Mesh: a new approach to memory compaction for C/C++
emery at cs.umass.edu
Sun Sep 22 16:15:08 UTC 2019
On Wednesday, 18 September 2019 at 09:31:07 UTC, Gregor Mückl
> On Tuesday, 17 September 2019 at 11:42:51 UTC, Per Nordlöw
>> strangeloop talk here:
>> and github repo here:
>> Sounds to me like making D's GC precise by default to enable
>> memory compaction is worth pursuing.
> I'm am thinking about the implications for debugging. Mapping
> the same page to two virtual memory addresses on the heap
> creates weird situations where writing over the bounds of one
> object doesn't trash allocations with nearby memory addresses,
> but can affect seemingly far away allocations that ended up
> randomly aliased to the same page. Even worse, Mesh randomizes
> allocations within pages to get more opportunities to alias
> pages. This means that some heap-smashing bug will likely
> present itself differently on each run. Have fun finding the
> root cause of that :/.
You can always seed the random number generator with a fixed
value to get reproducible runs.
More interestingly, it's also possible to exploit an
Exterminator-like approach (see
automatically find the source of such bugs! This is specifically
enabled by randomization. We implemented Exterminator for a
previous randomizing allocator (DieHard: code here, including
Exterminator -- https://github.com/plasma-umass/DieHard), and
there's no technical barrier to doing the same for Mesh.
-- emery (Mesh co-author)
More information about the Digitalmars-d