diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/zisp/gc/meta_alloc.zig | 30 |
1 files changed, 12 insertions, 18 deletions
diff --git a/src/zisp/gc/meta_alloc.zig b/src/zisp/gc/meta_alloc.zig index f8b9e92..4dec92d 100644 --- a/src/zisp/gc/meta_alloc.zig +++ b/src/zisp/gc/meta_alloc.zig @@ -138,29 +138,23 @@ inline fn getSizeClassIndex(size: usize) u8 { /// Pointer to start of all slabs as a contiguous array. var slabs: *[SIZES.len]Slab = undefined; -/// Free-list head pointer with ABA counter. -const FlHead = packed struct(u64) { +/// Linked-list head pointer with ABA counter. +const ListHead = packed struct(u64) { // Putting aba first leads to slightly better codegen. aba: UnitIdx, idx: UnitIdx, }; -/// Vacancy-list head pointer with ABA counter. -const VlHead = packed struct(u64) { - aba: UnitIdx, - idx: UnitIdx, -}; - /// Global shared metadata per slab / size class. const SlabInfo = struct { /// Force cache line alignment to prevent false sharing. _: void align(std.atomic.cache_line) = {}, /// Head of shared free-list for the size class; index value SLAB_LEN is /// used to mean NULL, since it's an invalid slab index. - free_list: FlHead = .{ .aba = 0, .idx = SLAB_LEN }, + free_list: ListHead = .{ .aba = 0, .idx = SLAB_LEN }, /// Head of shared vacancy-list for the size class; index value SLAB_LEN /// used to mean NULL, since it's an invalid slab index. - vacancy_list: VlHead = .{ .aba = 0, .idx = SLAB_LEN }, + vacancy_list: ListHead = .{ .aba = 0, .idx = SLAB_LEN }, /// Global slab watermark: Start address of unused vmem, as 8-byte index. watermark: UnitIdx = 0, }; @@ -311,7 +305,7 @@ fn alloc_from_fl( var ptr: SlotPtr = undefined; var arr: [*]UnitIdx = undefined; - var fl_head = @atomicLoad(FlHead, &info.free_list, .acquire); + var fl_head = @atomicLoad(ListHead, &info.free_list, .acquire); while (true) : (std.atomic.spinLoopHint()) { // Checking for >= SLAB_LEN is optimal; it'll just test the sign bit. if (fl_head.idx >= SLAB_LEN) return null; @@ -324,7 +318,7 @@ fn alloc_from_fl( const next_head = @atomicLoad(UnitIdx, &arr[0], .unordered); fl_head = @cmpxchgWeak( - FlHead, + ListHead, &info.free_list, fl_head, .{ .aba = fl_head.aba +% 1, .idx = next_head }, @@ -355,7 +349,7 @@ fn alloc_from_vl( var ptr: SlotPtr = undefined; var arr: [*]UnitIdx = undefined; - var vl_head = @atomicLoad(VlHead, &info.vacancy_list, .acquire); + var vl_head = @atomicLoad(ListHead, &info.vacancy_list, .acquire); while (true) : (std.atomic.spinLoopHint()) { if (vl_head.idx >= SLAB_LEN) return null; @@ -366,7 +360,7 @@ fn alloc_from_vl( const next_head = @atomicLoad(UnitIdx, &arr[0], .unordered); vl_head = @cmpxchgWeak( - VlHead, + ListHead, &info.vacancy_list, vl_head, .{ .aba = vl_head.aba +% 1, .idx = next_head }, @@ -451,12 +445,12 @@ fn free_into_fl( @memcpy(arr[16 .. 16 + max], tl.fsc[split .. split + max]); // Now atomically announce the new free-list head to global visibility. - var fl_head = @atomicLoad(FlHead, &info.free_list, .acquire); + var fl_head = @atomicLoad(ListHead, &info.free_list, .acquire); while (true) : (std.atomic.spinLoopHint()) { // Still owned exclusively; no need for atomic store. arr[0] = fl_head.idx; fl_head = @cmpxchgWeak( - FlHead, + ListHead, &info.free_list, fl_head, .{ .aba = fl_head.aba +% 1, .idx = idx }, @@ -502,11 +496,11 @@ fn flush_to_vl(info: *SlabInfo, tl: *TlSlabInfo, slab: *Slab) void { arr[1] = tl.wm_hi; - var vl_head = @atomicLoad(VlHead, &info.vacancy_list, .acquire); + var vl_head = @atomicLoad(ListHead, &info.vacancy_list, .acquire); while (true) : (std.atomic.spinLoopHint()) { arr[0] = vl_head.idx; vl_head = @cmpxchgWeak( - VlHead, + ListHead, &info.vacancy_list, vl_head, .{ .aba = vl_head.aba +% 1, .idx = idx }, |