Most slab allocators in core use a sliced heap as backing store. Since
sliced-heap allocations are performed at page-granularity, it is
sensible to dimension the slab blocks to fill whole pages.
When using the Allocator interface, one can't tell which alignment
resulting allocations fulfill. However, at least on ARM, given the
architectural alignment requirements of ARM memory accesses, one wants
memory allocations (what allocators are for in most cases) to be word
aligned automatically. Previously, at least the AVL allocator simply
called alloc_aligned without defining align in its alloc implementation.
This led to unaligned access faults (the default was 0) when using the
AVL allocator as Allocator (as done in the metadata management of a SLAB
of an AVL that uses the AVL as backing store). To avoid such pitfalls
in the future, we force users of alloc_aligned to always specify align
(why use alloc_aligned without align anyway).
Ref #1941
This patch ensures that the 'Allocator_avl' releases all memory obtained
from the meta-data allocator at destruction time. If allocations are
still dangling, it produces a warning, hinting at possible memory leaks.
Finally, it properly reverts all 'add_range' operations.
This patch adds const qualifiers to the functions Allocator::consumed,
Allocator::overhead, Allocator::avail, and Range_allocator::valid_addr.
Fixes#1481
This patch changes the top-level directory layout as a preparatory
step for improving the tools for managing 3rd-party source codes.
The rationale is described in the issue referenced below.
Issue #1082
