* Improve testing of memcpy including adding perf test.
* Change remaining_bytes to be branch free.
Use reciprocal division followed by multiply to remove a branch.
* Post large deallocations to original thread
This change sets all large allocations to be owned by the originating
thread. This means they will be messaged back to the original thread
before they can be reused.
The following reason for making this change:
* This will improve producer/consumer apps involving large allocations.
* It enables the implementation of a more complex chunk allocator that
reassembles chunks.
* It addresses an issue with compartmentalisation where the handling of
large allocations can result in meta-data ownership changing.
The CHERI-RISC-V `CAndPerm` and `CSetBoundsExact` instructions trap on untagged
inputs, so avoid passing `nullptr` to primitives that become those instructions.
TSAN complained that there was a race that after some thoughts appears
to be due to this exchange needing to be an `acquire`.
I still wonder if the data dependence that is threaded through the
exchange induces enough order.
* export netbsd's reallocarr proposal.
acts subtly differently from reallocarray, returns an error code
and first argument as receiver.
* not export by default
* ci tests
* apply suggestions
* doc addition
* Apply suggestions from code review
Co-authored-by: Matthew Parkinson <mjp41@users.noreply.github.com>
On Open Enclave having the `local_alloc` directly in thread-local
storage was causing a crash. This changes the `local_alloc` to be
indirected, and thus puts less pressure on the thread-local storage.
The test also has deals with how to allocate before a thread-local
storage has been established.
If there is only one slab remaining, then we probabalisticly allocator a
new one. If a slab is barely in use, then this could cause us to
effectively double the number of slabs in use.
This commit checks if the remaining slab has enough remaining elements
to provide randomisation.
* Add default for getting chunk allocator state
Makes the API same between the two configurations.
* Reduce address space usage for Open Enclave
* Fix OE Pal concept
* Add support for Pal not to provide time.
The lazy return of pages to the OS uses a simple time
based heuristic. This enables a PAL to not support time,
and return the memory to a central pool immediately.
* Update src/backend/backend.h
Co-authored-by: Amaury Chamayou <amaury@xargs.fr>
Co-authored-by: Amaury Chamayou <amaury@xargs.fr>
The primary aim for this refactor is to use a representation for
sizeclasses that uniformly covers both large and small. This allows
certain operations such as alloc_size and external_pointer to be
uniformly implemented.
The additional types make clear which kind of sizeclass is in use.
This also tidies up the code for sizeclass based divisible by and
modulus.
It fixes a bug in rust_realloc that didn't correctly determine a realloc
was required for large classes.
The spelling of inline assembler constraints on Morello would be
different, but Jessica Clarke points out that we should just be using
the builtin when available, so do that instead.
Co-authored-by: Jessica Clarke <jrtc27@jrtc27.com>
With the new snmalloc2 changes it seems the larger window is leading to
more fragmentation and harming performance. Reducing size still
provides good batching, improves memory overhead.
This adds a way to periodically pool the PAL to see if any timers have
expired. Timers can be used to periodically provide callbacks to the
rest of snmalloc.
Consuming available slabs in LIFO order makes predicting address reuse harder
but appears to have performance implications. Condition this on CHECK_CLIENT
and instead use FIFO order on !CHECK_CLIENT builds.
Errno is not required to be 0 on return from malloc,
so don't bother trying to make it 0. Leads to false test failures where
libc calls have not reset it after a failure.
On systems with larger than 16KiB page size, we have chunks
that divide a page. This seems a little strange, and if we
want to disable the pages backing a chunk, this is not possible.
This change ensures the chunk is always at least a single page.
