Squeeze some bits out of allocator IDs so that we can land the sizeclass in
each Remote object. The intent is that, on StrictProvenance architectures like
CHERI, we will be able to route Remote messages through RemoteCache-s without
needing to amplify back to read the sizeclass metadata field out of the slab
headers.
* Add concept of natural alignment to tests.
snmalloc naturally aligns blocks very heavily, so that
the largest power-of-two in the rounded size is the alignment.
This checks that in the test, and provides a method for
finding the natural alignment of a block.
* Improve USE_MALLOC to provide alignment
snmalloc provides a lot of alginment guarantees. This ensures that when
we pass through to the system allocator we still get those alignment
guarantees.
The commit also fixes the tests to work with USE_MALLOC, and builds a
set of unit tests for ctest to check behaviour.
* Improved malloc style tests
Added comprehensive testing of realloc, and other minor improvements
to reporting errors.
* Fix realloc resizing for large sizeclasses.
The rounding by sizeclass was incorrect for large allocation. This fixes
that.
* Ensure alloc_size is committed
There is an awkward interaction between alloc_size and
committing only what is requested. If the user assumes
everything up to alloc_size is available, then we need to
either store the more precise size for alloc_size to return
or commit the whole 2^n range, so that alloc_size stays simple.
This changes to just make the whole range committed.
In the future, we might want to store a more precise size, so
that the allocation can be sized more precisely.
* Reduce size of objects.
* add rust support
* move aligned_size to sizeclass.h
* add static qualifier
* adjust CMakeLists.txt, may broke CI tests
* fix msvc's complaining on c++17
* use SNMALLOC_FAST_PATH as the decorator of aligned_size
* adapt new alignment algorithm and add related test
Co-authored-by: mjp41 <mattpark@microsoft.com>
* fix test cases for msvc
* add extra test for size == 0
* treat memory block of same sizeclass as the same
* fix formatting problem
* remove extra declarations
Co-authored-by: Matthew Parkinson <mjp41@users.noreply.github.com>
Used is now set to 1, when the slab is full. This means that the test
for
used - 1 == 0
can be used to detect leaving full, and entering empty, reducing fast
path deallocation branchs by 1.
This change introduces a per small sizeclass free list. That can be
used to access the free objects for that sizeclass with minimal
calculations being required.
It changes to a partial bump ptr. We bump allocate a whole OS
page worth of objects at a go, so we don't switch as frequently
between bump and free list allocation.
The code for the fast paths has been restructured to minimise the
work required on the common case, and also it is all inlined for the
common case.
Allocating a zero sized object is moved off the fast path. Ask for 1
byte if you want to be fast.
This is useful as codegen is nicer if we use size_t, but the semantics
is uint8_t, and is stored as that in many places in the metadata.
Ultimately should introduce a wrapper to check this invariant.
