1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
|
/*-
* Copyright (c) 2020 Emmanuel Vadot <manu@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/queue.h>
#include <sys/eventhandler.h>
#include <sys/sx.h>
#include <linux/compat.h>
#include <linux/shrinker.h>
#include <linux/slab.h>
TAILQ_HEAD(, shrinker) lkpi_shrinkers = TAILQ_HEAD_INITIALIZER(lkpi_shrinkers);
static struct sx sx_shrinker;
struct shrinker *
linuxkpi_shrinker_alloc(unsigned int flags, const char *fmt, ...)
{
struct shrinker *shrinker;
shrinker = kzalloc(sizeof(*shrinker), GFP_KERNEL);
if (shrinker == NULL)
return (NULL);
shrinker->flags = flags | SHRINKER_ALLOCATED;
shrinker->seeks = DEFAULT_SEEKS;
return (shrinker);
}
int
linuxkpi_register_shrinker(struct shrinker *s)
{
KASSERT(s != NULL, ("NULL shrinker"));
KASSERT(s->count_objects != NULL, ("NULL shrinker"));
KASSERT(s->scan_objects != NULL, ("NULL shrinker"));
sx_xlock(&sx_shrinker);
s->flags |= SHRINKER_REGISTERED;
TAILQ_INSERT_TAIL(&lkpi_shrinkers, s, next);
sx_xunlock(&sx_shrinker);
return (0);
}
void
linuxkpi_unregister_shrinker(struct shrinker *s)
{
sx_xlock(&sx_shrinker);
TAILQ_REMOVE(&lkpi_shrinkers, s, next);
s->flags &= ~SHRINKER_REGISTERED;
sx_xunlock(&sx_shrinker);
}
void
linuxkpi_shrinker_free(struct shrinker *shrinker)
{
if (shrinker->flags & SHRINKER_REGISTERED)
unregister_shrinker(shrinker);
kfree(shrinker);
}
void
linuxkpi_synchronize_shrinkers(void)
{
sx_xlock(&sx_shrinker);
sx_xunlock(&sx_shrinker);
}
#define SHRINKER_BATCH 512
static void
shrinker_shrink(struct shrinker *s)
{
struct shrink_control sc;
unsigned long can_free;
unsigned long batch;
unsigned long scanned = 0;
unsigned long ret;
can_free = s->count_objects(s, &sc);
if (can_free <= 0)
return;
batch = s->batch ? s->batch : SHRINKER_BATCH;
while (scanned <= can_free) {
sc.nr_to_scan = batch;
ret = s->scan_objects(s, &sc);
if (ret == SHRINK_STOP)
break;
scanned += batch;
}
}
static void
linuxkpi_vm_lowmem(void *arg __unused, int flags __unused)
{
struct shrinker *s;
sx_xlock(&sx_shrinker);
TAILQ_FOREACH(s, &lkpi_shrinkers, next) {
shrinker_shrink(s);
}
sx_xunlock(&sx_shrinker);
}
static eventhandler_tag lowmem_tag;
static void
linuxkpi_sysinit_shrinker(void *arg __unused)
{
sx_init(&sx_shrinker, "lkpi-shrinker");
lowmem_tag = EVENTHANDLER_REGISTER(vm_lowmem, linuxkpi_vm_lowmem,
NULL, EVENTHANDLER_PRI_FIRST);
}
static void
linuxkpi_sysuninit_shrinker(void *arg __unused)
{
sx_destroy(&sx_shrinker);
EVENTHANDLER_DEREGISTER(vm_lowmem, lowmem_tag);
}
SYSINIT(linuxkpi_shrinker, SI_SUB_DRIVERS, SI_ORDER_ANY,
linuxkpi_sysinit_shrinker, NULL);
SYSUNINIT(linuxkpi_shrinker, SI_SUB_DRIVERS, SI_ORDER_ANY,
linuxkpi_sysuninit_shrinker, NULL);
|
