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
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
|
// SPDX-License-Identifier: CDDL-1.0
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or https://opensource.org/licenses/CDDL-1.0.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
#include <sys/spa.h>
#include <sys/zio.h>
#include <sys/spa_impl.h>
#include <sys/counter.h>
#include <sys/zio_compress.h>
#include <sys/zio_checksum.h>
#include <sys/zfs_context.h>
#include <sys/arc.h>
#include <sys/arc_os.h>
#include <sys/zfs_refcount.h>
#include <sys/vdev.h>
#include <sys/vdev_trim.h>
#include <sys/vdev_impl.h>
#include <sys/dsl_pool.h>
#include <sys/zio_checksum.h>
#include <sys/multilist.h>
#include <sys/abd.h>
#include <sys/zil.h>
#include <sys/fm/fs/zfs.h>
#include <sys/eventhandler.h>
#include <sys/callb.h>
#include <sys/kstat.h>
#include <sys/zthr.h>
#include <zfs_fletcher.h>
#include <sys/arc_impl.h>
#include <sys/sdt.h>
#include <sys/aggsum.h>
#include <sys/vnode.h>
#include <cityhash.h>
#include <machine/vmparam.h>
#include <sys/vm.h>
#include <sys/vmmeter.h>
extern struct vfsops zfs_vfsops;
uint_t zfs_arc_free_target = 0;
static void
arc_free_target_init(void *unused __unused)
{
zfs_arc_free_target = vm_cnt.v_free_target;
}
SYSINIT(arc_free_target_init, SI_SUB_KTHREAD_PAGE, SI_ORDER_ANY,
arc_free_target_init, NULL);
/*
* We don't have a tunable for arc_free_target due to the dependency on
* pagedaemon initialisation.
*/
ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, free_target,
param_set_arc_free_target, 0, CTLFLAG_RW,
"Desired number of free pages below which ARC triggers reclaim");
ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, no_grow_shift,
param_set_arc_no_grow_shift, 0, ZMOD_RW,
"log2(fraction of ARC which must be free to allow growing)");
int64_t
arc_available_memory(void)
{
int64_t lowest = INT64_MAX;
int64_t n __unused;
/*
* Cooperate with pagedaemon when it's time for it to scan
* and reclaim some pages.
*/
n = PAGESIZE * ((int64_t)freemem - zfs_arc_free_target);
if (n < lowest) {
lowest = n;
}
#if !defined(UMA_MD_SMALL_ALLOC) && !defined(UMA_USE_DMAP)
/*
* If we're on a platform without a direct map, it's possible that we'll
* exhaust the kernel heap space before we ever run out of available
* physical memory. Most checks of the size of the heap_area compare
* against tune.t_minarmem, which is the minimum available real memory
* that we can have in the system. However, this is generally fixed at
* 25 pages which is so low that it's useless. In this comparison, we
* seek to calculate the total heap-size, and reclaim if more than
* 3/4ths of the heap is allocated. (Or, in the calculation, if less
* than 1/4th is free)
*/
n = uma_avail() - (long)(uma_limit() / 4);
if (n < lowest) {
lowest = n;
}
#endif
DTRACE_PROBE1(arc__available_memory, int64_t, lowest);
return (lowest);
}
/*
* Return a default max arc size based on the amount of physical memory.
*/
uint64_t
arc_default_max(uint64_t min, uint64_t allmem)
{
uint64_t size;
if (allmem >= 1 << 30)
size = allmem - (1 << 30);
else
size = min;
return (MAX(allmem * 5 / 8, size));
}
uint64_t
arc_all_memory(void)
{
return (ptob(physmem));
}
int
arc_memory_throttle(spa_t *spa, uint64_t reserve, uint64_t txg)
{
return (0);
}
uint64_t
arc_free_memory(void)
{
return (ptob(freemem));
}
static eventhandler_tag arc_event_lowmem = NULL;
static void
arc_lowmem(void *arg __unused, int howto __unused)
{
int64_t can_free, free_memory, to_free;
arc_no_grow = B_TRUE;
arc_warm = B_TRUE;
arc_growtime = gethrtime() + SEC2NSEC(arc_grow_retry);
free_memory = arc_available_memory();
can_free = arc_c - arc_c_min;
to_free = (MAX(can_free, 0) >> arc_shrink_shift) - MIN(free_memory, 0);
DTRACE_PROBE2(arc__needfree, int64_t, free_memory, int64_t, to_free);
to_free = arc_reduce_target_size(to_free);
/*
* It is unsafe to block here in arbitrary threads, because we can come
* here from ARC itself and may hold ARC locks and thus risk a deadlock
* with ARC reclaim thread.
*/
if (curproc == pageproc) {
arc_wait_for_eviction(to_free, B_FALSE, B_FALSE);
ARCSTAT_BUMP(arcstat_memory_indirect_count);
} else {
ARCSTAT_BUMP(arcstat_memory_direct_count);
}
}
void
arc_lowmem_init(void)
{
arc_event_lowmem = EVENTHANDLER_REGISTER(vm_lowmem, arc_lowmem, NULL,
EVENTHANDLER_PRI_FIRST);
}
void
arc_lowmem_fini(void)
{
if (arc_event_lowmem != NULL)
EVENTHANDLER_DEREGISTER(vm_lowmem, arc_event_lowmem);
}
void
arc_register_hotplug(void)
{
}
void
arc_unregister_hotplug(void)
{
}
|
