diff options
Diffstat (limited to 'src/readahead-collect.c')
| -rw-r--r-- | src/readahead-collect.c | 437 |
1 files changed, 437 insertions, 0 deletions
diff --git a/src/readahead-collect.c b/src/readahead-collect.c new file mode 100644 index 0000000000..93a04521f3 --- /dev/null +++ b/src/readahead-collect.c @@ -0,0 +1,437 @@ +/*-*- 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 <inttypes.h> +#include <fcntl.h> +#include <linux/limits.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/select.h> +#include <sys/time.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <unistd.h> +#include <linux/fanotify.h> +#include <sys/signalfd.h> +#include <sys/poll.h> +#include <sys/mman.h> +#include <linux/fs.h> +#include <linux/fiemap.h> +#include <sys/ioctl.h> + +#include "missing.h" +#include "util.h" +#include "set.h" +#include "sd-daemon.h" +#include "ioprio.h" +#include "readahead-common.h" + +/* + fixme: + + - BTRFS_IOC_DEFRAG +*/ + +#define MINCORE_VEC_SIZE (READAHEAD_FILE_SIZE_MAX/PAGE_SIZE) + +static int pack_file(FILE *pack, const char *fn) { + struct stat st; + void *start = MAP_FAILED; + uint8_t vec[MINCORE_VEC_SIZE]; + uint32_t b, c; + size_t l, pages; + bool mapped; + int r = 0, fd = -1, k; + + assert(pack); + assert(fn); + + if ((fd = open(fn, O_RDONLY|O_CLOEXEC|O_NOATIME|O_NOCTTY|O_NOFOLLOW)) < 0) { + log_warning("open(%s) failed: %m", fn); + r = -errno; + goto finish; + } + + if ((k = file_verify(fd, fn, &st)) <= 0) { + r = k; + goto finish; + } + + l = PAGE_ALIGN(st.st_size); + if ((start = mmap(NULL, l, PROT_READ, MAP_SHARED, fd, 0)) == MAP_FAILED) { + log_warning("mmap(%s) failed: %m", fn); + r = -errno; + goto finish; + } + + if (mincore(start, l, vec) < 0) { + log_warning("mincore(%s) failed: %m", fn); + r = -errno; + goto finish; + } + + fputs(fn, pack); + fputc('\n', pack); + + pages = l / PAGE_SIZE; + mapped = false; + for (c = 0; c < pages; c++) { + bool new_mapped = (vec[c] & 1); + + if (!mapped && new_mapped) + b = c; + else if (mapped && !new_mapped) { + fwrite(&b, sizeof(b), 1, pack); + fwrite(&c, sizeof(c), 1, pack); + + log_debug("%s: page %u to %u", fn, b, c); + } + + mapped = new_mapped; + } + + /* We don't write any range data if we should read the entire file */ + if (mapped && b > 0) { + fwrite(&b, sizeof(b), 1, pack); + fwrite(&c, sizeof(c), 1, pack); + + log_debug("%s: page %u to %u", fn, b, c); + } + + /* End marker */ + b = 0; + fwrite(&b, sizeof(b), 1, pack); + fwrite(&b, sizeof(b), 1, pack); + +finish: + if (start != MAP_FAILED) + munmap(start, l); + + if (fd >= 0) + close_nointr_nofail(fd); + + return r; +} + +static unsigned long fd_first_block(int fd) { + struct { + struct fiemap fiemap; + struct fiemap_extent extent; + } data; + + zero(data); + data.fiemap.fm_length = ~0ULL; + data.fiemap.fm_extent_count = 1; + + if (ioctl(fd, FS_IOC_FIEMAP, &data) < 0) + return 0; + + if (data.fiemap.fm_mapped_extents <= 0) + return 0; + + if (data.fiemap.fm_extents[0].fe_flags & FIEMAP_EXTENT_UNKNOWN) + return 0; + + return (unsigned long) data.fiemap.fm_extents[0].fe_physical; +} + +struct item { + const char *path; + unsigned long block; +}; + +static int qsort_compare(const void *a, const void *b) { + const struct item *i, *j; + + i = a; + j = b; + + if (i->block < j->block) + return -1; + if (i->block > j->block) + return 1; + + return strcmp(i->path, j->path); +} + +static int collect(const char *root) { + enum { + FD_FANOTIFY, + FD_SIGNAL, + _FD_MAX + }; + struct pollfd pollfd[_FD_MAX]; + int fanotify_fd = -1, signal_fd = -1, r = 0; + pid_t my_pid; + Hashmap *files = NULL; + Iterator i; + char *p, *q; + sigset_t mask; + FILE *pack = NULL; + char *pack_fn_new = NULL, *pack_fn = NULL; + bool on_ssd; + + assert(root); + + if (ioprio_set(IOPRIO_WHO_PROCESS, getpid(), IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0)) < 0) + log_warning("Failed to set IDLE IO priority class: %m"); + + assert_se(sigemptyset(&mask) == 0); + sigset_add_many(&mask, SIGINT, SIGTERM, -1); + assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0); + + if ((signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC)) < 0) { + log_error("signalfd(): %m"); + r = -errno; + goto finish; + } + + if (!(files = hashmap_new(string_hash_func, string_compare_func))) { + log_error("Failed to allocate set."); + r = -ENOMEM; + goto finish; + } + + if ((fanotify_fd = fanotify_init(FAN_CLOEXEC, O_RDONLY|O_LARGEFILE|O_CLOEXEC|O_NOATIME)) < 0) { + log_error("Failed to create fanotify object: %m"); + r = -errno; + goto finish; + } + + if (fanotify_mark(fanotify_fd, FAN_MARK_ADD|FAN_MARK_MOUNT, FAN_OPEN, AT_FDCWD, root) < 0) { + log_error("Failed to mark %s: %m", root); + r = -errno; + goto finish; + } + + my_pid = getpid(); + + zero(pollfd); + pollfd[FD_FANOTIFY].fd = fanotify_fd; + pollfd[FD_FANOTIFY].events = POLLIN; + pollfd[FD_SIGNAL].fd = signal_fd; + pollfd[FD_SIGNAL].events = POLLIN; + + sd_notify(0, + "READY=1\n" + "STATUS=Collecting readahead data"); + + log_debug("Collecting..."); + + for (;;) { + union { + struct fanotify_event_metadata metadata; + char buffer[4096]; + } data; + ssize_t n; + struct fanotify_event_metadata *m; + + if (poll(pollfd, _FD_MAX, -1) < 0) { + + if (errno == EINTR) + continue; + + log_error("poll(): %m"); + r = -errno; + goto finish; + } + + if (pollfd[FD_SIGNAL].revents != 0) + break; + + if ((n = read(fanotify_fd, &data, sizeof(data))) < 0) { + + if (errno == EINTR || errno == EAGAIN) + continue; + + log_error("Failed to read event: %m"); + r = -errno; + goto finish; + } + + m = &data.metadata; + while (FAN_EVENT_OK(m, n)) { + + if (m->pid != my_pid && m->fd >= 0) { + char fn[PATH_MAX]; + int k; + + snprintf(fn, sizeof(fn), "/proc/self/fd/%i", m->fd); + char_array_0(fn); + + if ((k = readlink_malloc(fn, &p)) >= 0) { + + if (hashmap_get(files, p)) + /* Already read */ + free(p); + else { + unsigned long ul; + + ul = fd_first_block(m->fd); + + if ((k = hashmap_put(files, p, ULONG_TO_PTR(ul))) < 0) { + + if (k != -EEXIST) + log_warning("set_put() failed: %s", strerror(-k)); + + free(p); + } + } + + } else + log_warning("readlink(%s) failed: %s", fn, strerror(-k)); + } + + if (m->fd) + close_nointr_nofail(m->fd); + + m = FAN_EVENT_NEXT(m, n); + } + + } + + if (fanotify_fd >= 0) { + close_nointr_nofail(fanotify_fd); + fanotify_fd = -1; + } + + log_debug("Writing Pack File..."); + + on_ssd = fs_on_ssd(root); + log_debug("On SSD: %s", yes_no(on_ssd)); + + asprintf(&pack_fn, "%s/.readahead", root); + asprintf(&pack_fn_new, "%s/.readahead.new", root); + + if (!pack_fn || !pack_fn_new) { + log_error("Out of memory"); + r = -ENOMEM; + goto finish; + } + + if (!(pack = fopen(pack_fn_new, "we"))) { + log_error("Failed to open pack file: %m"); + r = -errno; + goto finish; + } + + fputs(CANONICAL_HOST "\n", pack); + putc(on_ssd ? 'S' : 'R', pack); + + if (on_ssd) { + + /* On SSD, just write things out in the order the + * files where accessed */ + + HASHMAP_FOREACH_KEY(q, p, files, i) + pack_file(pack, p); + } else { + struct item *ordered, *j; + unsigned k, n; + + /* On rotating media, order things by the block + * numbers */ + + log_debug("Ordering..."); + + n = hashmap_size(files); + if (!(ordered = new(struct item, n))) { + log_error("Out of memory"); + r = -ENOMEM; + goto finish; + } + + j = ordered; + HASHMAP_FOREACH_KEY(q, p, files, i) { + j->path = p; + j->block = PTR_TO_ULONG(q); + j++; + } + + assert(ordered + n == j); + + qsort(ordered, n, sizeof(struct item), qsort_compare); + + for (k = 0; k < n; k++) + pack_file(pack, ordered[k].path); + + free(ordered); + } + + log_debug("Finalizing..."); + + fflush(pack); + + if (ferror(pack)) { + log_error("Failed to write pack file."); + r = -EIO; + goto finish; + } + + if (rename(pack_fn_new, pack_fn) < 0) { + log_error("Failed to rename readahead file: %m"); + r = -errno; + goto finish; + } + + fclose(pack); + pack = NULL; + + log_debug("Done."); + +finish: + if (fanotify_fd >= 0) + close_nointr_nofail(fanotify_fd); + + if (signal_fd >= 0) + close_nointr_nofail(signal_fd); + + if (pack) { + fclose(pack); + unlink(pack_fn_new); + } + + free(pack_fn_new); + free(pack_fn); + + while ((p = hashmap_steal_first_key(files))) + free(q); + + hashmap_free(files); + + return r; +} + +int main(int argc, char *argv[]) { + /* log_set_target(LOG_TARGET_SYSLOG_OR_KMSG); */ + log_parse_environment(); + log_open(); + + log_set_max_level(LOG_DEBUG); + + if (collect("/") < 0) + return 1; + + return 0; +} |