<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Hi Roman,</div><div><br>On 25 Oct 2017, at 17:54, Roman Kennke <<a href="mailto:rkennke@redhat.com">rkennke@redhat.com</a>> wrote:<br><br></div><blockquote type="cite"><div>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<div class="moz-cite-prefix">Hi Erik,<br>
<br>
thank you for your suggestions and changes.<br>
<br>
I like it: if you look at webrev.00 you will notice that my
original proposal had both the static stuff and the virtual stuff
in the same class too. So from there it's mostly the renaming
exercise :-)<br></div></div></blockquote><div><br></div><div>Yeah. Sounds like we are aligned.</div><br><blockquote type="cite"><div><div class="moz-cite-prefix">
So let me just put your changes up for review (again), if you
don't mind:<br>
<br>
Full webrev:
<br>
<a moz-do-not-send="true" href="http://cr.openjdk.java.net/%7Eeosterlund/8189171/webrev.03/">http://cr.openjdk.java.net/~eosterlund/8189171/webrev.03/
</a><br>
<br>
Incremental over webrev.02:
<br>
<a moz-do-not-send="true" href="http://cr.openjdk.java.net/%7Eeosterlund/8189171/webrev.02_03/">
http://cr.openjdk.java.net/~eosterlund/8189171/webrev.02_03/
</a><br>
<br>
So I suppose we can count it by reviewed ok by you?<br></div></div></blockquote><div><br></div><div>Yes. Looks fantastic.</div><br><blockquote type="cite"><div><div class="moz-cite-prefix">
Then it requires one more review to go in, right?<br></div></div></blockquote><div><br></div><div>Yup.</div><div><br></div><div>Thanks,</div><div>/Erik</div><br><blockquote type="cite"><div><div class="moz-cite-prefix">
Thanks, Roman<br>
<br>
<br>
</div>
<blockquote type="cite" cite="mid:59F0AD40.3020307@oracle.com">Hi
Roman,
<br>
<br>
Definitely looks better. So the static GCArgumentProcessor has a
singleton GCCollectedHeapFactory that is created during
GCArgumentProcessor::initialize().
<br>
That makes sense to me, but I think it can be even better.
<br>
<br>
First off - sorry for bikeshedding a bit here.
<br>
<br>
To save you from having to update the code due to my bikeshedding,
I have prepared a patch to show you what I meant, and you can tell
me whether you agree or not.
<br>
<br>
Full webrev:
<br>
<a class="moz-txt-link-freetext" href="http://cr.openjdk.java.net/~eosterlund/8189171/webrev.03/">http://cr.openjdk.java.net/~eosterlund/8189171/webrev.03/</a>
<br>
<br>
Incremental over yours:
<br>
<a class="moz-txt-link-freetext" href="http://cr.openjdk.java.net/~eosterlund/8189171/webrev.02_03/">http://cr.openjdk.java.net/~eosterlund/8189171/webrev.02_03/</a>
<br>
<br>
My changes are the following:
<br>
<br>
I collapsed the all-static GCArgumentProcessor and the
CollectedHeapFactory into the same class called GCArguments (the
natural GC helper for Arguments). It's a singleton object that
deals with GC arguments stuff.
<br>
<br>
GCArguments has some static functions to create_instance(),
creating the singleton GCArguments object, and after you have
created the singleton instance, you access it through
GCArguments::instance(), and it will point to a GC-specific
GCArguments, e.g. G1Arguments, CMSArguments, etc.
<br>
<br>
The main reason why I think it's better to have a GC-specific
GCArguments class compared to a CollectedHeapFactory class, is
that I would like to eventually move all arguments processing into
the GCArguments class, regardless of where (before or after
CollectedHeap exists) in the boot strapping process. For example,
today some argument stuff is dumped in the arguments.cpp file, and
other stuff is dumped in CollectorPolicy::initialize_flags which
is called later when the heap exists where it seemingly reads
values out from flags, into internal variables, then changes them
to what they should be and write the values back to the flags, and
subsequently asserts that the internal and flag variants have the
same value. Seems to me like we could in a subsequent refactoring
move some of that kind of stuff into GCArguments instead, so that
the argument setting logic is contained in the same class rather
than split all over the place. But that seems like a separate RFE.
<br>
<br>
Other than that, noticed some precompile header include was
missing, the GCArgumentProcessor::initialize() function returned
jint but it always returned JNI_OK, and called fatal() if
something went wrong, instead of logging an error and returning
JNI_ERR. And now that these types are collapsed, I moved
initialize_flags_global into the abstract initial_flags, allowing
GCs to override it completely if necessary, but in practice having
them now call the super initial_flags(). So yeah, went ahead and
fixed that for you.
<br>
<br>
As for your subsequent patch creating the heap, that will just be
a virtual call into the specific GCArguments class.
<br>
<br>
I hope you agree with my proposal. It seemed easier for me to
provide a patch describing what I'm thinking than to write it down
in text.
<br>
<br>
Thanks,
<br>
/Erik
<br>
<br>
On 2017-10-23 17:19, Roman Kennke wrote:
<br>
<blockquote type="cite">Hi Erik,
<br>
<br>
thanks for your suggestions. So I renamed 'GC' ->
'CollectedHeapFactory' (and subclasses likewise) and 'GCFactory'
to 'GCArgumentProcessor'. This will make even more sense once I
added heap creation to CollectedHeapFactory (JDK-8189389).
<br>
<br>
Differential:
<br>
<a class="moz-txt-link-freetext" href="http://cr.openjdk.java.net/~rkennke/8189171/webrev.02.diff/">http://cr.openjdk.java.net/~rkennke/8189171/webrev.02.diff/</a>
<a class="moz-txt-link-rfc2396E" href="http://cr.openjdk.java.net/%7Erkennke/8189171/webrev.02.diff/"><http://cr.openjdk.java.net/%7Erkennke/8189171/webrev.02.diff/></a>
<br>
<br>
Full webrev:
<br>
<a class="moz-txt-link-freetext" href="http://cr.openjdk.java.net/~rkennke/8189171/webrev.02/">http://cr.openjdk.java.net/~rkennke/8189171/webrev.02/</a>
<a class="moz-txt-link-rfc2396E" href="http://cr.openjdk.java.net/%7Erkennke/8189171/webrev.02/"><http://cr.openjdk.java.net/%7Erkennke/8189171/webrev.02/></a>
<br>
<br>
Better?
<br>
<br>
Roman
<br>
<br>
<blockquote type="cite">Hi Roman,
<br>
<br>
I'm usually not one to really mind names too much, but I don't
believe some bootstrapping code for the GC should hog the name
"GC".
<br>
<br>
Instead of GC::initialize(), I'm thinking a static
GCArgumentProcessor::initialize() and instead of
GC::factory(), I am thinking a static
CollectedHeapFactory::create(). Or something like that.
<br>
<br>
The reason is that I think the name GC is too general for the
bootstraping-only problems its code touches. Hope I am making
sense.
<br>
<br>
Thanks,
<br>
/Erik
<br>
<br>
On 2017-10-20 14:25, Roman Kennke wrote:
<br>
<blockquote type="cite">Hi Erik,
<br>
<br>
Yes that is fine.
<br>
<br>
Keep in mind that I'm planning to put heap creation into
that class too.
<br>
<br>
I was thinking maybe to simply reverse the current naming:
name the all-static 'factory factory' 'GC', and thus call
GC::initialize() and GC::factory() or such, and the main
interface GCFactory or CollectedHeapFactory. What do you
think?
<br>
<br>
Roman
<br>
<br>
<br>
<blockquote type="cite">I would like to keep the
CollectedHeap as the facade interface to the GC, like it
is today, instead of having a new GC class making it two
facade interfaces.
<br>
Of course, the CollectedHeap may only be used as a facade
after it has been created. And now we are dealing with
code before it was created during the bootstrapping
process.
<br>
<br>
So what I would like to have here is a class specifically
for that, rather than another GC facade interface. I think
this is mostly an exercise of finding a better name for
the class you call "GC". Now I am not an expert in coming
up with good names myself, but some name that indicates
this is being used for flag processing would be good.
Perhaps GCArgumentProcessor. The benefit of calling it
something like that is that if a GC requires argument
processing later in the bootstrapping, possibly after
CollectedHeap has been created, it can still be used for
this purpose without having to feel weird about it.
<br>
<br>
How would you feel about that? Does it seem to make sense?
<br>
<br>
Thanks,
<br>
/Erik
<br>
<br>
On 2017-10-19 21:14, Roman Kennke wrote:
<br>
<blockquote type="cite">Am 13.10.2017 um 03:20 schrieb
David Holmes:
<br>
<blockquote type="cite">Hi Roman,
<br>
<br>
Not a review as GC folk need to do that.
<br>
<br>
On 13/10/2017 5:59 AM, Roman Kennke wrote:
<br>
<blockquote type="cite">I'm posting it to both
hotspot-runtime-dev and hotspot-gc-dev because it
touches both areas (i.e. the GC interface).
<br>
<br>
Currently, all GC related argument processing is
done in arguments.cpp, littering it with #ifdef
INCLUDE_ALL_GCS and all sorts of GC specific methods
etc.
<br>
</blockquote>
<br>
From a runtime perspective I like all the GC specific
ifdefs and settings moved out-of-line of the main
argument processing.
<br>
<br>
From a refactoring perspective I noticed that
set_object_alignment() no longer calls
set_cms_values(). I presume setting it elsewhere is
okay?
<br>
</blockquote>
I totally forgot to reply to this.
<br>
<br>
What's important is that the CMS alignment values are
set after set_object_alignment() figured out the object
alignment. The patch moves that a little further down
the road to the beginning of its GC specific argument
processing, but from GC perspective should be the same.
I looked thoroughly through the involved code paths and
cannot see what could go wrong.
<br>
<br>
I need one more review. GC folks? The current webrev is:
<br>
<a class="moz-txt-link-freetext" href="http://cr.openjdk.java.net/~rkennke/8189171/webrev.01/">http://cr.openjdk.java.net/~rkennke/8189171/webrev.01/</a>
<a class="moz-txt-link-rfc2396E" href="http://cr.openjdk.java.net/%7Erkennke/8189171/webrev.01/"><http://cr.openjdk.java.net/%7Erkennke/8189171/webrev.01/></a>
<br>
<br>
Thanks,
<br>
Roman
<br>
<br>
</blockquote>
<br>
</blockquote>
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