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
201
|
/* Huge Page support. Linux implementation.
Copyright (C) 2021-2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, see <https://www.gnu.org/licenses/>. */
#include <intprops.h>
#include <dirent.h>
#include <malloc-hugepages.h>
#include <not-cancel.h>
#include <sys/mman.h>
unsigned long int
__malloc_default_thp_pagesize (void)
{
int fd = __open64_nocancel (
"/sys/kernel/mm/transparent_hugepage/hpage_pmd_size", O_RDONLY);
if (fd == -1)
return 0;
char str[INT_BUFSIZE_BOUND (unsigned long int)];
ssize_t s = __read_nocancel (fd, str, sizeof (str));
__close_nocancel (fd);
if (s < 0)
return 0;
unsigned long int r = 0;
for (ssize_t i = 0; i < s; i++)
{
if (str[i] == '\n')
break;
r *= 10;
r += str[i] - '0';
}
return r;
}
enum malloc_thp_mode_t
__malloc_thp_mode (void)
{
int fd = __open64_nocancel ("/sys/kernel/mm/transparent_hugepage/enabled",
O_RDONLY);
if (fd == -1)
return malloc_thp_mode_not_supported;
static const char mode_always[] = "[always] madvise never\n";
static const char mode_madvise[] = "always [madvise] never\n";
static const char mode_never[] = "always madvise [never]\n";
char str[sizeof(mode_always)];
ssize_t s = __read_nocancel (fd, str, sizeof (str));
__close_nocancel (fd);
if (s == sizeof (mode_always) - 1)
{
if (strcmp (str, mode_always) == 0)
return malloc_thp_mode_always;
else if (strcmp (str, mode_madvise) == 0)
return malloc_thp_mode_madvise;
else if (strcmp (str, mode_never) == 0)
return malloc_thp_mode_never;
}
return malloc_thp_mode_not_supported;
}
static size_t
malloc_default_hugepage_size (void)
{
int fd = __open64_nocancel ("/proc/meminfo", O_RDONLY);
if (fd == -1)
return 0;
size_t hpsize = 0;
char buf[512];
off64_t off = 0;
while (1)
{
ssize_t r = __pread64_nocancel (fd, buf, sizeof (buf) - 1, off);
if (r < 0)
break;
buf[r] = '\0';
/* If the tag is not found, read the last line again. */
const char *s = strstr (buf, "Hugepagesize:");
if (s == NULL)
{
char *nl = strrchr (buf, '\n');
if (nl == NULL)
break;
off += (nl + 1) - buf;
continue;
}
/* The default huge page size is in the form:
Hugepagesize: NUMBER kB */
s += sizeof ("Hugepagesize: ") - 1;
for (int i = 0; (s[i] >= '0' && s[i] <= '9') || s[i] == ' '; i++)
{
if (s[i] == ' ')
continue;
hpsize *= 10;
hpsize += s[i] - '0';
}
hpsize *= 1024;
break;
}
__close_nocancel (fd);
return hpsize;
}
static inline int
hugepage_flags (size_t pagesize)
{
return MAP_HUGETLB | (__builtin_ctzll (pagesize) << MAP_HUGE_SHIFT);
}
void
__malloc_hugepage_config (size_t requested, size_t *pagesize, int *flags)
{
*pagesize = 0;
*flags = 0;
if (requested == 0)
{
*pagesize = malloc_default_hugepage_size ();
if (*pagesize != 0)
*flags = hugepage_flags (*pagesize);
return;
}
/* Each entry represents a supported huge page in the form of:
hugepages-<size>kB. */
int dirfd = __open64_nocancel ("/sys/kernel/mm/hugepages",
O_RDONLY | O_DIRECTORY, 0);
if (dirfd == -1)
return;
char buffer[1024];
while (true)
{
#if !IS_IN(libc)
# define __getdents64 getdents64
#endif
ssize_t ret = __getdents64 (dirfd, buffer, sizeof (buffer));
if (ret == -1)
break;
else if (ret == 0)
break;
bool found = false;
char *begin = buffer, *end = buffer + ret;
while (begin != end)
{
unsigned short int d_reclen;
memcpy (&d_reclen, begin + offsetof (struct dirent64, d_reclen),
sizeof (d_reclen));
const char *dname = begin + offsetof (struct dirent64, d_name);
begin += d_reclen;
if (dname[0] == '.'
|| strncmp (dname, "hugepages-", sizeof ("hugepages-") - 1) != 0)
continue;
size_t hpsize = 0;
const char *sizestr = dname + sizeof ("hugepages-") - 1;
for (int i = 0; sizestr[i] >= '0' && sizestr[i] <= '9'; i++)
{
hpsize *= 10;
hpsize += sizestr[i] - '0';
}
hpsize *= 1024;
if (hpsize == requested)
{
*pagesize = hpsize;
*flags = hugepage_flags (*pagesize);
found = true;
break;
}
}
if (found)
break;
}
__close_nocancel (dirfd);
}
|
