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8268893: jcmd to trim the glibc heap 
Reviewed-by: simonis, dholmes
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@tstuefe
tstuefe committed Jul 22, 2021
1 parent c36755d commit 6096dd9765eaf280890f65c0ff1ab64864b9316a
Showing 6 changed files with 239 additions and 26 deletions.
57 src/hotspot/os/linux/os_linux.cpp
View file
@@ -2148,44 +2148,51 @@ void os::Linux::print_system_memory_info(outputStream* st) {
"/sys/kernel/mm/transparent_hugepage/defrag", st);
}

void os::Linux::print_process_memory_info(outputStream* st) {

st->print_cr("Process Memory:");

// Print virtual and resident set size; peak values; swap; and for
// rss its components if the kernel is recent enough.
ssize_t vmsize = -1, vmpeak = -1, vmswap = -1,
vmrss = -1, vmhwm = -1, rssanon = -1, rssfile = -1, rssshmem = -1;
const int num_values = 8;
int num_found = 0;
bool os::Linux::query_process_memory_info(os::Linux::meminfo_t* info) {
FILE* f = ::fopen("/proc/self/status", "r");
const int num_values = sizeof(os::Linux::meminfo_t) / sizeof(size_t);
int num_found = 0;
char buf[256];
info->vmsize = info->vmpeak = info->vmrss = info->vmhwm = info->vmswap =
info->rssanon = info->rssfile = info->rssshmem = -1;
if (f != NULL) {
while (::fgets(buf, sizeof(buf), f) != NULL && num_found < num_values) {
if ( (vmsize == -1 && sscanf(buf, "VmSize: " SSIZE_FORMAT " kB", &vmsize) == 1) ||
(vmpeak == -1 && sscanf(buf, "VmPeak: " SSIZE_FORMAT " kB", &vmpeak) == 1) ||
(vmswap == -1 && sscanf(buf, "VmSwap: " SSIZE_FORMAT " kB", &vmswap) == 1) ||
(vmhwm == -1 && sscanf(buf, "VmHWM: " SSIZE_FORMAT " kB", &vmhwm) == 1) ||
(vmrss == -1 && sscanf(buf, "VmRSS: " SSIZE_FORMAT " kB", &vmrss) == 1) ||
(rssanon == -1 && sscanf(buf, "RssAnon: " SSIZE_FORMAT " kB", &rssanon) == 1) ||
(rssfile == -1 && sscanf(buf, "RssFile: " SSIZE_FORMAT " kB", &rssfile) == 1) ||
(rssshmem == -1 && sscanf(buf, "RssShmem: " SSIZE_FORMAT " kB", &rssshmem) == 1)
if ( (info->vmsize == -1 && sscanf(buf, "VmSize: " SSIZE_FORMAT " kB", &info->vmsize) == 1) ||
(info->vmpeak == -1 && sscanf(buf, "VmPeak: " SSIZE_FORMAT " kB", &info->vmpeak) == 1) ||
(info->vmswap == -1 && sscanf(buf, "VmSwap: " SSIZE_FORMAT " kB", &info->vmswap) == 1) ||
(info->vmhwm == -1 && sscanf(buf, "VmHWM: " SSIZE_FORMAT " kB", &info->vmhwm) == 1) ||
(info->vmrss == -1 && sscanf(buf, "VmRSS: " SSIZE_FORMAT " kB", &info->vmrss) == 1) ||
(info->rssanon == -1 && sscanf(buf, "RssAnon: " SSIZE_FORMAT " kB", &info->rssanon) == 1) || // Needs Linux 4.5
(info->rssfile == -1 && sscanf(buf, "RssFile: " SSIZE_FORMAT " kB", &info->rssfile) == 1) || // Needs Linux 4.5
(info->rssshmem == -1 && sscanf(buf, "RssShmem: " SSIZE_FORMAT " kB", &info->rssshmem) == 1) // Needs Linux 4.5
)
{
num_found ++;
}
}
fclose(f);
return true;
}
return false;
}

void os::Linux::print_process_memory_info(outputStream* st) {

st->print_cr("Virtual Size: " SSIZE_FORMAT "K (peak: " SSIZE_FORMAT "K)", vmsize, vmpeak);
st->print("Resident Set Size: " SSIZE_FORMAT "K (peak: " SSIZE_FORMAT "K)", vmrss, vmhwm);
if (rssanon != -1) { // requires kernel >= 4.5
st->print_cr("Process Memory:");

// Print virtual and resident set size; peak values; swap; and for
// rss its components if the kernel is recent enough.
meminfo_t info;
if (query_process_memory_info(&info)) {
st->print_cr("Virtual Size: " SSIZE_FORMAT "K (peak: " SSIZE_FORMAT "K)", info.vmsize, info.vmpeak);
st->print("Resident Set Size: " SSIZE_FORMAT "K (peak: " SSIZE_FORMAT "K)", info.vmrss, info.vmhwm);
if (info.rssanon != -1) { // requires kernel >= 4.5
st->print(" (anon: " SSIZE_FORMAT "K, file: " SSIZE_FORMAT "K, shmem: " SSIZE_FORMAT "K)",
rssanon, rssfile, rssshmem);
info.rssanon, info.rssfile, info.rssshmem);
}
st->cr();
if (vmswap != -1) { // requires kernel >= 2.6.34
st->print_cr("Swapped out: " SSIZE_FORMAT "K", vmswap);
if (info.vmswap != -1) { // requires kernel >= 2.6.34
st->print_cr("Swapped out: " SSIZE_FORMAT "K", info.vmswap);
}
} else {
st->print_cr("Could not open /proc/self/status to get process memory related information");
@@ -2206,7 +2213,7 @@ void os::Linux::print_process_memory_info(outputStream* st) {
struct glibc_mallinfo mi = _mallinfo();
total_allocated = (size_t)(unsigned)mi.uordblks;
// Since mallinfo members are int, glibc values may have wrapped. Warn about this.
might_have_wrapped = (vmrss * K) > UINT_MAX && (vmrss * K) > (total_allocated + UINT_MAX);
might_have_wrapped = (info.vmrss * K) > UINT_MAX && (info.vmrss * K) > (total_allocated + UINT_MAX);
}
if (_mallinfo2 != NULL || _mallinfo != NULL) {
st->print_cr("C-Heap outstanding allocations: " SIZE_FORMAT "K%s",
17 src/hotspot/os/linux/os_linux.hpp
View file
@@ -174,6 +174,23 @@ class Linux {
// Return the namespace pid if so, otherwise -1.
static int get_namespace_pid(int vmid);

// Output structure for query_process_memory_info()
struct meminfo_t {
ssize_t vmsize; // current virtual size
ssize_t vmpeak; // peak virtual size
ssize_t vmrss; // current resident set size
ssize_t vmhwm; // peak resident set size
ssize_t vmswap; // swapped out
ssize_t rssanon; // resident set size (anonymous mappings, needs 4.5)
ssize_t rssfile; // resident set size (file mappings, needs 4.5)
ssize_t rssshmem; // resident set size (shared mappings, needs 4.5)
};

// Attempts to query memory information about the current process and return it in the output structure.
// May fail (returns false) or succeed (returns true) but not all output fields are available; unavailable
// fields will contain -1.
static bool query_process_memory_info(meminfo_t* info);

// Stack repair handling

// none present
79 src/hotspot/os/linux/trimCHeapDCmd.cpp
View file
@@ -0,0 +1,79 @@
/*
* Copyright (c) 2021 SAP SE. All rights reserved.
* Copyright (c) 2021, 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.
*
*/

#include "precompiled.hpp"
#include "logging/log.hpp"
#include "runtime/os.hpp"
#include "utilities/debug.hpp"
#include "utilities/ostream.hpp"
#include "trimCHeapDCmd.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 (!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
}
52 src/hotspot/os/linux/trimCHeapDCmd.hpp
View file
@@ -0,0 +1,52 @@
/*
* Copyright (c) 2021 SAP SE. All rights reserved.
* Copyright (c) 2021, 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.
*
*/

#ifndef OS_LINUX_TRIMCHEAPDCMD_HPP
#define OS_LINUX_TRIMCHEAPDCMD_HPP

#include "services/diagnosticCommand.hpp"

class outputStream;

class TrimCLibcHeapDCmd : public DCmd {
public:
TrimCLibcHeapDCmd(outputStream* output, bool heap) : DCmd(output, heap) {}
static const char* name() {
return "System.trim_native_heap";
}
static const char* description() {
return "Attempts to free up memory by trimming the C-heap.";
}
static const char* impact() {
return "Low";
}
static const JavaPermission permission() {
JavaPermission p = { "java.lang.management.ManagementPermission", "control", NULL };
return p;
}
virtual void execute(DCmdSource source, TRAPS);
};

#endif // OS_LINUX_TRIMCHEAPDCMD_HPP
5 src/hotspot/share/services/diagnosticCommand.cpp
View file
@@ -58,7 +58,9 @@
#include "utilities/events.hpp"
#include "utilities/formatBuffer.hpp"
#include "utilities/macros.hpp"

#ifdef LINUX
#include "trimCHeapDCmd.hpp"
#endif

static void loadAgentModule(TRAPS) {
ResourceMark rm(THREAD);
@@ -118,6 +120,7 @@ void DCmdRegistrant::register_dcmds(){
DCmdFactory::register_DCmdFactory(new DCmdFactoryImpl<CodeCacheDCmd>(full_export, true, false));
#ifdef LINUX
DCmdFactory::register_DCmdFactory(new DCmdFactoryImpl<PerfMapDCmd>(full_export, true, false));
DCmdFactory::register_DCmdFactory(new DCmdFactoryImpl<TrimCLibcHeapDCmd>(full_export, true, false));
#endif // LINUX
DCmdFactory::register_DCmdFactory(new DCmdFactoryImpl<TouchedMethodsDCmd>(full_export, true, false));
DCmdFactory::register_DCmdFactory(new DCmdFactoryImpl<CodeHeapAnalyticsDCmd>(full_export, true, false));
55 test/hotspot/jtreg/serviceability/dcmd/vm/TrimLibcHeapTest.java
View file
@@ -0,0 +1,55 @@
/*
* Copyright (c) 2021 SAP SE. All rights reserved.
* Copyright (c) 2021, 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.
*/

import org.testng.annotations.Test;
import jdk.test.lib.dcmd.CommandExecutor;
import jdk.test.lib.dcmd.JMXExecutor;
import jdk.test.lib.process.OutputAnalyzer;

/*
* @test
* @summary Test of diagnostic command VM.trim_libc_heap
* @library /test/lib
* @requires os.family == "linux"
* @modules java.base/jdk.internal.misc
* java.compiler
* java.management
* jdk.internal.jvmstat/sun.jvmstat.monitor
* @run testng TrimLibcHeapTest
*/
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)");
}
}

@Test
public void jmx() {
run(new JMXExecutor());
}
}

7 comments on commit 6096dd9

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@openjdk-notifier openjdk-notifier bot commented on 6096dd9 Jul 22, 2021

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Review

Issues

@tstuefe
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@tstuefe tstuefe commented on 6096dd9 Sep 10, 2021

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/backport jdk17u-dev

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@openjdk openjdk bot commented on 6096dd9 Sep 10, 2021

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@tstuefe the target repository jdk17u-dev is not a valid target for backports.
List of valid target repositories: openjdk/jdk11u, openjdk/jdk11u-dev, openjdk/jdk12u, openjdk/jdk13u, openjdk/jdk13u-dev, openjdk/jdk14u, openjdk/jdk15u, openjdk/jdk15u-dev, openjdk/jdk16u, openjdk/jdk17, openjdk/jdk17u.
Supplying the organization/group prefix is optional.

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@tstuefe tstuefe commented on 6096dd9 Sep 10, 2021

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/backport openjdk/jdk17u

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@openjdk openjdk bot commented on 6096dd9 Sep 10, 2021

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@tstuefe the backport was successfully created on the branch tstuefe-backport-6096dd97 in my personal fork of openjdk/jdk17u. To create a pull request with this backport targeting openjdk/jdk17u:master, just click the following link:

➡️ Create pull request

The title of the pull request is automatically filled in correctly and below you find a suggestion for the pull request body:

Hi all,

this pull request contains a backport of commit 6096dd97 from the openjdk/jdk repository.

The commit being backported was authored by Thomas Stuefe on 22 Jul 2021 and was reviewed by Volker Simonis and David Holmes.

Thanks!

If you need to update the source branch of the pull then run the following commands in a local clone of your personal fork of openjdk/jdk17u:

$ git fetch https://github.com/openjdk-bots/jdk17u tstuefe-backport-6096dd97:tstuefe-backport-6096dd97
$ git checkout tstuefe-backport-6096dd97
# make changes
$ git add paths/to/changed/files
$ git commit --message 'Describe additional changes made'
$ git push https://github.com/openjdk-bots/jdk17u tstuefe-backport-6096dd97

@tstuefe
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@tstuefe tstuefe commented on 6096dd9 Sep 11, 2021

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/backport jdk11u-dev

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@openjdk openjdk bot commented on 6096dd9 Sep 11, 2021

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@tstuefe could not automatically backport 6096dd97 to Optional[openjdk/jdk11u-dev] due to conflicts in the following files:

  • src/hotspot/os/linux/os_linux.cpp
  • src/hotspot/share/services/diagnosticCommand.cpp

To manually resolve these conflicts run the following commands in your personal fork of Optional[openjdk/jdk11u-dev]:

$ git checkout -b tstuefe-backport-6096dd97
$ git fetch --no-tags https://git.openjdk.java.net/jdk 6096dd9765eaf280890f65c0ff1ab64864b9316a
$ git cherry-pick --no-commit 6096dd9765eaf280890f65c0ff1ab64864b9316a
$ # Resolve conflicts
$ git add files/with/resolved/conflicts
$ git commit -m 'Backport 6096dd9765eaf280890f65c0ff1ab64864b9316a'

Once you have resolved the conflicts as explained above continue with creating a pull request towards the Optional[openjdk/jdk11u-dev] with the title Backport 6096dd9765eaf280890f65c0ff1ab64864b9316a.

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