(S) 8237750: Load libzip.so only if necessary
Calvin Cheung
calvin.cheung at oracle.com
Tue May 5 19:18:15 UTC 2020
On 5/5/20 10:59 AM, Ioi Lam wrote:
> 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.
How about putting the function in classloader.inline.hpp which already
includes runtime/atomic.hpp?
thanks,
Calvin
>
> 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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