Introduce disposable call-cache.

This patch contains several ideas:

(1) Disposable inline method cache (IMC) for race-free inline method cache
    * Making call-cache (CC) as a RVALUE (GC target object) and allocate new
      CC on cache miss.
    * This technique allows race-free access from parallel processing
      elements like RCU.
(2) Introduce per-Class method cache (pCMC)
    * Instead of fixed-size global method cache (GMC), pCMC allows flexible
      cache size.
    * Caching CCs reduces CC allocation and allow sharing CC's fast-path
      between same call-info (CI) call-sites.
(3) Invalidate an inline method cache by invalidating corresponding method
    entries (MEs)
    * Instead of using class serials, we set "invalidated" flag for method
      entry itself to represent cache invalidation.
    * Compare with using class serials, the impact of method modification
      (add/overwrite/delete) is small.
    * Updating class serials invalidate all method caches of the class and
      sub-classes.
    * Proposed approach only invalidate the method cache of only one ME.

See [Feature #16614] for more details.

1 files changed, 7 insertions, 6 deletions

diff --git a/insns.def b/insns.def
index 2385f33f75..aab5cca065 100644
--- a/insns.def
+++ b/insns.def
@@ -827,7 +827,7 @@ opt_nil_p
 (VALUE recv)
 (VALUE val)
 {
-    val = vm_opt_nil_p(cd, recv);
+    val = vm_opt_nil_p(GET_ISEQ(), cd, recv);
 
     if (val == Qundef) {
         CALL_SIMPLE_METHOD();
@@ -903,8 +903,9 @@ invokeblock
 // attr rb_snum_t sp_inc = sp_inc_of_invokeblock(cd->ci);
 // attr rb_snum_t comptime_sp_inc = sp_inc_of_invokeblock(ci);
 {
-    if (UNLIKELY(cd->cc.call != vm_invokeblock_i)) {
-        cd->cc.call = vm_invokeblock_i; // check before setting to avoid CoW
+    if (UNLIKELY(vm_cc_call(cd->cc) != vm_invokeblock_i)) {
+        const struct rb_callcache *cc = vm_cc_new(0, NULL, vm_invokeblock_i);
+        RB_OBJ_WRITE(GET_ISEQ(), &cd->cc, cc);
     }
 
     VALUE bh = VM_BLOCK_HANDLER_NONE;
@@ -1167,7 +1168,7 @@ opt_eq
 (VALUE recv, VALUE obj)
 (VALUE val)
 {
-    val = opt_eq_func(recv, obj, cd);
+    val = opt_eq_func(GET_ISEQ(), recv, obj, cd);
 
     if (val == Qundef) {
         CALL_SIMPLE_METHOD();
@@ -1181,7 +1182,7 @@ opt_neq
 (VALUE recv, VALUE obj)
 (VALUE val)
 {
-    val = vm_opt_neq(cd, cd_eq, recv, obj);
+    val = vm_opt_neq(GET_ISEQ(), cd, cd_eq, recv, obj);
 
     if (val == Qundef) {
         CALL_SIMPLE_METHOD();
@@ -1431,7 +1432,7 @@ opt_not
 (VALUE recv)
 (VALUE val)
 {
-    val = vm_opt_not(cd, recv);
+    val = vm_opt_not(GET_ISEQ(), cd, recv);
 
     if (val == Qundef) {
         CALL_SIMPLE_METHOD();