8209387: Follow ups to JDK-8195100 Use a low latency hashtable for SymbolTable
Summary: Use size_t, replaced macros with const, reverted incorrect API name change.
Reviewed-by: coleenp, kbarrett
--- a/src/hotspot/share/classfile/stringTable.cpp Mon Dec 10 09:51:23 2018 -0800
+++ b/src/hotspot/share/classfile/stringTable.cpp Mon Dec 10 11:59:55 2018 -0600
@@ -54,13 +54,13 @@
#include "utilities/macros.hpp"
// We prefer short chains of avg 2
-#define PREF_AVG_LIST_LEN 2
+const double PREF_AVG_LIST_LEN = 2.0;
// 2^24 is max size
-#define END_SIZE 24
+const size_t END_SIZE = 24;
// If a chain gets to 32 something might be wrong
-#define REHASH_LEN 32
+const size_t REHASH_LEN = 32;
// If we have as many dead items as 50% of the number of bucket
-#define CLEAN_DEAD_HIGH_WATER_MARK 0.5
+const double CLEAN_DEAD_HIGH_WATER_MARK = 0.5;
#if INCLUDE_CDS_JAVA_HEAP
inline oop read_string_from_compact_hashtable(address base_address, u4 offset) {
@@ -216,7 +216,7 @@
return Atomic::add((size_t)1, &(the_table()->_items_count));
}
-size_t StringTable::add_items_count_to_clean(size_t ndead) {
+size_t StringTable::add_items_to_clean(size_t ndead) {
size_t total = Atomic::add((size_t)ndead, &(the_table()->_uncleaned_items_count));
log_trace(stringtable)(
"Uncleaned items:" SIZE_FORMAT " added: " SIZE_FORMAT " total:" SIZE_FORMAT,
@@ -228,11 +228,11 @@
Atomic::add((size_t)-1, &(the_table()->_items_count));
}
-double StringTable::get_load_factor() {
+double StringTable::get_load_factor() const {
return (double)_items_count/_current_size;
}
-double StringTable::get_dead_factor() {
+double StringTable::get_dead_factor() const {
return (double)_uncleaned_items_count/_current_size;
}
@@ -432,7 +432,7 @@
_par_state_string->weak_oops_do(&stiac, &dnc);
// Accumulate the dead strings.
- the_table()->add_items_count_to_clean(stiac._count);
+ the_table()->add_items_to_clean(stiac._count);
*processed = stiac._count_total;
*removed = stiac._count;
--- a/src/hotspot/share/classfile/stringTable.hpp Mon Dec 10 09:51:23 2018 -0800
+++ b/src/hotspot/share/classfile/stringTable.hpp Mon Dec 10 11:59:55 2018 -0600
@@ -72,15 +72,15 @@
volatile size_t _uncleaned_items_count;
DEFINE_PAD_MINUS_SIZE(2, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t));
- double get_load_factor();
- double get_dead_factor();
+ double get_load_factor() const;
+ double get_dead_factor() const;
void check_concurrent_work();
void trigger_concurrent_work();
static size_t item_added();
static void item_removed();
- size_t add_items_count_to_clean(size_t ndead);
+ size_t add_items_to_clean(size_t ndead);
StringTable();
@@ -125,7 +125,7 @@
// If GC uses ParState directly it should add the number of cleared
// strings to this method.
static void inc_dead_counter(size_t ndead) {
- the_table()->add_items_count_to_clean(ndead);
+ the_table()->add_items_to_clean(ndead);
}
// Delete pointers to otherwise-unreachable objects.
--- a/src/hotspot/share/classfile/symbolTable.cpp Mon Dec 10 09:51:23 2018 -0800
+++ b/src/hotspot/share/classfile/symbolTable.cpp Mon Dec 10 11:59:55 2018 -0600
@@ -42,19 +42,19 @@
// We used to not resize at all, so let's be conservative
// and not set it too short before we decide to resize,
// to match previous startup behavior
-#define PREF_AVG_LIST_LEN 8
+const double PREF_AVG_LIST_LEN = 8.0;
// 2^17 (131,072) is max size, which is about 6.5 times as large
// as the previous table size (used to be 20,011),
// which never resized
-#define END_SIZE 17
+const size_t END_SIZE = 17;
// If a chain gets to 100 something might be wrong
-#define REHASH_LEN 100
+const size_t REHASH_LEN = 100;
// We only get a chance to check whether we need
// to clean infrequently (on class unloading),
// so if we have even one dead entry then mark table for cleaning
-#define CLEAN_DEAD_HIGH_WATER_MARK 0.0
+const double CLEAN_DEAD_HIGH_WATER_MARK = 0.0;
-#define ON_STACK_BUFFER_LENGTH 128
+const size_t ON_STACK_BUFFER_LENGTH = 128;
// --------------------------------------------------------------------------
@@ -171,8 +171,9 @@
log_trace(symboltable)("Set uncleaned items:" SIZE_FORMAT, SymbolTable::the_table()->_uncleaned_items_count);
}
+// Mark one item as needing to be cleaned, but only if no other items are marked yet
void SymbolTable::mark_item_clean_count() {
- if (Atomic::cmpxchg((size_t)1, &(SymbolTable::the_table()->_uncleaned_items_count), (size_t)0) == 0) { // only mark if unset
+ if (Atomic::cmpxchg((size_t)1, &(SymbolTable::the_table()->_uncleaned_items_count), (size_t)0) == 0) {
log_trace(symboltable)("Marked uncleaned items:" SIZE_FORMAT, SymbolTable::the_table()->_uncleaned_items_count);
}
}
@@ -182,11 +183,11 @@
Atomic::dec(&(SymbolTable::the_table()->_items_count));
}
-double SymbolTable::get_load_factor() {
+double SymbolTable::get_load_factor() const {
return (double)_items_count/_current_size;
}
-double SymbolTable::get_dead_factor() {
+double SymbolTable::get_dead_factor() const {
return (double)_uncleaned_items_count/_current_size;
}
@@ -386,7 +387,7 @@
assert(*value != NULL, "value should point to a symbol");
_return = *value;
}
- Symbol* get_res_sym() {
+ Symbol* get_res_sym() const {
return _return;
}
};
@@ -694,7 +695,7 @@
}
struct SymbolTableDoDelete : StackObj {
- int _deleted;
+ size_t _deleted;
SymbolTableDoDelete() : _deleted(0) {}
void operator()(Symbol** value) {
assert(value != NULL, "expected valid value");
@@ -706,7 +707,7 @@
};
struct SymbolTableDeleteCheck : StackObj {
- int _processed;
+ size_t _processed;
SymbolTableDeleteCheck() : _processed(0) {}
bool operator()(Symbol** value) {
assert(value != NULL, "expected valid value");
@@ -738,9 +739,9 @@
bdt.done(jt);
}
- Atomic::add((size_t)stdc._processed, &_symbols_counted);
+ Atomic::add(stdc._processed, &_symbols_counted);
- log_debug(symboltable)("Cleaned " INT32_FORMAT " of " INT32_FORMAT,
+ log_debug(symboltable)("Cleaned " SIZE_FORMAT " of " SIZE_FORMAT,
stdd._deleted, stdc._processed);
}
@@ -775,7 +776,7 @@
}
class CountDead : StackObj {
- int _count;
+ size_t _count;
public:
CountDead() : _count(0) {}
bool operator()(Symbol** value) {
@@ -787,7 +788,7 @@
}
return true;
};
- int get_dead_count() {
+ size_t get_dead_count() const {
return _count;
}
};
--- a/src/hotspot/share/classfile/symbolTable.hpp Mon Dec 10 09:51:23 2018 -0800
+++ b/src/hotspot/share/classfile/symbolTable.hpp Mon Dec 10 11:59:55 2018 -0600
@@ -123,8 +123,8 @@
volatile size_t _items_count;
volatile size_t _uncleaned_items_count;
- double get_load_factor();
- double get_dead_factor();
+ double get_load_factor() const;
+ double get_dead_factor() const;
void check_concurrent_work();
void trigger_concurrent_work();