RFR: 8324817: Parallel GC does not pre-touch all heap pages when AlwaysPreTouch enabled and large page disabled [v5]

[Thomas Schatzl]

On Thu, 1 Feb 2024 11:37:19 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> Wang Zhuo has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   update test
>
> test/hotspot/jtreg/gc/parallel/TestAlwaysPreTouchBehavior.java line 69:
> 
>> 67: 
>> 68:         String content = stringBuilder.toString();
>> 69:         return Long.valueOf(content.split("\\s+")[1].trim());
> 
> There does not need to be a reason to use the `StringBuilder` here. I also do not see a reason for the `deleteCharAt` call. Just use `line`.
> 
> Suggestion:
> 
>         String line = null;
>         while ((line = reader.readLine()) != null) {
>             if (line.startsWith("VmRSS:")) {
>                 break;
>             }
>         }
>         reader.close();
> 
>         return Long.valueOf(line.split("\\s+")[1].trim());
> 
> If `line` is `null`, the NPE will be caught in the `catch` in the caller all the same.

Note that in case of an `IOException` the file will not be closed in either case. Maybe some `try-with-resources` is appropriate here when opening the `Reader`. I do not see this as critical as the test will be terminated soon enough anyway, freeing the file handle.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17610#discussion_r1474320686