Hi Yumin,
This looks good overall. Here are my comments:
=====================
6065 size_t new_id = Atomic::add(&counter, (size_t)1);
6066 jio_snprintf(addr_buf, 20, INTPTR_FORMAT, new_id);
I think this should be SIZE_FORMAT
=====================
65 class KlassFactory : AllStatic {
66
67 // approved clients
68 friend class ClassLoader;
69 friend class ClassLoaderExt;
70 friend class SystemDictionary;
71 friend class LambdaFormInvokers;
72
73 private:
74 static InstanceKlass* create_from_stream(ClassFileStream* stream,
I think instead of adding everyone who uses create_from_stream as a
friend class, we should just change create_from_stream into a public
function and remove the friend declarations.
=====================
146 // add to hierarchy and set state to loaded.
147 {
148 MutexLocker mu_r(THREAD, Compile_lock); //
add_shared_to_hierarchy asserts this.
149 SystemDictionaryShared::add_shared_to_hierarchy(result, THREAD);
150 }
I think the function name can be changed to
SystemDictionaryShared::add_to_hierarchy as the "_shared" seems
redundant. The "set state to loaded" comment seems wrong, as we have the
assert on line 1155. I think the comment can be removed.
1153 void SystemDictionaryShared::add_shared_to_hierarchy(InstanceKlass*
k, TRAPS) {
1154 Arguments::assert_is_dumping_archive();
1155 assert(!k->is_loaded(), "Invariant");
1156 assert_locked_or_safepoint(Compile_lock); // add_to_hierarchy
assert on it.
1157 SystemDictionary::add_to_hierarchy(k, CHECK);
1158 }
Also, I think it's better to move the MutexLocker call into
SystemDictionaryShared::add_shared_to_hierarchy.
========================
before:
478 if (TRACE_RESOLVE && salvage != null) {
479 // Used by jlink species pregeneration plugin, see
480 //
jdk.tools.jlink.internal.plugins.GenerateJLIClassesPlugin
481 System.out.println("[SPECIES_RESOLVE] " +
className + " (salvaged)");
482 }
after:
488 // Used by jlink species pregeneration plugin, see
489 //
jdk.tools.jlink.internal.plugins.GenerateJLIClassesPlugin
490 traceResolve("[SPECIES_RESOLVE] " + className + "
(salvaged)");
When tracing is disabled, this will make extra allocations and cause a
small slowdown. I think it's better to
if ((TRACE_RESOLVE|TRACE_RESOLVE_CDS) && salvage != null) {
traceResolve("[SPECIES_RESOLVE] " + className + " (salvaged)");
}
Because TRACE_RESOLVE is a static final boolean, the JIT compiler will
completely optimize this block out.
For the same reason, instead of calling
VM.isDumpLoadedClassListSetAndOpen() every time, it's better to use a
static final variable.
=======================
698 if (TRACE_RESOLVE) {
699 System.out.println("[LF_RESOLVE] " + holder.getName()
+ " " + name + " " +
700 shortenSignature(basicTypeSignature(type)) + (resolvedMember !=
null ? " (success)" : " (fail)") );
701 }
702 if (VM.isDumpLoadedClassListSetAndOpen()) {
703 GenerateJLIClassesHelper.cdsTraceResolve("[LF_RESOLVE] " +
holder.getName() + " " + name + " " +
704 shortenSignature(basicTypeSignature(type)) + (resolvedMember !=
null ? " (success)" : " (fail)") );
705 }
706 return resolvedMember;
I think the two "if" blocks should be combined similarly to
ClassSpecializer::traceResolve().
=========================
34
Java_java_lang_invoke_GenerateJLIClassesHelper_cdsTraceResolve(JNIEnv
*env, jclass ignore, jstring line) {
Maybe this should be moved to the "VM" class as well?
=========================
lambdaFormInvokers.hpp:
Need these declarations:
#include "memory/allocation.hpp" <-- for AllStatic
#include "runtime/handles.hpp" <-- for typeArrayHandle and Handle
#include "utilities/exceptions.hpp" <-- for TRAPS
template <class T> class GrowableArray;
=========================
Thanks
- Ioi
On 8/23/20 3:56 PM, Yumin Qi wrote:
Hi, Mandy, Ioi and Calvin
I have updated the new changed at:
http://cr.openjdk.java.net/~minqi/2020/8247536/webrev-03/
In this version:
1) Added a new API to check if flag DumpLoadedClassList set and
the file is open. If true, call into vm to print out the trace line to
the log file.
Just thinking if we just call the cdsTraceResolve without
checking if the flag DumpLoadedClassList set and file open, this way,
the check logic is in the vm side like before, so save code by not
adding the new API.
2) The returned holder class names now are just
'package/className', removed head and tail.
3) Remove add_extra_classes from CollectClassesClosure since
after bug 8250990: https://bugs.openjdk.java.net/browse/JDK-8250990
pushed, the CollectClassesClosure no longer exist.
4) Still keep the parsing for TRACE_RESOLVE in
java/lang/invoke/GenerateJLIClassesHelper.java, so VM call its
function to regenerate holder classes.
Re-tested Mach5 tier1-4
Thanks
Yumin
On 8/20/20 8:05 PM, Yumin Qi wrote:
Hi, Mandy
On 8/20/20 5:10 PM, Mandy Chung wrote:
On 8/19/20 10:14 PM, Yumin Qi wrote:
HI, Mandy
Thanks for the review, I took one day off yesterday so just got a
detail look of your reply.
On 8/19/20 1:30 PM, Mandy Chung wrote:
On 8/17/20 12:37 PM, Yumin Qi wrote:
Hi, Ioi
Thanks for review/suggestion. I have updated the webrev at the
following link:
http://cr.openjdk.java.net/~minqi/2020/8247536/webrev-02/
This patch leverages the TRACE_RESOLVE output and passes the trace
output to VM. VM then calls
GenerateJLIClassesHelper::generateMHHolderClasses to do the
parsing and generate Holder class per the resolved LFs. I think
there are other cleaner alternatives implementing this. jlink
--generate-jli-classes plugin depends the trace output whereas
-Xshare:dump does not. It's cleaner to skip generating the trace
output and parsing for dumping shared archive purpose. In
addition, the implementation needs some cleanup (I can send you
feedback on the next revision)
Current patch did not change the existing code for JLinkPlugin
part. I just moved the parsing code from
GenerateJLIClassesPlugin.java to GenerateJLIClassesHelper.java
since the former is an internal class to which we shouldn't call to
generate holder classes.
Instead of relying on a system property
"java.lang.invoke.MethodHandle.CDS_TRACE_RESOLVE", it's better to
use jdk.internal.vm.isCDSDumpingEnabled() to detect if this is CDS
dump time.
I remember we have such API to query if flag -Xshare:dump or
-Xshare:on used. Do you mean if DumpLoadedClassList flag set? This
flag is the one used to log class name to list file. In
GenerateLinkOptData.gmk:
$(CLASSLIST_FILE): $(INTERIM_IMAGE_DIR)/bin/java$(EXE_SUFFIX)
$(CLASSLIST_JAR)
$(call MakeDir, $(LINK_OPT_DIR))
$(call LogInfo, Generating $(patsubst $(OUTPUTDIR)/%, %, $@))
$(call LogInfo, Generating $(patsubst $(OUTPUTDIR)/%, %,
$(JLI_TRACE_FILE)))
$(FIXPATH) $(INTERIM_IMAGE_DIR)/bin/java
-XX:[email protected] \
-Duser.language=en -Duser.country=US \
-cp $(SUPPORT_OUTPUTDIR)/classlist.jar \
build.tools.classlist.HelloClasslist $(LOG_DEBUG)
$(GREP) -v HelloClasslist [email protected] > [email protected]
$(FIXPATH) $(INTERIM_IMAGE_DIR)/bin/java -Xshare:dump \
-XX:[email protected]
-XX:[email protected] \
-Xmx128M -Xms128M $(LOG_INFO)
$(FIXPATH) $(INTERIM_IMAGE_DIR)/bin/java
-XX:[email protected] \
-XX:[email protected]
-XX:[email protected] \
-Djava.lang.invoke.MethodHandle.TRACE_RESOLVE=true \
-Duser.language=en -Duser.country=US \
--module-path $(SUPPORT_OUTPUTDIR)/classlist.jar \
-cp $(SUPPORT_OUTPUTDIR)/classlist.jar \
build.tools.classlist.HelloClasslist \
2> $(LINK_OPT_DIR)/stderr > $(JLI_TRACE_FILE) \
|| ( \
exitcode=$$? ; \
$(ECHO) "ERROR: Failed to generate link
optimization data." \
"This is likely a problem with the newly built
JVM/JDK." ; \
$(CAT) $(LINK_OPT_DIR)/stderr $(JLI_TRACE_FILE) ; \
exit $$exitcode \
)
$(GREP) -v HelloClasslist [email protected] > $@
The $(JLI_TRACE_FILE) is generated with both
-XX:DumpLoadedClassList and
-Djava.lang.invoke.MethodHandle.TRACE_RESOLVE=true, in current
implementation, DumpLoadedClassList will turn on property
java.lang.invoke.MethodHandle.CDS_TRACE_RESOLVE=true. So the same
output sent to stdout and log file DumpLoadedClassList specified.
These entries are duplicated in two different files: one for jlink
--generate-jli-classes plugin and another for CDS use. CDS
-Xshare:dump attempts to do what jlink plugin does but writes those
generated classes in to shared archive.
Like the above make logic to build JDK image, the same entries are
written in both default-jli-trace.txt via System.out and to
classlist via JNI call to the VM. I guess VM also implements the
logic to do some kind of diffing and write to CDS archive.
In current implementation, vm side only records the line as from
TRACE_RESOLVE at pre-run with -XX:DumpLoadedClassList, and at dump
time, call back to java for parsing those recordings and generating
the holder classes, this uses the existing JLI code.
Now instead of this property, using a vm interface API to query if
this flag is set, I think it is better choice. But here I am NOT
sure I understand your suggestion, I think there are two choices:
1) Using DumpLoadedClassList to collect TRACE_RESOLVE but not via
CDS_TRACE_RESOLVE, using new API to query if DumpLoadedClassList is
set
2) Do not use DumpLoadedClassList, when -Xshare:dump collecting
those name, type and holder name to regenerate holder classes?
I misunderstood that this CDS_TRACE_RESOLVE flag is set during
-Xshare:dump time.
Ioi has clarified to me offline that this step is actually part of
-XX:DumpLoadedClassList and includes these TRACE_RESOLVE logs to the
given class list file, i.e. you repurpose the class list file to
include the log output that was initially designed for jlink plugin.
To me, I'd prefer to see this support depending on `jlink
--generate-jli-classes` which is an existing functionality and much
cleaner. This way this does not require any VM change. It will
generate the holder classes in the custom image per the
application-specific config file.
What it means is that: a customer would need to create a custom
image with their application-specific config file. It might need a
new CDS option to specify a separate TRACE_RESOLVE file. It would
turn on this feature by default by defining a default path of the
log file if it helps.
So for now, I would implement an API to query if flag
DumpLoadedClassList set in cmd line, remove new added property of
java.lang.invoke.MethodHandle.CDS_TRACE_RESOLVE. We can address
custom image with CDS in future in a separate issue.
Thanks
Yumin
I understand that this is not the existing CDS work flow and CDS
archive does not require to run on a custom image. I see the value
of this approach which can prepare customers to start building and
using its own custom image.
Of course the implementation would be much simpler (adding a flag to
write these traces to a given file path, that is).
Mandy
