8323779: Serial: Remove Generation::promotion_attempt_is_safe

Reviewed-by: stefank, cjplummer

src/hotspot/share/gc/serial/defNewGeneration.hpp

@@ -27,6 +27,7 @@
 
 #include "gc/serial/cSpaceCounters.hpp"
 #include "gc/serial/generation.hpp"
+#include "gc/serial/tenuredGeneration.hpp"
 #include "gc/shared/ageTable.hpp"
 #include "gc/shared/copyFailedInfo.hpp"
 #include "gc/shared/gc_globals.hpp"
@@ -52,7 +53,8 @@ class STWGCTimer;
 class DefNewGeneration: public Generation {
   friend class VMStructs;
 
-  Generation* _old_gen;
+  TenuredGeneration* _old_gen;
+
   uint        _tenuring_threshold;   // Tenuring threshold for next collection.
   AgeTable    _age_table;
   // Size of object to pretenure in words; command line provides bytes

src/hotspot/share/gc/serial/generation.cpp

@@ -113,14 +113,6 @@ size_t Generation::max_contiguous_available() const {
   return MAX2(avail, old_avail);
 }
 
-bool Generation::promotion_attempt_is_safe(size_t max_promotion_in_bytes) const {
-  size_t available = max_contiguous_available();
-  bool   res = (available >= max_promotion_in_bytes);
-  log_trace(gc)("Generation: promo attempt is%s safe: available(" SIZE_FORMAT ") %s max_promo(" SIZE_FORMAT ")",
-                res? "":" not", available, res? ">=":"<", max_promotion_in_bytes);
-  return res;
-}
-
 // Ignores "ref" and calls allocate().
 oop Generation::promote(oop obj, size_t obj_size) {
   assert(obj_size == obj->size(), "bad obj_size passed in");

src/hotspot/share/gc/serial/generation.hpp

@@ -122,12 +122,6 @@ class Generation: public CHeapObj<mtGC> {
   // The largest number of contiguous free bytes in this or any higher generation.
   virtual size_t max_contiguous_available() const;
 
-  // Returns true if promotions of the specified amount are
-  // likely to succeed without a promotion failure.
-  // Promotion of the full amount is not guaranteed but
-  // might be attempted in the worst case.
-  virtual bool promotion_attempt_is_safe(size_t max_promotion_in_bytes) const;
-
   // Return an estimate of the maximum allocation that could be performed
   // in the generation without triggering any collection or expansion
   // activity.  It is "unsafe" because no locks are taken; the result

src/hotspot/share/gc/serial/tenuredGeneration.hpp

@@ -156,7 +156,11 @@ class TenuredGeneration: public Generation {
 
   virtual void update_gc_stats(Generation* current_generation, bool full);
 
-  virtual bool promotion_attempt_is_safe(size_t max_promoted_in_bytes) const;
+  // Returns true if promotions of the specified amount are
+  // likely to succeed without a promotion failure.
+  // Promotion of the full amount is not guaranteed but
+  // might be attempted in the worst case.
+  bool promotion_attempt_is_safe(size_t max_promoted_in_bytes) const;
 
   virtual void verify();
   virtual void print_on(outputStream* st) const;

src/hotspot/share/gc/serial/vmStructs_serial.hpp

@@ -40,7 +40,7 @@
   nonstatic_field(TenuredGeneration,                 _min_heap_delta_bytes,  size_t)                        \
   nonstatic_field(TenuredGeneration,                 _the_space,             TenuredSpace*)                 \
                                                                                                             \
-  nonstatic_field(DefNewGeneration,                  _old_gen,               Generation*)                   \
+  nonstatic_field(DefNewGeneration,                  _old_gen,               TenuredGeneration*)            \
   nonstatic_field(DefNewGeneration,                  _tenuring_threshold,    uint)                          \
   nonstatic_field(DefNewGeneration,                  _age_table,             AgeTable)                      \
   nonstatic_field(DefNewGeneration,                  _eden_space,            ContiguousSpace*)              \