RFR [XS]: 8208744: remove unneeded -DUSE_MMAP settings for JDK native libs builds -was : RE: unneeded -DUSE_MMAP in JDK native libs builds

[Baesken, Matthias]

Thank  you  David ,  can the change be pushed ,  or do I need a second review for an XS change  ?
(any way a second review would be good 😊 )

Best regards, Matthias



> -----Original Message-----
> From: David Holmes <david.holmes at oracle.com>
> Sent: Freitag, 3. August 2018 08:18
> To: Baesken, Matthias <matthias.baesken at sap.com>; Magnus Ihse Bursie
> <magnus.ihse.bursie at oracle.com>
> Cc: build-dev at openjdk.java.net
> Subject: Re: RFR [XS]: 8208744: remove unneeded -DUSE_MMAP settings for
> JDK native libs builds -was : RE: unneeded -DUSE_MMAP in JDK native libs
> builds
> 
> Looks fine to me.
> 
> Thanks,
> David
> 
> On 3/08/2018 4:13 PM, Baesken, Matthias wrote:
> > Hello,  I can confirm what David said .
> > Additionally I grepped through /usr/include on my Linux machine and did
> not  find any  USE_MMAP occurences.
> >
> > I created this  webrev +  bug :
> >
> > http://cr.openjdk.java.net/~mbaesken/webrevs/8208744/
> >
> > https://bugs.openjdk.java.net/browse/JDK-8208744
> >
> >
> > Please review !
> >
> >
> > Thanks, Matthias
> >
> >
> >> -----Original Message-----
> >> From: David Holmes <david.holmes at oracle.com>
> >> Sent: Freitag, 3. August 2018 02:56
> >> To: Magnus Ihse Bursie <magnus.ihse.bursie at oracle.com>; Baesken,
> >> Matthias <matthias.baesken at sap.com>
> >> Cc: build-dev at openjdk.java.net
> >> Subject: Re: unneeded -DUSE_MMAP in JDK native libs builds
> >>
> >> On 3/08/2018 3:44 AM, Magnus Ihse Bursie wrote:
> >>>
> >>>> 2 aug. 2018 kl. 05:33 skrev Baesken, Matthias
> >> <matthias.baesken at sap.com>:
> >>>>
> >>>> Hello I noticed that   -DUSE_MMAP  is set for these  JDK native libs, but
> I
> >> cannot find it in the code   (for libzip it is different there the flag shows up
> in
> >> the code too ) :
> >>>
> >>> I've always assumed that this was used to control the behavior in some
> >> imported header files. Have you verified that this is not the case?
> >>
> >> It is only used in
> >>
> >> ./java.base/share/native/libzip/zip_util.c
> >> ./java.base/share/native/libzip/zip_util.h
> >>
> >> and the header itself is only included in the .c file. So unless this
> >> source file is used for the other libraries (which I don't see) then we
> >> don't need -DUSE_MMAP when building them.
> >>
> >> AFAIKS the use of this for BUILD_LIBDT_SOCKET and
> BUILD_LIBDT_SHMEM
> >> dates back to the build-infra changes in JDK 8.
> >>
> >> http://hg.openjdk.java.net/jdk8/jdk8/jdk/rev/9d3d01aca52c
> >>
> >> But I can't see why it was introduced there.
> >>
> >> In JDK 7 it's only applied to the zip library.
> >>
> >> Cheers,
> >> David
> >> -----
> >>
> >>>
> >>> /Magnus
> >>>
> >>>>
> >>>> Lib-jdk.jdi.gmk  :
> >>>>
> >>>> 32  $(eval $(call SetupJdkLibrary, BUILD_LIBDT_SHMEM, \
> >>>> ......
> >>>> 35 CFLAGS := $(CFLAGS_JDKLIB) -DUSE_MMAP, \
> >>>>
> >>>>
> >>>> Lib-jdk.jdwp.agent.gmk :
> >>>>
> >>>> 30 $(eval $(call SetupJdkLibrary, BUILD_LIBDT_SOCKET, \
> >>>> ......
> >>>> 33 CFLAGS := $(CFLAGS_JDKLIB) -DUSE_MMAP \
> >>>>
> >>>>
> >>>> Any objections  to remove those  2    -DUSE_MMAP    settings ?
> >>>> If it is fine to remove I would prepare a  webrev .
> >>>>
> >>>> Thanks, Matthias
> >>>