2 * Xen implementation for transcendent memory (tmem)
4 * Copyright (C) 2009-2011 Oracle Corp. All rights reserved.
5 * Author: Dan Magenheimer
8 #include <linux/module.h>
9 #include <linux/kernel.h>
10 #include <linux/types.h>
11 #include <linux/init.h>
12 #include <linux/pagemap.h>
13 #include <linux/cleancache.h>
14 #include <linux/frontswap.h>
17 #include <xen/interface/xen.h>
18 #include <asm/xen/hypercall.h>
19 #include <asm/xen/page.h>
20 #include <asm/xen/hypervisor.h>
23 #ifndef CONFIG_XEN_TMEM_MODULE
24 bool __read_mostly tmem_enabled
= false;
26 static int __init
enable_tmem(char *s
)
31 __setup("tmem", enable_tmem
);
34 #ifdef CONFIG_CLEANCACHE
35 static bool cleancache __read_mostly
= true;
36 module_param(cleancache
, bool, S_IRUGO
);
37 static bool selfballooning __read_mostly
= true;
38 module_param(selfballooning
, bool, S_IRUGO
);
39 #endif /* CONFIG_CLEANCACHE */
41 #ifdef CONFIG_FRONTSWAP
42 static bool frontswap __read_mostly
= true;
43 module_param(frontswap
, bool, S_IRUGO
);
44 #else /* CONFIG_FRONTSWAP */
46 #endif /* CONFIG_FRONTSWAP */
48 #ifdef CONFIG_XEN_SELFBALLOONING
49 static bool selfshrinking __read_mostly
= true;
50 module_param(selfshrinking
, bool, S_IRUGO
);
51 #endif /* CONFIG_XEN_SELFBALLOONING */
53 #define TMEM_CONTROL 0
54 #define TMEM_NEW_POOL 1
55 #define TMEM_DESTROY_POOL 2
56 #define TMEM_NEW_PAGE 3
57 #define TMEM_PUT_PAGE 4
58 #define TMEM_GET_PAGE 5
59 #define TMEM_FLUSH_PAGE 6
60 #define TMEM_FLUSH_OBJECT 7
65 /* Bits for HYPERVISOR_tmem_op(TMEM_NEW_POOL) */
66 #define TMEM_POOL_PERSIST 1
67 #define TMEM_POOL_SHARED 2
68 #define TMEM_POOL_PAGESIZE_SHIFT 4
69 #define TMEM_VERSION_SHIFT 24
72 struct tmem_pool_uuid
{
81 #define TMEM_POOL_PRIVATE_UUID { 0, 0 }
83 /* flags for tmem_ops.new_pool */
84 #define TMEM_POOL_PERSIST 1
85 #define TMEM_POOL_SHARED 2
87 /* xen tmem foundation ops/hypercalls */
89 static inline int xen_tmem_op(u32 tmem_cmd
, u32 tmem_pool
, struct tmem_oid oid
,
90 u32 index
, unsigned long gmfn
, u32 tmem_offset
, u32 pfn_offset
, u32 len
)
96 op
.pool_id
= tmem_pool
;
97 op
.u
.gen
.oid
[0] = oid
.oid
[0];
98 op
.u
.gen
.oid
[1] = oid
.oid
[1];
99 op
.u
.gen
.oid
[2] = oid
.oid
[2];
100 op
.u
.gen
.index
= index
;
101 op
.u
.gen
.tmem_offset
= tmem_offset
;
102 op
.u
.gen
.pfn_offset
= pfn_offset
;
104 set_xen_guest_handle(op
.u
.gen
.gmfn
, (void *)gmfn
);
105 rc
= HYPERVISOR_tmem_op(&op
);
109 static int xen_tmem_new_pool(struct tmem_pool_uuid uuid
,
110 u32 flags
, unsigned long pagesize
)
113 int rc
= 0, pageshift
;
115 for (pageshift
= 0; pagesize
!= 1; pageshift
++)
117 flags
|= (pageshift
- 12) << TMEM_POOL_PAGESIZE_SHIFT
;
118 flags
|= TMEM_SPEC_VERSION
<< TMEM_VERSION_SHIFT
;
119 op
.cmd
= TMEM_NEW_POOL
;
120 op
.u
.new.uuid
[0] = uuid
.uuid_lo
;
121 op
.u
.new.uuid
[1] = uuid
.uuid_hi
;
122 op
.u
.new.flags
= flags
;
123 rc
= HYPERVISOR_tmem_op(&op
);
127 /* xen generic tmem ops */
129 static int xen_tmem_put_page(u32 pool_id
, struct tmem_oid oid
,
130 u32 index
, unsigned long pfn
)
132 unsigned long gmfn
= xen_pv_domain() ? pfn_to_mfn(pfn
) : pfn
;
134 return xen_tmem_op(TMEM_PUT_PAGE
, pool_id
, oid
, index
,
138 static int xen_tmem_get_page(u32 pool_id
, struct tmem_oid oid
,
139 u32 index
, unsigned long pfn
)
141 unsigned long gmfn
= xen_pv_domain() ? pfn_to_mfn(pfn
) : pfn
;
143 return xen_tmem_op(TMEM_GET_PAGE
, pool_id
, oid
, index
,
147 static int xen_tmem_flush_page(u32 pool_id
, struct tmem_oid oid
, u32 index
)
149 return xen_tmem_op(TMEM_FLUSH_PAGE
, pool_id
, oid
, index
,
153 static int xen_tmem_flush_object(u32 pool_id
, struct tmem_oid oid
)
155 return xen_tmem_op(TMEM_FLUSH_OBJECT
, pool_id
, oid
, 0, 0, 0, 0, 0);
159 #ifdef CONFIG_CLEANCACHE
160 static int xen_tmem_destroy_pool(u32 pool_id
)
162 struct tmem_oid oid
= { { 0 } };
164 return xen_tmem_op(TMEM_DESTROY_POOL
, pool_id
, oid
, 0, 0, 0, 0, 0);
169 static void tmem_cleancache_put_page(int pool
, struct cleancache_filekey key
,
170 pgoff_t index
, struct page
*page
)
172 u32 ind
= (u32
) index
;
173 struct tmem_oid oid
= *(struct tmem_oid
*)&key
;
174 unsigned long pfn
= page_to_pfn(page
);
180 mb(); /* ensure page is quiescent; tmem may address it with an alias */
181 (void)xen_tmem_put_page((u32
)pool
, oid
, ind
, pfn
);
184 static int tmem_cleancache_get_page(int pool
, struct cleancache_filekey key
,
185 pgoff_t index
, struct page
*page
)
187 u32 ind
= (u32
) index
;
188 struct tmem_oid oid
= *(struct tmem_oid
*)&key
;
189 unsigned long pfn
= page_to_pfn(page
);
192 /* translate return values to linux semantics */
197 ret
= xen_tmem_get_page((u32
)pool
, oid
, ind
, pfn
);
204 static void tmem_cleancache_flush_page(int pool
, struct cleancache_filekey key
,
207 u32 ind
= (u32
) index
;
208 struct tmem_oid oid
= *(struct tmem_oid
*)&key
;
214 (void)xen_tmem_flush_page((u32
)pool
, oid
, ind
);
217 static void tmem_cleancache_flush_inode(int pool
, struct cleancache_filekey key
)
219 struct tmem_oid oid
= *(struct tmem_oid
*)&key
;
223 (void)xen_tmem_flush_object((u32
)pool
, oid
);
226 static void tmem_cleancache_flush_fs(int pool
)
230 (void)xen_tmem_destroy_pool((u32
)pool
);
233 static int tmem_cleancache_init_fs(size_t pagesize
)
235 struct tmem_pool_uuid uuid_private
= TMEM_POOL_PRIVATE_UUID
;
237 return xen_tmem_new_pool(uuid_private
, 0, pagesize
);
240 static int tmem_cleancache_init_shared_fs(char *uuid
, size_t pagesize
)
242 struct tmem_pool_uuid shared_uuid
;
244 shared_uuid
.uuid_lo
= *(u64
*)uuid
;
245 shared_uuid
.uuid_hi
= *(u64
*)(&uuid
[8]);
246 return xen_tmem_new_pool(shared_uuid
, TMEM_POOL_SHARED
, pagesize
);
249 static struct cleancache_ops tmem_cleancache_ops
= {
250 .put_page
= tmem_cleancache_put_page
,
251 .get_page
= tmem_cleancache_get_page
,
252 .invalidate_page
= tmem_cleancache_flush_page
,
253 .invalidate_inode
= tmem_cleancache_flush_inode
,
254 .invalidate_fs
= tmem_cleancache_flush_fs
,
255 .init_shared_fs
= tmem_cleancache_init_shared_fs
,
256 .init_fs
= tmem_cleancache_init_fs
260 #ifdef CONFIG_FRONTSWAP
261 /* frontswap tmem operations */
263 /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
264 static int tmem_frontswap_poolid
;
267 * Swizzling increases objects per swaptype, increasing tmem concurrency
268 * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
271 #define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
272 #define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
273 #define iswiz(_ind) (_ind >> SWIZ_BITS)
275 static inline struct tmem_oid
oswiz(unsigned type
, u32 ind
)
277 struct tmem_oid oid
= { .oid
= { 0 } };
278 oid
.oid
[0] = _oswiz(type
, ind
);
282 /* returns 0 if the page was successfully put into frontswap, -1 if not */
283 static int tmem_frontswap_store(unsigned type
, pgoff_t offset
,
286 u64 ind64
= (u64
)offset
;
287 u32 ind
= (u32
)offset
;
288 unsigned long pfn
= page_to_pfn(page
);
289 int pool
= tmem_frontswap_poolid
;
296 mb(); /* ensure page is quiescent; tmem may address it with an alias */
297 ret
= xen_tmem_put_page(pool
, oswiz(type
, ind
), iswiz(ind
), pfn
);
298 /* translate Xen tmem return values to linux semantics */
306 * returns 0 if the page was successfully gotten from frontswap, -1 if
307 * was not present (should never happen!)
309 static int tmem_frontswap_load(unsigned type
, pgoff_t offset
,
312 u64 ind64
= (u64
)offset
;
313 u32 ind
= (u32
)offset
;
314 unsigned long pfn
= page_to_pfn(page
);
315 int pool
= tmem_frontswap_poolid
;
322 ret
= xen_tmem_get_page(pool
, oswiz(type
, ind
), iswiz(ind
), pfn
);
323 /* translate Xen tmem return values to linux semantics */
330 /* flush a single page from frontswap */
331 static void tmem_frontswap_flush_page(unsigned type
, pgoff_t offset
)
333 u64 ind64
= (u64
)offset
;
334 u32 ind
= (u32
)offset
;
335 int pool
= tmem_frontswap_poolid
;
341 (void) xen_tmem_flush_page(pool
, oswiz(type
, ind
), iswiz(ind
));
344 /* flush all pages from the passed swaptype */
345 static void tmem_frontswap_flush_area(unsigned type
)
347 int pool
= tmem_frontswap_poolid
;
352 for (ind
= SWIZ_MASK
; ind
>= 0; ind
--)
353 (void)xen_tmem_flush_object(pool
, oswiz(type
, ind
));
356 static void tmem_frontswap_init(unsigned ignored
)
358 struct tmem_pool_uuid
private = TMEM_POOL_PRIVATE_UUID
;
360 /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
361 if (tmem_frontswap_poolid
< 0)
362 tmem_frontswap_poolid
=
363 xen_tmem_new_pool(private, TMEM_POOL_PERSIST
, PAGE_SIZE
);
366 static struct frontswap_ops tmem_frontswap_ops
= {
367 .store
= tmem_frontswap_store
,
368 .load
= tmem_frontswap_load
,
369 .invalidate_page
= tmem_frontswap_flush_page
,
370 .invalidate_area
= tmem_frontswap_flush_area
,
371 .init
= tmem_frontswap_init
375 static int xen_tmem_init(void)
379 #ifdef CONFIG_FRONTSWAP
380 if (tmem_enabled
&& frontswap
) {
382 struct frontswap_ops
*old_ops
=
383 frontswap_register_ops(&tmem_frontswap_ops
);
385 tmem_frontswap_poolid
= -1;
386 if (IS_ERR(old_ops
) || old_ops
) {
388 return PTR_ERR(old_ops
);
389 s
= " (WARNING: frontswap_ops overridden)";
391 printk(KERN_INFO
"frontswap enabled, RAM provided by "
392 "Xen Transcendent Memory%s\n", s
);
395 #ifdef CONFIG_CLEANCACHE
396 BUG_ON(sizeof(struct cleancache_filekey
) != sizeof(struct tmem_oid
));
397 if (tmem_enabled
&& cleancache
) {
399 struct cleancache_ops
*old_ops
=
400 cleancache_register_ops(&tmem_cleancache_ops
);
402 s
= " (WARNING: cleancache_ops overridden)";
403 printk(KERN_INFO
"cleancache enabled, RAM provided by "
404 "Xen Transcendent Memory%s\n", s
);
407 #ifdef CONFIG_XEN_SELFBALLOONING
409 * There is no point of driving pages to the swap system if they
410 * aren't going anywhere in tmem universe.
413 selfshrinking
= false;
414 selfballooning
= false;
416 xen_selfballoon_init(selfballooning
, selfshrinking
);
421 module_init(xen_tmem_init
)
422 MODULE_LICENSE("GPL");
423 MODULE_AUTHOR("Dan Magenheimer <dan.magenheimer@oracle.com>");
424 MODULE_DESCRIPTION("Shim to Xen transcendent memory");