This adds a new `sdallocx` function to the external API, allowing the
size to be passed by the caller. It avoids some extra reads in the
thread cache fast path. In the case where stats are enabled, this
avoids the work of calculating the size from the pointer.
An assertion validates the size that's passed in, so enabling debugging
will allow users of the API to debug cases where an incorrect size is
passed in.
The performance win for a contrived microbenchmark doing an allocation
and immediately freeing it is ~10%. It may have a different impact on a
real workload.
Closes#28
Use nallocx() rather than mallctl() to trigger initialization, because
nallocx() has no side effects other than initialization, whereas
mallctl() does a bunch of internal memory allocation.
Refactor huge allocation to be managed by arenas (though the global
red-black tree of huge allocations remains for lookup during
deallocation). This is the logical conclusion of recent changes that 1)
made per arena dss precedence apply to huge allocation, and 2) made it
possible to replace the per arena chunk allocation/deallocation
functions.
Remove the top level huge stats, and replace them with per arena huge
stats.
Normalize function names and types to *dalloc* (some were *dealloc*).
Remove the --enable-mremap option. As jemalloc currently operates, this
is a performace regression for some applications, but planned work to
logarithmically space huge size classes should provide similar amortized
performance. The motivation for this change was that mremap-based huge
reallocation forced leaky abstractions that prevented refactoring.
Add new mallctl endpoints "arena<i>.chunk.alloc" and
"arena<i>.chunk.dealloc" to allow userspace to configure
jemalloc's chunk allocator and deallocator on a per-arena
basis.
Make dss non-optional on all platforms which support sbrk(2).
Fix the "arena.<i>.dss" mallctl to return an error if "primary" or
"secondary" precedence is specified, but sbrk(2) is not supported.
The hash code, which has MurmurHash3 at its core, generates different
output depending on system endianness, so adapt the expected output on
big-endian systems. MurmurHash3 code also makes the assumption that
unaligned access is okay (not true on all systems), but jemalloc only
hashes data structures that have sufficient alignment to dodge this
limitation.
Reduce maximum tested alignment from 2^29 to 2^25. Some systems may not
have enough contiguous virtual memory to satisfy the larger alignment,
but the smaller alignment is still adequate to test multi-chunk
alignment.
p_test_fail() was passing a va_list to two separate functions with the
expectation that no reset would occur. Refactor p_test_fail()'s callers
to instead format two strings and pass them to p_test_fail().
Add a missing parameter to an assert_u64_eq() call, which the compiler
warned about after the assertion macro refactoring.
Restore the essence of 898960247a, which
sabotages tail call optimization. This is necessary even when the
mutually recursive functions are in separate compilation units.
If mremap(2) is used for huge reallocation, physical pages are mapped to
new virtual addresses rather than data being copied to new pages. This
bypasses the normal junk filling that would happen during allocation, so
add junk filling that is specific to this case.
Break prof_accum into multiple compilation units, in order to thwart
compiler optimizations such as inlining and tail call optimization that
would alter backtraces.
Remove the allocm() test equivalent to the mallocx() test removed in the
previous commit. The flawed test attempted to cause OOM due to large
request size and alignment constraint. Although this test "passed" on
64-bit systems due to the virtual memory hole, it could pass on some
32-bit systems.
Fix/remove three related flawed tests that attempted to cause OOM due to
large request size and alignment constraint. Although these tests
"passed" on 64-bit systems due to the virtual memory hole, they could
pass on some 32-bit systems.
Re-structure alloc_[01](), which are mutually tail-recursive functions,
to do (unnecessary) work post-recursion so that the compiler cannot
perform tail call optimization, thus preserving intentionally unique
call paths in captured backtraces.
