| /* ---------------------------------------------------------------------------- |
| Copyright (c) 2019-2023 Microsoft Research, Daan Leijen |
| This is free software; you can redistribute it and/or modify it under the |
| terms of the MIT license. A copy of the license can be found in the file |
| "LICENSE" at the root of this distribution. |
| -----------------------------------------------------------------------------*/ |
| |
| /* ---------------------------------------------------------------------------- |
| Concurrent bitmap that can set/reset sequences of bits atomically, |
| represeted as an array of fields where each field is a machine word (`size_t`) |
| |
| There are two api's; the standard one cannot have sequences that cross |
| between the bitmap fields (and a sequence must be <= MI_BITMAP_FIELD_BITS). |
| (this is used in region allocation) |
| |
| The `_across` postfixed functions do allow sequences that can cross over |
| between the fields. (This is used in arena allocation) |
| ---------------------------------------------------------------------------- */ |
| #pragma once |
| #ifndef MI_BITMAP_H |
| #define MI_BITMAP_H |
| |
| /* ----------------------------------------------------------- |
| Bitmap definition |
| ----------------------------------------------------------- */ |
| |
| #define MI_BITMAP_FIELD_BITS (8*MI_SIZE_SIZE) |
| #define MI_BITMAP_FIELD_FULL (~((size_t)0)) // all bits set |
| |
| // An atomic bitmap of `size_t` fields |
| typedef _Atomic(size_t) mi_bitmap_field_t; |
| typedef mi_bitmap_field_t* mi_bitmap_t; |
| |
| // A bitmap index is the index of the bit in a bitmap. |
| typedef size_t mi_bitmap_index_t; |
| |
| // Create a bit index. |
| static inline mi_bitmap_index_t mi_bitmap_index_create(size_t idx, size_t bitidx) { |
| mi_assert_internal(bitidx < MI_BITMAP_FIELD_BITS); |
| return (idx*MI_BITMAP_FIELD_BITS) + bitidx; |
| } |
| |
| // Create a bit index. |
| static inline mi_bitmap_index_t mi_bitmap_index_create_from_bit(size_t full_bitidx) { |
| return mi_bitmap_index_create(full_bitidx / MI_BITMAP_FIELD_BITS, full_bitidx % MI_BITMAP_FIELD_BITS); |
| } |
| |
| // Get the field index from a bit index. |
| static inline size_t mi_bitmap_index_field(mi_bitmap_index_t bitmap_idx) { |
| return (bitmap_idx / MI_BITMAP_FIELD_BITS); |
| } |
| |
| // Get the bit index in a bitmap field |
| static inline size_t mi_bitmap_index_bit_in_field(mi_bitmap_index_t bitmap_idx) { |
| return (bitmap_idx % MI_BITMAP_FIELD_BITS); |
| } |
| |
| // Get the full bit index |
| static inline size_t mi_bitmap_index_bit(mi_bitmap_index_t bitmap_idx) { |
| return bitmap_idx; |
| } |
| |
| /* ----------------------------------------------------------- |
| Claim a bit sequence atomically |
| ----------------------------------------------------------- */ |
| |
| // Try to atomically claim a sequence of `count` bits in a single |
| // field at `idx` in `bitmap`. Returns `true` on success. |
| bool _mi_bitmap_try_find_claim_field(mi_bitmap_t bitmap, size_t idx, const size_t count, mi_bitmap_index_t* bitmap_idx); |
| |
| // Starts at idx, and wraps around to search in all `bitmap_fields` fields. |
| // For now, `count` can be at most MI_BITMAP_FIELD_BITS and will never cross fields. |
| bool _mi_bitmap_try_find_from_claim(mi_bitmap_t bitmap, const size_t bitmap_fields, const size_t start_field_idx, const size_t count, mi_bitmap_index_t* bitmap_idx); |
| |
| // Like _mi_bitmap_try_find_from_claim but with an extra predicate that must be fullfilled |
| typedef bool (mi_cdecl *mi_bitmap_pred_fun_t)(mi_bitmap_index_t bitmap_idx, void* pred_arg); |
| bool _mi_bitmap_try_find_from_claim_pred(mi_bitmap_t bitmap, const size_t bitmap_fields, const size_t start_field_idx, const size_t count, mi_bitmap_pred_fun_t pred_fun, void* pred_arg, mi_bitmap_index_t* bitmap_idx); |
| |
| // Set `count` bits at `bitmap_idx` to 0 atomically |
| // Returns `true` if all `count` bits were 1 previously. |
| bool _mi_bitmap_unclaim(mi_bitmap_t bitmap, size_t bitmap_fields, size_t count, mi_bitmap_index_t bitmap_idx); |
| |
| // Try to set `count` bits at `bitmap_idx` from 0 to 1 atomically. |
| // Returns `true` if successful when all previous `count` bits were 0. |
| bool _mi_bitmap_try_claim(mi_bitmap_t bitmap, size_t bitmap_fields, size_t count, mi_bitmap_index_t bitmap_idx); |
| |
| // Set `count` bits at `bitmap_idx` to 1 atomically |
| // Returns `true` if all `count` bits were 0 previously. `any_zero` is `true` if there was at least one zero bit. |
| bool _mi_bitmap_claim(mi_bitmap_t bitmap, size_t bitmap_fields, size_t count, mi_bitmap_index_t bitmap_idx, bool* any_zero); |
| |
| bool _mi_bitmap_is_claimed(mi_bitmap_t bitmap, size_t bitmap_fields, size_t count, mi_bitmap_index_t bitmap_idx); |
| bool _mi_bitmap_is_any_claimed(mi_bitmap_t bitmap, size_t bitmap_fields, size_t count, mi_bitmap_index_t bitmap_idx); |
| |
| |
| //-------------------------------------------------------------------------- |
| // the `_across` functions work on bitmaps where sequences can cross over |
| // between the fields. This is used in arena allocation |
| //-------------------------------------------------------------------------- |
| |
| // Find `count` bits of zeros and set them to 1 atomically; returns `true` on success. |
| // Starts at idx, and wraps around to search in all `bitmap_fields` fields. |
| bool _mi_bitmap_try_find_from_claim_across(mi_bitmap_t bitmap, const size_t bitmap_fields, const size_t start_field_idx, const size_t count, mi_bitmap_index_t* bitmap_idx); |
| |
| // Set `count` bits at `bitmap_idx` to 0 atomically |
| // Returns `true` if all `count` bits were 1 previously. |
| bool _mi_bitmap_unclaim_across(mi_bitmap_t bitmap, size_t bitmap_fields, size_t count, mi_bitmap_index_t bitmap_idx); |
| |
| // Set `count` bits at `bitmap_idx` to 1 atomically |
| // Returns `true` if all `count` bits were 0 previously. `any_zero` is `true` if there was at least one zero bit. |
| bool _mi_bitmap_claim_across(mi_bitmap_t bitmap, size_t bitmap_fields, size_t count, mi_bitmap_index_t bitmap_idx, bool* pany_zero); |
| |
| bool _mi_bitmap_is_claimed_across(mi_bitmap_t bitmap, size_t bitmap_fields, size_t count, mi_bitmap_index_t bitmap_idx); |
| bool _mi_bitmap_is_any_claimed_across(mi_bitmap_t bitmap, size_t bitmap_fields, size_t count, mi_bitmap_index_t bitmap_idx); |
| |
| #endif |