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Diffstat (limited to 'source/luametatex/source/libraries/mimalloc/src/region.c')
| -rw-r--r-- | source/luametatex/source/libraries/mimalloc/src/region.c | 505 |
1 files changed, 505 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/mimalloc/src/region.c b/source/luametatex/source/libraries/mimalloc/src/region.c new file mode 100644 index 000000000..72ce84947 --- /dev/null +++ b/source/luametatex/source/libraries/mimalloc/src/region.c @@ -0,0 +1,505 @@ +/* ---------------------------------------------------------------------------- +Copyright (c) 2019-2020, 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. +-----------------------------------------------------------------------------*/ + +/* ---------------------------------------------------------------------------- +This implements a layer between the raw OS memory (VirtualAlloc/mmap/sbrk/..) +and the segment and huge object allocation by mimalloc. There may be multiple +implementations of this (one could be the identity going directly to the OS, +another could be a simple cache etc), but the current one uses large "regions". +In contrast to the rest of mimalloc, the "regions" are shared between threads and +need to be accessed using atomic operations. +We need this memory layer between the raw OS calls because of: +1. on `sbrk` like systems (like WebAssembly) we need our own memory maps in order + to reuse memory effectively. +2. It turns out that for large objects, between 1MiB and 32MiB (?), the cost of + an OS allocation/free is still (much) too expensive relative to the accesses + in that object :-( (`malloc-large` tests this). This means we need a cheaper + way to reuse memory. +3. This layer allows for NUMA aware allocation. + +Possible issues: +- (2) can potentially be addressed too with a small cache per thread which is much + simpler. Generally though that requires shrinking of huge pages, and may overuse + memory per thread. (and is not compatible with `sbrk`). +- Since the current regions are per-process, we need atomic operations to + claim blocks which may be contended +- In the worst case, we need to search the whole region map (16KiB for 256GiB) + linearly. At what point will direct OS calls be faster? Is there a way to + do this better without adding too much complexity? +-----------------------------------------------------------------------------*/ +#include "mimalloc.h" +#include "mimalloc-internal.h" +#include "mimalloc-atomic.h" + +#include <string.h> // memset + +#include "bitmap.h" + +// Internal raw OS interface +size_t _mi_os_large_page_size(void); +bool _mi_os_protect(void* addr, size_t size); +bool _mi_os_unprotect(void* addr, size_t size); +bool _mi_os_commit(void* p, size_t size, bool* is_zero, mi_stats_t* stats); +bool _mi_os_decommit(void* p, size_t size, mi_stats_t* stats); +bool _mi_os_reset(void* p, size_t size, mi_stats_t* stats); +bool _mi_os_unreset(void* p, size_t size, bool* is_zero, mi_stats_t* stats); + +// arena.c +void _mi_arena_free(void* p, size_t size, size_t memid, bool all_committed, mi_stats_t* stats); +void* _mi_arena_alloc(size_t size, bool* commit, bool* large, bool* is_pinned, bool* is_zero, size_t* memid, mi_os_tld_t* tld); +void* _mi_arena_alloc_aligned(size_t size, size_t alignment, bool* commit, bool* large, bool* is_pinned, bool* is_zero, size_t* memid, mi_os_tld_t* tld); + + + +// Constants +#if (MI_INTPTR_SIZE==8) +#define MI_HEAP_REGION_MAX_SIZE (256 * MI_GiB) // 64KiB for the region map +#elif (MI_INTPTR_SIZE==4) +#define MI_HEAP_REGION_MAX_SIZE (3 * MI_GiB) // ~ KiB for the region map +#else +#error "define the maximum heap space allowed for regions on this platform" +#endif + +#define MI_SEGMENT_ALIGN MI_SEGMENT_SIZE + +#define MI_REGION_MAX_BLOCKS MI_BITMAP_FIELD_BITS +#define MI_REGION_SIZE (MI_SEGMENT_SIZE * MI_BITMAP_FIELD_BITS) // 256MiB (64MiB on 32 bits) +#define MI_REGION_MAX (MI_HEAP_REGION_MAX_SIZE / MI_REGION_SIZE) // 1024 (48 on 32 bits) +#define MI_REGION_MAX_OBJ_BLOCKS (MI_REGION_MAX_BLOCKS/4) // 64MiB +#define MI_REGION_MAX_OBJ_SIZE (MI_REGION_MAX_OBJ_BLOCKS*MI_SEGMENT_SIZE) + +// Region info +typedef union mi_region_info_u { + size_t value; + struct { + bool valid; // initialized? + bool is_large:1; // allocated in fixed large/huge OS pages + bool is_pinned:1; // pinned memory cannot be decommitted + short numa_node; // the associated NUMA node (where -1 means no associated node) + } x; +} mi_region_info_t; + + +// A region owns a chunk of REGION_SIZE (256MiB) (virtual) memory with +// a bit map with one bit per MI_SEGMENT_SIZE (4MiB) block. +typedef struct mem_region_s { + _Atomic(size_t) info; // mi_region_info_t.value + _Atomic(void*) start; // start of the memory area + mi_bitmap_field_t in_use; // bit per in-use block + mi_bitmap_field_t dirty; // track if non-zero per block + mi_bitmap_field_t commit; // track if committed per block + mi_bitmap_field_t reset; // track if reset per block + _Atomic(size_t) arena_memid; // if allocated from a (huge page) arena + _Atomic(size_t) padding; // round to 8 fields (needs to be atomic for msvc, see issue #508) +} mem_region_t; + +// The region map +static mem_region_t regions[MI_REGION_MAX]; + +// Allocated regions +static _Atomic(size_t) regions_count; // = 0; + + +/* ---------------------------------------------------------------------------- +Utility functions +-----------------------------------------------------------------------------*/ + +// Blocks (of 4MiB) needed for the given size. +static size_t mi_region_block_count(size_t size) { + return _mi_divide_up(size, MI_SEGMENT_SIZE); +} + +/* +// Return a rounded commit/reset size such that we don't fragment large OS pages into small ones. +static size_t mi_good_commit_size(size_t size) { + if (size > (SIZE_MAX - _mi_os_large_page_size())) return size; + return _mi_align_up(size, _mi_os_large_page_size()); +} +*/ + +// Return if a pointer points into a region reserved by us. +mi_decl_nodiscard bool mi_is_in_heap_region(const void* p) mi_attr_noexcept { + if (p==NULL) return false; + size_t count = mi_atomic_load_relaxed(®ions_count); + for (size_t i = 0; i < count; i++) { + uint8_t* start = (uint8_t*)mi_atomic_load_ptr_relaxed(uint8_t, ®ions[i].start); + if (start != NULL && (uint8_t*)p >= start && (uint8_t*)p < start + MI_REGION_SIZE) return true; + } + return false; +} + + +static void* mi_region_blocks_start(const mem_region_t* region, mi_bitmap_index_t bit_idx) { + uint8_t* start = (uint8_t*)mi_atomic_load_ptr_acquire(uint8_t, &((mem_region_t*)region)->start); + mi_assert_internal(start != NULL); + return (start + (bit_idx * MI_SEGMENT_SIZE)); +} + +static size_t mi_memid_create(mem_region_t* region, mi_bitmap_index_t bit_idx) { + mi_assert_internal(bit_idx < MI_BITMAP_FIELD_BITS); + size_t idx = region - regions; + mi_assert_internal(®ions[idx] == region); + return (idx*MI_BITMAP_FIELD_BITS + bit_idx)<<1; +} + +static size_t mi_memid_create_from_arena(size_t arena_memid) { + return (arena_memid << 1) | 1; +} + + +static bool mi_memid_is_arena(size_t id, mem_region_t** region, mi_bitmap_index_t* bit_idx, size_t* arena_memid) { + if ((id&1)==1) { + if (arena_memid != NULL) *arena_memid = (id>>1); + return true; + } + else { + size_t idx = (id >> 1) / MI_BITMAP_FIELD_BITS; + *bit_idx = (mi_bitmap_index_t)(id>>1) % MI_BITMAP_FIELD_BITS; + *region = ®ions[idx]; + return false; + } +} + + +/* ---------------------------------------------------------------------------- + Allocate a region is allocated from the OS (or an arena) +-----------------------------------------------------------------------------*/ + +static bool mi_region_try_alloc_os(size_t blocks, bool commit, bool allow_large, mem_region_t** region, mi_bitmap_index_t* bit_idx, mi_os_tld_t* tld) +{ + // not out of regions yet? + if (mi_atomic_load_relaxed(®ions_count) >= MI_REGION_MAX - 1) return false; + + // try to allocate a fresh region from the OS + bool region_commit = (commit && mi_option_is_enabled(mi_option_eager_region_commit)); + bool region_large = (commit && allow_large); + bool is_zero = false; + bool is_pinned = false; + size_t arena_memid = 0; + void* const start = _mi_arena_alloc_aligned(MI_REGION_SIZE, MI_SEGMENT_ALIGN, ®ion_commit, ®ion_large, &is_pinned, &is_zero, &arena_memid, tld); + if (start == NULL) return false; + mi_assert_internal(!(region_large && !allow_large)); + mi_assert_internal(!region_large || region_commit); + + // claim a fresh slot + const size_t idx = mi_atomic_increment_acq_rel(®ions_count); + if (idx >= MI_REGION_MAX) { + mi_atomic_decrement_acq_rel(®ions_count); + _mi_arena_free(start, MI_REGION_SIZE, arena_memid, region_commit, tld->stats); + _mi_warning_message("maximum regions used: %zu GiB (perhaps recompile with a larger setting for MI_HEAP_REGION_MAX_SIZE)", _mi_divide_up(MI_HEAP_REGION_MAX_SIZE, MI_GiB)); + return false; + } + + // allocated, initialize and claim the initial blocks + mem_region_t* r = ®ions[idx]; + r->arena_memid = arena_memid; + mi_atomic_store_release(&r->in_use, (size_t)0); + mi_atomic_store_release(&r->dirty, (is_zero ? 0 : MI_BITMAP_FIELD_FULL)); + mi_atomic_store_release(&r->commit, (region_commit ? MI_BITMAP_FIELD_FULL : 0)); + mi_atomic_store_release(&r->reset, (size_t)0); + *bit_idx = 0; + _mi_bitmap_claim(&r->in_use, 1, blocks, *bit_idx, NULL); + mi_atomic_store_ptr_release(void,&r->start, start); + + // and share it + mi_region_info_t info; + info.value = 0; // initialize the full union to zero + info.x.valid = true; + info.x.is_large = region_large; + info.x.is_pinned = is_pinned; + info.x.numa_node = (short)_mi_os_numa_node(tld); + mi_atomic_store_release(&r->info, info.value); // now make it available to others + *region = r; + return true; +} + +/* ---------------------------------------------------------------------------- + Try to claim blocks in suitable regions +-----------------------------------------------------------------------------*/ + +static bool mi_region_is_suitable(const mem_region_t* region, int numa_node, bool allow_large ) { + // initialized at all? + mi_region_info_t info; + info.value = mi_atomic_load_relaxed(&((mem_region_t*)region)->info); + if (info.value==0) return false; + + // numa correct + if (numa_node >= 0) { // use negative numa node to always succeed + int rnode = info.x.numa_node; + if (rnode >= 0 && rnode != numa_node) return false; + } + + // check allow-large + if (!allow_large && info.x.is_large) return false; + + return true; +} + + +static bool mi_region_try_claim(int numa_node, size_t blocks, bool allow_large, mem_region_t** region, mi_bitmap_index_t* bit_idx, mi_os_tld_t* tld) +{ + // try all regions for a free slot + const size_t count = mi_atomic_load_relaxed(®ions_count); // monotonic, so ok to be relaxed + size_t idx = tld->region_idx; // Or start at 0 to reuse low addresses? Starting at 0 seems to increase latency though + for (size_t visited = 0; visited < count; visited++, idx++) { + if (idx >= count) idx = 0; // wrap around + mem_region_t* r = ®ions[idx]; + // if this region suits our demand (numa node matches, large OS page matches) + if (mi_region_is_suitable(r, numa_node, allow_large)) { + // then try to atomically claim a segment(s) in this region + if (_mi_bitmap_try_find_claim_field(&r->in_use, 0, blocks, bit_idx)) { + tld->region_idx = idx; // remember the last found position + *region = r; + return true; + } + } + } + return false; +} + + +static void* mi_region_try_alloc(size_t blocks, bool* commit, bool* large, bool* is_pinned, bool* is_zero, size_t* memid, mi_os_tld_t* tld) +{ + mi_assert_internal(blocks <= MI_BITMAP_FIELD_BITS); + mem_region_t* region; + mi_bitmap_index_t bit_idx; + const int numa_node = (_mi_os_numa_node_count() <= 1 ? -1 : _mi_os_numa_node(tld)); + // try to claim in existing regions + if (!mi_region_try_claim(numa_node, blocks, *large, ®ion, &bit_idx, tld)) { + // otherwise try to allocate a fresh region and claim in there + if (!mi_region_try_alloc_os(blocks, *commit, *large, ®ion, &bit_idx, tld)) { + // out of regions or memory + return NULL; + } + } + + // ------------------------------------------------ + // found a region and claimed `blocks` at `bit_idx`, initialize them now + mi_assert_internal(region != NULL); + mi_assert_internal(_mi_bitmap_is_claimed(®ion->in_use, 1, blocks, bit_idx)); + + mi_region_info_t info; + info.value = mi_atomic_load_acquire(®ion->info); + uint8_t* start = (uint8_t*)mi_atomic_load_ptr_acquire(uint8_t,®ion->start); + mi_assert_internal(!(info.x.is_large && !*large)); + mi_assert_internal(start != NULL); + + *is_zero = _mi_bitmap_claim(®ion->dirty, 1, blocks, bit_idx, NULL); + *large = info.x.is_large; + *is_pinned = info.x.is_pinned; + *memid = mi_memid_create(region, bit_idx); + void* p = start + (mi_bitmap_index_bit_in_field(bit_idx) * MI_SEGMENT_SIZE); + + // commit + if (*commit) { + // ensure commit + bool any_uncommitted; + _mi_bitmap_claim(®ion->commit, 1, blocks, bit_idx, &any_uncommitted); + if (any_uncommitted) { + mi_assert_internal(!info.x.is_large && !info.x.is_pinned); + bool commit_zero = false; + if (!_mi_mem_commit(p, blocks * MI_SEGMENT_SIZE, &commit_zero, tld)) { + // failed to commit! unclaim and return + mi_bitmap_unclaim(®ion->in_use, 1, blocks, bit_idx); + return NULL; + } + if (commit_zero) *is_zero = true; + } + } + else { + // no need to commit, but check if already fully committed + *commit = _mi_bitmap_is_claimed(®ion->commit, 1, blocks, bit_idx); + } + mi_assert_internal(!*commit || _mi_bitmap_is_claimed(®ion->commit, 1, blocks, bit_idx)); + + // unreset reset blocks + if (_mi_bitmap_is_any_claimed(®ion->reset, 1, blocks, bit_idx)) { + // some blocks are still reset + mi_assert_internal(!info.x.is_large && !info.x.is_pinned); + mi_assert_internal(!mi_option_is_enabled(mi_option_eager_commit) || *commit || mi_option_get(mi_option_eager_commit_delay) > 0); + mi_bitmap_unclaim(®ion->reset, 1, blocks, bit_idx); + if (*commit || !mi_option_is_enabled(mi_option_reset_decommits)) { // only if needed + bool reset_zero = false; + _mi_mem_unreset(p, blocks * MI_SEGMENT_SIZE, &reset_zero, tld); + if (reset_zero) *is_zero = true; + } + } + mi_assert_internal(!_mi_bitmap_is_any_claimed(®ion->reset, 1, blocks, bit_idx)); + + #if (MI_DEBUG>=2) + if (*commit) { ((uint8_t*)p)[0] = 0; } + #endif + + // and return the allocation + mi_assert_internal(p != NULL); + return p; +} + + +/* ---------------------------------------------------------------------------- + Allocation +-----------------------------------------------------------------------------*/ + +// Allocate `size` memory aligned at `alignment`. Return non NULL on success, with a given memory `id`. +// (`id` is abstract, but `id = idx*MI_REGION_MAP_BITS + bitidx`) +void* _mi_mem_alloc_aligned(size_t size, size_t alignment, bool* commit, bool* large, bool* is_pinned, bool* is_zero, size_t* memid, mi_os_tld_t* tld) +{ + mi_assert_internal(memid != NULL && tld != NULL); + mi_assert_internal(size > 0); + *memid = 0; + *is_zero = false; + *is_pinned = false; + bool default_large = false; + if (large==NULL) large = &default_large; // ensure `large != NULL` + if (size == 0) return NULL; + size = _mi_align_up(size, _mi_os_page_size()); + + // allocate from regions if possible + void* p = NULL; + size_t arena_memid; + const size_t blocks = mi_region_block_count(size); + if (blocks <= MI_REGION_MAX_OBJ_BLOCKS && alignment <= MI_SEGMENT_ALIGN) { + p = mi_region_try_alloc(blocks, commit, large, is_pinned, is_zero, memid, tld); + if (p == NULL) { + _mi_warning_message("unable to allocate from region: size %zu\n", size); + } + } + if (p == NULL) { + // and otherwise fall back to the OS + p = _mi_arena_alloc_aligned(size, alignment, commit, large, is_pinned, is_zero, &arena_memid, tld); + *memid = mi_memid_create_from_arena(arena_memid); + } + + if (p != NULL) { + mi_assert_internal((uintptr_t)p % alignment == 0); +#if (MI_DEBUG>=2) + if (*commit) { ((uint8_t*)p)[0] = 0; } // ensure the memory is committed +#endif + } + return p; +} + + + +/* ---------------------------------------------------------------------------- +Free +-----------------------------------------------------------------------------*/ + +// Free previously allocated memory with a given id. +void _mi_mem_free(void* p, size_t size, size_t id, bool full_commit, bool any_reset, mi_os_tld_t* tld) { + mi_assert_internal(size > 0 && tld != NULL); + if (p==NULL) return; + if (size==0) return; + size = _mi_align_up(size, _mi_os_page_size()); + + size_t arena_memid = 0; + mi_bitmap_index_t bit_idx; + mem_region_t* region; + if (mi_memid_is_arena(id,®ion,&bit_idx,&arena_memid)) { + // was a direct arena allocation, pass through + _mi_arena_free(p, size, arena_memid, full_commit, tld->stats); + } + else { + // allocated in a region + mi_assert_internal(size <= MI_REGION_MAX_OBJ_SIZE); if (size > MI_REGION_MAX_OBJ_SIZE) return; + const size_t blocks = mi_region_block_count(size); + mi_assert_internal(blocks + bit_idx <= MI_BITMAP_FIELD_BITS); + mi_region_info_t info; + info.value = mi_atomic_load_acquire(®ion->info); + mi_assert_internal(info.value != 0); + void* blocks_start = mi_region_blocks_start(region, bit_idx); + mi_assert_internal(blocks_start == p); // not a pointer in our area? + mi_assert_internal(bit_idx + blocks <= MI_BITMAP_FIELD_BITS); + if (blocks_start != p || bit_idx + blocks > MI_BITMAP_FIELD_BITS) return; // or `abort`? + + // committed? + if (full_commit && (size % MI_SEGMENT_SIZE) == 0) { + _mi_bitmap_claim(®ion->commit, 1, blocks, bit_idx, NULL); + } + + if (any_reset) { + // set the is_reset bits if any pages were reset + _mi_bitmap_claim(®ion->reset, 1, blocks, bit_idx, NULL); + } + + // reset the blocks to reduce the working set. + if (!info.x.is_large && !info.x.is_pinned && mi_option_is_enabled(mi_option_segment_reset) + && (mi_option_is_enabled(mi_option_eager_commit) || + mi_option_is_enabled(mi_option_reset_decommits))) // cannot reset halfway committed segments, use only `option_page_reset` instead + { + bool any_unreset; + _mi_bitmap_claim(®ion->reset, 1, blocks, bit_idx, &any_unreset); + if (any_unreset) { + _mi_abandoned_await_readers(); // ensure no more pending write (in case reset = decommit) + _mi_mem_reset(p, blocks * MI_SEGMENT_SIZE, tld); + } + } + + // and unclaim + bool all_unclaimed = mi_bitmap_unclaim(®ion->in_use, 1, blocks, bit_idx); + mi_assert_internal(all_unclaimed); MI_UNUSED(all_unclaimed); + } +} + + +/* ---------------------------------------------------------------------------- + collection +-----------------------------------------------------------------------------*/ +void _mi_mem_collect(mi_os_tld_t* tld) { + // free every region that has no segments in use. + size_t rcount = mi_atomic_load_relaxed(®ions_count); + for (size_t i = 0; i < rcount; i++) { + mem_region_t* region = ®ions[i]; + if (mi_atomic_load_relaxed(®ion->info) != 0) { + // if no segments used, try to claim the whole region + size_t m = mi_atomic_load_relaxed(®ion->in_use); + while (m == 0 && !mi_atomic_cas_weak_release(®ion->in_use, &m, MI_BITMAP_FIELD_FULL)) { /* nothing */ }; + if (m == 0) { + // on success, free the whole region + uint8_t* start = (uint8_t*)mi_atomic_load_ptr_acquire(uint8_t,®ions[i].start); + size_t arena_memid = mi_atomic_load_relaxed(®ions[i].arena_memid); + size_t commit = mi_atomic_load_relaxed(®ions[i].commit); + memset((void*)®ions[i], 0, sizeof(mem_region_t)); // cast to void* to avoid atomic warning + // and release the whole region + mi_atomic_store_release(®ion->info, (size_t)0); + if (start != NULL) { // && !_mi_os_is_huge_reserved(start)) { + _mi_abandoned_await_readers(); // ensure no pending reads + _mi_arena_free(start, MI_REGION_SIZE, arena_memid, (~commit == 0), tld->stats); + } + } + } + } +} + + +/* ---------------------------------------------------------------------------- + Other +-----------------------------------------------------------------------------*/ + +bool _mi_mem_reset(void* p, size_t size, mi_os_tld_t* tld) { + return _mi_os_reset(p, size, tld->stats); +} + +bool _mi_mem_unreset(void* p, size_t size, bool* is_zero, mi_os_tld_t* tld) { + return _mi_os_unreset(p, size, is_zero, tld->stats); +} + +bool _mi_mem_commit(void* p, size_t size, bool* is_zero, mi_os_tld_t* tld) { + return _mi_os_commit(p, size, is_zero, tld->stats); +} + +bool _mi_mem_decommit(void* p, size_t size, mi_os_tld_t* tld) { + return _mi_os_decommit(p, size, tld->stats); +} + +bool _mi_mem_protect(void* p, size_t size) { + return _mi_os_protect(p, size); +} + +bool _mi_mem_unprotect(void* p, size_t size) { + return _mi_os_unprotect(p, size); +} |