Andy Wingo
67f9c89f2a
Use fragmentation_low_threshold for venerable_threshold
...
This way fragmentation from venerable blocks doesn't cause the collector
to keep evacuating.
2022-08-04 11:32:06 +02:00
Andy Wingo
0450a282dd
Skip mostly-tenured blocks during sweep/allocate after minor GC
2022-08-04 09:04:27 +02:00
Andy Wingo
0fe13e1cab
Accelerate scanning of remembered set
2022-08-03 21:25:18 +02:00
Andy Wingo
47c07dd0eb
Fix embarassing ctz issue
2022-08-03 16:40:34 +02:00
Andy Wingo
96b68095b7
Fix mark pattern updating for generational whippet
...
After a minor collection, we were erroneously failing to sweep dead
objects with the survivor tag.
2022-08-03 12:06:19 +02:00
Andy Wingo
0210a8caf0
Refactor out-of-memory detection
...
Firstly, we add a priority evacuation reserve to prioritize having a few
evacuation blocks on hand. Otherwise if we give them all to big
allocations first and we have a fragmented heap, we won't be able to
evacuate that fragmented heap to give more blocks to the large
allocations.
Secondly, we remove `enum gc_reason`. The issue is that with multiple
mutator threads, the precise thread triggering GC does not provide much
information. Instead we should make choices on how to collect based on
the state of the heap.
Finally, we move detection of out-of-memory inside the collector,
instead of the allocator.
Together, these changes let mt-gcbench (with fragmentation) operate in
smaller heaps.
2022-08-03 10:10:33 +02:00
Andy Wingo
1358d99abc
Fix yield calculation after evacuating collections
2022-08-02 22:15:13 +02:00
Andy Wingo
a4e1f55f37
Implement generational collection
...
Not really battle-tested but it seems to work. Need to implement
heuristics for when to do generational vs full-heap GC.
2022-08-02 15:37:02 +02:00
Andy Wingo
13b3bb5b24
Update barrier functions to also have the object being written
...
Also remove read barriers, as they were unused, and we have no plans to
use them.
2022-08-02 15:37:02 +02:00
Andy Wingo
7f405c929e
Initial live mask does not include young allocations
...
After rotation, the young bit wasn't being included anyway. This just
improves the first collection.
2022-08-02 15:37:02 +02:00
Andy Wingo
1781c5aed4
Fix evacuation allocator to clear any holes
2022-08-02 15:36:59 +02:00
Andy Wingo
d106f3ca71
Mutator collects evacuation target blocks
2022-07-20 14:40:47 +02:00
Andy Wingo
92b05a6310
Add implementation of parallel evacuation
2022-07-20 14:40:47 +02:00
Andy Wingo
4a9908bc4d
Refactor evacuation vs pinning support
...
Marking conservative roots in place effectively prohibits them from
being moved, and we need to trace the roots anyway to discover
conservative roots. No need therefore for a pin bit.
2022-07-20 14:40:47 +02:00
Andy Wingo
a16bb1833c
Add logic to compute evacuation candidate blocks
2022-07-20 14:40:47 +02:00
Andy Wingo
c7c8fa2d32
Refactor to add "block_list" type
2022-07-20 14:40:47 +02:00
Andy Wingo
a8214af467
Whippet reserves a bit in object kind for forwarding
...
Tags without the bit are forwarding addresses.
2022-07-20 14:40:47 +02:00
Andy Wingo
8409383ee1
Refactor post-collection for mark space
2022-07-20 14:40:47 +02:00
Andy Wingo
69caead182
Add heuristics to choose when to compact or mark in place
...
We can choose to compact (evacuate) or mark in place. What we choose
has some effects on how we mark.
2022-07-20 14:40:47 +02:00
Andy Wingo
09d2df1626
Compute GC yield as fraction of total heap size
2022-07-20 14:40:47 +02:00
Andy Wingo
c998f1cd5c
Measure fragmentation as fraction of total heap size
...
This allows a relatively more fragmented mark space if the majority of
the heap is taken up by lospace.
2022-07-20 14:40:47 +02:00
Andy Wingo
7af8bb6bd0
Add machinery to disable ragged-stop marking
...
We'll need to disable the optimization that mutators mark their own
stacks once we support evacuation.
2022-07-20 14:40:47 +02:00
Andy Wingo
52166fe286
Add gc_edge data structure
...
Less casting in user programs, and it's a step on the way to evacuation
in whippet.
2022-07-20 14:40:47 +02:00
Andy Wingo
808d365f4b
We identify empty blocks lazily now
2022-07-20 14:40:47 +02:00
Andy Wingo
bc73c5ad02
Whitespace fix
2022-07-20 14:40:47 +02:00
Andy Wingo
157d40466b
mark_space_reacquire_memory updates pending_unavailable_bytes
2022-07-20 14:40:47 +02:00
Andy Wingo
33a3af2c73
Large object space properly acquires blocks from mark space
...
If the mutator finds completely empty blocks, it puts them on the side.
The large object space acquires empty blocks, sweeping if needed, and
causes them to be unmapped, possibly causing GC.
2022-07-20 14:40:47 +02:00
Andy Wingo
71b656bca4
When sweeping, return empty blocks to global freelist
...
This will facilitate management of overhead for defragmentation as well
as blocks to unmap, for compensating large object allocations.
2022-07-20 14:40:47 +02:00
Andy Wingo
8f06b914b0
Refactor to allow "next" pointer embedded in block summary
2022-07-20 14:40:47 +02:00
Andy Wingo
7d80d45c79
Rename mark-sweep.h to whippet.h
2022-07-20 14:40:44 +02:00
