RFR: JDK-8270308: Amalloc aligns size but not return value (take 2) [v4]

[Thomas Stuefe]

On Mon, 26 Jul 2021 13:39:29 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

> > My first patch filled alignment gaps in debug with a pattern, to trip off the analyzer. What do you think, should I do this here too?
> Maybe. Aren't arena's freed with a zap pattern so you'd find bugs that way? 

Yes, you are right, maybe that's sufficient. I thought that the zap pattern would be overwritten with the first allocation wave (allocate a bunch, reset-to-mark, allocate again) but I see reset-to-mark - ultimately Chunk::chop() - also zaps, so this may be fine.

> Anyway, it might be better as a separate RFE and new round of testing.

Yes. But the default pattern may be fine already.

> Thanks for default aligning the chunks though because this is what one would expect without looking at the code more closely.

Sure!

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PR: https://git.openjdk.java.net/jdk/pull/4835