configuring with --with-jvm-variants=minimal,server makes cds disappear in server

[Erik Joelsson]

On 2020-01-16 10:48, Ioi Lam wrote:
>
>
> On 1/16/20 9:09 AM, Erik Joelsson wrote:
>> I would lean towards changing the check from "if any of the variants 
>> do not support CDS, disable it" to "if any of the variants support 
>> CDS, enable it". The cds jvm feature is only added to the variants 
>> that support it anyway.
>>
>> If you do this, you probably need to figure out how to explicitly 
>> only generate the archive for the supported jvm variants in 
>> Images.gmk too. Not sure if the archive is jvm variant dependent or 
>> if the layout even supports multiple variants. It will likely get messy.
>
> The CDS archive is dependent on the exact libjvm.so, so each JDK image 
> should creates its own CDS archive during the build.
>
> I think this can be handled emitting a different value for 
> "BUILD_CDS_ARCHIVE" in the spec.gmk of each variant.
>
Building with multiple JVM variants does not create separate JDK images, 
the libjvm.so files simply end up in:

lib/server/libjvm.so
lib/minimal/libjvm.so

I don't think the default archive takes that into account.

/Erik

> Thanks
> - Ioi
>
>>
>> /Erik
>>
>> On 2020-01-16 08:22, Baesken, Matthias wrote:
>>> Hello, thanks for looking into it .
>>> Should I do a check just looking into single JVM configs, something 
>>> like
>>>
>>> AC_DEFUN([HOTSPOT_IS_JVM_VARIANT],
>>> [ [ [[ " $JVM_VARIANTS " == " $1 " ]] ] ])
>>>
>>> if HOTSPOT_IS_JVM_VARIANT(zero) || HOTSPOT_IS_JVM_VARIANT(minimal) 
>>> || HOTSPOT_IS_JVM_VARIANT(core); then
>>>
>>> instead of
>>>
>>> AC_DEFUN([HOTSPOT_CHECK_JVM_VARIANT],
>>> [ [ [[ " $JVM_VARIANTS " =~ " $1 " ]] ] ])
>>>
>>> if HOTSPOT_CHECK_JVM_VARIANT(zero) || 
>>> HOTSPOT_CHECK_JVM_VARIANT(minimal) || 
>>> HOTSPOT_CHECK_JVM_VARIANT(core); then
>>>
>>>
>>> This should  remove the error in case of multi-JVM configs .
>>> Or maybe  the whole check ( if HOTSPOT_CHECK_JVM_VARIANT(zero) ||  
>>> HOTSPOT_CHECK_JVM_VARIANT(minimal) || 
>>> HOTSPOT_CHECK_JVM_VARIANT(core); then .... fi )
>>>   might be removed , I see not so much value in it  because in case 
>>> one sets --enable-jvm-features   directly the check isn’t done .
>>>
>>> I opened  bug :
>>>
>>> https://bugs.openjdk.java.net/browse/JDK-8237374
>>>
>>> JDK-8237374 :  configuring with --with-jvm-variants=minimal,server 
>>> makes cds disappear in server
>>>
>>>
>>> Best regards, Matthias
>>>
>>>
>>>
>>>
>>>> This does indeed look like a bug to me. At least at Oracle, we no 
>>>> longer
>>>> build any multi JVM configs regularly, so things like this falls 
>>>> through
>>>> the cracks.
>>>>
>>>> /Erik
>>>>
>>>> On 2020-01-16 02:18, Baesken, Matthias wrote:
>>>>> Hello, I noticed the following strange "feature" (or is it a bug?) .
>>>>> When  building 2 VM variants in one build  and  using
>>>>>
>>>>>     --with-jvm-variants=minimal,server
>>>>>
>>>>> For this, the build works nicely. But I notice that  in the server 
>>>>> VM, cds  is
>>>> removed.
>>>>> Instead of
>>>>>
>>>>> checking if cds should be enabled... yes
>>>>>
>>>>> I get ( with the following patch that adds tracing)  :
>>>>>
>>>>> configure: WARNING: ENABLE_CDS set to false because we found a
>>>> minimal, core or zero JVM.
>>>>> checking if cds should be enabled... no
>>>>>     ...
>>>>>
>>>>> * JVM features:   minimal: 'compiler1 minimal serialgc'       
>>>>> server: 'compiler1
>>>> compiler2 epsilongc g1gc jfr jni-check jvmti management nmt parallelgc
>>>> serialgc services vm-structs'
>>>>> (patch is
>>>>>
>>>>> --- a/make/autoconf/hotspot.m4  Wed Jan 15 21:20:40 2020 -0800
>>>>> +++ b/make/autoconf/hotspot.m4  Thu Jan 16 10:24:43 2020 +0100
>>>>> @@ -528,6 +528,7 @@
>>>>>     if HOTSPOT_CHECK_JVM_VARIANT(zero) ||
>>>> HOTSPOT_CHECK_JVM_VARIANT(minimal) ||
>>>> HOTSPOT_CHECK_JVM_VARIANT(core); then
>>>>>        # ..except when the user explicitely requested it with 
>>>>> --enable-jvm-
>>>> features
>>>>>        if ! HOTSPOT_CHECK_JVM_FEATURE(cds); then
>>>>>          ENABLE_CDS="false"
>>>>> +      AC_MSG_WARN([ENABLE_CDS set to false because we found a
>>>> minimal, core or zero JVM.])
>>>>>          if test "x$enable_cds" = "xyes"; then
>>>>>            AC_MSG_ERROR([CDS not implemented for variants zero, 
>>>>> minimal,
>>>> core. Remove --enable-cds.])
>>>>>          Fi
>>>>>
>>>>>
>>>>> Is it expected that  cds goes away in "server"   when configuring  
>>>>> "--with-
>>>> jvm-variants=minimal,server"   ?   Looks like a bug to me, should 
>>>> it be fixed
>>>> (so that cds stays in the server   jvm-feature list) ?
>>>>>
>>>>> Thanks, Matthias
>>>>>
>