RFR: 8347337: ZGC: String dedups short-lived strings [v2]

[Kim Barrett]

On Tue, 11 Mar 2025 18:43:49 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

> About the style _guide_. I see that section more as a helpful guide, but not
> as a complete mandate to how to name files in HotSpot.

That's true for a lot of the style guide.  But there generally ought to be a
(good) reason to be different.  I don't see a particularly compelling reason
in this case, though zgc has a number of stylistic peculiarities of its own,
and maybe that's sufficient.

> Note, that even the StringDedup::Request class is placed in a file named
> stringDedup.hpp and not stringDedupRequest.hpp!

The StringDedup class (and associated header file) is the external interface
to the facility, so having the Request class be a member is natural. As such
it's natural to treat it as a "buddy" class in the sense used in the style
guide. So I don't see that as a compelling argument for the proposed zgc
structure.

> I could easily also create a structure that simulates the structure used in
> stringDedup.hpp:

Given that the Context class would be the only thing in such a notional
ZStringDedup class, I agree that doesn't seem like an improvement.

> This was intentional. I named them zStringDedup.* to show that this is the
> file that contains ZGC's support to interface with StringDedup. We do that for
> other sub-systems that ZGC interfaces with.

If I was looking for StringDedup-related stuff in zgc and only found files
named zStringDedupContext.*, I would certainly look there. Though I admit that
if I was looking for the class ZStringDedupContext I would look in
zStringDedup.* in the absence of any other zStringDedup*.*.

I don't feel super strongly about this, and it seems you do, so I'm not going
to block over it.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23965#discussion_r1994331071