Replaced different means of zone pooling/reusing by one zone segment pool

src/compiler/zone-stats.cc

 // Copyright 2014 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/compiler/zone-pool.h"
+#include "src/compiler/zone-stats.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
-ZonePool::StatsScope::StatsScope(ZonePool* zone_pool)
-    : zone_pool_(zone_pool),
-      total_allocated_bytes_at_start_(zone_pool->GetTotalAllocatedBytes()),
+ZoneStats::StatsScope::StatsScope(ZoneStats* zone_stats)
+    : zone_stats_(zone_stats),
+      total_allocated_bytes_at_start_(zone_stats->GetTotalAllocatedBytes()),
       max_allocated_bytes_(0) {
-  zone_pool_->stats_.push_back(this);
-  for (Zone* zone : zone_pool_->used_) {
+  zone_stats_->stats_.push_back(this);
+  for (Zone* zone : zone_stats_->used_) {
     size_t size = static_cast<size_t>(zone->allocation_size());
     std::pair<InitialValues::iterator, bool> res =
         initial_values_.insert(std::make_pair(zone, size));
     USE(res);
     DCHECK(res.second);
   }
 }
 
-
-ZonePool::StatsScope::~StatsScope() {
-  DCHECK_EQ(zone_pool_->stats_.back(), this);
-  zone_pool_->stats_.pop_back();
+ZoneStats::StatsScope::~StatsScope() {
+  DCHECK_EQ(zone_stats_->stats_.back(), this);
+  zone_stats_->stats_.pop_back();
 }
 
-
-size_t ZonePool::StatsScope::GetMaxAllocatedBytes() {
+size_t ZoneStats::StatsScope::GetMaxAllocatedBytes() {
   return std::max(max_allocated_bytes_, GetCurrentAllocatedBytes());
 }
 
-
-size_t ZonePool::StatsScope::GetCurrentAllocatedBytes() {
+size_t ZoneStats::StatsScope::GetCurrentAllocatedBytes() {
   size_t total = 0;
-  for (Zone* zone : zone_pool_->used_) {
+  for (Zone* zone : zone_stats_->used_) {
     total += static_cast<size_t>(zone->allocation_size());
     // Adjust for initial values.
     InitialValues::iterator it = initial_values_.find(zone);
     if (it != initial_values_.end()) {
       total -= it->second;
     }
   }
   return total;
 }
 
-
-size_t ZonePool::StatsScope::GetTotalAllocatedBytes() {
-  return zone_pool_->GetTotalAllocatedBytes() - total_allocated_bytes_at_start_;
+size_t ZoneStats::StatsScope::GetTotalAllocatedBytes() {
+  return zone_stats_->GetTotalAllocatedBytes() -
+         total_allocated_bytes_at_start_;
 }
 
-
-void ZonePool::StatsScope::ZoneReturned(Zone* zone) {
+void ZoneStats::StatsScope::ZoneReturned(Zone* zone) {
   size_t current_total = GetCurrentAllocatedBytes();
   // Update max.
   max_allocated_bytes_ = std::max(max_allocated_bytes_, current_total);
   // Drop zone from initial value map.
   InitialValues::iterator it = initial_values_.find(zone);
   if (it != initial_values_.end()) {
     initial_values_.erase(it);
   }
 }
 
-ZonePool::ZonePool(AccountingAllocator* allocator)
+ZoneStats::ZoneStats(AccountingAllocator* allocator)
     : max_allocated_bytes_(0), total_deleted_bytes_(0), allocator_(allocator) {}
 
-ZonePool::~ZonePool() {
+ZoneStats::~ZoneStats() {
   DCHECK(used_.empty());
   DCHECK(stats_.empty());
-  for (Zone* zone : unused_) {
-    delete zone;
-  }
 }
 
-
-size_t ZonePool::GetMaxAllocatedBytes() {
+size_t ZoneStats::GetMaxAllocatedBytes() {
   return std::max(max_allocated_bytes_, GetCurrentAllocatedBytes());
 }
 
-
-size_t ZonePool::GetCurrentAllocatedBytes() {
+size_t ZoneStats::GetCurrentAllocatedBytes() {
   size_t total = 0;
   for (Zone* zone : used_) {
     total += static_cast<size_t>(zone->allocation_size());
   }
   return total;
 }
 
-
-size_t ZonePool::GetTotalAllocatedBytes() {
+size_t ZoneStats::GetTotalAllocatedBytes() {
   return total_deleted_bytes_ + GetCurrentAllocatedBytes();
 }
 
-
-Zone* ZonePool::NewEmptyZone() {
-  Zone* zone;
-  // Grab a zone from pool if possible.
-  if (!unused_.empty()) {
-    zone = unused_.back();
-    unused_.pop_back();
-  } else {
-    zone = new Zone(allocator_);
-  }
+Zone* ZoneStats::NewEmptyZone() {
+  Zone* zone = new Zone(allocator_);
   used_.push_back(zone);

[Toon Verwaest, 2016/09/21 11:31:03]

Does it still make sense to call this "used_" rather than just "zones_"?

-  DCHECK_EQ(0u, zone->allocation_size());
   return zone;
 }
 
-
-void ZonePool::ReturnZone(Zone* zone) {
+void ZoneStats::ReturnZone(Zone* zone) {

[Toon Verwaest, 2016/09/21 11:31:03]

Does it make sense to call this Return, now that there's no pool?

   size_t current_total = GetCurrentAllocatedBytes();
   // Update max.
   max_allocated_bytes_ = std::max(max_allocated_bytes_, current_total);
   // Update stats.
   for (StatsScope* stat_scope : stats_) {
     stat_scope->ZoneReturned(zone);
   }
   // Remove from used.
   Used::iterator it = std::find(used_.begin(), used_.end(), zone);
   DCHECK(it != used_.end());
   used_.erase(it);
   total_deleted_bytes_ += static_cast<size_t>(zone->allocation_size());
-  // Delete zone or clear and stash on unused_.
-  if (unused_.size() >= kMaxUnusedSize) {
-    delete zone;
-  } else {
-    zone->DeleteAll();
-    DCHECK_EQ(0u, zone->allocation_size());
-    unused_.push_back(zone);
-  }
+  delete zone;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8