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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/cleancache.h> |
13 | |
14 | /* temporary ifdef until include/linux/frontswap.h is upstream */ |
15 | #ifdef CONFIG_FRONTSWAP |
16 | #include <linux/frontswap.h> |
17 | #endif |
18 | |
19 | #include <xen/xen.h> |
20 | #include <xen/interface/xen.h> |
21 | #include <asm/xen/hypercall.h> |
22 | #include <asm/xen/page.h> |
23 | #include <asm/xen/hypervisor.h> |
24 | #include <xen/tmem.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 | |
45 | struct tmem_pool_uuid { |
46 | u64 uuid_lo; |
47 | u64 uuid_hi; |
48 | }; |
49 | |
50 | struct 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 | |
62 | static 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 | |
82 | static 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 | |
102 | static 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 | |
111 | static 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 | |
120 | static 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 | |
126 | static 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 | |
131 | bool __read_mostly tmem_enabled = false; |
132 | |
133 | static int __init enable_tmem(char *s) |
134 | { |
135 | tmem_enabled = true; |
136 | return 1; |
137 | } |
138 | __setup("tmem", enable_tmem); |
139 | |
140 | #ifdef CONFIG_CLEANCACHE |
141 | static int xen_tmem_destroy_pool(u32 pool_id) |
142 | { |
143 | struct tmem_oid oid = { { 0 } }; |
144 | |
145 | return xen_tmem_op(TMEM_DESTROY_POOL, pool_id, oid, 0, 0, 0, 0, 0); |
146 | } |
147 | |
148 | /* cleancache ops */ |
149 | |
150 | static void tmem_cleancache_put_page(int pool, struct cleancache_filekey key, |
151 | pgoff_t index, struct page *page) |
152 | { |
153 | u32 ind = (u32) index; |
154 | struct tmem_oid oid = *(struct tmem_oid *)&key; |
155 | unsigned long pfn = page_to_pfn(page); |
156 | |
157 | if (pool < 0) |
158 | return; |
159 | if (ind != index) |
160 | return; |
161 | mb(); /* ensure page is quiescent; tmem may address it with an alias */ |
162 | (void)xen_tmem_put_page((u32)pool, oid, ind, pfn); |
163 | } |
164 | |
165 | static int tmem_cleancache_get_page(int pool, struct cleancache_filekey key, |
166 | pgoff_t index, struct page *page) |
167 | { |
168 | u32 ind = (u32) index; |
169 | struct tmem_oid oid = *(struct tmem_oid *)&key; |
170 | unsigned long pfn = page_to_pfn(page); |
171 | int ret; |
172 | |
173 | /* translate return values to linux semantics */ |
174 | if (pool < 0) |
175 | return -1; |
176 | if (ind != index) |
177 | return -1; |
178 | ret = xen_tmem_get_page((u32)pool, oid, ind, pfn); |
179 | if (ret == 1) |
180 | return 0; |
181 | else |
182 | return -1; |
183 | } |
184 | |
185 | static void tmem_cleancache_flush_page(int pool, struct cleancache_filekey key, |
186 | pgoff_t index) |
187 | { |
188 | u32 ind = (u32) index; |
189 | struct tmem_oid oid = *(struct tmem_oid *)&key; |
190 | |
191 | if (pool < 0) |
192 | return; |
193 | if (ind != index) |
194 | return; |
195 | (void)xen_tmem_flush_page((u32)pool, oid, ind); |
196 | } |
197 | |
198 | static void tmem_cleancache_flush_inode(int pool, struct cleancache_filekey key) |
199 | { |
200 | struct tmem_oid oid = *(struct tmem_oid *)&key; |
201 | |
202 | if (pool < 0) |
203 | return; |
204 | (void)xen_tmem_flush_object((u32)pool, oid); |
205 | } |
206 | |
207 | static void tmem_cleancache_flush_fs(int pool) |
208 | { |
209 | if (pool < 0) |
210 | return; |
211 | (void)xen_tmem_destroy_pool((u32)pool); |
212 | } |
213 | |
214 | static int tmem_cleancache_init_fs(size_t pagesize) |
215 | { |
216 | struct tmem_pool_uuid uuid_private = TMEM_POOL_PRIVATE_UUID; |
217 | |
218 | return xen_tmem_new_pool(uuid_private, 0, pagesize); |
219 | } |
220 | |
221 | static int tmem_cleancache_init_shared_fs(char *uuid, size_t pagesize) |
222 | { |
223 | struct tmem_pool_uuid shared_uuid; |
224 | |
225 | shared_uuid.uuid_lo = *(u64 *)uuid; |
226 | shared_uuid.uuid_hi = *(u64 *)(&uuid[8]); |
227 | return xen_tmem_new_pool(shared_uuid, TMEM_POOL_SHARED, pagesize); |
228 | } |
229 | |
230 | static bool __initdata use_cleancache = true; |
231 | |
232 | static int __init no_cleancache(char *s) |
233 | { |
234 | use_cleancache = false; |
235 | return 1; |
236 | } |
237 | __setup("nocleancache", no_cleancache); |
238 | |
239 | static struct cleancache_ops __initdata tmem_cleancache_ops = { |
240 | .put_page = tmem_cleancache_put_page, |
241 | .get_page = tmem_cleancache_get_page, |
242 | .invalidate_page = tmem_cleancache_flush_page, |
243 | .invalidate_inode = tmem_cleancache_flush_inode, |
244 | .invalidate_fs = tmem_cleancache_flush_fs, |
245 | .init_shared_fs = tmem_cleancache_init_shared_fs, |
246 | .init_fs = tmem_cleancache_init_fs |
247 | }; |
248 | #endif |
249 | |
250 | #ifdef CONFIG_FRONTSWAP |
251 | /* frontswap tmem operations */ |
252 | |
253 | /* a single tmem poolid is used for all frontswap "types" (swapfiles) */ |
254 | static int tmem_frontswap_poolid; |
255 | |
256 | /* |
257 | * Swizzling increases objects per swaptype, increasing tmem concurrency |
258 | * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS |
259 | */ |
260 | #define SWIZ_BITS 4 |
261 | #define SWIZ_MASK ((1 << SWIZ_BITS) - 1) |
262 | #define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK)) |
263 | #define iswiz(_ind) (_ind >> SWIZ_BITS) |
264 | |
265 | static inline struct tmem_oid oswiz(unsigned type, u32 ind) |
266 | { |
267 | struct tmem_oid oid = { .oid = { 0 } }; |
268 | oid.oid[0] = _oswiz(type, ind); |
269 | return oid; |
270 | } |
271 | |
272 | /* returns 0 if the page was successfully put into frontswap, -1 if not */ |
273 | static int tmem_frontswap_store(unsigned type, pgoff_t offset, |
274 | struct page *page) |
275 | { |
276 | u64 ind64 = (u64)offset; |
277 | u32 ind = (u32)offset; |
278 | unsigned long pfn = page_to_pfn(page); |
279 | int pool = tmem_frontswap_poolid; |
280 | int ret; |
281 | |
282 | if (pool < 0) |
283 | return -1; |
284 | if (ind64 != ind) |
285 | return -1; |
286 | mb(); /* ensure page is quiescent; tmem may address it with an alias */ |
287 | ret = xen_tmem_put_page(pool, oswiz(type, ind), iswiz(ind), pfn); |
288 | /* translate Xen tmem return values to linux semantics */ |
289 | if (ret == 1) |
290 | return 0; |
291 | else |
292 | return -1; |
293 | } |
294 | |
295 | /* |
296 | * returns 0 if the page was successfully gotten from frontswap, -1 if |
297 | * was not present (should never happen!) |
298 | */ |
299 | static int tmem_frontswap_load(unsigned type, pgoff_t offset, |
300 | struct page *page) |
301 | { |
302 | u64 ind64 = (u64)offset; |
303 | u32 ind = (u32)offset; |
304 | unsigned long pfn = page_to_pfn(page); |
305 | int pool = tmem_frontswap_poolid; |
306 | int ret; |
307 | |
308 | if (pool < 0) |
309 | return -1; |
310 | if (ind64 != ind) |
311 | return -1; |
312 | ret = xen_tmem_get_page(pool, oswiz(type, ind), iswiz(ind), pfn); |
313 | /* translate Xen tmem return values to linux semantics */ |
314 | if (ret == 1) |
315 | return 0; |
316 | else |
317 | return -1; |
318 | } |
319 | |
320 | /* flush a single page from frontswap */ |
321 | static void tmem_frontswap_flush_page(unsigned type, pgoff_t offset) |
322 | { |
323 | u64 ind64 = (u64)offset; |
324 | u32 ind = (u32)offset; |
325 | int pool = tmem_frontswap_poolid; |
326 | |
327 | if (pool < 0) |
328 | return; |
329 | if (ind64 != ind) |
330 | return; |
331 | (void) xen_tmem_flush_page(pool, oswiz(type, ind), iswiz(ind)); |
332 | } |
333 | |
334 | /* flush all pages from the passed swaptype */ |
335 | static void tmem_frontswap_flush_area(unsigned type) |
336 | { |
337 | int pool = tmem_frontswap_poolid; |
338 | int ind; |
339 | |
340 | if (pool < 0) |
341 | return; |
342 | for (ind = SWIZ_MASK; ind >= 0; ind--) |
343 | (void)xen_tmem_flush_object(pool, oswiz(type, ind)); |
344 | } |
345 | |
346 | static void tmem_frontswap_init(unsigned ignored) |
347 | { |
348 | struct tmem_pool_uuid private = TMEM_POOL_PRIVATE_UUID; |
349 | |
350 | /* a single tmem poolid is used for all frontswap "types" (swapfiles) */ |
351 | if (tmem_frontswap_poolid < 0) |
352 | tmem_frontswap_poolid = |
353 | xen_tmem_new_pool(private, TMEM_POOL_PERSIST, PAGE_SIZE); |
354 | } |
355 | |
356 | static bool __initdata use_frontswap = true; |
357 | |
358 | static int __init no_frontswap(char *s) |
359 | { |
360 | use_frontswap = false; |
361 | return 1; |
362 | } |
363 | __setup("nofrontswap", no_frontswap); |
364 | |
365 | static struct frontswap_ops __initdata tmem_frontswap_ops = { |
366 | .store = tmem_frontswap_store, |
367 | .load = tmem_frontswap_load, |
368 | .invalidate_page = tmem_frontswap_flush_page, |
369 | .invalidate_area = tmem_frontswap_flush_area, |
370 | .init = tmem_frontswap_init |
371 | }; |
372 | #endif |
373 | |
374 | static int __init xen_tmem_init(void) |
375 | { |
376 | if (!xen_domain()) |
377 | return 0; |
378 | #ifdef CONFIG_FRONTSWAP |
379 | if (tmem_enabled && use_frontswap) { |
380 | char *s = ""; |
381 | struct frontswap_ops old_ops = |
382 | frontswap_register_ops(&tmem_frontswap_ops); |
383 | |
384 | tmem_frontswap_poolid = -1; |
385 | if (old_ops.init != NULL) |
386 | s = " (WARNING: frontswap_ops overridden)"; |
387 | printk(KERN_INFO "frontswap enabled, RAM provided by " |
388 | "Xen Transcendent Memory%s\n", s); |
389 | } |
390 | #endif |
391 | #ifdef CONFIG_CLEANCACHE |
392 | BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid)); |
393 | if (tmem_enabled && use_cleancache) { |
394 | char *s = ""; |
395 | struct cleancache_ops old_ops = |
396 | cleancache_register_ops(&tmem_cleancache_ops); |
397 | if (old_ops.init_fs != NULL) |
398 | s = " (WARNING: cleancache_ops overridden)"; |
399 | printk(KERN_INFO "cleancache enabled, RAM provided by " |
400 | "Xen Transcendent Memory%s\n", s); |
401 | } |
402 | #endif |
403 | return 0; |
404 | } |
405 | |
406 | module_init(xen_tmem_init) |
407 |
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