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 disable_cleancache __read_mostly
;
36 static bool disable_selfballooning __read_mostly
;
37 #ifdef CONFIG_XEN_TMEM_MODULE
38 module_param(disable_cleancache
, bool, S_IRUGO
);
39 module_param(disable_selfballooning
, bool, S_IRUGO
);
41 static int __init
no_cleancache(char *s
)
43 disable_cleancache
= true;
46 __setup("nocleancache", no_cleancache
);
48 #endif /* CONFIG_CLEANCACHE */
50 #ifdef CONFIG_FRONTSWAP
51 static bool disable_frontswap __read_mostly
;
52 #ifdef CONFIG_XEN_TMEM_MODULE
53 module_param(disable_frontswap
, bool, S_IRUGO
);
55 static int __init
no_frontswap(char *s
)
57 disable_frontswap
= true;
60 __setup("nofrontswap", no_frontswap
);
62 #endif /* CONFIG_FRONTSWAP */
64 #ifdef CONFIG_FRONTSWAP
65 static bool disable_frontswap_selfshrinking __read_mostly
;
66 #ifdef CONFIG_XEN_TMEM_MODULE
67 module_param(disable_frontswap_selfshrinking
, bool, S_IRUGO
);
69 #define disable_frontswap_selfshrinking 1
71 #endif /* CONFIG_FRONTSWAP */
73 #define TMEM_CONTROL 0
74 #define TMEM_NEW_POOL 1
75 #define TMEM_DESTROY_POOL 2
76 #define TMEM_NEW_PAGE 3
77 #define TMEM_PUT_PAGE 4
78 #define TMEM_GET_PAGE 5
79 #define TMEM_FLUSH_PAGE 6
80 #define TMEM_FLUSH_OBJECT 7
85 /* Bits for HYPERVISOR_tmem_op(TMEM_NEW_POOL) */
86 #define TMEM_POOL_PERSIST 1
87 #define TMEM_POOL_SHARED 2
88 #define TMEM_POOL_PAGESIZE_SHIFT 4
89 #define TMEM_VERSION_SHIFT 24
92 struct tmem_pool_uuid
{
101 #define TMEM_POOL_PRIVATE_UUID { 0, 0 }
103 /* flags for tmem_ops.new_pool */
104 #define TMEM_POOL_PERSIST 1
105 #define TMEM_POOL_SHARED 2
107 /* xen tmem foundation ops/hypercalls */
109 static inline int xen_tmem_op(u32 tmem_cmd
, u32 tmem_pool
, struct tmem_oid oid
,
110 u32 index
, unsigned long gmfn
, u32 tmem_offset
, u32 pfn_offset
, u32 len
)
116 op
.pool_id
= tmem_pool
;
117 op
.u
.gen
.oid
[0] = oid
.oid
[0];
118 op
.u
.gen
.oid
[1] = oid
.oid
[1];
119 op
.u
.gen
.oid
[2] = oid
.oid
[2];
120 op
.u
.gen
.index
= index
;
121 op
.u
.gen
.tmem_offset
= tmem_offset
;
122 op
.u
.gen
.pfn_offset
= pfn_offset
;
124 set_xen_guest_handle(op
.u
.gen
.gmfn
, (void *)gmfn
);
125 rc
= HYPERVISOR_tmem_op(&op
);
129 static int xen_tmem_new_pool(struct tmem_pool_uuid uuid
,
130 u32 flags
, unsigned long pagesize
)
133 int rc
= 0, pageshift
;
135 for (pageshift
= 0; pagesize
!= 1; pageshift
++)
137 flags
|= (pageshift
- 12) << TMEM_POOL_PAGESIZE_SHIFT
;
138 flags
|= TMEM_SPEC_VERSION
<< TMEM_VERSION_SHIFT
;
139 op
.cmd
= TMEM_NEW_POOL
;
140 op
.u
.new.uuid
[0] = uuid
.uuid_lo
;
141 op
.u
.new.uuid
[1] = uuid
.uuid_hi
;
142 op
.u
.new.flags
= flags
;
143 rc
= HYPERVISOR_tmem_op(&op
);
147 /* xen generic tmem ops */
149 static int xen_tmem_put_page(u32 pool_id
, struct tmem_oid oid
,
150 u32 index
, unsigned long pfn
)
152 unsigned long gmfn
= xen_pv_domain() ? pfn_to_mfn(pfn
) : pfn
;
154 return xen_tmem_op(TMEM_PUT_PAGE
, pool_id
, oid
, index
,
158 static int xen_tmem_get_page(u32 pool_id
, struct tmem_oid oid
,
159 u32 index
, unsigned long pfn
)
161 unsigned long gmfn
= xen_pv_domain() ? pfn_to_mfn(pfn
) : pfn
;
163 return xen_tmem_op(TMEM_GET_PAGE
, pool_id
, oid
, index
,
167 static int xen_tmem_flush_page(u32 pool_id
, struct tmem_oid oid
, u32 index
)
169 return xen_tmem_op(TMEM_FLUSH_PAGE
, pool_id
, oid
, index
,
173 static int xen_tmem_flush_object(u32 pool_id
, struct tmem_oid oid
)
175 return xen_tmem_op(TMEM_FLUSH_OBJECT
, pool_id
, oid
, 0, 0, 0, 0, 0);
179 #ifdef CONFIG_CLEANCACHE
180 static int xen_tmem_destroy_pool(u32 pool_id
)
182 struct tmem_oid oid
= { { 0 } };
184 return xen_tmem_op(TMEM_DESTROY_POOL
, pool_id
, oid
, 0, 0, 0, 0, 0);
189 static void tmem_cleancache_put_page(int pool
, struct cleancache_filekey key
,
190 pgoff_t index
, struct page
*page
)
192 u32 ind
= (u32
) index
;
193 struct tmem_oid oid
= *(struct tmem_oid
*)&key
;
194 unsigned long pfn
= page_to_pfn(page
);
200 mb(); /* ensure page is quiescent; tmem may address it with an alias */
201 (void)xen_tmem_put_page((u32
)pool
, oid
, ind
, pfn
);
204 static int tmem_cleancache_get_page(int pool
, struct cleancache_filekey key
,
205 pgoff_t index
, struct page
*page
)
207 u32 ind
= (u32
) index
;
208 struct tmem_oid oid
= *(struct tmem_oid
*)&key
;
209 unsigned long pfn
= page_to_pfn(page
);
212 /* translate return values to linux semantics */
217 ret
= xen_tmem_get_page((u32
)pool
, oid
, ind
, pfn
);
224 static void tmem_cleancache_flush_page(int pool
, struct cleancache_filekey key
,
227 u32 ind
= (u32
) index
;
228 struct tmem_oid oid
= *(struct tmem_oid
*)&key
;
234 (void)xen_tmem_flush_page((u32
)pool
, oid
, ind
);
237 static void tmem_cleancache_flush_inode(int pool
, struct cleancache_filekey key
)
239 struct tmem_oid oid
= *(struct tmem_oid
*)&key
;
243 (void)xen_tmem_flush_object((u32
)pool
, oid
);
246 static void tmem_cleancache_flush_fs(int pool
)
250 (void)xen_tmem_destroy_pool((u32
)pool
);
253 static int tmem_cleancache_init_fs(size_t pagesize
)
255 struct tmem_pool_uuid uuid_private
= TMEM_POOL_PRIVATE_UUID
;
257 return xen_tmem_new_pool(uuid_private
, 0, pagesize
);
260 static int tmem_cleancache_init_shared_fs(char *uuid
, size_t pagesize
)
262 struct tmem_pool_uuid shared_uuid
;
264 shared_uuid
.uuid_lo
= *(u64
*)uuid
;
265 shared_uuid
.uuid_hi
= *(u64
*)(&uuid
[8]);
266 return xen_tmem_new_pool(shared_uuid
, TMEM_POOL_SHARED
, pagesize
);
269 static struct cleancache_ops tmem_cleancache_ops
= {
270 .put_page
= tmem_cleancache_put_page
,
271 .get_page
= tmem_cleancache_get_page
,
272 .invalidate_page
= tmem_cleancache_flush_page
,
273 .invalidate_inode
= tmem_cleancache_flush_inode
,
274 .invalidate_fs
= tmem_cleancache_flush_fs
,
275 .init_shared_fs
= tmem_cleancache_init_shared_fs
,
276 .init_fs
= tmem_cleancache_init_fs
280 #ifdef CONFIG_FRONTSWAP
281 /* frontswap tmem operations */
283 /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
284 static int tmem_frontswap_poolid
;
287 * Swizzling increases objects per swaptype, increasing tmem concurrency
288 * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
291 #define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
292 #define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
293 #define iswiz(_ind) (_ind >> SWIZ_BITS)
295 static inline struct tmem_oid
oswiz(unsigned type
, u32 ind
)
297 struct tmem_oid oid
= { .oid
= { 0 } };
298 oid
.oid
[0] = _oswiz(type
, ind
);
302 /* returns 0 if the page was successfully put into frontswap, -1 if not */
303 static int tmem_frontswap_store(unsigned type
, pgoff_t offset
,
306 u64 ind64
= (u64
)offset
;
307 u32 ind
= (u32
)offset
;
308 unsigned long pfn
= page_to_pfn(page
);
309 int pool
= tmem_frontswap_poolid
;
316 mb(); /* ensure page is quiescent; tmem may address it with an alias */
317 ret
= xen_tmem_put_page(pool
, oswiz(type
, ind
), iswiz(ind
), pfn
);
318 /* translate Xen tmem return values to linux semantics */
326 * returns 0 if the page was successfully gotten from frontswap, -1 if
327 * was not present (should never happen!)
329 static int tmem_frontswap_load(unsigned type
, pgoff_t offset
,
332 u64 ind64
= (u64
)offset
;
333 u32 ind
= (u32
)offset
;
334 unsigned long pfn
= page_to_pfn(page
);
335 int pool
= tmem_frontswap_poolid
;
342 ret
= xen_tmem_get_page(pool
, oswiz(type
, ind
), iswiz(ind
), pfn
);
343 /* translate Xen tmem return values to linux semantics */
350 /* flush a single page from frontswap */
351 static void tmem_frontswap_flush_page(unsigned type
, pgoff_t offset
)
353 u64 ind64
= (u64
)offset
;
354 u32 ind
= (u32
)offset
;
355 int pool
= tmem_frontswap_poolid
;
361 (void) xen_tmem_flush_page(pool
, oswiz(type
, ind
), iswiz(ind
));
364 /* flush all pages from the passed swaptype */
365 static void tmem_frontswap_flush_area(unsigned type
)
367 int pool
= tmem_frontswap_poolid
;
372 for (ind
= SWIZ_MASK
; ind
>= 0; ind
--)
373 (void)xen_tmem_flush_object(pool
, oswiz(type
, ind
));
376 static void tmem_frontswap_init(unsigned ignored
)
378 struct tmem_pool_uuid
private = TMEM_POOL_PRIVATE_UUID
;
380 /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
381 if (tmem_frontswap_poolid
< 0)
382 tmem_frontswap_poolid
=
383 xen_tmem_new_pool(private, TMEM_POOL_PERSIST
, PAGE_SIZE
);
386 static struct frontswap_ops tmem_frontswap_ops
= {
387 .store
= tmem_frontswap_store
,
388 .load
= tmem_frontswap_load
,
389 .invalidate_page
= tmem_frontswap_flush_page
,
390 .invalidate_area
= tmem_frontswap_flush_area
,
391 .init
= tmem_frontswap_init
395 static int xen_tmem_init(void)
399 #ifdef CONFIG_FRONTSWAP
400 if (tmem_enabled
&& !disable_frontswap
) {
402 struct frontswap_ops
*old_ops
=
403 frontswap_register_ops(&tmem_frontswap_ops
);
405 tmem_frontswap_poolid
= -1;
406 if (IS_ERR(old_ops
) || old_ops
) {
408 return PTR_ERR(old_ops
);
409 s
= " (WARNING: frontswap_ops overridden)";
411 printk(KERN_INFO
"frontswap enabled, RAM provided by "
412 "Xen Transcendent Memory%s\n", s
);
415 #ifdef CONFIG_CLEANCACHE
416 BUG_ON(sizeof(struct cleancache_filekey
) != sizeof(struct tmem_oid
));
417 if (tmem_enabled
&& !disable_cleancache
) {
419 struct cleancache_ops
*old_ops
=
420 cleancache_register_ops(&tmem_cleancache_ops
);
422 s
= " (WARNING: cleancache_ops overridden)";
423 printk(KERN_INFO
"cleancache enabled, RAM provided by "
424 "Xen Transcendent Memory%s\n", s
);
427 #ifdef CONFIG_XEN_SELFBALLOONING
428 xen_selfballoon_init(!disable_selfballooning
,
429 !disable_frontswap_selfshrinking
);
434 module_init(xen_tmem_init
)
435 MODULE_LICENSE("GPL");
436 MODULE_AUTHOR("Dan Magenheimer <dan.magenheimer@oracle.com>");
437 MODULE_DESCRIPTION("Shim to Xen transcendent memory");