1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2010 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
25 #include <sys/sysinfo.h>
26 #include <sys/inotify.h>
33 #include "readahead-common.h"
36 int file_verify(int fd, const char *fn, off_t file_size_max, struct stat *st) {
41 if (fstat(fd, st) < 0) {
42 log_warning("fstat(%s) failed: %m", fn);
46 if (!S_ISREG(st->st_mode)) {
47 log_debug("Not preloading special file %s", fn);
51 if (st->st_size <= 0 || st->st_size > file_size_max) {
52 log_debug("Not preloading file %s with size out of bounds %llu", fn, (unsigned long long) st->st_size);
59 int fs_on_ssd(const char *p) {
61 struct udev *udev = NULL;
62 struct udev_device *udev_device = NULL, *look_at = NULL;
64 const char *devtype, *rotational, *model, *id;
71 if (major(st.st_dev) == 0)
74 if (!(udev = udev_new()))
77 if (!(udev_device = udev_device_new_from_devnum(udev, 'b', st.st_dev)))
80 if ((devtype = udev_device_get_property_value(udev_device, "DEVTYPE")) &&
81 streq(devtype, "partition"))
82 look_at = udev_device_get_parent(udev_device);
84 look_at = udev_device;
89 /* First, try high-level property */
90 if ((id = udev_device_get_property_value(look_at, "ID_SSD"))) {
95 /* Second, try kernel attribute */
96 if ((rotational = udev_device_get_sysattr_value(look_at, "queue/rotational")))
97 if ((b = streq(rotational, "0")))
100 /* Finally, fallback to heuristics */
101 if (!(look_at = udev_device_get_parent(look_at)))
104 if ((model = udev_device_get_sysattr_value(look_at, "model")))
105 b = !!strstr(model, "SSD");
109 udev_device_unref(udev_device);
117 bool enough_ram(void) {
120 assert_se(sysinfo(&si) >= 0);
122 return si.totalram > 127 * 1024*1024; /* Enable readahead only
123 * with at least 128MB
127 int open_inotify(void) {
130 if ((fd = inotify_init1(IN_CLOEXEC|IN_NONBLOCK)) < 0) {
131 log_error("Failed to create inotify handle: %m");
135 mkdir("/dev/.systemd", 0755);
136 mkdir("/dev/.systemd/readahead", 0755);
138 if (inotify_add_watch(fd, "/dev/.systemd/readahead", IN_CREATE) < 0) {
139 log_error("Failed to watch /dev/.systemd/readahead: %m");
140 close_nointr_nofail(fd);
147 ReadaheadShared *shared_get(void) {
149 ReadaheadShared *m = NULL;
151 mkdir("/dev/.systemd", 0755);
152 mkdir("/dev/.systemd/readahead", 0755);
154 if ((fd = open("/dev/.systemd/readahead/shared", O_CREAT|O_RDWR|O_CLOEXEC, 0644)) < 0) {
155 log_error("Failed to create shared memory segment: %m");
159 if (ftruncate(fd, sizeof(ReadaheadShared)) < 0) {
160 log_error("Failed to truncate shared memory segment: %m");
164 if ((m = mmap(NULL, sizeof(ReadaheadShared), PROT_WRITE|PROT_READ, MAP_SHARED, fd, 0)) == MAP_FAILED) {
165 log_error("Failed to mmap shared memory segment: %m");
172 close_nointr_nofail(fd);
178 #define BUMP_REQUEST_NR (16*1024)
180 int bump_request_nr(const char *p) {
182 struct udev *udev = NULL;
183 struct udev_device *udev_device = NULL, *look_at = NULL;
184 const char *nr_requests;
186 char nr[64], *ap = NULL;
191 if (stat(p, &st) < 0)
194 if (major(st.st_dev) == 0)
197 if (!(udev = udev_new()))
200 if (!(udev_device = udev_device_new_from_devnum(udev, 'b', st.st_dev))) {
205 look_at = udev_device;
206 if (!(nr_requests = udev_device_get_sysattr_value(look_at, "queue/nr_requests"))) {
208 /* Hmm, if the block device doesn't have a queue
209 * subdir, the let's look in the parent */
210 look_at = udev_device_get_parent(udev_device);
211 nr_requests = udev_device_get_sysattr_value(look_at, "queue/nr_requests");
219 if (safe_atou64(nr_requests, &u) >= 0 && u >= BUMP_REQUEST_NR) {
224 if (asprintf(&ap, "%s/queue/nr_requests", udev_device_get_syspath(look_at)) < 0) {
229 snprintf(nr, sizeof(nr), "%lu", (unsigned long) BUMP_REQUEST_NR);
231 if ((r = write_one_line_file(ap, nr)) < 0)
234 log_info("Bumped block_nr parameter of %s to %lu. This is a temporary hack and should be removed one day.", udev_device_get_devnode(look_at), (unsigned long) BUMP_REQUEST_NR);
239 udev_device_unref(udev_device);