RFR (S/M): 8178105: Switch mark bitmaps during Remark
stefan.johansson at oracle.com
Tue Apr 3 15:00:58 UTC 2018
On 2018-04-03 16:55, Thomas Schatzl wrote:
> thanks for your patience...
> On Tue, 2018-04-03 at 14:49 +0200, Stefan Johansson wrote:
>> On 2018-04-03 14:25, Thomas Schatzl wrote:
>>> Hi Stefan,
>>> On Tue, 2018-04-03 at 12:58 +0200, Stefan Johansson wrote:
>>>> Hi Thomas,
>>>> On 2018-03-29 16:35, Thomas Schatzl wrote:
>>>>> Hi all,
>>>> Looks good, but a few comments:
>>> I added a different kind of check that verifies what you probably
>>> thought of, and that is that the number of words to add to the
>>> current region must always be larger than zero. If it is zero,
>>> there is something really wrong.
>> Exactly, that's what I wanted. But I don't see that check now, just
>> having a assert(marked_words != 0, "") on row 1032 would be enough.
> My fault. I did not upload the latest version of the change :( It is up
> now, the only difference to previous is line
> 1036 assert(words_to_add > 0, "Out of space to distribute before
> end of humongous object in region %u (starts %u)", i, region_idx);
> But there is a new webrev anyway... in the 1_to_2 webrev it is line
>>>> 1047 log_trace(gc)("Added " SIZE_FORMAT " words to region
>>>> (%s)", marked_words, region_idx, hr->get_type_str());
>>>> I think the logging should use at least one more tag, maybe
>>>> "region" or "marking", but you probably know what makes most
>>>> sense in this area. I also think it would be nice if we got this
>>>> same log-line for all regions. Now we get this for "normal"
>>>> regions, but we get "Distributing..." for humongous start regions
>>>> and "Not Added..." for humongous continuous. So I would suggest
>>>> adding the same log-line to the distribute-function after line
>> Sorry for being picky but the current solution won't print anything
>> for continuous humongous. Adding the log to distribute_marked_bytes()
>> would solve this and we would still get info on region type so I see
>> no need for:
> Okay. I think I got your intention right this time :)
>> 1052 log_trace(gc, marking)("Adding " SIZE_FORMAT " words to
>> humongous start region %u (%s), word size %d (%f)",
>> 1053 marked_words, region_idx,
>> 1054 oop(hr->bottom())->size(),
>> (double)oop(hr->bottom())->size() / HeapRegion::GrainWords);
>>> All fixed.
>>> http://cr.openjdk.java.net/~tschatzl/8178105/webrev.0_to_1/ (diff)
>>> http://cr.openjdk.java.net/~tschatzl/8178105/webrev.1/ (full)
>> Apart from the small things above this looks great.
> http://cr.openjdk.java.net/~tschatzl/8178105/webrev.1_to_2/ (diff)
> http://cr.openjdk.java.net/~tschatzl/8178105/webrev.2/ (full)
> Ran gc/g1 tests successfully with that change.
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