Like alloc_size, this will require amplification internally.
This patch also restores performance to the status quo ante; Clang can once
again see enough to generate the same code as it did before de-static-ing
alloc_size.
We're going to need to amplify the pointer and that's going to require access
to our AddressSpaceManager, which we only get non-statically through our
LargeAlloc.
This patch unto itself makes the world slower, perhaps because Clang can't see
the certainty of aliasing of the static and non-static paths to the same
structure. However, when we also de-static external_pointer, that goes away and
things return to the status quo ante.
- Make GlobalPagemapTemplate and ExternalGlobalPagemap generic in the type of
the pagemap they're encapsulating.
We're going to want to use these for other kinds of pagemaps in the near
future.
- Rename snmalloc_pagemap_global_get to snmalloc_chunkmap_global_get.
- Rename GlobalPagemap to GlobalChunkmap.
* 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.
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.
* 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>
Previous implementation of aligned_alloc met the specification, but was
not particularly useful. This uses the same implementation for
alligned_alloc and memalign.
There are two things calling themselves pagemaps:
- the src/mem/pagemap.h objects of that name
- the SuperslabMap object gets called a PageMap inside the Allocator
Rename the latter to chunkmap, with appropriate case and snake,
everywhere, and pull it out to its own file (chunkmap.h).
The default implementation of a chunkmap is a purely static object, but
we nevertheless instantiate it per allocator, so that other
implementations can use stateful instances when interposing on the
mutation methods. Note that the "get" method, however, must remain
static to support the interface required by Allocator objects.
The pagemap global is now an inline static of a template class, so that
we will see different symbols for the different types.
Issue #84 showed that it's possible to compile two compilation units
with different pagemaps, link them together, and have them attempt to
interpret the global pagemap as two different types. This change should
make that impossible.
Also make the `pagemap()` function static so that it can be used from
static functions, avoiding other things that directly reference the
global pagemap.
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.
Introduce a `OnePastEnd` option for the pointer immediately after the
end of the allocation. This simplifies some of the logic in callers,
where they wants to say 'is base + length safe to use?'.
Also restructure some of the other logic somewhat.
Move slow_allocator into a separate header in the snmalloc namespace and
rename it for consistency with the rest of the codebase. Delete its
copy and move constructors / assignment operators.
Provide a hook so that the exported malloc symbols can be weak. This is
mostly needed so that rtld, which statically links libc.a, can override
the symbols.
Add a bootstrap allocator so that statically linked binaries can have
their TLS space allocated before malloc is called and uses TLS.
