1/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
2// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4:
3#ident "$Id$"
4/*======
5This file is part of PerconaFT.
6
7
8Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved.
9
10 PerconaFT is free software: you can redistribute it and/or modify
11 it under the terms of the GNU General Public License, version 2,
12 as published by the Free Software Foundation.
13
14 PerconaFT is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with PerconaFT. If not, see <http://www.gnu.org/licenses/>.
21
22----------------------------------------
23
24 PerconaFT is free software: you can redistribute it and/or modify
25 it under the terms of the GNU Affero General Public License, version 3,
26 as published by the Free Software Foundation.
27
28 PerconaFT is distributed in the hope that it will be useful,
29 but WITHOUT ANY WARRANTY; without even the implied warranty of
30 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
31 GNU Affero General Public License for more details.
32
33 You should have received a copy of the GNU Affero General Public License
34 along with PerconaFT. If not, see <http://www.gnu.org/licenses/>.
35======= */
36
37#ident "Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved."
38
39#include <sys/mman.h>
40#include <stdlib.h>
41#include <stdio.h>
42#include <string.h>
43
44#include <portability/toku_assert.h>
45#include <portability/toku_os.h>
46
47static bool check_huge_pages_config_file(const char *fname)
48// Effect: Return true if huge pages are there. If so, print diagnostics.
49{
50 bool huge_pages_enabled = false;
51 FILE *f = fopen(fname, "r");
52 if (f) {
53 // It's redhat and the feature appears to be there. Is it enabled?
54 char buf[1000];
55 char *r = fgets(buf, sizeof(buf), f);
56 assert(r != NULL);
57 if (strstr(buf, "[always]")) {
58 fprintf(stderr, "Transparent huge pages are enabled, according to %s\n", fname);
59 huge_pages_enabled = true;
60 } else {
61 huge_pages_enabled =false;
62 }
63 fclose(f);
64 }
65 return huge_pages_enabled;
66}
67
68static bool check_huge_pages_in_practice(void)
69// Effect: Return true if huge pages appear to be defined in practice.
70{
71#ifdef HAVE_MINCORE
72#ifdef HAVE_MAP_ANONYMOUS
73 const int map_anonymous = MAP_ANONYMOUS;
74#else
75 const int map_anonymous = MAP_ANON;
76#endif
77 const size_t TWO_MB = 2UL*1024UL*1024UL;
78
79 void *first = mmap(NULL, 2*TWO_MB, PROT_READ|PROT_WRITE, MAP_PRIVATE|map_anonymous, -1, 0);
80 if ((long)first==-1) perror("mmap failed");
81 {
82 int r = munmap(first, 2*TWO_MB);
83 assert(r==0);
84 }
85
86 void *second_addr = (void*)(((unsigned long)first + TWO_MB) & ~(TWO_MB -1));
87 void *second = mmap(second_addr, TWO_MB, PROT_READ|PROT_WRITE, MAP_FIXED|MAP_PRIVATE|map_anonymous, -1, 0);
88 if ((long)second==-1) perror("mmap failed");
89 assert((long)second%TWO_MB == 0);
90
91 const long pagesize = 4096;
92 const long n_pages = TWO_MB/pagesize;
93#ifdef __linux__
94 // On linux mincore is defined as mincore(void *, size_t, unsigned char *)
95 unsigned char vec[n_pages];
96#else
97 // On BSD (OS X included) it is defined as mincore(void *, size_t, char *)
98 char vec[n_pages];
99#endif
100 {
101 int r = mincore(second, TWO_MB, vec);
102 if (r!=0 && errno==ENOMEM) {
103 // On some kernels (e.g., Centos 5.8), mincore doesn't work. It seems unlikely that huge pages are here.
104 munmap(second, TWO_MB);
105 return false;
106 }
107 assert(r==0);
108 }
109 for (long i=0; i<n_pages; i++) {
110 assert(!vec[i]);
111 }
112 ((char*)second)[0] = 1;
113 {
114 int r = mincore(second, TWO_MB, vec);
115 // If the mincore worked the first time, it probably works here too.x
116 assert(r==0);
117 }
118 assert(vec[0]);
119 {
120 int r = munmap(second, TWO_MB);
121 assert(r==0);
122 }
123 if (vec[1]) {
124 fprintf(stderr, "Transparent huge pages appear to be enabled according to mincore()\n");
125 return true;
126 } else {
127 return false;
128 }
129#else
130 // No mincore, so no way to check this in practice
131 return false;
132#endif
133}
134
135bool toku_os_huge_pages_enabled(void)
136// Effect: Return true if huge pages appear to be enabled. If so, print some diagnostics to stderr.
137// If environment variable TOKU_HUGE_PAGES_OK is set, then don't complain.
138{
139 char *toku_huge_pages_ok = getenv("TOKU_HUGE_PAGES_OK");
140 if (toku_huge_pages_ok) {
141 return false;
142 } else {
143 bool conf1 = check_huge_pages_config_file("/sys/kernel/mm/redhat_transparent_hugepage/enabled");
144 bool conf2 = check_huge_pages_config_file("/sys/kernel/mm/transparent_hugepage/enabled");
145 bool prac = check_huge_pages_in_practice();
146 return conf1|conf2|prac;
147 }
148}
149