Fwd: Primitive objects vs memory model
dl at cs.oswego.edu
Mon Aug 2 16:20:20 UTC 2021
Unless I've missed some follow-up decision, the intent has always been
to only guarantee atomicity under opaque-or-stronger mode. Although
perhaps something could be said about only extracting one primitive
field from a compound value.
On 8/2/21 11:45 AM, Brian Goetz wrote:
> From the -comments list.
> -------- Forwarded Message --------
> Subject: Primitive objects vs memory model
> Date: Mon, 2 Aug 2021 16:55:50 +0200
> From: Raffaello Giulietti <raffaello.giulietti at gmail.com>
> To: valhalla-spec-comments at openjdk.java.net
> I'm wondering if the relationship between primitive objects and the
> memory model (JLS 17 and j.l.i.VarHandle) has been discussed before. I
> couldn't find aything in JEP 401, nor is the mailing list archive,
> spanning more than 5 years of intense discussions, easily searchable
> for keywords.
> For example, does plain access mode guarantee bitwise atomicity (aka
> access atomicity) on JEP 401 Point instances (2 double fields for the
> coords), as if they were 32 bit values? Or perhaps only opaque mode
> can make such guarantees?
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