RFR(L): 8031581: PPC64: Addons and fixes for AIX to pass the jdk regression tests

David Holmes david.holmes at oracle.com
Tue Jan 14 11:29:48 UTC 2014

Just a note on this part (I havent looked at the code):

> On AIX, the constants used for the polling events (i.e. POLLIN, POLLOUT, ...) are defined to different values than on other operating systems. The problem is however, that these constants are hardcoded as public final static members of various, shared Java classes.

Sounds like this should be handled the same way that the other "system 
constants" are handled - you can either store a platform file in the 
repo (for cross-compiling) or you generate the class containing the 
constants at build time.


On 14/01/2014 6:40 PM, Volker Simonis wrote:
> Hi,
> could you please review the following changes for the ppc-aix-port
> stage/stage-9 repositories (the changes are planned for integration into
> ppc-aix-port/stage-9 and subsequent backporting to ppc-aix-port/stage):
> http://cr.openjdk.java.net/~simonis/webrevs/8031581/
> I've build and smoke tested without any problems on Linux/x86_64 and
> PPC64, Windows/x86_64, MacOSX, Solaris/SPARC64 and AIX7PPC64.
> With these changes (and together with the changes from "8028537: PPC64:
> Updated jdk/test scripts to understand the AIX os and environment" and
> "8031134 : PPC64: implement printing on AIX") our port passes all but
> the following 7 jtreg regression tests on AIX (compared to the
> Linux/x86_64 baseline from
> www.java.net/download/jdk8/testresults/testresults.html
> <http://www.java.net/download/jdk8/testresults/testresults.html>‎):
> java/net/Inet6Address/B6558853.java
> java/nio/channels/AsynchronousChannelGroup/Basic.java (sporadically)
> java/nio/channels/AsynchronousChannelGroup/GroupOfOne.java
> java/nio/channels/AsynchronousChannelGroup/Unbounded.java (sporadically)
> java/nio/channels/Selector/RacyDeregister.java
> sun/security/krb5/auto/Unreachable.java (only on IPv6)
> Thank you and best regards,
> Volker
> Following a detailed description of the various changes:
>         src/share/native/java/util/zip/zip_util.c
>         src/share/native/sun/management/DiagnosticCommandImpl.c
>   * According to ISO C it is perfectly legal for malloc to return zero
>     if called with a zero argument. Fix various places where malloc can
>     potentially correctly return zero because it was called with a zero
>     argument.
>   * Also fixed |DiagnosticCommandImpl.c| to include |stdlib.h|. This
>     only fixes a compiler warning on Linux, but on AIX it prevents a VM
>     crash later on because the return value of |malloc()| will be casted
>     to |int| which is especially bad if that pointer was bigger than
>     32-bit.
>         make/CompileJavaClasses.gmk
>   * Also use |PollingWatchService| on AIX.
>         make/lib/NioLibraries.gmk
>         src/aix/native/sun/nio/ch/AixNativeThread.c
>   * Put the implementation for the native methods of |NativeThread| into
>     |AixNativeThread.c| on AIX.
>         src/solaris/native/sun/nio/ch/PollArrayWrapper.c
>         src/solaris/native/sun/nio/ch/Net.c
>         src/aix/classes/sun/nio/ch/AixPollPort.java
>         src/aix/native/sun/nio/ch/AixPollPort.c
>         src/aix/native/java/net/aix_close.c
>   * On AIX, the constants used for the polling events (i.e. |POLLIN|,
>     |POLLOUT|, ...) are defined to different values than on other
>     operating systems. The problem is however, that these constants are
>     hardcoded as public final static members of various, shared Java
>     classes. We therefore have to map them from Java to native every
>     time before calling one of the native poll functions and back to
>     Java after the call on AIX in order to get the right semantics.
>         src/share/classes/java/nio/file/CopyMoveHelper.java
>   * As discussed on the core-libs mailing list (see
>     http://mail.openjdk.java.net/pipermail/core-libs-dev/2013-December/024119.html)
>     it is not necessary to call |Files.getFileAttributeView()| with any
>     |linkOptions| because at that place we've already checked that the
>     target file can not be a symbolic link. This change makes the
>     implementation more robust on platforms which support symbolic links
>     but do not support the |O_NOFOLLOW| flag to the |open| system call.
>     It also makes the JDK pass the |demo/zipfs/basic.sh| test on AIX.
>         src/share/classes/sun/nio/cs/ext/ExtendedCharsets.java
>   * Support "compound text" on AIX in the same way like on other Unix
>     platforms.
>         src/share/classes/sun/tools/attach/META-INF/services/com.sun.tools.attach.spi.AttachProvider
>   * Define the correct attach provider for AIX.
>         src/solaris/native/java/net/net_util_md.h
>         src/solaris/native/sun/nio/ch/FileDispatcherImpl.c
>         src/solaris/native/sun/nio/ch/ServerSocketChannelImpl.c
>   * AIX needs a workaround for I/O cancellation (see:
>     http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.basetechref/doc/basetrf1/close.htm).
>     "..The |close()| subroutine is blocked until all subroutines which
>     use the file descriptor return to usr space. For example, when a
>     thread is calling close and another thread is calling select with
>     the same file descriptor, the close subroutine does not return until
>     the select call returns...". To fix this problem, we have to use the
>     various |NET_| wrappers which are declared in |net_util_md.h| and
>     defined in |aix_close.c| and we also need some additional wrappers
>     for |fcntl()|, |read()| and |write()| on AIX.
>     While the current solution isn't really nice because it introduces
>     some more AIX-specifc sections in shared code, I think it is the
>     best way to go for JDK 8 because it imposes the smallest possible
>     changes and risks for the existing platforms. I'm ready to change
>     the code to unconditionally use the wrappers for all platforms and
>     implement the wrappers empty on platforms which don't need any
>     wrapping. I think it would also be nice to clean up the names (e.g.
>     |NET_Read()| is currently a wrapper for |recv()| and the |NET_|
>     prefix is probably not appropriate any more so maybe change it to
>     something like |IO_|). But again, I'll prefer to keep that as a
>     follow up change for JDK9.
>   * Calling |fsync()| on a "read-only" file descriptor on AIX will
>     result in an error (i.e. "EBADF: The FileDescriptor parameter is not
>     a valid file descriptor open for writing."). To prevent this error
>     we have to query if the corresponding file descriptor is writeable.
>     Notice that at that point we can not access the |writable| attribute
>     of the corresponding file channel so we have to use |fcntl()|.
>         src/solaris/classes/java/lang/UNIXProcess.java.aix
>   * On AIX the implementation is especially tricky, because the
>     |close()| system call will block if another thread is at the same
>     time blocked in a file operation (e.g. 'read()') on the same file
>     descriptor. We therefore combine the AIX |ProcessPipeInputStream|
>     implemenatation with the |DeferredCloseInputStream| approach used on
>     Solaris (see |UNIXProcess.java.solaris|). This means that every
>     potentially blocking operation on the file descriptor increments a
>     counter before it is executed and decrements it once it finishes.
>     The 'close()' operation will only be executed if there are no
>     pending operations. Otherwise it is deferred after the last pending
>     operation has finished.
>         src/share/transport/socket/socketTransport.c
>   * On AIX we have to call |shutdown()| on a socket descriptor before
>     closing it, otherwise the |close()| call may be blocked. This is the
>     same problem as described before. Unfortunately the JDI framework
>     doesn't use the same IO wrappers like other class library components
>     so we can not easily use the |NET_| abstractions from |aix_close.c|
>     here.
>   * Without this small change all JDI regression tests will fail on AIX
>     because of the way how the tests act as a "debugger" which launches
>     another VM (the "debugge") which connects itself back to the
>     debugger. In this scenario the "debugge" can not shut down itself
>     because one thread will always be blocked in the |close()| call on
>     one of the communication sockets.
>         src/solaris/native/java/net/NetworkInterface.c
>   * Set the scope identifier for IPv6 addresses on AIX.
>         src/solaris/native/java/net/net_util_md.c
>   * It turns out that we do not always have to replace |SO_REUSEADDR| on
>     AIX by |SO_REUSEPORT|. Instead we can simply use the same approach
>     like BSD and only use |SO_REUSEPORT| additionally, if several
>     datagram sockets try to bind to the same port.
>   * Also fixed a comment and removed unused local variables.
>   * Fixed the obviously inverted assignment |newTime = prevTime;| which
>     should read |prevTime = newTime;|. Otherwise |prevTime| will never
>     change and the timeout will be potential reached too fast.
>         src/solaris/native/sun/management/OperatingSystemImpl.c
>   * AIX does not understand |/proc/self| so we have to query the real
>     process ID to access the proc file system.
>         src/solaris/native/sun/nio/ch/DatagramChannelImpl.c
>   * On AIX, |connect()| may legally return |EAFNOSUPPORT| if called on a
>     socket with the address family set to |AF_UNSPEC|.

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