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Dan Magenheimer5bc20fc2011-05-26 10:02:21 -06001/*
2 * Xen implementation for transcendent memory (tmem)
3 *
Dan Magenheimerafec6e02011-06-17 15:06:20 -06004 * Copyright (C) 2009-2011 Oracle Corp. All rights reserved.
Dan Magenheimer5bc20fc2011-05-26 10:02:21 -06005 * Author: Dan Magenheimer
6 */
7
Joe Perches283c0972013-06-28 03:21:41 -07008#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
9
Dan Magenheimer10a7a0772013-04-30 15:27:00 -070010#include <linux/module.h>
Dan Magenheimer5bc20fc2011-05-26 10:02:21 -060011#include <linux/kernel.h>
12#include <linux/types.h>
13#include <linux/init.h>
14#include <linux/pagemap.h>
15#include <linux/cleancache.h>
Dan Magenheimerafec6e02011-06-17 15:06:20 -060016#include <linux/frontswap.h>
Dan Magenheimerafec6e02011-06-17 15:06:20 -060017
Dan Magenheimer5bc20fc2011-05-26 10:02:21 -060018#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>
Konrad Rzeszutek Wilkb8b0f552012-08-21 14:49:34 -040023#include <xen/tmem.h>
Dan Magenheimer5bc20fc2011-05-26 10:02:21 -060024
Konrad Rzeszutek Wilk0cb401d2013-05-08 15:50:59 -040025#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
Konrad Rzeszutek Wilk9fd19652013-05-08 17:10:08 -040037static bool cleancache __read_mostly = true;
Konrad Rzeszutek Wilk9fd19652013-05-08 17:10:08 -040038module_param(cleancache, bool, S_IRUGO);
Konrad Rzeszutek Wilk2ca62b02013-05-08 17:12:44 -040039static bool selfballooning __read_mostly = true;
Konrad Rzeszutek Wilk9fd19652013-05-08 17:10:08 -040040module_param(selfballooning, bool, S_IRUGO);
Konrad Rzeszutek Wilk0cb401d2013-05-08 15:50:59 -040041#endif /* CONFIG_CLEANCACHE */
42
43#ifdef CONFIG_FRONTSWAP
Konrad Rzeszutek Wilk9fd19652013-05-08 17:10:08 -040044static bool frontswap __read_mostly = true;
Konrad Rzeszutek Wilk9fd19652013-05-08 17:10:08 -040045module_param(frontswap, bool, S_IRUGO);
Frederico Cadete1d7004f2013-05-25 22:48:57 +020046#else /* CONFIG_FRONTSWAP */
47#define frontswap (0)
Konrad Rzeszutek Wilke8f9cb02013-05-08 15:58:06 -040048#endif /* CONFIG_FRONTSWAP */
49
Konrad Rzeszutek Wilk23972c62013-05-08 16:57:35 -040050#ifdef CONFIG_XEN_SELFBALLOONING
Konrad Rzeszutek Wilk2ca62b02013-05-08 17:12:44 -040051static bool selfshrinking __read_mostly = true;
52module_param(selfshrinking, bool, S_IRUGO);
Konrad Rzeszutek Wilk23972c62013-05-08 16:57:35 -040053#endif /* CONFIG_XEN_SELFBALLOONING */
Konrad Rzeszutek Wilk0cb401d2013-05-08 15:50:59 -040054
Dan Magenheimer5bc20fc2011-05-26 10:02:21 -060055#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
Dan Magenheimer5bc20fc2011-05-26 10:02:21 -0600160
Dan Magenheimerafec6e02011-06-17 15:06:20 -0600161#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
Dan Magenheimer5bc20fc2011-05-26 10:02:21 -0600169/* 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
Konrad Rzeszutek Wilk833f8662013-04-30 15:26:57 -0700251static struct cleancache_ops tmem_cleancache_ops = {
Dan Magenheimer5bc20fc2011-05-26 10:02:21 -0600252 .put_page = tmem_cleancache_put_page,
253 .get_page = tmem_cleancache_get_page,
Dan Magenheimer91c6cc92012-01-12 14:03:25 -0500254 .invalidate_page = tmem_cleancache_flush_page,
255 .invalidate_inode = tmem_cleancache_flush_inode,
256 .invalidate_fs = tmem_cleancache_flush_fs,
Dan Magenheimer5bc20fc2011-05-26 10:02:21 -0600257 .init_shared_fs = tmem_cleancache_init_shared_fs,
258 .init_fs = tmem_cleancache_init_fs
259};
Dan Magenheimerafec6e02011-06-17 15:06:20 -0600260#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 */
Konrad Rzeszutek Wilk165c8ae2012-05-15 11:32:15 -0400285static int tmem_frontswap_store(unsigned type, pgoff_t offset,
Dan Magenheimerafec6e02011-06-17 15:06:20 -0600286 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 */
Konrad Rzeszutek Wilk165c8ae2012-05-15 11:32:15 -0400311static int tmem_frontswap_load(unsigned type, pgoff_t offset,
Dan Magenheimerafec6e02011-06-17 15:06:20 -0600312 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
Konrad Rzeszutek Wilk1e01c962013-04-30 15:26:51 -0700368static struct frontswap_ops tmem_frontswap_ops = {
Konrad Rzeszutek Wilk165c8ae2012-05-15 11:32:15 -0400369 .store = tmem_frontswap_store,
370 .load = tmem_frontswap_load,
Dan Magenheimer91c6cc92012-01-12 14:03:25 -0500371 .invalidate_page = tmem_frontswap_flush_page,
372 .invalidate_area = tmem_frontswap_flush_area,
Dan Magenheimerafec6e02011-06-17 15:06:20 -0600373 .init = tmem_frontswap_init
374};
375#endif
Dan Magenheimer5bc20fc2011-05-26 10:02:21 -0600376
Jan Beulich144c61a2015-01-23 08:37:01 +0000377static int __init xen_tmem_init(void)
Dan Magenheimer5bc20fc2011-05-26 10:02:21 -0600378{
Dan Magenheimer5bc20fc2011-05-26 10:02:21 -0600379 if (!xen_domain())
380 return 0;
Dan Magenheimerafec6e02011-06-17 15:06:20 -0600381#ifdef CONFIG_FRONTSWAP
Konrad Rzeszutek Wilk9fd19652013-05-08 17:10:08 -0400382 if (tmem_enabled && frontswap) {
Dan Magenheimerafec6e02011-06-17 15:06:20 -0600383 char *s = "";
Konrad Rzeszutek Wilkb2c75c42013-06-07 15:26:03 -0400384 struct frontswap_ops *old_ops;
Dan Magenheimerafec6e02011-06-17 15:06:20 -0600385
386 tmem_frontswap_poolid = -1;
Konrad Rzeszutek Wilkb2c75c42013-06-07 15:26:03 -0400387 old_ops = frontswap_register_ops(&tmem_frontswap_ops);
Konrad Rzeszutek Wilkf42158f2013-04-30 15:27:01 -0700388 if (IS_ERR(old_ops) || old_ops) {
389 if (IS_ERR(old_ops))
390 return PTR_ERR(old_ops);
Dan Magenheimerafec6e02011-06-17 15:06:20 -0600391 s = " (WARNING: frontswap_ops overridden)";
Konrad Rzeszutek Wilkf42158f2013-04-30 15:27:01 -0700392 }
Joe Perches283c0972013-06-28 03:21:41 -0700393 pr_info("frontswap enabled, RAM provided by Xen Transcendent Memory%s\n",
394 s);
Dan Magenheimerafec6e02011-06-17 15:06:20 -0600395 }
396#endif
Dan Magenheimer5bc20fc2011-05-26 10:02:21 -0600397#ifdef CONFIG_CLEANCACHE
398 BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
Konrad Rzeszutek Wilk9fd19652013-05-08 17:10:08 -0400399 if (tmem_enabled && cleancache) {
Vladimir Davydov53d85c92015-04-14 15:46:45 -0700400 int err;
401
402 err = cleancache_register_ops(&tmem_cleancache_ops);
403 if (err)
404 pr_warn("xen-tmem: failed to enable cleancache: %d\n",
405 err);
406 else
407 pr_info("cleancache enabled, RAM provided by "
408 "Xen Transcendent Memory\n");
Dan Magenheimer5bc20fc2011-05-26 10:02:21 -0600409 }
410#endif
Dan Magenheimer10a7a0772013-04-30 15:27:00 -0700411#ifdef CONFIG_XEN_SELFBALLOONING
Konrad Rzeszutek Wilk37d46e12013-05-14 13:56:42 -0400412 /*
413 * There is no point of driving pages to the swap system if they
414 * aren't going anywhere in tmem universe.
415 */
416 if (!frontswap) {
417 selfshrinking = false;
418 selfballooning = false;
419 }
Konrad Rzeszutek Wilk2ca62b02013-05-08 17:12:44 -0400420 xen_selfballoon_init(selfballooning, selfshrinking);
Dan Magenheimer10a7a0772013-04-30 15:27:00 -0700421#endif
Dan Magenheimer5bc20fc2011-05-26 10:02:21 -0600422 return 0;
423}
424
425module_init(xen_tmem_init)
Dan Magenheimer10a7a0772013-04-30 15:27:00 -0700426MODULE_LICENSE("GPL");
427MODULE_AUTHOR("Dan Magenheimer <dan.magenheimer@oracle.com>");
428MODULE_DESCRIPTION("Shim to Xen transcendent memory");