161	return;
	162	if (ind != index)
	163	return;
	164	mb(); /* ensure page is quiescent; tmem may address it with an alias */
	165	(void)xen_tmem_put_page((u32)pool, oid, ind, pfn);
	166	}
	167
	168	static int tmem_cleancache_get_page(int pool, struct cleancache_filekey key,
	169	pgoff_t index, struct page *page)
	170	{
	171	u32 ind = (u32) index;
	172	struct tmem_oid oid = (struct tmem_oid )&key;
	173	unsigned long pfn = page_to_pfn(page);
	174	int ret;
	175
	176	/* translate return values to linux semantics */
	177	if (pool < 0)
	178	return -1;
	179	if (ind != index)
	180	return -1;
	181	ret = xen_tmem_get_page((u32)pool, oid, ind, pfn);
	182	if (ret == 1)
	183	return 0;
	184	else
	185	return -1;
	186	}
	187
	188	static void tmem_cleancache_flush_page(int pool, struct cleancache_filekey key,
	189	pgoff_t index)
	190	{
	191	u32 ind = (u32) index;
	192	struct tmem_oid oid = (struct tmem_oid )&key;
	193
	194	if (pool < 0)
	195	return;
	196	if (ind != index)
	197	return;
	198	(void)xen_tmem_flush_page((u32)pool, oid, ind);
	199	}
	200
	201	static void tmem_cleancache_flush_inode(int pool, struct cleancache_filekey key)
	202	{
	203	struct tmem_oid oid = (struct tmem_oid )&key;
	204
	205	if (pool < 0)
	206	return;
	207	(void)xen_tmem_flush_object((u32)pool, oid);
	208	}
	209
	210	static void tmem_cleancache_flush_fs(int pool)
	211	{
	212	if (pool < 0)
	213	return;
	214	(void)xen_tmem_destroy_pool((u32)pool);
215	}
216
217	static int tmem_cleancache_init_fs(size_t pagesize)
218	{
219	struct tmem_pool_uuid uuid_private = TMEM_POOL_PRIVATE_UUID;
220
221	return xen_tmem_new_pool(uuid_private, 0, pagesize);
222	}
223
224	static int tmem_cleancache_init_shared_fs(char *uuid, size_t pagesize)
225	{
226	struct tmem_pool_uuid shared_uuid;
227
228	shared_uuid.uuid_lo = (u64 )uuid;
229	shared_uuid.uuid_hi = (u64 )(&uuid[8]);
230	return xen_tmem_new_pool(shared_uuid, TMEM_POOL_SHARED, pagesize);
231	}
232
10a7a077 DM	233	static bool disable_cleancache __read_mostly;
	234	static bool disable_selfballooning __read_mostly;
	235	#ifdef CONFIG_XEN_TMEM_MODULE
	236	module_param(disable_cleancache, bool, S_IRUGO);
	237	module_param(disable_selfballooning, bool, S_IRUGO);
	238	#else
5bc20fc5 DM	239	static int __init no_cleancache(char *s)
5bc20fc5 DM	240	{
10a7a077	241	disable_cleancache = true;
5bc20fc5 DM	242	return 1;
5bc20fc5 DM	243	}
5bc20fc5	244	__setup("nocleancache", no_cleancache);
10a7a077	245	#endif
5bc20fc5	246
833f8662	247	static struct cleancache_ops tmem_cleancache_ops = {
5bc20fc5 DM	248	.put_page = tmem_cleancache_put_page,
5bc20fc5 DM	249	.get_page = tmem_cleancache_get_page,
91c6cc9b DM	250	.invalidate_page = tmem_cleancache_flush_page,
	251	.invalidate_inode = tmem_cleancache_flush_inode,
	252	.invalidate_fs = tmem_cleancache_flush_fs,
5bc20fc5 DM	253	.init_shared_fs = tmem_cleancache_init_shared_fs,
	254	.init_fs = tmem_cleancache_init_fs
	255	};
afec6e04	256	#endif
5bc20fc5	257
afec6e04 DM	258	#ifdef CONFIG_FRONTSWAP
	259	/* frontswap tmem operations */
	260
	261	/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
	262	static int tmem_frontswap_poolid;
	263
	264	/*
	265	* Swizzling increases objects per swaptype, increasing tmem concurrency
	266	* for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
	267	*/
	268	#define SWIZ_BITS 4
	269	#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
	270	#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) \| (_ind & SWIZ_MASK))
	271	#define iswiz(_ind) (_ind >> SWIZ_BITS)
	272
	273	static inline struct tmem_oid oswiz(unsigned type, u32 ind)
5bc20fc5	274	{
afec6e04 DM	275	struct tmem_oid oid = { .oid = { 0 } };
	276	oid.oid[0] = _oswiz(type, ind);
	277	return oid;
	278	}
5bc20fc5	279
afec6e04	280	/* returns 0 if the page was successfully put into frontswap, -1 if not */
165c8aed	281	static int tmem_frontswap_store(unsigned type, pgoff_t offset,
afec6e04 DM	282	struct page *page)
	283	{
	284	u64 ind64 = (u64)offset;
	285	u32 ind = (u32)offset;
	286	unsigned long pfn = page_to_pfn(page);
	287	int pool = tmem_frontswap_poolid;
	288	int ret;
	289
	290	if (pool < 0)
	291	return -1;
	292	if (ind64 != ind)
	293	return -1;
	294	mb(); /* ensure page is quiescent; tmem may address it with an alias */
	295	ret = xen_tmem_put_page(pool, oswiz(type, ind), iswiz(ind), pfn);
	296	/* translate Xen tmem return values to linux semantics */
	297	if (ret == 1)
	298	return 0;
	299	else
	300	return -1;
	301	}
	302
	303	/*
	304	* returns 0 if the page was successfully gotten from frontswap, -1 if
	305	* was not present (should never happen!)
	306	*/
165c8aed	307	static int tmem_frontswap_load(unsigned type, pgoff_t offset,
afec6e04 DM	308	struct page *page)
	309	{
	310	u64 ind64 = (u64)offset;
	311	u32 ind = (u32)offset;
	312	unsigned long pfn = page_to_pfn(page);
	313	int pool = tmem_frontswap_poolid;
	314	int ret;
	315
	316	if (pool < 0)
	317	return -1;
	318	if (ind64 != ind)
	319	return -1;
	320	ret = xen_tmem_get_page(pool, oswiz(type, ind), iswiz(ind), pfn);
	321	/* translate Xen tmem return values to linux semantics */
	322	if (ret == 1)
	323	return 0;
	324	else
	325	return -1;
	326	}
	327
	328	/* flush a single page from frontswap */
	329	static void tmem_frontswap_flush_page(unsigned type, pgoff_t offset)
	330	{
	331	u64 ind64 = (u64)offset;
	332	u32 ind = (u32)offset;
	333	int pool = tmem_frontswap_poolid;
	334
	335	if (pool < 0)
	336	return;
	337	if (ind64 != ind)
	338	return;
	339	(void) xen_tmem_flush_page(pool, oswiz(type, ind), iswiz(ind));
	340	}
	341
	342	/* flush all pages from the passed swaptype */
	343	static void tmem_frontswap_flush_area(unsigned type)
	344	{
	345	int pool = tmem_frontswap_poolid;
	346	int ind;
	347
	348	if (pool < 0)
	349	return;
	350	for (ind = SWIZ_MASK; ind >= 0; ind--)
	351	(void)xen_tmem_flush_object(pool, oswiz(type, ind));
	352	}
	353
	354	static void tmem_frontswap_init(unsigned ignored)
	355	{
	356	struct tmem_pool_uuid private = TMEM_POOL_PRIVATE_UUID;
	357
	358	/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
	359	if (tmem_frontswap_poolid < 0)
	360	tmem_frontswap_poolid =
	361	xen_tmem_new_pool(private, TMEM_POOL_PERSIST, PAGE_SIZE);
	362	}
	363
10a7a077 DM	364	static bool disable_frontswap __read_mostly;
	365	static bool disable_frontswap_selfshrinking __read_mostly;
	366	#ifdef CONFIG_XEN_TMEM_MODULE
	367	module_param(disable_frontswap, bool, S_IRUGO);
	368	module_param(disable_frontswap_selfshrinking, bool, S_IRUGO);
	369	#else
afec6e04 DM	370	static int __init no_frontswap(char *s)
afec6e04 DM	371	{
10a7a077	372	disable_frontswap = true;
afec6e04 DM	373	return 1;
afec6e04 DM	374	}
afec6e04	375	__setup("nofrontswap", no_frontswap);
10a7a077	376	#endif
afec6e04	377
1e01c968	378	static struct frontswap_ops tmem_frontswap_ops = {
165c8aed KRW	379	.store = tmem_frontswap_store,
165c8aed KRW	380	.load = tmem_frontswap_load,
91c6cc9b DM	381	.invalidate_page = tmem_frontswap_flush_page,
91c6cc9b DM	382	.invalidate_area = tmem_frontswap_flush_area,
afec6e04 DM	383	.init = tmem_frontswap_init
afec6e04 DM	384	};
10a7a077 DM	385	#else /* CONFIG_FRONTSWAP */
10a7a077 DM	386	#define disable_frontswap_selfshrinking 1
afec6e04 DM	387	#endif
afec6e04 DM	388
10a7a077	389	static int xen_tmem_init(void)
afec6e04	390	{
5bc20fc5 DM	391	if (!xen_domain())
5bc20fc5 DM	392	return 0;
afec6e04	393	#ifdef CONFIG_FRONTSWAP
10a7a077	394	if (tmem_enabled && !disable_frontswap) {
afec6e04	395	char *s = "";
1e01c968	396	struct frontswap_ops *old_ops =
afec6e04 DM	397	frontswap_register_ops(&tmem_frontswap_ops);
	398
	399	tmem_frontswap_poolid = -1;
f42158fe KRW	400	if (IS_ERR(old_ops) \|\| old_ops) {
	401	if (IS_ERR(old_ops))
	402	return PTR_ERR(old_ops);
afec6e04	403	s = " (WARNING: frontswap_ops overridden)";
f42158fe	404	}
afec6e04	405	printk(KERN_INFO "frontswap enabled, RAM provided by "
22230c18	406	"Xen Transcendent Memory%s\n", s);
afec6e04 DM	407	}
afec6e04 DM	408	#endif
5bc20fc5 DM	409	#ifdef CONFIG_CLEANCACHE
5bc20fc5 DM	410	BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
10a7a077	411	if (tmem_enabled && !disable_cleancache) {
5bc20fc5	412	char *s = "";
833f8662	413	struct cleancache_ops *old_ops =
afec6e04	414	cleancache_register_ops(&tmem_cleancache_ops);
833f8662	415	if (old_ops)
5bc20fc5 DM	416	s = " (WARNING: cleancache_ops overridden)";
	417	printk(KERN_INFO "cleancache enabled, RAM provided by "
	418	"Xen Transcendent Memory%s\n", s);
	419	}
10a7a077 DM	420	#endif
	421	#ifdef CONFIG_XEN_SELFBALLOONING
	422	xen_selfballoon_init(!disable_selfballooning,
	423	!disable_frontswap_selfshrinking);
5bc20fc5 DM	424	#endif
	425	return 0;
	426	}
	427
	428	module_init(xen_tmem_init)
10a7a077 DM	429	MODULE_LICENSE("GPL");
	430	MODULE_AUTHOR("Dan Magenheimer <dan.magenheimer@oracle.com>");
	431	MODULE_DESCRIPTION("Shim to Xen transcendent memory");