RFR: 8292201: serviceability/sa/ClhsdbThreadContext.java fails with "'Thread "Common-Cleaner"' missing from stdout/stderr" [v2]

[Chris Plummer]

On Thu, 1 Sep 2022 20:10:45 GMT, Alex Menkov <amenkov at openjdk.org> wrote:

>> Chris Plummer has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains four commits:
>> 
>>  - Merge
>>  - Fix jcheck error
>>  - Undo some temp test changes.
>>  - Fix 64-bit alignment requirements
>
> src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/debugger/DebuggerBase.java line 242:
> 
>> 240:   private boolean canUsePageCacheFor64bitRead(long address) {
>> 241:     long pageMask = ~(pageSize - 1);
>> 242:     if ((address & pageMask) != ((address + 4) & pageMask)) {
> 
> This looks a bit over-complicated.
> Maybe something like
> `    long pageMask = pageSize - 1;
>     if ((address & pageMask) > (pageSize - 8)) {
>       return false;
>     }`

I tinkered with this code quite a bit before I had something that both worked and I liked. I don't know that your approach is actually any simpler, and at the moment I still prefer mine, but that might just be because I'm more familiar with it. However, it does seem that there should be a more elegant way of doing this.

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PR: https://git.openjdk.org/jdk/pull/10090