diff --git a/src/hotspot/os/aix/os_aix.inline.hpp b/src/hotspot/os/aix/os_aix.inline.hpp
index edc50a9fae4..5f7415e4a51 100644
--- a/src/hotspot/os/aix/os_aix.inline.hpp
+++ b/src/hotspot/os/aix/os_aix.inline.hpp
@@ -52,4 +52,8 @@ inline bool os::must_commit_stack_guard_pages() {
inline void os::map_stack_shadow_pages(address sp) {
}
+// stubbed-out trim-native support
+inline bool os::can_trim_native_heap() { return false; }
+inline bool os::trim_native_heap(os::size_change_t* rss_change) { return false; }
+
#endif // OS_AIX_OS_AIX_INLINE_HPP
diff --git a/src/hotspot/os/bsd/os_bsd.inline.hpp b/src/hotspot/os/bsd/os_bsd.inline.hpp
index ba8edb0d462..f30ac61e463 100644
--- a/src/hotspot/os/bsd/os_bsd.inline.hpp
+++ b/src/hotspot/os/bsd/os_bsd.inline.hpp
@@ -55,4 +55,8 @@ inline bool os::must_commit_stack_guard_pages() {
inline void os::map_stack_shadow_pages(address sp) {
}
+// stubbed-out trim-native support
+inline bool os::can_trim_native_heap() { return false; }
+inline bool os::trim_native_heap(os::size_change_t* rss_change) { return false; }
+
#endif // OS_BSD_OS_BSD_INLINE_HPP
diff --git a/src/hotspot/os/linux/os_linux.cpp b/src/hotspot/os/linux/os_linux.cpp
index 90d54da9376..3a56d4a2833 100644
--- a/src/hotspot/os/linux/os_linux.cpp
+++ b/src/hotspot/os/linux/os_linux.cpp
@@ -5331,3 +5331,32 @@ void os::print_memory_mappings(char* addr, size_t bytes, outputStream* st) {
st->cr();
}
}
+
+bool os::trim_native_heap(os::size_change_t* rss_change) {
+#ifdef __GLIBC__
+ os::Linux::meminfo_t info1;
+ os::Linux::meminfo_t info2;
+
+ bool have_info1 = rss_change != nullptr &&
+ os::Linux::query_process_memory_info(&info1);
+ ::malloc_trim(0);
+ bool have_info2 = rss_change != nullptr && have_info1 &&
+ os::Linux::query_process_memory_info(&info2);
+ ssize_t delta = (ssize_t) -1;
+ if (rss_change != nullptr) {
+ if (have_info1 && have_info2 &&
+ info1.vmrss != -1 && info2.vmrss != -1 &&
+ info1.vmswap != -1 && info2.vmswap != -1) {
+ // Note: query_process_memory_info returns values in K
+ rss_change->before = (info1.vmrss + info1.vmswap) * K;
+ rss_change->after = (info2.vmrss + info2.vmswap) * K;
+ } else {
+ rss_change->after = rss_change->before = SIZE_MAX;
+ }
+ }
+
+ return true;
+#else
+ return false; // musl
+#endif
+}
diff --git a/src/hotspot/os/linux/os_linux.inline.hpp b/src/hotspot/os/linux/os_linux.inline.hpp
index 416e3f4f71b..f9d798404b5 100644
--- a/src/hotspot/os/linux/os_linux.inline.hpp
+++ b/src/hotspot/os/linux/os_linux.inline.hpp
@@ -47,4 +47,13 @@ inline bool os::must_commit_stack_guard_pages() {
inline void os::map_stack_shadow_pages(address sp) {
}
+// Trim-native support
+inline bool os::can_trim_native_heap() {
+#ifdef __GLIBC__
+ return true;
+#else
+ return false; // musl
+#endif
+}
+
#endif // OS_LINUX_OS_LINUX_INLINE_HPP
diff --git a/src/hotspot/os/linux/trimCHeapDCmd.cpp b/src/hotspot/os/linux/trimCHeapDCmd.cpp
index ec212e2c70c..33dd6f3a5bd 100644
--- a/src/hotspot/os/linux/trimCHeapDCmd.cpp
+++ b/src/hotspot/os/linux/trimCHeapDCmd.cpp
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2021 SAP SE. All rights reserved.
+ * Copyright (c) 2022 SAP SE. All rights reserved.
* Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
@@ -24,57 +24,29 @@
*/
#include "precompiled.hpp"
-#include "logging/log.hpp"
-#include "os_linux.hpp"
-#include "runtime/os.hpp"
-#include "utilities/debug.hpp"
-#include "utilities/ostream.hpp"
+#include "runtime/os.inline.hpp"
#include "trimCHeapDCmd.hpp"
+#include "utilities/debug.hpp"
+#include "utilities/globalDefinitions.hpp"
+#include "utilities/ostream.hpp"
#include <malloc.h>
void TrimCLibcHeapDCmd::execute(DCmdSource source, TRAPS) {
-#ifdef __GLIBC__
- stringStream ss_report(1024); // Note: before calling trim
-
- os::Linux::meminfo_t info1;
- os::Linux::meminfo_t info2;
- // Query memory before...
- bool have_info1 = os::Linux::query_process_memory_info(&info1);
-
- _output->print_cr("Attempting trim...");
- ::malloc_trim(0);
- _output->print_cr("Done.");
-
- // ...and after trim.
- bool have_info2 = os::Linux::query_process_memory_info(&info2);
-
- // Print report both to output stream as well to UL
- bool wrote_something = false;
- if (have_info1 && have_info2) {
- if (info1.vmsize != -1 && info2.vmsize != -1) {
- ss_report.print_cr("Virtual size before: " SSIZE_FORMAT "k, after: " SSIZE_FORMAT "k, (" SSIZE_FORMAT "k)",
- info1.vmsize, info2.vmsize, (info2.vmsize - info1.vmsize));
- wrote_something = true;
- }
- if (info1.vmrss != -1 && info2.vmrss != -1) {
- ss_report.print_cr("RSS before: " SSIZE_FORMAT "k, after: " SSIZE_FORMAT "k, (" SSIZE_FORMAT "k)",
- info1.vmrss, info2.vmrss, (info2.vmrss - info1.vmrss));
- wrote_something = true;
- }
- if (info1.vmswap != -1 && info2.vmswap != -1) {
- ss_report.print_cr("Swap before: " SSIZE_FORMAT "k, after: " SSIZE_FORMAT "k, (" SSIZE_FORMAT "k)",
- info1.vmswap, info2.vmswap, (info2.vmswap - info1.vmswap));
- wrote_something = true;
+ if (os::can_trim_native_heap()) {
+ os::size_change_t sc;
+ if (os::trim_native_heap(&sc)) {
+ _output->print("Trim native heap: ");
+ if (sc.after != SIZE_MAX) {
+ const size_t delta = sc.after < sc.before ? (sc.before - sc.after) : (sc.after - sc.before);
+ const char sign = sc.after < sc.before ? '-' : '+';
+ _output->print_cr("RSS+Swap: " PROPERFMT "->" PROPERFMT " (%c" PROPERFMT ")",
+ PROPERFMTARGS(sc.before), PROPERFMTARGS(sc.after), sign, PROPERFMTARGS(delta));
+ } else {
+ _output->print_cr("(no details available).");
+ }
}
+ } else {
+ _output->print_cr("Not available.");
}
- if (!wrote_something) {
- ss_report.print_raw("No details available.");
- }
-
- _output->print_raw(ss_report.base());
- log_info(os)("malloc_trim:\n%s", ss_report.base());
-#else
- _output->print_cr("Not available.");
-#endif
}
diff --git a/src/hotspot/os/windows/os_windows.inline.hpp b/src/hotspot/os/windows/os_windows.inline.hpp
index 81f5ab4bb90..276863e95b5 100644
--- a/src/hotspot/os/windows/os_windows.inline.hpp
+++ b/src/hotspot/os/windows/os_windows.inline.hpp
@@ -98,4 +98,8 @@ inline void PlatformMonitor::notify_all() {
WakeAllConditionVariable(&_cond);
}
+// stubbed-out trim-native support
+inline bool os::can_trim_native_heap() { return false; }
+inline bool os::trim_native_heap(os::size_change_t* rss_change) { return false; }
+
#endif // OS_WINDOWS_OS_WINDOWS_INLINE_HPP
diff --git a/src/hotspot/share/runtime/os.hpp b/src/hotspot/share/runtime/os.hpp
index 3c23075bbc9..971d78950b3 100644
--- a/src/hotspot/share/runtime/os.hpp
+++ b/src/hotspot/share/runtime/os.hpp
@@ -440,6 +440,15 @@ class os: AllStatic {
static bool uncommit_memory(char* addr, size_t bytes, bool executable = false);
static bool release_memory(char* addr, size_t bytes);
+ // Does the platform support trimming the native heap?
+ static bool can_trim_native_heap();
+
+ // Trim the C-heap. Optionally returns working set size change (RSS+Swap) in *rss_change.
+ // Note: If trimming succeeded but no size change information could be obtained,
+ // rss_change.after will contain SIZE_MAX upon return.
+ struct size_change_t { size_t before; size_t after; };
+ static bool trim_native_heap(size_change_t* rss_change = nullptr);
+
// A diagnostic function to print memory mappings in the given range.
static void print_memory_mappings(char* addr, size_t bytes, outputStream* st);
// Prints all mappings
diff --git a/src/hotspot/share/utilities/globalDefinitions.hpp b/src/hotspot/share/utilities/globalDefinitions.hpp
index f21bb89d0a0..3771ac0f277 100644
--- a/src/hotspot/share/utilities/globalDefinitions.hpp
+++ b/src/hotspot/share/utilities/globalDefinitions.hpp
@@ -372,6 +372,9 @@ inline T byte_size_in_proper_unit(T s) {
}
}
+#define PROPERFMT SIZE_FORMAT "%s"
+#define PROPERFMTARGS(s) byte_size_in_proper_unit(s), proper_unit_for_byte_size(s)
+
inline const char* exact_unit_for_byte_size(size_t s) {
#ifdef _LP64
if (s >= G && (s % G) == 0) {
diff --git a/test/hotspot/gtest/runtime/test_os.cpp b/test/hotspot/gtest/runtime/test_os.cpp
index 151e51ecb0a..376e544c09a 100644
--- a/test/hotspot/gtest/runtime/test_os.cpp
+++ b/test/hotspot/gtest/runtime/test_os.cpp
@@ -24,7 +24,7 @@
#include "precompiled.hpp"
#include "memory/allocation.hpp"
#include "memory/resourceArea.hpp"
-#include "runtime/os.hpp"
+#include "runtime/os.inline.hpp"
#include "runtime/thread.hpp"
#include "services/memTracker.hpp"
#include "utilities/globalDefinitions.hpp"
@@ -890,3 +890,27 @@ TEST_VM(os, is_first_C_frame) {
EXPECT_FALSE(os::is_first_C_frame(&cur_frame));
#endif // _WIN32
}
+
+#ifdef __GLIBC__
+TEST_VM(os, trim_native_heap) {
+ EXPECT_TRUE(os::can_trim_native_heap());
+ os::size_change_t sc;
+ sc.before = sc.after = (size_t)-1;
+ EXPECT_TRUE(os::trim_native_heap(&sc));
+ tty->print_cr(SIZE_FORMAT "->" SIZE_FORMAT, sc.before, sc.after);
+ // Regardless of whether we freed memory, both before and after
+ // should be somewhat believable numbers (RSS).
+ const size_t min = 5 * M;
+ const size_t max = LP64_ONLY(20 * G) NOT_LP64(3 * G);
+ ASSERT_LE(min, sc.before);
+ ASSERT_GT(max, sc.before);
+ ASSERT_LE(min, sc.after);
+ ASSERT_GT(max, sc.after);
+ // Should also work
+ EXPECT_TRUE(os::trim_native_heap());
+}
+#else
+TEST_VM(os, trim_native_heap) {
+ EXPECT_FALSE(os::can_trim_native_heap());
+}
+#endif // __GLIBC__
diff --git a/test/hotspot/jtreg/serviceability/dcmd/vm/TrimLibcHeapTest.java b/test/hotspot/jtreg/serviceability/dcmd/vm/TrimLibcHeapTest.java
index 2688c8e8fe7..5c18d711c7e 100644
--- a/test/hotspot/jtreg/serviceability/dcmd/vm/TrimLibcHeapTest.java
+++ b/test/hotspot/jtreg/serviceability/dcmd/vm/TrimLibcHeapTest.java
@@ -31,7 +31,7 @@ import jdk.test.lib.process.OutputAnalyzer;
* @test
* @summary Test of diagnostic command VM.trim_libc_heap
* @library /test/lib
- * @requires os.family == "linux"
+ * @requires (os.family=="linux") & !vm.musl
* @modules java.base/jdk.internal.misc
* java.compiler
* java.management
@@ -42,10 +42,7 @@ public class TrimLibcHeapTest {
public void run(CommandExecutor executor) {
OutputAnalyzer output = executor.execute("System.trim_native_heap");
output.reportDiagnosticSummary();
- output.shouldMatch("(Done|Not available)"); // Not available could happen on Linux + non-glibc (eg. muslc)
- if (output.firstMatch("Done") != null) {
- output.shouldMatch("(Virtual size before|RSS before|Swap before|No details available)");
- }
+ output.shouldMatch(".*Trim native heap: RSS\\+Swap: \\d+[BKM]->\\d+[BKM].*");
}
@Test