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