NoAllocationGuard is an RAII stack guard that prevents allocations
while it exists. This is done through a thread-local global flag which
causes malloc to crash on a VERIFY if it is false. The guard allows for
recursion.
The intended use case for this class is in real-time audio code. In such
code, allocations are really bad, and this is an easy way of dynamically
enforcing the no-allocations rule while giving the user good feedback if
it is violated. Before real-time audio code is executed, e.g. in LibDSP,
a NoAllocationGuard is instantiated. This is not done with this commit,
as currently some code in LibDSP may still incorrectly allocate in real-
time situations.
Other use cases for the Kernel have also been added, so this commit
builds on the previous to add the support both in Userland and in the
Kernel.
This is required to make SSE instructions work when building with
Clang. Apparently Clang uses SSE instructions where GCC didn't so
we didn't previously run into this problem.
Problem:
- `size_classes` is a C-style array which makes it difficult to use in
algorithms.
- `all_of` algorithm is re-written for the specific implementation.
Solution:
- Change `size_classes` to be an `Array`.
- Directly use the generic `all_of` algorithm instead of
reimplementing.
By default malloc manages memory internally in larger blocks. When
one of those blocks is added we initialize a free list by touching
each of the new block's pages, thereby committing all that memory
upfront.
This changes malloc to build the free list on demand which as a
bonus also distributes the latency hit for new blocks more evenly
because the page faults for the zero pages now don't happen all at
once.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
