RFR: 8273916: Remove 'special' ranking

[David Holmes]

On Fri, 17 Sep 2021 11:50:22 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

> This change removes the special ranking and folds it into nosafepoint.  You have to look at commit #3 to see this actual part of the change that doesn't include JDK-8273915.
> This passes tier1-6 also.

Sorry I don't follow. Lets examine that first example. We currently have:

CompiledMethod_lock (special-1) ->
CodeCache_lock (special) ->
VtableStubs_lock (leaf-2 == special + 11) ->
CompiledIC_lock(leaf+2 == special + 15)

If we change special to nosafepoint then we would have:

CompiledMethod_lock (nosafepoint-1) ->
CodeCache_lock (nosafepoint) ->
VtableStubs_lock (leaf-2 == nosafepoint + 4) ->
CompiledIC_lock(leaf+2 == nosafepoint + 8 == safepoint - 8)

so I don't see why we would have CodeCache_lock instead be nosafepoint-3 ?

If all you have done is change special to nosafepoint then all the existing relative rankings remain for things like leaf and leaf-2. The only adjustment you have to make is for a leaf+2 to instead be expressed as safepoint-8.

David

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PR: https://git.openjdk.java.net/jdk/pull/5563