Revert "Improve performance of creating Hash object"

This reverts commit r61309
Because it was unstable on mswin CI.

[ruby-dev:50370][Bug #14203]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61341 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

inits.c

@@ -16,7 +16,6 @@
 void
 rb_call_inits(void)
 {
-    CALL(st);
     CALL(Method);
     CALL(RandomSeedCore);
     CALL(sym);

st.c

@@ -108,7 +108,6 @@
 #endif
 #include <string.h>
 #include <assert.h>
-#include "ccan/list/list.h"
 
 #ifdef __GNUC__
 #define PREFETCH(addr, write_p) __builtin_prefetch(addr, write_p)
@@ -126,18 +125,6 @@
 #define st_assert(cond) ((void)(0 && (cond)))
 #endif
 
-typedef struct st_table_list {
-    st_table table;
-    struct list_node node;
-} st_table_list;
-
-struct st_table_pool {
-    struct list_head head;
-    int length;
-};
-static struct st_table_pool st_table_pool;
-#define ST_TABLE_POOL_MAX_LENGTH 500
-
 /* The type of hashes.  */
 typedef st_index_t st_hash_t;
 
@@ -561,38 +548,6 @@ stat_col(void)
 }
 #endif
 
-static st_table *
-get_st_table(void)
-{
-    st_table_list *table;
-
-    if (!ruby_thread_has_gvl_p() || st_table_pool.length == 0) {
-	table = (st_table_list*)malloc(sizeof (st_table_list));
-	list_node_init(&table->node);
-	return (st_table*)table;
-    }
-
-    table = list_pop(&st_table_pool.head, st_table_list, node);
-    st_table_pool.length--;
-
-    return (st_table*)table;
-}
-
-static void
-pool_st_table(st_table *_table)
-{
-    st_table_list *table = (st_table_list*)_table;
-
-    if (!ruby_thread_has_gvl_p() ||
-	    st_table_pool.length >= ST_TABLE_POOL_MAX_LENGTH) {
-	free(table);
-	return;
-    }
-
-    list_add_tail(&st_table_pool.head, &table->node);
-    st_table_pool.length++;
-}
-
 /* Create and return table with TYPE which can hold at least SIZE
    entries.  The real number of entries which the table can hold is
    the nearest power of two for SIZE.  */
@@ -616,7 +571,7 @@ st_init_table_with_size(const struct st_hash_type *type, st_index_t size)
 #endif
 
     n = get_power2(size);
-    tab = get_st_table();
+    tab = (st_table *) malloc(sizeof (st_table));
     tab->type = type;
     tab->entry_power = n;
     tab->bin_power = features[n].bin_power;
@@ -713,14 +668,14 @@ st_free_table(st_table *tab)
     if (tab->bins != NULL)
         free(tab->bins);
     free(tab->entries);
-    pool_st_table(tab);
+    free(tab);
 }
 
 /* Return byte size of memory allocted for table TAB.  */
 size_t
 st_memsize(const st_table *tab)
 {
-    return(sizeof(st_table_list)
+    return(sizeof(st_table)
            + (tab->bins == NULL ? 0 : bins_size(tab))
            + get_allocated_entries(tab) * sizeof(st_table_entry));
 }
@@ -836,7 +791,7 @@ rebuild_table(st_table *tab)
 	tab->bins = new_tab->bins;
 	free(tab->entries);
 	tab->entries = new_tab->entries;
-	pool_st_table(new_tab);
+	free(new_tab);
     }
     tab->entries_start = 0;
     tab->entries_bound = tab->num_entries;
@@ -1283,7 +1238,7 @@ st_copy(st_table *old_tab)
 {
     st_table *new_tab;
 
-    new_tab = (st_table *) malloc(sizeof(st_table_list));
+    new_tab = (st_table *) malloc(sizeof(st_table));
     *new_tab = *old_tab;
     if (old_tab->bins == NULL)
         new_tab->bins = NULL;
@@ -2057,7 +2012,7 @@ st_expand_table(st_table *tab, st_index_t siz)
     tab->entries = tmp->entries;
     tab->bins = NULL;
     tab->rebuilds_num++;
-    pool_st_table(tmp);
+    free(tmp);
 }
 
 /* Rehash using linear search. */
@@ -2237,11 +2192,3 @@ rb_hash_bulk_insert(long argc, const VALUE *argv, VALUE hash)
         st_insert_generic(tab, argc, argv, hash);
 }
 #endif
-
-void
-Init_st(void)
-{
-    /* initialize st_table pool */
-    list_head_init(&st_table_pool.head);
-    st_table_pool.length = 0;
-}