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
26 bool __read_mostly tmem_enabled = false;
27
enable_tmem(char * s)28 static 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
37 static bool cleancache __read_mostly = true;
38 module_param(cleancache, bool, S_IRUGO);
39 static bool selfballooning __read_mostly = true;
40 module_param(selfballooning, bool, S_IRUGO);
41 #endif /* CONFIG_CLEANCACHE */
42
43 #ifdef CONFIG_FRONTSWAP
44 static bool frontswap __read_mostly = true;
45 module_param(frontswap, bool, S_IRUGO);
46 #else /* CONFIG_FRONTSWAP */
47 #define frontswap (0)
48 #endif /* CONFIG_FRONTSWAP */
49
50 #ifdef CONFIG_XEN_SELFBALLOONING
51 static bool selfshrinking __read_mostly = true;
52 module_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
74 struct tmem_pool_uuid {
75 u64 uuid_lo;
76 u64 uuid_hi;
77 };
78
79 struct 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
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)91 static 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
xen_tmem_new_pool(struct tmem_pool_uuid uuid,u32 flags,unsigned long pagesize)111 static 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
xen_tmem_put_page(u32 pool_id,struct tmem_oid oid,u32 index,unsigned long pfn)131 static 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
xen_tmem_get_page(u32 pool_id,struct tmem_oid oid,u32 index,unsigned long pfn)140 static 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
xen_tmem_flush_page(u32 pool_id,struct tmem_oid oid,u32 index)149 static 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
xen_tmem_flush_object(u32 pool_id,struct tmem_oid oid)155 static 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
xen_tmem_destroy_pool(u32 pool_id)162 static 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
tmem_cleancache_put_page(int pool,struct cleancache_filekey key,pgoff_t index,struct page * page)171 static 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
tmem_cleancache_get_page(int pool,struct cleancache_filekey key,pgoff_t index,struct page * page)186 static 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
tmem_cleancache_flush_page(int pool,struct cleancache_filekey key,pgoff_t index)206 static 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
tmem_cleancache_flush_inode(int pool,struct cleancache_filekey key)219 static 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
tmem_cleancache_flush_fs(int pool)228 static void tmem_cleancache_flush_fs(int pool)
229 {
230 if (pool < 0)
231 return;
232 (void)xen_tmem_destroy_pool((u32)pool);
233 }
234
tmem_cleancache_init_fs(size_t pagesize)235 static 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
tmem_cleancache_init_shared_fs(char * uuid,size_t pagesize)242 static 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
251 static 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) */
266 static 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
oswiz(unsigned type,u32 ind)277 static 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 */
tmem_frontswap_store(unsigned type,pgoff_t offset,struct page * page)285 static 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 */
tmem_frontswap_load(unsigned type,pgoff_t offset,struct page * page)311 static 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 */
tmem_frontswap_flush_page(unsigned type,pgoff_t offset)333 static 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 */
tmem_frontswap_flush_area(unsigned type)347 static 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
tmem_frontswap_init(unsigned ignored)358 static 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
368 static 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
xen_tmem_init(void)377 static 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
423 module_init(xen_tmem_init)
424 MODULE_LICENSE("GPL");
425 MODULE_AUTHOR("Dan Magenheimer <dan.magenheimer@oracle.com>");
426 MODULE_DESCRIPTION("Shim to Xen transcendent memory");
427