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

[David Holmes]

On 3/08/2018 4:59 PM, Baesken, Matthias wrote:
> 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 😊 )

Need a review from official build team member :)

Cheers,
David

> 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
>>>>>