diff options
Diffstat (limited to 'src/readahead/readahead-common.c')
| -rw-r--r-- | src/readahead/readahead-common.c | 269 |
1 files changed, 269 insertions, 0 deletions
diff --git a/src/readahead/readahead-common.c b/src/readahead/readahead-common.c new file mode 100644 index 0000000000..67214ec379 --- /dev/null +++ b/src/readahead/readahead-common.c @@ -0,0 +1,269 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +/*** + This file is part of systemd. + + Copyright 2010 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + systemd 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 + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <errno.h> +#include <stdlib.h> +#include <string.h> +#include <sys/sysinfo.h> +#include <sys/inotify.h> +#include <fcntl.h> +#include <sys/mman.h> +#include <unistd.h> +#include <libudev.h> + +#include "log.h" +#include "readahead-common.h" +#include "util.h" + +int file_verify(int fd, const char *fn, off_t file_size_max, struct stat *st) { + assert(fd >= 0); + assert(fn); + assert(st); + + if (fstat(fd, st) < 0) { + log_warning("fstat(%s) failed: %m", fn); + return -errno; + } + + if (!S_ISREG(st->st_mode)) { + log_debug("Not preloading special file %s", fn); + return 0; + } + + if (st->st_size <= 0 || st->st_size > file_size_max) { + log_debug("Not preloading file %s with size out of bounds %llu", fn, (unsigned long long) st->st_size); + return 0; + } + + return 1; +} + +int fs_on_ssd(const char *p) { + struct stat st; + struct udev *udev = NULL; + struct udev_device *udev_device = NULL, *look_at = NULL; + bool b = false; + const char *devtype, *rotational, *model, *id; + + assert(p); + + if (stat(p, &st) < 0) + return -errno; + + if (major(st.st_dev) == 0) + return false; + + if (!(udev = udev_new())) + return -ENOMEM; + + if (!(udev_device = udev_device_new_from_devnum(udev, 'b', st.st_dev))) + goto finish; + + if ((devtype = udev_device_get_property_value(udev_device, "DEVTYPE")) && + streq(devtype, "partition")) + look_at = udev_device_get_parent(udev_device); + else + look_at = udev_device; + + if (!look_at) + goto finish; + + /* First, try high-level property */ + if ((id = udev_device_get_property_value(look_at, "ID_SSD"))) { + b = streq(id, "1"); + goto finish; + } + + /* Second, try kernel attribute */ + if ((rotational = udev_device_get_sysattr_value(look_at, "queue/rotational"))) + if ((b = streq(rotational, "0"))) + goto finish; + + /* Finally, fallback to heuristics */ + if (!(look_at = udev_device_get_parent(look_at))) + goto finish; + + if ((model = udev_device_get_sysattr_value(look_at, "model"))) + b = !!strstr(model, "SSD"); + +finish: + if (udev_device) + udev_device_unref(udev_device); + + if (udev) + udev_unref(udev); + + return b; +} + +int fs_on_read_only(const char *p) { + struct stat st; + struct udev *udev = NULL; + struct udev_device *udev_device = NULL; + bool b = false; + const char *read_only; + + assert(p); + + if (stat(p, &st) < 0) + return -errno; + + if (major(st.st_dev) == 0) + return false; + + if (!(udev = udev_new())) + return -ENOMEM; + + if (!(udev_device = udev_device_new_from_devnum(udev, 'b', st.st_dev))) + goto finish; + + if ((read_only = udev_device_get_sysattr_value(udev_device, "ro"))) + if ((b = streq(read_only, "1"))) + goto finish; + +finish: + if (udev_device) + udev_device_unref(udev_device); + + if (udev) + udev_unref(udev); + + return b; +} + +bool enough_ram(void) { + struct sysinfo si; + + assert_se(sysinfo(&si) >= 0); + + /* Enable readahead only with at least 128MB memory */ + return si.totalram > 127 * 1024*1024 / si.mem_unit; +} + +int open_inotify(void) { + int fd; + + if ((fd = inotify_init1(IN_CLOEXEC|IN_NONBLOCK)) < 0) { + log_error("Failed to create inotify handle: %m"); + return -errno; + } + + mkdir("/run/systemd", 0755); + mkdir("/run/systemd/readahead", 0755); + + if (inotify_add_watch(fd, "/run/systemd/readahead", IN_CREATE) < 0) { + log_error("Failed to watch /run/systemd/readahead: %m"); + close_nointr_nofail(fd); + return -errno; + } + + return fd; +} + +ReadaheadShared *shared_get(void) { + int fd; + ReadaheadShared *m = NULL; + + mkdir("/run/systemd", 0755); + mkdir("/run/systemd/readahead", 0755); + + if ((fd = open("/run/systemd/readahead/shared", O_CREAT|O_RDWR|O_CLOEXEC, 0644)) < 0) { + log_error("Failed to create shared memory segment: %m"); + goto finish; + } + + if (ftruncate(fd, sizeof(ReadaheadShared)) < 0) { + log_error("Failed to truncate shared memory segment: %m"); + goto finish; + } + + if ((m = mmap(NULL, sizeof(ReadaheadShared), PROT_WRITE|PROT_READ, MAP_SHARED, fd, 0)) == MAP_FAILED) { + log_error("Failed to mmap shared memory segment: %m"); + m = NULL; + goto finish; + } + +finish: + if (fd >= 0) + close_nointr_nofail(fd); + + return m; +} + +#define BUMP_REQUEST_NR (16*1024) + +int bump_request_nr(const char *p) { + struct stat st; + uint64_t u; + char *ap = NULL, *line = NULL; + int r; + dev_t d; + + assert(p); + + if (stat(p, &st) < 0) + return -errno; + + if (major(st.st_dev) == 0) + return 0; + + d = st.st_dev; + block_get_whole_disk(d, &d); + + if (asprintf(&ap, "/sys/dev/block/%u:%u/queue/nr_requests", major(d), minor(d)) < 0) { + r= -ENOMEM; + goto finish; + } + + r = read_one_line_file(ap, &line); + if (r < 0) { + if (r == -ENOENT) + r = 0; + goto finish; + } + + r = safe_atou64(line, &u); + if (r >= 0 && u >= BUMP_REQUEST_NR) { + r = 0; + goto finish; + } + + free(line); + line = NULL; + + if (asprintf(&line, "%lu", (unsigned long) BUMP_REQUEST_NR) < 0) { + r = -ENOMEM; + goto finish; + } + + r = write_one_line_file(ap, line); + if (r < 0) + goto finish; + + log_info("Bumped block_nr parameter of %u:%u to %lu. This is a temporary hack and should be removed one day.", major(d), minor(d), (unsigned long) BUMP_REQUEST_NR); + r = 1; + +finish: + free(ap); + free(line); + + return r; +} |