604339 - Unify page maps and queries of GCHeap, GC, FixedMalloc, etc

Status: RESOLVED WONTFIX

(Tamarin Graveyard :: Garbage Collection (mmGC), enhancement)

Description

[Felix S. Klock II [:pnkfelix, :fklock]]

Work item broken out from Bug 445780:

Lars:
"""
- in FixedMalloc we're using an expensive search in debug builds to query
ownership of pages, this is not working out well in practice.  The reasonable
thing to do would be to ask GCHeap.

Thus IMO the design we may be looking for here is a generic design in GCHeap
that sparsely stores information about every page allocated by GCHeap, and
which can be queried about any pointer in the address space.  If the page is
assigned to a GC it needs to be able to extract a pointer to the GC that owns
it; if it is assigned to FixedMalloc it should be possible to figure out
whether it's a large-block or small-block page, etc.  Right now we're storing
per-block information in the block itself but with such a global data structure
we could reconsider that, esp if it is fast enough and if the storage can be
more efficient (eg if multiple pages with the same attributes can share one
information blob).  Information sharing in this table is in fact something that
is appealing, the current structure in GCHeap appears to me to be a little
profligate in its use of memory.
"""

Comment 1

[Sylvestre Ledru [:Sylvestre]]

Tamarin is a dead project now. Mass WONTFIX.

Comment 2

[Sylvestre Ledru [:Sylvestre]]

Tamarin isn't maintained anymore. WONTFIX remaining bugs.