[heap] Evacuation for young generation

src/flag-definitions.h

 // Copyright 2012 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.
 
 // This file defines all of the flags.  It is separated into different section,
 // for Debug, Release, Logging and Profiling, etc.  To add a new flag, find the
 // correct section, and use one of the DEFINE_ macros, without a trailing ';'.
 //
 // This include does not have a guard, because it is a template-style include,
 // which can be included multiple times in different modes.  It expects to have
@@ skipping 653 matching lines @@
 DEFINE_BOOL(incremental_marking, true, "use incremental marking")
 DEFINE_BOOL(incremental_marking_wrappers, true,
             "use incremental marking for marking wrappers")
 DEFINE_BOOL(concurrent_marking, false, "use concurrent marking")
 DEFINE_BOOL(trace_concurrent_marking, false, "trace concurrent marking")
 DEFINE_INT(min_progress_during_incremental_marking_finalization, 32,
            "keep finalizing incremental marking as long as we discover at "
            "least this many unmarked objects")
 DEFINE_INT(max_incremental_marking_finalization_rounds, 3,
            "at most try this many times to finalize incremental marking")
-DEFINE_BOOL(minor_mc, false, "perform young generation mark compact GCs")
-DEFINE_NEG_IMPLICATION(minor_mc, page_promotion)
+DEFINE_BOOL(minor_mc, true, "perform young generation mark compact GCs")

[Hannes Payer (out of office), 2017/05/02 16:17:26]

Make sure you do not turn it on on ToT unless performance says "yey".

[Michael Lippautz, 2017/05/02 16:56:17]

Sure.

 DEFINE_NEG_IMPLICATION(minor_mc, flush_code)
 DEFINE_BOOL(black_allocation, true, "use black allocation")
 DEFINE_BOOL(concurrent_store_buffer, true,
             "use concurrent store buffer processing")
 DEFINE_BOOL(concurrent_sweeping, true, "use concurrent sweeping")
 DEFINE_BOOL(parallel_compaction, true, "use parallel compaction")
 DEFINE_BOOL(parallel_pointer_update, true,
             "use parallel pointer update during compaction")
 DEFINE_BOOL(trace_incremental_marking, false,
             "trace progress of the incremental marking")
@@ skipping 663 matching lines @@
 #undef DEFINE_ALIAS_FLOAT
 #undef DEFINE_ALIAS_ARGS
 
 #undef FLAG_MODE_DECLARE
 #undef FLAG_MODE_DEFINE
 #undef FLAG_MODE_DEFINE_DEFAULTS
 #undef FLAG_MODE_META
 #undef FLAG_MODE_DEFINE_IMPLICATIONS
 
 #undef COMMA