Change the GC so that it can mark and sweep objects in-place, instead
of always copying. This change is helpful for reducing peak memory
use while performing a collection on a large, old heap.
Some non-copying support was already in place for locked objects,
but the new implementation is faster and more general. As an
alternative to locking, the storage manager now provides "immobile"
allocation (currently only for bytevectors, vectors, and boxes),
which allocates an object that won't move but that can be GCed if
it's not referenced. A locked object is an object that has been
immobiled and that is on a global list --- mostly the old,
non-scalable implementation of locked objects brought back, since
immobile objects cover the cases that need to scale.
original commit: aecb7b736cb1d52764c292fa6364a674958dfde3
Replace repetitive C code in "gc.c" and "vfasl.c" with an
implementation using a little "Parenthe-C" language, which is a
somewhat declarative description of object tracing. From that
descrition, we generate different kinds of tracing functions, such as
the copy function or the sweep function.
The little language is still bascially C, just with parentheses and
parameterization that is much better than trying to use the C
preprocessor. (The "mkgc.ss" file includes the compiler from
Parenthe-C to C.)
Besides replacing existing code, we also generate a new traversal to
implement `compute-object-sizes`. Finally, the GC can now perform a
fused `collect` and `compute-object-sizes` in a single traversal.
Also improve the way that locked objects are detected during GC. This
can make a significant difference (on the order of 10-20% for a full
collection) when locked objects are long-lived.
original commit: de1f5c41d729ac75822a1f1e633ec6d042c883dc
A 0 relocation is used by fcallable code as a recognizable cookie, and
its relocations must be preserved.
original commit: 38fb3fdf75cf6540d6bd2568f015af6272d22995
When starting a new segment to keep an object on a single segment,
terminate the old one with e forwarding marker.
original commit: 1f1db6d3d2cd930455a3592f2d76a465b30a5592
Use `vfasl-convert-file` to convert to the vfasl format, something
like this:
(vfasl-convert-file "orig/petite.boot" "new/petite.boot" '())
(vfasl-convert-file "orig/scheme.boot" "new/scheme.boot" '("petite"))
(vfasl-convert-file "orig/racket.boot" "new/racket.boot" '("petite" "scheme"))
original commit: a40886e2fba741ca8cfc5ebd16b902d6414da0ae
