Add the config.cache_oblivious mallctl.

ChangeLog

@@ -102,7 +102,8 @@ brevity.  Much more detail can be found in the git revision history:
     cache set distribution.
   - Randomly distribute large allocation base pointer alignment relative to page
     boundaries in order to more uniformly utilize CPU cache sets.  This can be
-    disabled via the --disable-cache-oblivious configure option.
+    disabled via the --disable-cache-oblivious configure option, and queried via
+    the "config.cache_oblivious" mallctl.
   - Micro-optimize the fast paths for the public API functions.
   - Refactor thread-specific data to reside in a single structure.  This assures
     that only a single TLS read is necessary per call into the public API.

doc/jemalloc.xml.in

@@ -731,6 +731,16 @@ for (i = 0; i < nbins; i++) {
         detecting whether another thread caused a refresh.</para></listitem>
       </varlistentry>
 
+      <varlistentry id="config.cache_oblivious">
+        <term>
+          <mallctl>config.cache_oblivious</mallctl>
+          (<type>bool</type>)
+          <literal>r-</literal>
+        </term>
+        <listitem><para><option>--enable-cache-oblivious</option> was specified
+        during build configuration.</para></listitem>
+      </varlistentry>
+
       <varlistentry id="config.debug">
         <term>
           <mallctl>config.debug</mallctl>

src/ctl.c

@@ -73,6 +73,7 @@ CTL_PROTO(thread_allocated)
 CTL_PROTO(thread_allocatedp)
 CTL_PROTO(thread_deallocated)
 CTL_PROTO(thread_deallocatedp)
+CTL_PROTO(config_cache_oblivious)
 CTL_PROTO(config_debug)
 CTL_PROTO(config_fill)
 CTL_PROTO(config_lazy_lock)
@@ -238,6 +239,7 @@ static const ctl_named_node_t	thread_node[] = {
 };
 
 static const ctl_named_node_t	config_node[] = {
+	{NAME("cache_oblivious"), CTL(config_cache_oblivious)},
 	{NAME("debug"),		CTL(config_debug)},
 	{NAME("fill"),		CTL(config_fill)},
 	{NAME("lazy_lock"),	CTL(config_lazy_lock)},
@@ -1247,6 +1249,7 @@ label_return:
 
 /******************************************************************************/
 
+CTL_RO_BOOL_CONFIG_GEN(config_cache_oblivious)
 CTL_RO_BOOL_CONFIG_GEN(config_debug)
 CTL_RO_BOOL_CONFIG_GEN(config_fill)
 CTL_RO_BOOL_CONFIG_GEN(config_lazy_lock)

test/unit/mallctl.c

@@ -126,6 +126,7 @@ TEST_BEGIN(test_mallctl_config)
 	assert_zu_eq(sz, sizeof(oldval), "Unexpected output size");	\
 } while (0)
 
+	TEST_MALLCTL_CONFIG(cache_oblivious);
 	TEST_MALLCTL_CONFIG(debug);
 	TEST_MALLCTL_CONFIG(fill);
 	TEST_MALLCTL_CONFIG(lazy_lock);