bjoernager/rust
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alloc_jemalloc: don’t assume MIN_ALIGN for small sizes

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See previous commit’s message for what is expected of allocators
in general, and https://github.com/jemalloc/jemalloc/issues/1072
for discussion of what jemalloc does specifically.
This commit is contained in:
Simon Sapin 2017-11-20 15:42:34 +01:00
parent 21d899272a
commit 2dd268b652
2 changed files with 16 additions and 11 deletions
Download patch file Download diff file Expand all files Collapse all files

5
src/liballoc/tests/heap.rs
View file

@ -20,6 +20,11 @@ fn alloc_system_overaligned_request() {
check_overalign_requests(System) check_overalign_requests(System)
} }
#[test]
fn std_heap_overaligned_request() {
check_overalign_requests(Heap)
}
fn check_overalign_requests<T: Alloc>(mut allocator: T) { fn check_overalign_requests<T: Alloc>(mut allocator: T) {
let size = 8; let size = 8;
let align = 16; // greater than size let align = 16; // greater than size

22
src/liballoc_jemalloc/lib.rs
View file

@ -92,8 +92,8 @@ mod contents {
a.trailing_zeros() as c_int a.trailing_zeros() as c_int
} }
fn align_to_flags(align: usize) -> c_int { fn align_to_flags(align: usize, size: usize) -> c_int {
if align <= MIN_ALIGN { if align <= MIN_ALIGN && align <= size {
0 0
} else { } else {
mallocx_align(align) mallocx_align(align)
@ -111,7 +111,7 @@ mod contents {
pub unsafe extern fn __rde_alloc(size: usize, pub unsafe extern fn __rde_alloc(size: usize,
align: usize, align: usize,
err: *mut u8) -> *mut u8 { err: *mut u8) -> *mut u8 {
let flags = align_to_flags(align); let flags = align_to_flags(align, size);
let ptr = mallocx(size as size_t, flags) as *mut u8; let ptr = mallocx(size as size_t, flags) as *mut u8;
if ptr.is_null() { if ptr.is_null() {
let layout = Layout::from_size_align_unchecked(size, align); let layout = Layout::from_size_align_unchecked(size, align);
@ -132,7 +132,7 @@ mod contents {
pub unsafe extern fn __rde_dealloc(ptr: *mut u8, pub unsafe extern fn __rde_dealloc(ptr: *mut u8,
size: usize, size: usize,
align: usize) { align: usize) {
let flags = align_to_flags(align); let flags = align_to_flags(align, size);
sdallocx(ptr as *mut c_void, size, flags); sdallocx(ptr as *mut c_void, size, flags);
} }
@ -142,7 +142,7 @@ mod contents {
min: *mut usize, min: *mut usize,
max: *mut usize) { max: *mut usize) {
let layout = &*(layout as *const Layout); let layout = &*(layout as *const Layout);
let flags = align_to_flags(layout.align()); let flags = align_to_flags(layout.align(), layout.size());
let size = nallocx(layout.size(), flags) as usize; let size = nallocx(layout.size(), flags) as usize;
*min = layout.size(); *min = layout.size();
if size > 0 { if size > 0 {
@ -166,7 +166,7 @@ mod contents {
return 0 as *mut u8 return 0 as *mut u8
} }
let flags = align_to_flags(new_align); let flags = align_to_flags(new_align, new_size);
let ptr = rallocx(ptr as *mut c_void, new_size, flags) as *mut u8; let ptr = rallocx(ptr as *mut c_void, new_size, flags) as *mut u8;
if ptr.is_null() { if ptr.is_null() {
let layout = Layout::from_size_align_unchecked(new_size, new_align); let layout = Layout::from_size_align_unchecked(new_size, new_align);
@ -181,10 +181,10 @@ mod contents {
pub unsafe extern fn __rde_alloc_zeroed(size: usize, pub unsafe extern fn __rde_alloc_zeroed(size: usize,
align: usize, align: usize,
err: *mut u8) -> *mut u8 { err: *mut u8) -> *mut u8 {
let ptr = if align <= MIN_ALIGN { let ptr = if align <= MIN_ALIGN && align <= size {
calloc(size as size_t, 1) as *mut u8 calloc(size as size_t, 1) as *mut u8
} else { } else {
let flags = align_to_flags(align) | MALLOCX_ZERO; let flags = align_to_flags(align, size) | MALLOCX_ZERO;
mallocx(size as size_t, flags) as *mut u8 mallocx(size as size_t, flags) as *mut u8
}; };
if ptr.is_null() { if ptr.is_null() {
@ -203,7 +203,7 @@ mod contents {
err: *mut u8) -> *mut u8 { err: *mut u8) -> *mut u8 {
let p = __rde_alloc(size, align, err); let p = __rde_alloc(size, align, err);
if !p.is_null() { if !p.is_null() {
let flags = align_to_flags(align); let flags = align_to_flags(align, size);
*excess = nallocx(size, flags) as usize; *excess = nallocx(size, flags) as usize;
} }
return p return p
@ -220,7 +220,7 @@ mod contents {
err: *mut u8) -> *mut u8 { err: *mut u8) -> *mut u8 {
let p = __rde_realloc(ptr, old_size, old_align, new_size, new_align, err); let p = __rde_realloc(ptr, old_size, old_align, new_size, new_align, err);
if !p.is_null() { if !p.is_null() {
let flags = align_to_flags(new_align); let flags = align_to_flags(new_align, new_size);
*excess = nallocx(new_size, flags) as usize; *excess = nallocx(new_size, flags) as usize;
} }
p p
@ -244,7 +244,7 @@ mod contents {
new_size: usize, new_size: usize,
new_align: usize) -> u8 { new_align: usize) -> u8 {
if old_align == new_align { if old_align == new_align {
let flags = align_to_flags(new_align); let flags = align_to_flags(new_align, new_size);
(xallocx(ptr as *mut c_void, new_size, 0, flags) == new_size) as u8 (xallocx(ptr as *mut c_void, new_size, 0, flags) == new_size) as u8
} else { } else {
0 0