622844 - Need optimized GCMember->GCMember move operation

Status: RESOLVED WONTFIX

(Tamarin Graveyard :: Garbage Collection (mmGC), defect, P2)

Description

[Tommy Reilly]

Some write barriers are elided manually when this occurs in a critical spot but we could support it without having to leave off GCMember.  The optimization is to skip the ref count traffic involved.

Comment 1

[Tommy Reilly]

There a couple scenarios that could be imagined here but the only one that matters is the one where one GCMember is being transfered to a newly constructed GCMember that's being constructed.   The old code would just copy the pointer to the dest and null out the source pointer.   A new contructor form is probably warranted, maybe GCMember(GCMember& incoming, GCMember::kMoveFlag)?

Comment 2

[Lars T Hansen]

Looking more carefully at it there appears to be some design work required here, and the only thing we miss out on by not doing it now is that some uses of DRCWB et al cannot be converted to GCMember in the Serrano time frame.  Is that correct?  If so I vote that we defer the bug until Brannan, and make it a blocker for RC removal.

Comment 3

[Tommy Reilly]

Yes this problem cannot be solved w/o a new API or going back to raw pointers.

Comment 4

[Sylvestre Ledru [:Sylvestre]]

Tamarin is a dead project now. Mass WONTFIX.

Comment 5

[Sylvestre Ledru [:Sylvestre]]

Tamarin isn't maintained anymore. WONTFIX remaining bugs.