On Tue, 8 Oct 2024 07:40:24 GMT, Albert Mingkun Yang <ay...@openjdk.org> wrote:
>> After re-reading this again I agree with what you're writing. If you make
>> the change to use:
>>
>> if (MinObjAlignment >= CollectedHeap::min_fill_size()) {
>> return;
>> }
>>
>>
>> do you even have to check for UCOH in this function?
>>
>> I also wonder if you could tweak the comment now that this is not true when
>> UCOH is on:
>>
>> // The size of the filler (min-obj-size) is 2 heap words with the default
>> // MinObjAlignment, since both markword and klass take 1 heap word.
>
> I took UCOH into account when this code was written -- the current version of
> PR would fail the following assert.
>
>
> // Note: If min-fill-size decreases to 1, this whole method becomes
> redundant.
> assert(CollectedHeap::min_fill_size() >= 2, "inv");
>
>
> The least intrusive way, IMO, is to put `if (UCOH) { return; }` right before
> `// Note: ...`, kind of like what Roman originally put it. I believe the
> advantage of this style is that when UCOH before always-true, it's obvious
> this whole method essentially becomes `return`and can be removed right away.
I was thinking that we should remove the entire:
// Note: If min-fill-size decreases to 1, this whole method becomes redundant.
assert(CollectedHeap::min_fill_size() >= 2, "inv");
block, since it is now incorrect, guarded by the proper check, and the comment
is misleading since we now can have a min-fill-size that is 1.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/20677#discussion_r1791409345
