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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
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
25#define TMEM_CONTROL 0
26#define TMEM_NEW_POOL 1
27#define TMEM_DESTROY_POOL 2
28#define TMEM_NEW_PAGE 3
29#define TMEM_PUT_PAGE 4
30#define TMEM_GET_PAGE 5
31#define TMEM_FLUSH_PAGE 6
32#define TMEM_FLUSH_OBJECT 7
33#define TMEM_READ 8
34#define TMEM_WRITE 9
35#define TMEM_XCHG 10
36
37/* Bits for HYPERVISOR_tmem_op(TMEM_NEW_POOL) */
38#define TMEM_POOL_PERSIST 1
39#define TMEM_POOL_SHARED 2
40#define TMEM_POOL_PAGESIZE_SHIFT 4
41#define TMEM_VERSION_SHIFT 24
42
43
44struct tmem_pool_uuid {
45 u64 uuid_lo;
46 u64 uuid_hi;
47};
48
49struct tmem_oid {
50 u64 oid[3];
51};
52
53#define TMEM_POOL_PRIVATE_UUID { 0, 0 }
54
55/* flags for tmem_ops.new_pool */
56#define TMEM_POOL_PERSIST 1
57#define TMEM_POOL_SHARED 2
58
59/* xen tmem foundation ops/hypercalls */
60
61static inline int xen_tmem_op(u32 tmem_cmd, u32 tmem_pool, struct tmem_oid oid,
62 u32 index, unsigned long gmfn, u32 tmem_offset, u32 pfn_offset, u32 len)
63{
64 struct tmem_op op;
65 int rc = 0;
66
67 op.cmd = tmem_cmd;
68 op.pool_id = tmem_pool;
69 op.u.gen.oid[0] = oid.oid[0];
70 op.u.gen.oid[1] = oid.oid[1];
71 op.u.gen.oid[2] = oid.oid[2];
72 op.u.gen.index = index;
73 op.u.gen.tmem_offset = tmem_offset;
74 op.u.gen.pfn_offset = pfn_offset;
75 op.u.gen.len = len;
76 set_xen_guest_handle(op.u.gen.gmfn, (void *)gmfn);
77 rc = HYPERVISOR_tmem_op(&op);
78 return rc;
79}
80
81static int xen_tmem_new_pool(struct tmem_pool_uuid uuid,
82 u32 flags, unsigned long pagesize)
83{
84 struct tmem_op op;
85 int rc = 0, pageshift;
86
87 for (pageshift = 0; pagesize != 1; pageshift++)
88 pagesize >>= 1;
89 flags |= (pageshift - 12) << TMEM_POOL_PAGESIZE_SHIFT;
90 flags |= TMEM_SPEC_VERSION << TMEM_VERSION_SHIFT;
91 op.cmd = TMEM_NEW_POOL;
92 op.u.new.uuid[0] = uuid.uuid_lo;
93 op.u.new.uuid[1] = uuid.uuid_hi;
94 op.u.new.flags = flags;
95 rc = HYPERVISOR_tmem_op(&op);
96 return rc;
97}
98
99/* xen generic tmem ops */
100
101static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid,
102 u32 index, unsigned long pfn)
103{
104 unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
105
106 return xen_tmem_op(TMEM_PUT_PAGE, pool_id, oid, index,
107 gmfn, 0, 0, 0);
108}
109
110static int xen_tmem_get_page(u32 pool_id, struct tmem_oid oid,
111 u32 index, unsigned long pfn)
112{
113 unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
114
115 return xen_tmem_op(TMEM_GET_PAGE, pool_id, oid, index,
116 gmfn, 0, 0, 0);
117}
118
119static int xen_tmem_flush_page(u32 pool_id, struct tmem_oid oid, u32 index)
120{
121 return xen_tmem_op(TMEM_FLUSH_PAGE, pool_id, oid, index,
122 0, 0, 0, 0);
123}
124
125static int xen_tmem_flush_object(u32 pool_id, struct tmem_oid oid)
126{
127 return xen_tmem_op(TMEM_FLUSH_OBJECT, pool_id, oid, 0, 0, 0, 0, 0);
128}
129
130bool __read_mostly tmem_enabled = false;
131
132static int __init enable_tmem(char *s)
133{
134 tmem_enabled = true;
135 return 1;
136}
137__setup("tmem", enable_tmem);
138
139#ifdef CONFIG_CLEANCACHE
140static 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
147/* cleancache ops */
148
149static 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
164static 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
184static 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
197static 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
206static void tmem_cleancache_flush_fs(int pool)
207{
208 if (pool < 0)
209 return;
210 (void)xen_tmem_destroy_pool((u32)pool);
211}
212
213static 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
220static 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
229static bool __initdata use_cleancache = true;
230
231static int __init no_cleancache(char *s)
232{
233 use_cleancache = false;
234 return 1;
235}
236__setup("nocleancache", no_cleancache);
237
238static struct cleancache_ops __initdata tmem_cleancache_ops = {
239 .put_page = tmem_cleancache_put_page,
240 .get_page = tmem_cleancache_get_page,
241 .invalidate_page = tmem_cleancache_flush_page,
242 .invalidate_inode = tmem_cleancache_flush_inode,
243 .invalidate_fs = tmem_cleancache_flush_fs,
244 .init_shared_fs = tmem_cleancache_init_shared_fs,
245 .init_fs = tmem_cleancache_init_fs
246};
247#endif
248
249#ifdef CONFIG_FRONTSWAP
250/* frontswap tmem operations */
251
252/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
253static int tmem_frontswap_poolid;
254
255/*
256 * Swizzling increases objects per swaptype, increasing tmem concurrency
257 * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
258 */
259#define SWIZ_BITS 4
260#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
261#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
262#define iswiz(_ind) (_ind >> SWIZ_BITS)
263
264static inline struct tmem_oid oswiz(unsigned type, u32 ind)
265{
266 struct tmem_oid oid = { .oid = { 0 } };
267 oid.oid[0] = _oswiz(type, ind);
268 return oid;
269}
270
271/* returns 0 if the page was successfully put into frontswap, -1 if not */
272static int tmem_frontswap_store(unsigned type, pgoff_t offset,
273 struct page *page)
274{
275 u64 ind64 = (u64)offset;
276 u32 ind = (u32)offset;
277 unsigned long pfn = page_to_pfn(page);
278 int pool = tmem_frontswap_poolid;
279 int ret;
280
281 if (pool < 0)
282 return -1;
283 if (ind64 != ind)
284 return -1;
285 mb(); /* ensure page is quiescent; tmem may address it with an alias */
286 ret = xen_tmem_put_page(pool, oswiz(type, ind), iswiz(ind), pfn);
287 /* translate Xen tmem return values to linux semantics */
288 if (ret == 1)
289 return 0;
290 else
291 return -1;
292}
293
294/*
295 * returns 0 if the page was successfully gotten from frontswap, -1 if
296 * was not present (should never happen!)
297 */
298static int tmem_frontswap_load(unsigned type, pgoff_t offset,
299 struct page *page)
300{
301 u64 ind64 = (u64)offset;
302 u32 ind = (u32)offset;
303 unsigned long pfn = page_to_pfn(page);
304 int pool = tmem_frontswap_poolid;
305 int ret;
306
307 if (pool < 0)
308 return -1;
309 if (ind64 != ind)
310 return -1;
311 ret = xen_tmem_get_page(pool, oswiz(type, ind), iswiz(ind), pfn);
312 /* translate Xen tmem return values to linux semantics */
313 if (ret == 1)
314 return 0;
315 else
316 return -1;
317}
318
319/* flush a single page from frontswap */
320static void tmem_frontswap_flush_page(unsigned type, pgoff_t offset)
321{
322 u64 ind64 = (u64)offset;
323 u32 ind = (u32)offset;
324 int pool = tmem_frontswap_poolid;
325
326 if (pool < 0)
327 return;
328 if (ind64 != ind)
329 return;
330 (void) xen_tmem_flush_page(pool, oswiz(type, ind), iswiz(ind));
331}
332
333/* flush all pages from the passed swaptype */
334static void tmem_frontswap_flush_area(unsigned type)
335{
336 int pool = tmem_frontswap_poolid;
337 int ind;
338
339 if (pool < 0)
340 return;
341 for (ind = SWIZ_MASK; ind >= 0; ind--)
342 (void)xen_tmem_flush_object(pool, oswiz(type, ind));
343}
344
345static void tmem_frontswap_init(unsigned ignored)
346{
347 struct tmem_pool_uuid private = TMEM_POOL_PRIVATE_UUID;
348
349 /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
350 if (tmem_frontswap_poolid < 0)
351 tmem_frontswap_poolid =
352 xen_tmem_new_pool(private, TMEM_POOL_PERSIST, PAGE_SIZE);
353}
354
355static bool __initdata use_frontswap = true;
356
357static int __init no_frontswap(char *s)
358{
359 use_frontswap = false;
360 return 1;
361}
362__setup("nofrontswap", no_frontswap);
363
364static struct frontswap_ops __initdata tmem_frontswap_ops = {
365 .store = tmem_frontswap_store,
366 .load = tmem_frontswap_load,
367 .invalidate_page = tmem_frontswap_flush_page,
368 .invalidate_area = tmem_frontswap_flush_area,
369 .init = tmem_frontswap_init
370};
371#endif
372
373static int __init xen_tmem_init(void)
374{
375 if (!xen_domain())
376 return 0;
377#ifdef CONFIG_FRONTSWAP
378 if (tmem_enabled && use_frontswap) {
379 char *s = "";
380 struct frontswap_ops old_ops =
381 frontswap_register_ops(&tmem_frontswap_ops);
382
383 tmem_frontswap_poolid = -1;
384 if (old_ops.init != NULL)
385 s = " (WARNING: frontswap_ops overridden)";
386 printk(KERN_INFO "frontswap enabled, RAM provided by "
387 "Xen Transcendent Memory\n");
388 }
389#endif
390#ifdef CONFIG_CLEANCACHE
391 BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
392 if (tmem_enabled && use_cleancache) {
393 char *s = "";
394 struct cleancache_ops old_ops =
395 cleancache_register_ops(&tmem_cleancache_ops);
396 if (old_ops.init_fs != NULL)
397 s = " (WARNING: cleancache_ops overridden)";
398 printk(KERN_INFO "cleancache enabled, RAM provided by "
399 "Xen Transcendent Memory%s\n", s);
400 }
401#endif
402 return 0;
403}
404
405module_init(xen_tmem_init)