svn commit: r1037470 - /subversion/branches/performance/subversion/libsvn_fs_fs/caching.c

[st...@apache.org]

Author: stefan2
Date: Sun Nov 21 14:32:47 2010
New Revision: 1037470

URL: http://svn.apache.org/viewvc?rev=1037470&view=rev
Log:
Close all unused open files upon the end of *any* server request.
Otherwise, those APR files will hold 4k chunks of content cached
and will not see changes done *outside* the server process. This
fixes: http://svn.haxx.se/dev/archive-2010-10/0501.shtml

* subversion/libsvn_fs_fs/caching.c
  (close_unused_file_handles): new cleanup function
  (svn_fs_fs__initialize_caches): register new cleanup for the end 
   of the server request

Modified:
    subversion/branches/performance/subversion/libsvn_fs_fs/caching.c

Modified: subversion/branches/performance/subversion/libsvn_fs_fs/caching.c
URL: http://svn.apache.org/viewvc/subversion/branches/performance/subversion/libsvn_fs_fs/caching.c?rev=1037470&r1=1037469&r2=1037470&view=diff
==============================================================================
--- subversion/branches/performance/subversion/libsvn_fs_fs/caching.c (original)
+++ subversion/branches/performance/subversion/libsvn_fs_fs/caching.c Sun Nov 21 14:32:47 2010
@@ -67,6 +67,34 @@ warn_on_cache_errors(svn_error_t *err,
   return SVN_NO_ERROR;
 }
 
+static apr_status_t
+close_unused_file_handles(void *cache_void)
+{
+  svn_file_handle_cache_t *cache = cache_void;
+  apr_status_t result = APR_SUCCESS;
+
+  /* Close all file handles that are not in use anymore. So, as long as
+   * no requests to a given repository are being processed, we may change
+   * the file content and / or structure. However, content that has been
+   * cached *above* the APR layer (e.g. fulltext caches) will *not* be
+   * changed and may become inconsistent with the disk content.
+   *
+   * This will cause concurrent threads to perform somewhat slower because
+   * they might have put those handles to good use a few moments later.
+   * They now have to actually re-open the respective files.
+   */
+  svn_error_t *err = svn_file_handle_cache__flush(cache);
+
+  /* process error returns */
+  if (err)
+  {
+    result = err->apr_err;
+    svn_error_clear(err);
+  }
+
+  return result;
+}
+
 svn_error_t *
 svn_fs_fs__initialize_caches(svn_fs_t *fs,
                              apr_pool_t *pool)
@@ -81,6 +109,12 @@ svn_fs_fs__initialize_caches(svn_fs_t *f
 
   SVN_ERR(read_config(&memcache, &no_handler, fs, pool));
 
+  /* Schedule file handle cache cleanup after finishing the request. */
+  apr_pool_cleanup_register(pool,
+                            svn_fs__get_global_file_handle_cache(),
+                            close_unused_file_handles,
+                            apr_pool_cleanup_null);
+
   /* Make the cache for revision roots.  For the vast majority of
    * commands, this is only going to contain a few entries (svnadmin
    * dump/verify is an exception here), so to reduce overhead let's