jemalloc cache_oblivious configurable, default false (arangodb#17870)

neunhoef · web-flow · commit bb1e80b9fa78 · 2023-01-04T11:23:33.000+01:00
diff --git a/3rdParty/jemalloc/CMakeLists.txt b/3rdParty/jemalloc/CMakeLists.txt
@@ -28,7 +28,7 @@ if (LINUX OR DARWIN)
   else ()
     set(JEMALLOC_CC_TMP "${CMAKE_C_COMPILER}")
     set(JEMALLOC_CXX_TMP "${CMAKE_CXX_COMPILER}")
-    set(JEMALLOC_CONFIG "background_thread:true")
+    set(JEMALLOC_CONFIG "background_thread:true,cache_oblivious:false")
   endif ()
 
   if (USE_JEMALLOC_PROF)
diff --git a/3rdParty/jemalloc/v5.3.0/src/jemalloc.c b/3rdParty/jemalloc/v5.3.0/src/jemalloc.c
@@ -1220,6 +1220,7 @@ malloc_conf_init_helper(sc_data_t *sc_data, unsigned bin_shard_sizes[SC_NBINS],
 
 			CONF_HANDLE_BOOL(opt_abort, "abort")
 			CONF_HANDLE_BOOL(opt_abort_conf, "abort_conf")
+			CONF_HANDLE_BOOL(opt_cache_oblivious, "cache_oblivious")
 			CONF_HANDLE_BOOL(opt_trust_madvise, "trust_madvise")
 			if (strncmp("metadata_thp", k, klen) == 0) {
 				int m;
diff --git a/CHANGELOG b/CHANGELOG
@@ -1,6 +1,11 @@
 devel
 -----
 
+* Make the cache_oblivious option of jemalloc configurable from the
+  environment and set its default to `false`. This helps to save
+  4096 bytes of RAM for every allocation which is at least 16384 bytes
+  large. This is particularly beneficial for the RocksDB buffer cache.
+
 * Updated ArangoDB Starter to 0.15.6-preview-1.
 
 * Acquire a snapshot of the (list of) indexes when starting document insert, 
