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Re: [rvm-research] to utilize methods in syscall
by Robin Garner
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Liangliang Tong wrote:
> Dear all,
>
> In org.mmtk.plan.generational.Gen.java, I want to modify the vmRequest
> to request for an explicit region of memory, like the following:
> private static final VMRequest vmRequest =
> VMRequest.create(sysCall.sysMalloc(1 << 20), Extent.fromIntSignExtend(1
> << 20));
> correspondingly I add a new import statement:
> import static org.jikesrvm.runtime.SysCall.sysCall;
>
> Yet when I complied the generational copy plan, it prompts these errors:
> compile-mmtk:
> [javac] Compiling 1 source file to
> /home/lltong/jikesrvm/target/mmtk/classes
> [javac]
> /home/lltong/jikesrvm/MMTk/src/org/mmtk/plan/crgenerational/CRGen.java:33:
> package org.jikesrvm.runtime does not exist
> [javac] import static org.jikesrvm.runtime.SysCall.sysCall;
> [javac] ^
> [javac]
> /home/lltong/jikesrvm/MMTk/src/org/mmtk/plan/crgenerational/CRGen.java:33:
> static import only from classes and interfaces
> [javac] import static org.jikesrvm.runtime.SysCall.sysCall;
> [javac] ^
> [javac]
> /home/lltong/jikesrvm/MMTk/src/org/mmtk/plan/crgenerational/CRGen.java:91:
> cannot find symbol
> [javac] symbol : variable sysCall
> [javac] location: class org.mmtk.plan.crgenerational.CRGen
>
> Why should this happen? Thanks in advance.
>
>Hi Liangliang,
As far as I can see, you are trying to request a 1MB chunk of memory,
and you don't care where in the heap it is. Is this right ?
MMTk uses the 'Space' class to abstract over various ways to allocate
memory. If you simply want a 1MB chunk of raw memory, then you can do
RawPageSpace mySpace = new RawPageSpace("mySpace", Integer.MAX_VALUE,
VMRequest.create());
Address chunkAddr = mySpace.acquire(1<<(20-LOG_BYTES_IN_PAGE));
If you're using memory as storage for your collector, you should
probably allocate it in the existing metaDataSpace. If you're
allocating it to give to the mutator, you should probably define a new
space for it.
Note that a VMRequest is simply a way to communicate your virtual memory
layout requirements to the Space class, and passing it a chunk of
'malloc'ed memory doesn't make a great deal of sense. In fact MMTk
itself generally takes the place of 'malloc' in the virtual machine.
The reason you can't directly call sysMalloc from MMTk is that MMTk
separates itself from JikesRVM (and its various other host environments)
via the org.mmtk.vm package (the VM interface). In order to call a new
method on the JikesRVM side of the fence you need to:
- Choose an interface class to host the method (eg org.mmtk.vm.Memory)
- Add an abstract method to the interface class
- Add a concrete method to the implementation on the VM side of the
fence (for JikesRVM that is org.jikesrvm.mm.mmtk, in the
MMTk/ext/vm/jikesrvm directory)
but I think it would generally be a bad idea for you to allocate memory
for JikesRVM using sysMalloc.
Regards,
Robin
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> Dear all,
>
> In org.mmtk.plan.generational.Gen.java, I want to modify the vmRequest
> to request for an explicit region of memory, like the following:
> private static final VMRequest vmRequest =
> VMRequest.create(sysCall.sysMalloc(1 << 20), Extent.fromIntSignExtend(1
> << 20));
> correspondingly I add a new import statement:
> import static org.jikesrvm.runtime.SysCall.sysCall;
>
> Yet when I complied the generational copy plan, it prompts these errors:
> compile-mmtk:
> [javac] Compiling 1 source file to
> /home/lltong/jikesrvm/target/mmtk/classes
> [javac]
> /home/lltong/jikesrvm/MMTk/src/org/mmtk/plan/crgenerational/CRGen.java:33:
> package org.jikesrvm.runtime does not exist
> [javac] import static org.jikesrvm.runtime.SysCall.sysCall;
> [javac] ^
> [javac]
> /home/lltong/jikesrvm/MMTk/src/org/mmtk/plan/crgenerational/CRGen.java:33:
> static import only from classes and interfaces
> [javac] import static org.jikesrvm.runtime.SysCall.sysCall;
> [javac] ^
> [javac]
> /home/lltong/jikesrvm/MMTk/src/org/mmtk/plan/crgenerational/CRGen.java:91:
> cannot find symbol
> [javac] symbol : variable sysCall
> [javac] location: class org.mmtk.plan.crgenerational.CRGen
>
> Why should this happen? Thanks in advance.
>
>
As far as I can see, you are trying to request a 1MB chunk of memory,
and you don't care where in the heap it is. Is this right ?
MMTk uses the 'Space' class to abstract over various ways to allocate
memory. If you simply want a 1MB chunk of raw memory, then you can do
RawPageSpace mySpace = new RawPageSpace("mySpace", Integer.MAX_VALUE,
VMRequest.create());
Address chunkAddr = mySpace.acquire(1<<(20-LOG_BYTES_IN_PAGE));
If you're using memory as storage for your collector, you should
probably allocate it in the existing metaDataSpace. If you're
allocating it to give to the mutator, you should probably define a new
space for it.
Note that a VMRequest is simply a way to communicate your virtual memory
layout requirements to the Space class, and passing it a chunk of
'malloc'ed memory doesn't make a great deal of sense. In fact MMTk
itself generally takes the place of 'malloc' in the virtual machine.
The reason you can't directly call sysMalloc from MMTk is that MMTk
separates itself from JikesRVM (and its various other host environments)
via the org.mmtk.vm package (the VM interface). In order to call a new
method on the JikesRVM side of the fence you need to:
- Choose an interface class to host the method (eg org.mmtk.vm.Memory)
- Add an abstract method to the interface class
- Add a concrete method to the implementation on the VM side of the
fence (for JikesRVM that is org.jikesrvm.mm.mmtk, in the
MMTk/ext/vm/jikesrvm directory)
but I think it would generally be a bad idea for you to allocate memory
for JikesRVM using sysMalloc.
Regards,
Robin
------------------------------------------------------------------------------
Crystal Reports - New Free Runtime and 30 Day Trial
Check out the new simplified licensing option that enables unlimited
royalty-free distribution of the report engine for externally facing
server and web deployment.
http://p.sf.net/sfu/businessobjects
_______________________________________________
Jikesrvm-researchers mailing list
Jikesrvm-researchers@...
https://lists.sourceforge.net/lists/listinfo/jikesrvm-researchers
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