Merge branch 'release/4.4.12'

Author: GrahamDumpleton

docs/release-notes/index.rst

@@ -5,6 +5,7 @@ Release Notes
 .. toctree::
    :maxdepth: 2
 
+   version-4.4.12.rst
    version-4.4.11.rst
    version-4.4.10.rst
    version-4.4.9.rst

docs/release-notes/version-4.4.12.rst

@@ -0,0 +1,22 @@
+==============
+Version 4.4.12
+==============
+
+Version 4.4.12 of mod_wsgi can be obtained from:
+
+  https://codeload.github.com/GrahamDumpleton/mod_wsgi/tar.gz/4.4.12
+
+For details on the availability of Windows binaries see:
+
+  https://github.com/GrahamDumpleton/mod_wsgi/tree/master/win32
+
+Bugs Fixed
+----------
+
+1. If the WSGI application when run under daemon mode returned response
+content as many small blocks, this could result in excessive memory
+usage in the Apache child worker process proxying the request due to
+many buckets being buffered until the buffer size threshold was reached.
+If the number of buckets reaches a builtin threshold the buffered data
+will now be forcibly flushed even if the size threshold hadn't been
+reached.

src/server/__init__.py

@@ -1736,7 +1736,7 @@ def check_percentage(option, opt_str, value, parser):
             'over the secure connection.'),
 
     optparse.make_option('--hsts-policy', default=None, metavar='PARAMS',
-            help='Specify the HTST policy that should be applied when '
+            help='Specify the HSTS policy that should be applied when '
             'HTTPS only connections are being enforced.'),
 
     optparse.make_option('--server-name', default=None, metavar='HOSTNAME',

src/server/mod_wsgi.c

@@ -10590,6 +10590,8 @@ static int wsgi_transfer_response(request_rec *r, apr_bucket_brigade *bb,
 
     apr_size_t bytes_transfered = 0;
 
+    int bucket_count = 0;
+
     if (buffer_size == 0)
         buffer_size = 65536;
 
@@ -10676,6 +10678,8 @@ static int wsgi_transfer_response(request_rec *r, apr_bucket_brigade *bb,
 
             bytes_transfered = 0;
 
+            bucket_count = 0;
+
             /*
              * Retry read from daemon using a blocking read. We do
              * not delete the bucket as we want to operate on the
@@ -10713,19 +10717,31 @@ static int wsgi_transfer_response(request_rec *r, apr_bucket_brigade *bb,
         APR_BRIGADE_INSERT_TAIL(tmpbb, e);
 
         /*
-         * If we have reached the threshold, we want to flush the
-         * data so that we aren't buffering too much in memory
-         * and blowing out memory size.
+         * If we have reached the buffer size threshold, we want
+         * to flush the data so that we aren't buffering too much
+         * in memory and blowing out memory size. We also have a
+         * check on the number of buckets we have accumulated as
+         * a large number of buckets with very small amounts of
+         * data will also accumulate a lot of memory. Apache's
+         * own flow control doesn't cope with such a situation.
+         * Right now hard wire the max number of buckets at 16
+         * which equates to worst case number of separate data
+         * blocks can be written by a writev() call on systems
+         * such as Solaris.
          */
 
         bytes_transfered += length;
 
-        if (bytes_transfered > buffer_size) {
+        bucket_count += 1;
+
+        if (bytes_transfered > buffer_size || bucket_count >= 16) {
             APR_BRIGADE_INSERT_TAIL(tmpbb, apr_bucket_flush_create(
                                     r->connection->bucket_alloc));
 
             bytes_transfered = 0;
 
+            bucket_count = 0;
+
             /*
              * Since we flushed the data out to the client, it is
              * okay to go back and do a blocking read the next time.

src/server/wsgi_version.h

@@ -25,8 +25,8 @@
 
 #define MOD_WSGI_MAJORVERSION_NUMBER 4
 #define MOD_WSGI_MINORVERSION_NUMBER 4
-#define MOD_WSGI_MICROVERSION_NUMBER 11
-#define MOD_WSGI_VERSION_STRING "4.4.11"
+#define MOD_WSGI_MICROVERSION_NUMBER 12
+#define MOD_WSGI_VERSION_STRING "4.4.12"
 
 /* ------------------------------------------------------------------------- */