[heap] make inline allocation step size dynamic

src/heap/spaces.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/spaces.h"
 
 #include "src/base/bits.h"
 #include "src/base/platform/platform.h"
 #include "src/full-codegen/full-codegen.h"
 #include "src/heap/slots-buffer.h"
@@ skipping 1498 matching lines @@
     Address high = to_space_.page_high();
     Address new_top = allocation_info_.top() + size_in_bytes;
     allocation_info_.set_limit(Min(new_top, high));
   } else if (top_on_previous_step_ == 0) {
     // Normal limit is the end of the current page.
     allocation_info_.set_limit(to_space_.page_high());
   } else {
     // Lower limit during incremental marking.
     Address high = to_space_.page_high();
     Address new_top = allocation_info_.top() + size_in_bytes;
-    Address new_limit = new_top + inline_allocation_limit_step_;
+
+    intptr_t next_step = 0;
+    for (int i = 0; i < inline_allocation_observers_.length(); ++i) {

[Hannes Payer (out of office), 2015/11/09 19:26:39]

Can we move that code into a helper function?

[ofrobots, 2015/11/09 23:00:32]

Done.

+      InlineAllocationObserver* o = inline_allocation_observers_[i];
+      next_step = next_step ? Min(next_step, o->bytes_to_next_step())
+                            : o->bytes_to_next_step();
+    }
+    DCHECK(next_step != 0);
+    Address new_limit = new_top + next_step;
     allocation_info_.set_limit(Min(new_limit, high));
   }
   DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
 }
 
 
 bool NewSpace::AddFreshPage() {
   Address top = allocation_info_.top();
   if (NewSpacePage::IsAtStart(top)) {
     // The current page is already empty. Don't try to make another.
@@ skipping 65 matching lines @@
     // Set the new limit accordingly.
     Address new_top = old_top + aligned_size_in_bytes;
     InlineAllocationStep(new_top, new_top);
     UpdateInlineAllocationLimit(aligned_size_in_bytes);
   }
   return true;
 }
 
 
 void NewSpace::UpdateInlineAllocationLimitStep() {
-  intptr_t step = 0;
-  for (int i = 0; i < inline_allocation_observers_.length(); ++i) {
-    InlineAllocationObserver* observer = inline_allocation_observers_[i];
-    step = step ? Min(step, observer->step_size()) : observer->step_size();
-  }
-  inline_allocation_limit_step_ = step;
-  top_on_previous_step_ = step ? allocation_info_.top() : 0;
+  top_on_previous_step_ =

[Hannes Payer (out of office), 2015/11/09 19:26:39]

This method is now just updating top_on_previous_step_. We should rename this
method to reflect that.

[ofrobots, 2015/11/09 23:00:32]

Done.

+      inline_allocation_observers_.length() ? allocation_info_.top() : 0;
   UpdateInlineAllocationLimit(0);
 }
 
 
 void NewSpace::AddInlineAllocationObserver(InlineAllocationObserver* observer) {
   inline_allocation_observers_.Add(observer);
   UpdateInlineAllocationLimitStep();
 }
 
 
@@ skipping 1676 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 }  // namespace internal
 }  // namespace v8