Optimize memory allocation

A number of memory allocation optimizations have been implemented. Most
optimizations reduce contention caused by synchronization between
threads during allocation and deallocation of memory. Most notably:
* Synchronization of memory management in scheduler specific allocator
  instances has been rewritten to use lock-free synchronization.
* Synchronization of memory management in scheduler specific
  pre-allocators has been rewritten to use lock-free synchronization.
* The 'mseg_alloc' memory segment allocator now use scheduler specific
  instances instead of one instance. Apart from reducing contention
  this also ensures that memory allocators always create memory
  segments on the local NUMA node on a NUMA system.

1 files changed, 11 insertions, 7 deletions

diff --git a/erts/emulator/beam/erl_afit_alloc.c b/erts/emulator/beam/erl_afit_alloc.c
index bcc7ea04ae..570cc59be2 100644
--- a/erts/emulator/beam/erl_afit_alloc.c
+++ b/erts/emulator/beam/erl_afit_alloc.c
@@ -65,16 +65,20 @@ erts_afalc_start(AFAllctr_t *afallctr,
 		 AFAllctrInit_t *afinit,
 		 AllctrInit_t *init)
 {
-    AFAllctr_t nulled_state = {{0}};
-    /* {{0}} is used instead of {0}, in order to avoid (an incorrect) gcc
-       warning. gcc warns if {0} is used as initializer of a struct when
-       the first member is a struct (not if, for example, the third member
-       is a struct). */
+    struct {
+	int dummy;
+	AFAllctr_t allctr;
+    } zero = {0};
+    /* The struct with a dummy element first is used in order to avoid (an
+       incorrect) gcc warning. gcc warns if {0} is used as initializer of
+       a struct when the first member is a struct (not if, for example,
+       the third member is a struct). */
+
     Allctr_t *allctr = (Allctr_t *) afallctr;
 
-    init->sbmbct = 0; /* Small mbc not supported by afit */
+    sys_memcpy((void *) afallctr, (void *) &zero.allctr, sizeof(AFAllctr_t));
 
-    sys_memcpy((void *) afallctr, (void *) &nulled_state, sizeof(AFAllctr_t));
+    init->sbmbct = 0; /* Small mbc not supported by afit */
 
     allctr->mbc_header_size		= sizeof(Carrier_t);
     allctr->min_mbc_size		= MIN_MBC_SZ;