* 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.

diff --git a/ChangeLog b/ChangeLog
index c9e36fd..9459120 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,21 @@
 2008-06-12  Ulrich Drepper  <drepper@redhat.com>
 
+       * 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/grpcache.c (cache_addgr): Correctly compute size of
        fixed-size portion of the record.
        * nscd/servicescache.c (cache_addserv): Likewise.

diff --git a/nscd/cache.c b/nscd/cache.c
index 2faaf34..cd6e6b4 100644 (file)
--- a/nscd/cache.c
+++ b/nscd/cache.c
@@ -274,7 +274,7 @@ prune_cache (struct database_dyn *table, time_t now, int fd)
 
   /* If we check for the modification of the underlying file we invalidate
      the entries also in this case.  */
-  if (table->check_file && now != LONG_MAX)
+  if (table->inotify_descr < 0 && table->check_file && now != LONG_MAX)
     {
       struct stat64 st;
 

diff --git a/nscd/connections.c b/nscd/connections.c
index e6a2c94..bef1c16 100644 (file)
--- a/nscd/connections.c
+++ b/nscd/connections.c
@@ -35,6 +35,9 @@
 #ifdef HAVE_EPOLL
 # include <sys/epoll.h>
 #endif
+#ifdef HAVE_INOTIFY
+# include <sys/inotify.h>
+#endif
 #include <sys/mman.h>
 #include <sys/param.h>
 #include <sys/poll.h>
@@ -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.  */

diff --git a/nscd/nscd.h b/nscd/nscd.h
index b07256d..5c77dd3 100644 (file)
--- a/nscd/nscd.h
+++ b/nscd/nscd.h
@@ -73,6 +73,8 @@ struct database_dyn
 
   int enabled;
   int check_file;
+  int inotify_descr;
+  int clear_cache;
   int persistent;
   int shared;
   int propagate;

diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index ddbb4f6..c93538c 100644 (file)
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -154,7 +154,7 @@ CFLAGS-mq_receive.c += -fexceptions
 endif
 
 ifeq ($(subdir),nscd)
-CFLAGS-connections.c += -DHAVE_EPOLL -DHAVE_SENDFILE
+CFLAGS-connections.c += -DHAVE_EPOLL -DHAVE_SENDFILE -DHAVE_INOTIFY
 CFLAGS-pwdcache.c += -DHAVE_SENDFILE
 CFLAGS-grpcache.c += -DHAVE_SENDFILE
 CFLAGS-hstcache.c += -DHAVE_SENDFILE