提交 9c6cffe3 编写于 作者: E ehelin

8049599: MetaspaceGC::_capacity_until_GC can overflow

Reviewed-by: jmasa, stefank
上级 03da718b
......@@ -1414,10 +1414,31 @@ size_t MetaspaceGC::capacity_until_GC() {
return value;
}
size_t MetaspaceGC::inc_capacity_until_GC(size_t v) {
bool MetaspaceGC::inc_capacity_until_GC(size_t v, size_t* new_cap_until_GC, size_t* old_cap_until_GC) {
assert_is_size_aligned(v, Metaspace::commit_alignment());
return (size_t)Atomic::add_ptr(v, &_capacity_until_GC);
size_t capacity_until_GC = (size_t) _capacity_until_GC;
size_t new_value = capacity_until_GC + v;
if (new_value < capacity_until_GC) {
// The addition wrapped around, set new_value to aligned max value.
new_value = align_size_down(max_uintx, Metaspace::commit_alignment());
}
intptr_t expected = (intptr_t) capacity_until_GC;
intptr_t actual = Atomic::cmpxchg_ptr((intptr_t) new_value, &_capacity_until_GC, expected);
if (expected != actual) {
return false;
}
if (new_cap_until_GC != NULL) {
*new_cap_until_GC = new_value;
}
if (old_cap_until_GC != NULL) {
*old_cap_until_GC = capacity_until_GC;
}
return true;
}
size_t MetaspaceGC::dec_capacity_until_GC(size_t v) {
......@@ -1517,7 +1538,10 @@ void MetaspaceGC::compute_new_size() {
expand_bytes = align_size_up(expand_bytes, Metaspace::commit_alignment());
// Don't expand unless it's significant
if (expand_bytes >= MinMetaspaceExpansion) {
size_t new_capacity_until_GC = MetaspaceGC::inc_capacity_until_GC(expand_bytes);
size_t new_capacity_until_GC = 0;
bool succeeded = MetaspaceGC::inc_capacity_until_GC(expand_bytes, &new_capacity_until_GC);
assert(succeeded, "Should always succesfully increment HWM when at safepoint");
Metaspace::tracer()->report_gc_threshold(capacity_until_GC,
new_capacity_until_GC,
MetaspaceGCThresholdUpdater::ComputeNewSize);
......@@ -3319,19 +3343,29 @@ MetaWord* Metaspace::expand_and_allocate(size_t word_size, MetadataType mdtype)
size_t delta_bytes = MetaspaceGC::delta_capacity_until_GC(word_size * BytesPerWord);
assert(delta_bytes > 0, "Must be");
size_t after_inc = MetaspaceGC::inc_capacity_until_GC(delta_bytes);
// capacity_until_GC might be updated concurrently, must calculate previous value.
size_t before_inc = after_inc - delta_bytes;
tracer()->report_gc_threshold(before_inc, after_inc,
MetaspaceGCThresholdUpdater::ExpandAndAllocate);
if (PrintGCDetails && Verbose) {
gclog_or_tty->print_cr("Increase capacity to GC from " SIZE_FORMAT
" to " SIZE_FORMAT, before_inc, after_inc);
size_t before = 0;
size_t after = 0;
MetaWord* res;
bool incremented;
// Each thread increments the HWM at most once. Even if the thread fails to increment
// the HWM, an allocation is still attempted. This is because another thread must then
// have incremented the HWM and therefore the allocation might still succeed.
do {
incremented = MetaspaceGC::inc_capacity_until_GC(delta_bytes, &after, &before);
res = allocate(word_size, mdtype);
} while (!incremented && res == NULL);
if (incremented) {
tracer()->report_gc_threshold(before, after,
MetaspaceGCThresholdUpdater::ExpandAndAllocate);
if (PrintGCDetails && Verbose) {
gclog_or_tty->print_cr("Increase capacity to GC from " SIZE_FORMAT
" to " SIZE_FORMAT, before, after);
}
}
return allocate(word_size, mdtype);
return res;
}
// Space allocated in the Metaspace. This may
......
......@@ -404,7 +404,9 @@ class MetaspaceGC : AllStatic {
static void post_initialize();
static size_t capacity_until_GC();
static size_t inc_capacity_until_GC(size_t v);
static bool inc_capacity_until_GC(size_t v,
size_t* new_cap_until_GC = NULL,
size_t* old_cap_until_GC = NULL);
static size_t dec_capacity_until_GC(size_t v);
static bool should_concurrent_collect() { return _should_concurrent_collect; }
......
......@@ -794,6 +794,33 @@ WB_ENTRY(void, WB_FreeMetaspace(JNIEnv* env, jobject wb, jobject class_loader, j
MetadataFactory::free_array(cld, (Array<u1>*)(uintptr_t)addr);
WB_END
WB_ENTRY(jlong, WB_IncMetaspaceCapacityUntilGC(JNIEnv* env, jobject wb, jlong inc))
if (inc < 0) {
THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
err_msg("WB_IncMetaspaceCapacityUntilGC: inc is negative: " JLONG_FORMAT, inc));
}
jlong max_size_t = (jlong) ((size_t) -1);
if (inc > max_size_t) {
THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(),
err_msg("WB_IncMetaspaceCapacityUntilGC: inc does not fit in size_t: " JLONG_FORMAT, inc));
}
size_t new_cap_until_GC = 0;
size_t aligned_inc = align_size_down((size_t) inc, Metaspace::commit_alignment());
bool success = MetaspaceGC::inc_capacity_until_GC(aligned_inc, &new_cap_until_GC);
if (!success) {
THROW_MSG_0(vmSymbols::java_lang_IllegalStateException(),
"WB_IncMetaspaceCapacityUntilGC: could not increase capacity until GC "
"due to contention with another thread");
}
return (jlong) new_cap_until_GC;
WB_END
WB_ENTRY(jlong, WB_MetaspaceCapacityUntilGC(JNIEnv* env, jobject wb))
return (jlong) MetaspaceGC::capacity_until_GC();
WB_END
//Some convenience methods to deal with objects from java
int WhiteBox::offset_for_field(const char* field_name, oop object,
Symbol* signature_symbol) {
......@@ -962,6 +989,8 @@ static JNINativeMethod methods[] = {
CC"(Ljava/lang/ClassLoader;J)J", (void*)&WB_AllocateMetaspace },
{CC"freeMetaspace",
CC"(Ljava/lang/ClassLoader;JJ)V", (void*)&WB_FreeMetaspace },
{CC"incMetaspaceCapacityUntilGC", CC"(J)J", (void*)&WB_IncMetaspaceCapacityUntilGC },
{CC"metaspaceCapacityUntilGC", CC"()J", (void*)&WB_MetaspaceCapacityUntilGC },
{CC"getCPUFeatures", CC"()Ljava/lang/String;", (void*)&WB_GetCPUFeatures },
{CC"getNMethod", CC"(Ljava/lang/reflect/Executable;Z)[Ljava/lang/Object;",
(void*)&WB_GetNMethod },
......
/*
* Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* @test
* @key gc
* @bug 8049831
* @library /testlibrary /testlibrary/whitebox
* @build TestCapacityUntilGCWrapAround
* @run main ClassFileInstaller sun.hotspot.WhiteBox
* sun.hotspot.WhiteBox$WhiteBoxPermission
* @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI TestCapacityUntilGCWrapAround
*/
import sun.hotspot.WhiteBox;
import com.oracle.java.testlibrary.Asserts;
import com.oracle.java.testlibrary.Platform;
public class TestCapacityUntilGCWrapAround {
private static long MB = 1024 * 1024;
private static long GB = 1024 * MB;
private static long MAX_UINT = 4 * GB - 1; // On 32-bit platforms
public static void main(String[] args) {
if (Platform.is32bit()) {
WhiteBox wb = WhiteBox.getWhiteBox();
long before = wb.metaspaceCapacityUntilGC();
// Now force possible overflow of capacity_until_GC.
long after = wb.incMetaspaceCapacityUntilGC(MAX_UINT);
Asserts.assertGTE(after, before,
"Increasing with MAX_UINT should not cause wrap around: " + after + " < " + before);
Asserts.assertLTE(after, MAX_UINT,
"Increasing with MAX_UINT should not cause value larger than MAX_UINT:" + after);
}
}
}
......@@ -152,6 +152,8 @@ public class WhiteBox {
public native void readReservedMemory();
public native long allocateMetaspace(ClassLoader classLoader, long size);
public native void freeMetaspace(ClassLoader classLoader, long addr, long size);
public native long incMetaspaceCapacityUntilGC(long increment);
public native long metaspaceCapacityUntilGC();
// force Young GC
public native void youngGC();
......
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