From 5228ba2fe881133ccc0f9b3ad8a1ebbe9112a6f2 Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Thu, 12 Jun 2008 22:40:27 +0000 Subject: * nscd/nscd.h (struct database_dyn): Add inotify_descr and clear_cache fields. * nscd/connections.c (inotify_fd): New variable. (nscd_init): Try to open an inotify descriptor. If successful, watch files for databases using inotify instead of having prune threads stat the files. (nscd_run_prune): Recognize clear_cache flag being set and call prune_cache appropriately. (main_loop_poll): Add inotify descriptor to wait set and handle the reported changes. (main_loop_epoll): Likewise. * nscd/cache.c (prune_cache): Don't stat files for databases if inotify is used. * sysdeps/unix/sysv/linux/Makefile [subdir=nscd] (CFLAGS-connections.c): Add -DHAVE_INOTIFY. --- nscd/connections.c | 143 +++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 129 insertions(+), 14 deletions(-) (limited to 'nscd/connections.c') diff --git a/nscd/connections.c b/nscd/connections.c index e6a2c94..bef1c16 100644 --- a/nscd/connections.c +++ b/nscd/connections.c @@ -35,6 +35,9 @@ #ifdef HAVE_EPOLL # include #endif +#ifdef HAVE_INOTIFY +# include +#endif #include #include #include @@ -222,6 +225,11 @@ int max_nthreads = 32; /* Socket for incoming connections. */ static int sock; +#ifdef HAVE_INOTIFY +/* Inotify descriptor. */ +static int inotify_fd = -1; +#endif + /* Number of times clients had to wait. */ unsigned long int client_queued; @@ -503,6 +511,13 @@ nscd_init (void) /* No configuration for this value, assume a default. */ nthreads = 4; +#ifdef HAVE_INOTIFY + /* Use inotify to recognize changed files. */ + inotify_fd = inotify_init (); + if (inotify_fd != -1) + fcntl (inotify_fd, F_SETFL, O_NONBLOCK); +#endif + for (size_t cnt = 0; cnt < lastdb; ++cnt) if (dbs[cnt].enabled) { @@ -805,20 +820,30 @@ cannot set socket to close on exec: %s; disabling paranoia mode"), assert (dbs[cnt].ro_fd == -1); } + dbs[cnt].inotify_descr = -1; if (dbs[cnt].check_file) { - /* We need the modification date of the file. */ - struct stat64 st; - - if (stat64 (dbs[cnt].filename, &st) < 0) +#ifdef HAVE_INOTIFY + if (inotify_fd == -1 + || (dbs[cnt].inotify_descr + = inotify_add_watch (inotify_fd, dbs[cnt].filename, + IN_DELETE_SELF | IN_MODIFY)) < 0) + /* We cannot notice changes in the main thread. */ +#endif { - /* We cannot stat() the file, disable file checking. */ - dbg_log (_("cannot stat() file `%s': %s"), - dbs[cnt].filename, strerror (errno)); - dbs[cnt].check_file = 0; + /* We need the modification date of the file. */ + struct stat64 st; + + if (stat64 (dbs[cnt].filename, &st) < 0) + { + /* We cannot stat() the file, disable file checking. */ + dbg_log (_("cannot stat() file `%s': %s"), + dbs[cnt].filename, strerror (errno)); + dbs[cnt].check_file = 0; + } + else + dbs[cnt].file_mtime = st.st_mtime; } - else - dbs[cnt].file_mtime = st.st_mtime; } } @@ -1428,12 +1453,15 @@ nscd_run_prune (void *p) while (1) { /* Wait, but not forever. */ - int e = pthread_cond_timedwait (prune_cond, prune_lock, &prune_ts); + int e = 0; + if (! dbs[my_number].clear_cache) + e = pthread_cond_timedwait (prune_cond, prune_lock, &prune_ts); assert (__builtin_expect (e == 0 || e == ETIMEDOUT, 1)); time_t next_wait; now = time (NULL); - if (e == ETIMEDOUT || now >= dbs[my_number].wakeup_time) + if (e == ETIMEDOUT || now >= dbs[my_number].wakeup_time + || dbs[my_number].clear_cache) { /* We will determine the new timout values based on the cache content. Should there be concurrent additions to @@ -1446,9 +1474,13 @@ nscd_run_prune (void *p) else dbs[my_number].wakeup_time = INT_MAX; + /* Unconditionally reset the flag. */ + time_t prune_now = dbs[my_number].clear_cache ? LONG_MAX : now; + dbs[my_number].clear_cache = 0; + pthread_mutex_unlock (prune_lock); - next_wait = prune_cache (&dbs[my_number], now, -1); + next_wait = prune_cache (&dbs[my_number], prune_now, -1); next_wait = MAX (next_wait, CACHE_PRUNE_INTERVAL); /* If clients cannot determine for sure whether nscd is running @@ -1703,6 +1735,16 @@ main_loop_poll (void) size_t nused = 1; size_t firstfree = 1; +#ifdef HAVE_INOTIFY + if (inotify_fd != -1) + { + conns[1].fd = inotify_fd; + conns[1].events = POLLRDNORM; + nused = 2; + firstfree = 2; + } +#endif + while (1) { /* Wait for any event. We wait at most a couple of seconds so @@ -1750,7 +1792,42 @@ main_loop_poll (void) --n; } - for (size_t cnt = 1; cnt < nused && n > 0; ++cnt) + size_t first = 1; +#ifdef HAVE_INOTIFY + if (conns[1].fd == inotify_fd) + { + if (conns[1].revents != 0) + { + union + { + struct inotify_event i; + char buf[100]; + } inev; + + while (TEMP_FAILURE_RETRY (read (inotify_fd, &inev, + sizeof (inev))) + >= sizeof (struct inotify_event)) + { + /* Check which of the files changed. */ + for (size_t dbcnt = 0; dbcnt < lastdb; ++dbcnt) + if (inev.i.wd == dbs[dbcnt].inotify_descr) + { + pthread_mutex_trylock (&dbs[dbcnt].prune_lock); + dbs[dbcnt].clear_cache = 1; + pthread_mutex_unlock (&dbs[dbcnt].prune_lock); + pthread_cond_signal (&dbs[dbcnt].prune_cond); + break; + } + } + + --n; + } + + first = 2; + } +#endif + + for (size_t cnt = first; cnt < nused && n > 0; ++cnt) if (conns[cnt].revents != 0) { fd_ready (conns[cnt].fd); @@ -1816,6 +1893,18 @@ main_loop_epoll (int efd) /* We cannot use epoll. */ return; +#ifdef HAVE_INOTIFY + if (inotify_fd != -1) + { + ev.events = EPOLLRDNORM; + ev.data.fd = inotify_fd; + if (epoll_ctl (efd, EPOLL_CTL_ADD, inotify_fd, &ev) == -1) + /* We cannot use epoll. */ + return; + nused = 2; + } +#endif + while (1) { struct epoll_event revs[100]; @@ -1852,6 +1941,32 @@ main_loop_epoll (int efd) } } } +#ifdef HAVE_INOTIFY + else if (revs[cnt].data.fd == inotify_fd) + { + union + { + struct inotify_event i; + char buf[100]; + } inev; + + while (TEMP_FAILURE_RETRY (read (inotify_fd, &inev, + sizeof (inev))) + >= sizeof (struct inotify_event)) + { + /* Check which of the files changed. */ + for (size_t dbcnt = 0; dbcnt < lastdb; ++dbcnt) + if (inev.i.wd == dbs[dbcnt].inotify_descr) + { + pthread_mutex_trylock (&dbs[dbcnt].prune_lock); + dbs[dbcnt].clear_cache = 1; + pthread_mutex_unlock (&dbs[dbcnt].prune_lock); + pthread_cond_signal (&dbs[dbcnt].prune_cond); + break; + } + } + } +#endif else { /* Remove the descriptor from the epoll descriptor. */ -- cgit v1.1