use crate::ptr;
use crate::sys_common::alloc::{MIN_ALIGN, realloc_fallback};
use crate::alloc::{GlobalAlloc, Layout, System};
+use crate::mem;
#[stable(feature = "alloc_system_type", since = "1.28.0")]
unsafe impl GlobalAlloc for System {
#[inline]
unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+ // jemalloc provides alignment less than MIN_ALIGN for small allocations.
+ // So only rely on MIN_ALIGN if size >= align.
+ // Also see <https://github.com/rust-lang/rust/issues/45955>.
if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() {
libc::malloc(layout.size()) as *mut u8
} else {
#[inline]
unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
+ // jemalloc provides alignment less than MIN_ALIGN for small allocations.
+ // So only rely on MIN_ALIGN if size >= align.
+ // Also see <https://github.com/rust-lang/rust/issues/45955>.
if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() {
libc::calloc(layout.size(), 1) as *mut u8
} else {
#[inline]
unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 {
let mut out = ptr::null_mut();
- let ret = libc::posix_memalign(&mut out, layout.align(), layout.size());
+ // posix_memalign requires that the alignment be a multiple of `sizeof(void*)`.
+ // Since these are all powers of 2, we can just use max.
+ let align = layout.align().max(mem::size_of::<usize>());
+ let ret = libc::posix_memalign(&mut out, align, layout.size());
if ret != 0 {
ptr::null_mut()
} else {