8181450: assert in BasicHashtable::verify_table
Summary: remove assert as it has small probability of happening and added logging
Reviewed-by: kbarrett, sspitsyn
--- a/hotspot/src/share/vm/classfile/placeholders.cpp Thu Jun 15 18:58:08 2017 +0000
+++ b/hotspot/src/share/vm/classfile/placeholders.cpp Fri Jun 16 09:13:56 2017 -0400
@@ -218,27 +218,19 @@
}
void PlaceholderTable::verify() {
- int element_count = 0;
- for (int pindex = 0; pindex < table_size(); pindex++) {
- for (PlaceholderEntry* probe = bucket(pindex);
- probe != NULL;
- probe = probe->next()) {
- probe->verify();
- element_count++; // both klasses and place holders count
- }
- }
- guarantee(number_of_entries() == element_count,
- "Verify of system dictionary failed");
+ verify_table<PlaceholderEntry>("Placeholder Table");
}
#ifndef PRODUCT
void PlaceholderTable::print() {
+ tty->print_cr("Placeholder table table_size=%d, entries=%d",
+ table_size(), number_of_entries());
for (int pindex = 0; pindex < table_size(); pindex++) {
for (PlaceholderEntry* probe = bucket(pindex);
probe != NULL;
probe = probe->next()) {
- if (Verbose) tty->print("%4d: ", pindex);
+ tty->print("%4d: ", pindex);
tty->print(" place holder ");
probe->print();
--- a/hotspot/src/share/vm/utilities/hashtable.cpp Thu Jun 15 18:58:08 2017 +0000
+++ b/hotspot/src/share/vm/utilities/hashtable.cpp Fri Jun 16 09:13:56 2017 -0400
@@ -28,6 +28,7 @@
#include "classfile/javaClasses.inline.hpp"
#include "classfile/moduleEntry.hpp"
#include "classfile/packageEntry.hpp"
+#include "classfile/placeholders.hpp"
#include "classfile/protectionDomainCache.hpp"
#include "classfile/stringTable.hpp"
#include "memory/allocation.inline.hpp"
@@ -307,11 +308,11 @@
}
}
-
template <MEMFLAGS F>
template <class T> void BasicHashtable<F>::verify_table(const char* table_name) {
int element_count = 0;
int max_bucket_count = 0;
+ int max_bucket_number = 0;
for (int index = 0; index < table_size(); index++) {
int bucket_count = 0;
for (T* probe = (T*)bucket(index); probe != NULL; probe = probe->next()) {
@@ -319,29 +320,32 @@
bucket_count++;
}
element_count += bucket_count;
- max_bucket_count = MAX2(max_bucket_count, bucket_count);
+ if (bucket_count > max_bucket_count) {
+ max_bucket_count = bucket_count;
+ max_bucket_number = index;
+ }
}
guarantee(number_of_entries() == element_count,
"Verify of %s failed", table_name);
- DEBUG_ONLY(verify_lookup_length(max_bucket_count, table_name));
+
+ // Log some statistics about the hashtable
+ log_info(hashtables)("%s max bucket size %d bucket %d element count %d table size %d", table_name,
+ max_bucket_count, max_bucket_number, _number_of_entries, _table_size);
+ if (_number_of_entries > 0 && log_is_enabled(Debug, hashtables)) {
+ for (int index = 0; index < table_size(); index++) {
+ int bucket_count = 0;
+ for (T* probe = (T*)bucket(index); probe != NULL; probe = probe->next()) {
+ log_debug(hashtables)("bucket %d hash " INTPTR_FORMAT, index, (intptr_t)probe->hash());
+ bucket_count++;
+ }
+ if (bucket_count > 0) {
+ log_debug(hashtables)("bucket %d count %d", index, bucket_count);
+ }
+ }
+ }
}
-
-
#endif // PRODUCT
-#ifdef ASSERT
-
-// Assert if the longest bucket is 10x longer than the average bucket size.
-// Could change back to a warning, but warnings are not noticed.
-template <MEMFLAGS F> void BasicHashtable<F>::verify_lookup_length(int max_bucket_count, const char *table_name) {
- log_info(hashtables)("%s max bucket size %d element count %d table size %d", table_name,
- max_bucket_count, _number_of_entries, _table_size);
- assert (max_bucket_count < ((1 + number_of_entries()/table_size())*10), "Table is unbalanced");
-}
-
-#endif
-
-
// Explicitly instantiate these types
#if INCLUDE_ALL_GCS
template class Hashtable<nmethod*, mtGC>;
@@ -383,3 +387,5 @@
template void BasicHashtable<mtModule>::verify_table<ModuleEntry>(char const*);
template void BasicHashtable<mtModule>::verify_table<PackageEntry>(char const*);
template void BasicHashtable<mtClass>::verify_table<ProtectionDomainCacheEntry>(char const*);
+template void BasicHashtable<mtClass>::verify_table<PlaceholderEntry>(char const*);
+
--- a/hotspot/src/share/vm/utilities/hashtable.hpp Thu Jun 15 18:58:08 2017 +0000
+++ b/hotspot/src/share/vm/utilities/hashtable.hpp Fri Jun 16 09:13:56 2017 -0400
@@ -170,10 +170,6 @@
protected:
-#ifdef ASSERT
- void verify_lookup_length(int max_bucket_count, const char *table_name);
-#endif
-
void initialize(int table_size, int entry_size, int number_of_entries);
// Accessor