(S) 8237750: Load libzip.so only if necessary
Ioi Lam
ioi.lam at oracle.com
Tue May 5 17:59:28 UTC 2020
Hi Yumin,
Looks good.
Just small nits. No need for new webrev.
[1] I think this should be named _libzip_loaded to be consistent with
other fields
static int libzip_loaded; // used to sync loading zip.
[2] This introduces dependency on atomic.hpp to classLoader.hpp
static void load_zip_library_if_needed() {
if (Atomic::load_acquire(&libzip_loaded) == 0) {
release_load_zip_library();
}
}
Since this function is used only privately in the cpp file, I think it's
better to change the hpp to this (to reduce unnecessary header file
dependencies)
inline static void load_zip_library_if_needed();
and then move the implementation to the classLoader.cpp file. You also
need to add include "runtime/atomic.hpp" to classLoader.cpp.
Thanks
- Ioi
On 5/4/20 4:40 PM, Yumin Qi wrote:
> Hi, Ioi
>
> Thanks. Updated webrev at:
> http://cr.openjdk.java.net/~minqi/8237750/webrev-02/
> libzip_loaded now is a class member of ClassLoader, no longer a file
> private integer since it is used in both .hpp and .cpp files.
>
> Thanks
> Yumin
>
> On 5/4/20 8:31 AM, Ioi Lam wrote:
>> Hi Yumin,
>>
>> 977 void ClassLoader::load_zip_library() {
>> 978 if (Atomic::load_acquire(&libzip_loaded) == 0) {
>> 979 MutexLocker locker(Zip_lock,
>> Monitor::_no_safepoint_check_flag);
>> 980 if (libzip_loaded == 0) {
>> 981 load_zip_library0();
>> 982 Atomic::release_store(&libzip_loaded, 1);
>> 983 }
>> 984 }
>> 985 }
>>
>> 1026 int ClassLoader::crc32(int crc, const char* buf, int len) {
>> 1027 if (libzip_loaded == 0) {
>> 1028 load_zip_library();
>> 1029 }
>> 1030 return (*Crc32)(crc, (const jbyte*)buf, len);
>> 1031 }
>>
>> ClassLoader::crc32 access libzip_loaded without a memory barrier, so
>> it may read libzip_loaded out-of-order from Crc32. This means, thread
>> 1 may be writing the memory in this order:
>>
>> Crc32 = <addr>;
>> libzip_loaded = 1;
>>
>> but the order observed in thread 2 may be
>>
>> libzip_loaded = 1;
>> >> ClassLoader::crc32 called here in thread 2
>> Crc32 = <addr>;
>>
>> as a result, thread 2 may read libzip_loaded = 1, but still reads a
>> NULL from Crc32.
>>
>> To ensure the memory barrier is used, I think we should do this:
>>
>> // private
>> inline void ClassLoader::load_zip_library_if_needed() {
>> if (Atomic::load_acquire(&libzip_loaded) == 0) {
>> release_load_zip_library();
>> }
>> }
>>
>> // private
>> void ClassLoader::release_load_zip_library() {
>> MutexLocker locker(Zip_lock, Monitor::_no_safepoint_check_flag);
>> if (libzip_loaded == 0) {
>> load_zip_library0();
>> Atomic::release_store(&libzip_loaded, 1);
>> }
>> }
>>
>> int ClassLoader::crc32(int crc, const char* buf, int len) {
>> load_zip_library_if_needed();
>> return (*Crc32)(crc, (const jbyte*)buf, len);
>> }
>>
>> HotSpot code uses the "release_" prefix to indicate that the function
>> must be used as a part of an acquire/release memory barrier. (E.g.,
>> InstanceKlass::release_set_array_klasses()).
>>
>> Some backgrounds:
>> https://preshing.com/20130922/acquire-and-release-fences/
>>
>> Thanks
>> - Ioi
>>
>>
>>
>> On 5/1/20 8:00 PM, Yumin Qi wrote:
>>> Dean,
>>>
>>> I have updated to use MutexLocker instead at same link:
>>> http://cr.openjdk.java.net/~minqi/8237750/webrev-01/
>>>
>>> Tested locally, passed jtreg/runtime.
>>>
>>> Thanks
>>> Yumin
>>>
>>> On 5/1/20 4:24 PM, Dean Long wrote:
>>>> OK, I didn't realize compute_fingerprint is using ZIP_CRC32.
>>>>
>>>> dl
>>>>
>>>> On 5/1/20 2:42 PM, Yumin Qi wrote:
>>>>> Hi, Dean
>>>>> Thanks for the review. I will try MutextLocker, for AOT, I think
>>>>> currently the tests are not using CDS then it will load classes
>>>>> from stream, that will use libzip's Crc32.
>>>>> I will check for AOT to see if it really loads libzip with the
>>>>> patch. For test compiler/aot/DeoptimizationTest.java:
>>>>>
>>>>> #0 ClassLoader::load_zip_library () at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/classfile/classLoader.cpp:978
>>>>>
>>>>> #1 0x00007ffff57d4693 in ClassLoader::crc32 (crc=0,
>>>>> buf=0x7ffff0244ee0 "\312\376\272\276", len=1888) at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/classfile/classLoader.cpp:1028
>>>>> #2 0x00007ffff57cef5d in ClassFileStream::compute_fingerprint
>>>>> (this=0x7ffff0245640) at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/classfile/classFileStream.cpp:80
>>>>> #3 0x00007ffff57c40ed in ClassFileParser::create_instance_klass
>>>>> (this=0x7ffff7fc6fc0, changed_by_loadhook=false, cl_inst_info=...,
>>>>> __the_thread__=0x7ffff0033000) at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/classfile/classFileParser.cpp:5630
>>>>> #4 0x00007ffff5dea647 in KlassFactory::create_from_stream
>>>>> (stream=0x7ffff0245640, name=0x7ffff40550f0,
>>>>> loader_data=0x7ffff022dbc0, cl_info=...,
>>>>> __the_thread__=0x7ffff0033000)
>>>>> at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/classfile/klassFactory.cpp:207
>>>>> #5 0x00007ffff57d53e4 in ClassLoader::load_class
>>>>> (name=0x7ffff40550f0, search_append_only=false,
>>>>> __the_thread__=0x7ffff0033000) at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/classfile/classLoader.cpp:1285
>>>>> #6 0x00007ffff6234fcf in SystemDictionary::load_instance_class
>>>>> (class_name=0x7ffff40550f0, class_loader=...,
>>>>> __the_thread__=0x7ffff0033000) at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/classfile/systemDictionary.cpp:1550
>>>>> #7 0x00007ffff6232d0a in
>>>>> SystemDictionary::resolve_instance_class_or_null
>>>>> (name=0x7ffff40550f0, class_loader=..., protection_domain=...,
>>>>> __the_thread__=0x7ffff0033000)
>>>>> at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/classfile/systemDictionary.cpp:882
>>>>> #8 0x00007ffff623137e in
>>>>> SystemDictionary::resolve_instance_class_or_null_helper
>>>>> (class_name=0x7ffff40550f0, class_loader=...,
>>>>> protection_domain=..., __the_thread__=0x7ffff0033000)
>>>>> at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/classfile/systemDictionary.cpp:302
>>>>> #9 0x00007ffff623124c in SystemDictionary::resolve_or_null
>>>>> (class_name=0x7ffff40550f0, class_loader=...,
>>>>> protection_domain=..., __the_thread__=0x7ffff0033000) at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/classfile/systemDictionary.cpp:285
>>>>> #10 0x00007ffff6230f57 in SystemDictionary::resolve_or_fail
>>>>> (class_name=0x7ffff40550f0, class_loader=...,
>>>>> protection_domain=..., throw_error=true,
>>>>> __the_thread__=0x7ffff0033000)
>>>>> at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/classfile/systemDictionary.cpp:233
>>>>> #11 0x00007ffff62311eb in SystemDictionary::resolve_or_fail
>>>>> (class_name=0x7ffff40550f0, throw_error=true,
>>>>> __the_thread__=0x7ffff0033000) at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/classfile/systemDictionary.cpp:275
>>>>> #12 0x00007ffff6236722 in SystemDictionary::resolve_wk_klass
>>>>> (id=SystemDictionary::Object_klass_knum,
>>>>> __the_thread__=0x7ffff0033000) at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/classfile/systemDictionary.cpp:2029
>>>>> #13 0x00007ffff623681e in
>>>>> SystemDictionary::resolve_wk_klasses_until
>>>>> (limit_id=SystemDictionary::Cloneable_klass_knum,
>>>>> start_id=@0x7ffff7fc79d4: SystemDictionary::Object_klass_knum,
>>>>> __the_thread__=0x7ffff0033000)
>>>>> at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/classfile/systemDictionary.cpp:2039
>>>>> #14 0x00007ffff623ac01 in
>>>>> SystemDictionary::resolve_wk_klasses_through
>>>>> (end_id=SystemDictionary::Class_klass_knum,
>>>>> start_id=@0x7ffff7fc79d4: SystemDictionary::Object_klass_knum,
>>>>> __the_thread__=0x7ffff0033000)
>>>>> at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/classfile/systemDictionary.hpp:418
>>>>> #15 0x00007ffff62369b0 in
>>>>> SystemDictionary::resolve_well_known_classes
>>>>> (__the_thread__=0x7ffff0033000) at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/classfile/systemDictionary.cpp:2082
>>>>> #16 0x00007ffff6236517 in SystemDictionary::initialize
>>>>> (__the_thread__=0x7ffff0033000) at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/classfile/systemDictionary.cpp:1985
>>>>> #17 0x00007ffff62afe15 in Universe::genesis
>>>>> (__the_thread__=0x7ffff0033000) at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/memory/universe.cpp:326
>>>>> #18 0x00007ffff62b1e51 in universe2_init () at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/memory/universe.cpp:847
>>>>> #19 0x00007ffff5af21ed in init_globals () at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/runtime/init.cpp:128
>>>>> #20 0x00007ffff627feff in Threads::create_vm (args=0x7ffff7fc7e50,
>>>>> canTryAgain=0x7ffff7fc7d5b) at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/runtime/thread.cpp:3879
>>>>> #21 0x00007ffff5bf537d in JNI_CreateJavaVM_inner
>>>>> (vm=0x7ffff7fc7ea8, penv=0x7ffff7fc7eb0, args=0x7ffff7fc7e50) at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/prims/jni.cpp:3789
>>>>> #22 0x00007ffff5bf5677 in JNI_CreateJavaVM (vm=0x7ffff7fc7ea8,
>>>>> penv=0x7ffff7fc7eb0, args=0x7ffff7fc7e50) at
>>>>> /home/minqi/ws/jdk15/jdk/src/hotspot/share/prims/jni.cpp:3872
>>>>> #23 0x00007ffff7bca4c9 in InitializeJVM (pvm=0x7ffff7fc7ea8,
>>>>> penv=0x7ffff7fc7eb0, ifn=0x7ffff7fc7f00) at
>>>>> /home/minqi/ws/jdk15/jdk/src/java.base/share/native/libjli/java.c:1538
>>>>>
>>>>> #24 0x00007ffff7bc70b5 in JavaMain (_args=0x7fffffffab10) at
>>>>> /home/minqi/ws/jdk15/jdk/src/java.base/share/native/libjli/java.c:417
>>>>> #25 0x00007ffff7bceb5f in ThreadJavaMain (args=0x7fffffffab10) at
>>>>> /home/minqi/ws/jdk15/jdk/src/java.base/unix/native/libjli/java_md_solinux.c:734
>>>>>
>>>>> #26 0x00007ffff71c56ba in start_thread (arg=0x7ffff7fc8700) at
>>>>> pthread_create.c:333
>>>>> #27 0x00007ffff790041d in clone () at
>>>>> ../sysdeps/unix/sysv/linux/x86_64/clone.S:109
>>>>>
>>>>> This is not with CDS.
>>>>>
>>>>> Thanks
>>>>> Yumin
>>>>>
>>>>> On 5/1/20 2:11 PM, Dean Long wrote:
>>>>>> It looks like Zip_lock could be a MutexLocker instead of a
>>>>>> MonitorLocker.
>>>>>>
>>>>>> dl
>>>>>>
>>>>>> On 5/1/20 10:24 AM, Yumin Qi wrote:
>>>>>>> Hi, please review:
>>>>>>> bug 8237750: https://bugs.openjdk.java.net/browse/JDK-8237750
>>>>>>> webrev: http://cr.openjdk.java.net/~minqi/8237750/webrev-01/
>>>>>>> Summary:
>>>>>>> zip library is loaded unconditionally at start up but it is
>>>>>>> only needed when
>>>>>>> 1) bootclasspath contains zip or
>>>>>>> 2) UseAOT enabled or
>>>>>>> 3) VerifySharedArchive turned on or
>>>>>>> 4) CDS archives custom loaded classes
>>>>>>> If none of above in java application, it is not necessary to
>>>>>>> have zip library loaded.
>>>>>>>
>>>>>>> Solution by loading zip library on demand when needed.
>>>>>>>
>>>>>>> Performance for java -Xint version:
>>>>>>>
>>>>>>> Results of " perf stat -r 50 bin/java -Xshare:on
>>>>>>> -XX:SharedArchiveFile=jdk2.jsa -Xint -version "
>>>>>>> 1: 59611556 59450206 (-161350) ----- 39.799
>>>>>>> 40.274 ( 0.475) ++
>>>>>>> 2: 59602708 59425234 (-177474) ----- 40.591
>>>>>>> 41.183 ( 0.592) ++
>>>>>>> 3: 59579718 59441272 (-138446) ---- 40.777 40.471
>>>>>>> ( -0.306) -
>>>>>>> 4: 59584882 59410155 (-174727) ----- 40.824
>>>>>>> 40.233 ( -0.591) --
>>>>>>> 5: 59590998 59447252 (-143746) ---- 40.400 40.493
>>>>>>> ( 0.093)
>>>>>>> 6: 59589523 59441934 (-147589) ---- 40.475 40.064
>>>>>>> ( -0.411) --
>>>>>>> 7: 59581820 59413612 (-168208) ----- 39.763
>>>>>>> 40.077 ( 0.314) +
>>>>>>> 8: 59593678 59418738 (-174940) ----- 40.912
>>>>>>> 39.724 ( -1.188) -----
>>>>>>> 9: 59573058 59412554 (-160504) ----- 40.126
>>>>>>> 40.033 ( -0.093)
>>>>>>> 10: 59591469 59419291 (-172178) ----- 40.731
>>>>>>> 40.689 ( -0.042)
>>>>>>> ============================================================
>>>>>>> 59589940 59428022 (-161917) ----- 40.438
>>>>>>> 40.322 ( -0.116)
>>>>>>> instr delta = -161917 -0.2717%
>>>>>>> time delta = -0.116 ms -0.2859%
>>>>>>>
>>>>>>> Tests: hs-tier1-4.
>>>>>>> Due to zip library not loaded at default, I removed 'zip' from
>>>>>>> pmap list in test case:
>>>>>>> *test/hotspot/jtreg/serviceability/sa/ClhsdbPmap.java
>>>>>>>
>>>>>>> **
>>>>>>> * Thanks
>>>>>>> Yumin
>>>>>>
>>>>>
>>>>
>>>
>>
>
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