Improve remote dealloc
- Outline the slow path to improve code gen significantly
- Handle message queue only on slow path for remote dealloc.
- Change remote size to count down 0, so fast path does not need a constant.
- Use signed value so that branch does not depend on addition.
The bootstrapping allocator needs to perform a memcpy to bypass the
removed move constructors on std::atomic. This is safe as there is no
concurrency at this point, but GCC is unhappy with this.
This commit moves CI to GCC8 and disables this warning for that line.
The readme was considerably out of date, with the introduction
being over a year old. This commit reflects the developments and
improvements in stabiity of snmalloc.
On platforms that support low-memory notifications register callbacks
that perform lazy decommit. This allows idle processes to return memory
to the OS. Without incurring the cost of constantly committing and
decommitting memory.
Code review and CI changes
* Fixed test to use a template to make constexpr magic work
* Factored out basic notification mechanism so can be reused on other
platforms.
If the external thread statics are used, then
we don't need to include some C++ runtime
concepts. This refactoring moves some global initialization under
conditional compilation.
With clangformat9 the AfterCaseLabel is introduced.
And this defaults to false, but our code is formatted
implicitly with this set to true.
PRs to Verona and Snmalloc are being formatted with clangformat9,
and this is causing complexity. Let's move forward to clangformat9
in CI.
Windows is only sending low-memory notifications when the machine
is reaching low-memory. So running a 32bit process on 64bit machine
can easily exhaust address space before machine gets close to
low-memory.
The low-memory notification was getting into an infinite loop. This
fixes the loop termination, and provides a test for platforms which
support low-memory notification.
