RFR(M): 8144847: PPC64: Update Transactional Memory and Atomic::cmpxchg code

[Thomas Stüfe]

Hi Martin,

thanks for this addition :)

It may make a lot of sense to rebase this change to hs-rt, because
os_aix.cpp is quite different there after
http://hg.openjdk.java.net/jdk9/hs-rt/hotspot/rev/ce87b1141c12. Otherwise
we may have problems later applying your change atop of my change.

-------------

About the AIX kernel version recognition: I know we talked about this, but
I have second thoughts now. I guess I did not think it really through
before, sorry.
So, now I have a change request:

Instead of introducing os::Aix::os_kernel_version
(version,release,techlevel,sp) beside the already existing
os::Aix::os_version (version,release) I would prefer just one parameter,
os_version, end enriching this by techlevel and sp. So, exactly what you
did for os_kernel_version.

Basically, as a prototype:

// -1 = uninitialized, otherwise 32 bit number:
//  0xVVRRTTSS
//  VV - major version
//  RR - minor version
//  TT - tech level, if known, 0 otherwise
//  SS - service pack, if known, 0 otherwise
static uint32_t os_version ();

Then please change the few users of os::Aix::os_version() to now expect a
32bit unsigned number. As far as I see there are only 3 callsites.

-------------------

Other small nitpicks:

- in libodm_aix.cpp, please use trcVerbose() instead of if (Verbose)
tty->.. . Please include misc_aix.hpp for trcVerbose(). We will change all
those tracecalls to Unified logging in the near future and this would help
me finding all trace occurrences.

- please move ~dynamicOdm() and odmWrapper::clean_wrapper() from
libodm_aix.hpp to libodm_aix.cpp and accordingly remove the includes
dlfcn.h and stdlib.h from libodm_aix.hpp.

- I probably would change "static unsigned int
determine_os_kernel_version(int major_aix_version, int minor_aix_version);"
to " "static bool fill_in_os_kernel_version(unsigned int* p_os_version);",
but that is just a matter of taste.

Kind Regards, Thomas


On Mon, Dec 7, 2015 at 6:10 PM, Doerr, Martin <martin.doerr at sap.com> wrote:

> Hi,
>
>
>
> I have created a webrev for further PPC64 updates:
>
> AIX supports Transactional Memory with a certain kernel patch level. Add a
> detection for it and make UseRTMLocking usable on AIX.
> In addition, implement Atomic::cmpxchg for jbyte.
>
>
>
> The webrev is here:
>
> http://cr.openjdk.java.net/~mdoerr/8144847_ppc_updates/webrev.00/
>
>
>
> Please review.
>
>
>
> Best regards,
>
>   Martin
>
>
>
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