On Tue, 10 Nov 2020 23:27:52 GMT, Daniel D. Daugherty <dcu...@openjdk.org>
wrote:
>> Well since it controls async deflation, it should probably get a mention
>> since this comment on its own is not true:
>>
>> // Keep track of contention for JVM/TI and M&M queries and control async
>> deflation.
>>
>> The field _contentions has a good comment.
>
> The comment for **that** location is correct. That's the location
> where we keep track of contended monitors for JVM/TI and M&M.
> The comments at the other locations are also correct (very verbose
> for two of them, but correct).
Look at the entire context of that location:
// Keep track of contention for JVM/TI and M&M queries.
add_to_contentions(1);
if (is_being_async_deflated()) {
// Async deflation is in progress and our contentions increment
// above lost the race to async deflation. Undo the work and
// force the caller to retry.
const oop l_object = object();
if (l_object != NULL) {
// Attempt to restore the header/dmw to the object's header so that
// we only retry once if the deflater thread happens to be slow.
install_displaced_markword_in_object(l_object);
}
Self->_Stalled = 0;
add_to_contentions(-1);
return false;
}
We do the increment for JVM/TI and M&M purposes and
then we check to see if async deflation beat us...
-------------
PR: https://git.openjdk.java.net/jdk/pull/642
