Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2#include <string.h>
3#include <fcntl.h>
4#include "../kselftest.h"
5#include "vm_util.h"
6
7#define PMD_SIZE_FILE_PATH "/sys/kernel/mm/transparent_hugepage/hpage_pmd_size"
8#define SMAP_FILE_PATH "/proc/self/smaps"
9#define MAX_LINE_LENGTH 500
10
11uint64_t pagemap_get_entry(int fd, char *start)
12{
13 const unsigned long pfn = (unsigned long)start / getpagesize();
14 uint64_t entry;
15 int ret;
16
17 ret = pread(fd, &entry, sizeof(entry), pfn * sizeof(entry));
18 if (ret != sizeof(entry))
19 ksft_exit_fail_msg("reading pagemap failed\n");
20 return entry;
21}
22
23bool pagemap_is_softdirty(int fd, char *start)
24{
25 uint64_t entry = pagemap_get_entry(fd, start);
26
27 // Check if dirty bit (55th bit) is set
28 return entry & 0x0080000000000000ull;
29}
30
31void clear_softdirty(void)
32{
33 int ret;
34 const char *ctrl = "4";
35 int fd = open("/proc/self/clear_refs", O_WRONLY);
36
37 if (fd < 0)
38 ksft_exit_fail_msg("opening clear_refs failed\n");
39 ret = write(fd, ctrl, strlen(ctrl));
40 close(fd);
41 if (ret != strlen(ctrl))
42 ksft_exit_fail_msg("writing clear_refs failed\n");
43}
44
45bool check_for_pattern(FILE *fp, const char *pattern, char *buf, size_t len)
46{
47 while (fgets(buf, len, fp)) {
48 if (!strncmp(buf, pattern, strlen(pattern)))
49 return true;
50 }
51 return false;
52}
53
54uint64_t read_pmd_pagesize(void)
55{
56 int fd;
57 char buf[20];
58 ssize_t num_read;
59
60 fd = open(PMD_SIZE_FILE_PATH, O_RDONLY);
61 if (fd == -1)
62 ksft_exit_fail_msg("Open hpage_pmd_size failed\n");
63
64 num_read = read(fd, buf, 19);
65 if (num_read < 1) {
66 close(fd);
67 ksft_exit_fail_msg("Read hpage_pmd_size failed\n");
68 }
69 buf[num_read] = '\0';
70 close(fd);
71
72 return strtoul(buf, NULL, 10);
73}
74
75bool __check_huge(void *addr, char *pattern, int nr_hpages,
76 uint64_t hpage_size)
77{
78 uint64_t thp = -1;
79 int ret;
80 FILE *fp;
81 char buffer[MAX_LINE_LENGTH];
82 char addr_pattern[MAX_LINE_LENGTH];
83
84 ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "%08lx-",
85 (unsigned long) addr);
86 if (ret >= MAX_LINE_LENGTH)
87 ksft_exit_fail_msg("%s: Pattern is too long\n", __func__);
88
89 fp = fopen(SMAP_FILE_PATH, "r");
90 if (!fp)
91 ksft_exit_fail_msg("%s: Failed to open file %s\n", __func__, SMAP_FILE_PATH);
92
93 if (!check_for_pattern(fp, addr_pattern, buffer, sizeof(buffer)))
94 goto err_out;
95
96 /*
97 * Fetch the pattern in the same block and check the number of
98 * hugepages.
99 */
100 if (!check_for_pattern(fp, pattern, buffer, sizeof(buffer)))
101 goto err_out;
102
103 snprintf(addr_pattern, MAX_LINE_LENGTH, "%s%%9ld kB", pattern);
104
105 if (sscanf(buffer, addr_pattern, &thp) != 1)
106 ksft_exit_fail_msg("Reading smap error\n");
107
108err_out:
109 fclose(fp);
110 return thp == (nr_hpages * (hpage_size >> 10));
111}
112
113bool check_huge_anon(void *addr, int nr_hpages, uint64_t hpage_size)
114{
115 return __check_huge(addr, "AnonHugePages: ", nr_hpages, hpage_size);
116}
117
118bool check_huge_file(void *addr, int nr_hpages, uint64_t hpage_size)
119{
120 return __check_huge(addr, "FilePmdMapped:", nr_hpages, hpage_size);
121}
122
123bool check_huge_shmem(void *addr, int nr_hpages, uint64_t hpage_size)
124{
125 return __check_huge(addr, "ShmemPmdMapped:", nr_hpages, hpage_size);
126}