From 27da4ade70d45312bfdf334aa8cf0d63bf78df14 Mon Sep 17 00:00:00 2001
From: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Date: Tue, 21 Feb 2017 00:41:43 -0800
Subject: reduce size of class_to_size_ array

Since 32-bit int is enough and accessing smaller array will use a bit
less of cache.
---
 src/common.h        | 6 +++---
 src/tcmalloc.cc     | 6 +++---
 src/thread_cache.cc | 2 +-
 src/thread_cache.h  | 2 +-
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/common.h b/src/common.h
index fe09d5b..d137084 100644
--- a/src/common.h
+++ b/src/common.h
@@ -222,7 +222,7 @@ class SizeMap {
   int NumMoveSize(size_t size);
 
   // Mapping from size class to max size storable in that class
-  size_t class_to_size_[kNumClasses];
+  int32 class_to_size_[kNumClasses];
 
   // Mapping from size class to number of pages to allocate at a time
   size_t class_to_pages_[kNumClasses];
@@ -253,12 +253,12 @@ class SizeMap {
   }
 
   // Get the byte-size for a specified class
-  inline size_t ByteSizeForClass(size_t cl) {
+  inline int32 ByteSizeForClass(size_t cl) {
     return class_to_size_[cl];
   }
 
   // Mapping from size class to max size storable in that class
-  inline size_t class_to_size(size_t cl) {
+  inline int32 class_to_size(size_t cl) {
     return class_to_size_[cl];
   }
 
diff --git a/src/tcmalloc.cc b/src/tcmalloc.cc
index 0438b69..2db0efe 100644
--- a/src/tcmalloc.cc
+++ b/src/tcmalloc.cc
@@ -434,12 +434,12 @@ static void DumpStats(TCMalloc_Printer* out, int level) {
     uint64_t cumulative = 0;
     for (int cl = 0; cl < kNumClasses; ++cl) {
       if (class_count[cl] > 0) {
-        uint64_t class_bytes =
-            class_count[cl] * Static::sizemap()->ByteSizeForClass(cl);
+        size_t cl_size = Static::sizemap()->ByteSizeForClass(cl);
+        uint64_t class_bytes = class_count[cl] * cl_size;
         cumulative += class_bytes;
         out->printf("class %3d [ %8" PRIuS " bytes ] : "
                 "%8" PRIu64 " objs; %5.1f MiB; %5.1f cum MiB\n",
-                cl, Static::sizemap()->ByteSizeForClass(cl),
+                cl, cl_size,
                 class_count[cl],
                 class_bytes / MiB,
                 cumulative / MiB);
diff --git a/src/thread_cache.cc b/src/thread_cache.cc
index 82474e6..f0f6bfc 100644
--- a/src/thread_cache.cc
+++ b/src/thread_cache.cc
@@ -115,7 +115,7 @@ void ThreadCache::Cleanup() {
 
 // Remove some objects of class "cl" from central cache and add to thread heap.
 // On success, return the first object for immediate use; otherwise return NULL.
-void* ThreadCache::FetchFromCentralCache(size_t cl, size_t byte_size) {
+void* ThreadCache::FetchFromCentralCache(size_t cl, int32_t byte_size) {
   FreeList* list = &list_[cl];
   ASSERT(list->empty());
   const int batch_size = Static::sizemap()->num_objects_to_move(cl);
diff --git a/src/thread_cache.h b/src/thread_cache.h
index c6e3eb4..ad5ce3e 100644
--- a/src/thread_cache.h
+++ b/src/thread_cache.h
@@ -231,7 +231,7 @@ class ThreadCache {
 
   // Gets and returns an object from the central cache, and, if possible,
   // also adds some objects of that size class to this thread cache.
-  void* FetchFromCentralCache(size_t cl, size_t byte_size);
+  void* FetchFromCentralCache(size_t cl, int32_t byte_size);
 
   // Releases some number of items from src.  Adjusts the list's max_length
   // to eventually converge on num_objects_to_move(cl).
-- 
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