diff --git a/ide/vs2019/mimalloc.vcxproj b/ide/vs2019/mimalloc.vcxproj
index f38a7a11..6cfd76fa 100644
--- a/ide/vs2019/mimalloc.vcxproj
+++ b/ide/vs2019/mimalloc.vcxproj
@@ -116,7 +116,7 @@
true
true
../../include
- MI_DEBUG=1;%(PreprocessorDefinitions);
+ MI_DEBUG=2;%(PreprocessorDefinitions);
CompileAsCpp
false
stdcpp17
diff --git a/src/arena.c b/src/arena.c
new file mode 100644
index 00000000..b25732d7
--- /dev/null
+++ b/src/arena.c
@@ -0,0 +1,366 @@
+/* ----------------------------------------------------------------------------
+Copyright (c) 2019, 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.
+-----------------------------------------------------------------------------*/
+
+/* ----------------------------------------------------------------------------
+
+-----------------------------------------------------------------------------*/
+#include "mimalloc.h"
+#include "mimalloc-internal.h"
+#include "mimalloc-atomic.h"
+
+#include // memset
+
+/* -----------------------------------------------------------
+ Arena allocation
+----------------------------------------------------------- */
+
+#define MI_SEGMENT_ALIGN MI_SEGMENT_SIZE
+#define MI_ARENA_BLOCK_SIZE MI_SEGMENT_SIZE
+#define MI_MAX_ARENAS (64)
+
+// Block info: bit 0 contains the `in_use` bit, the upper bits the
+// size in count of arena blocks.
+typedef uintptr_t mi_block_info_t;
+
+// A memory arena descriptor
+typedef struct mi_arena_s {
+ uint8_t* start; // the start of the memory area
+ size_t block_count; // size of the area in arena blocks (of `MI_ARENA_BLOCK_SIZE`)
+ bool is_zero_init; // is the arena zero initialized?
+ bool is_large; // large OS page allocated
+ _Atomic(uintptr_t) block_bottom; // optimization to start the search for free blocks
+ _Atomic(mi_block_info_t) blocks[1]; // `block_count` block info's
+} mi_arena_t;
+
+
+// The available arenas
+static _Atomic(mi_arena_t*) mi_arenas[MI_MAX_ARENAS];
+static _Atomic(uintptr_t) mi_arena_count; // = 0
+
+
+/* -----------------------------------------------------------
+ Arena allocations get a memory id where the lower 8 bits are
+ the arena index +1, and the upper bits the block index.
+----------------------------------------------------------- */
+
+// Use `SIZE_MAX` as a special id for direct OS allocated memory.
+#define MI_MEMID_OS (SIZE_MAX)
+
+static size_t mi_memid_create(size_t arena_index, size_t block_index) {
+ mi_assert_internal(arena_index < 0xFE);
+ return ((block_index << 8) | ((arena_index+1) & 0xFF));
+}
+
+static void mi_memid_indices(size_t memid, size_t* arena_index, size_t* block_index) {
+ mi_assert_internal(memid != MI_MEMID_OS);
+ mi_assert_internal(memid != 0);
+ *arena_index = (memid & 0xFF) - 1;
+ *block_index = (memid >> 8);
+}
+
+/* -----------------------------------------------------------
+ Block info
+----------------------------------------------------------- */
+
+static bool mi_block_is_in_use(mi_block_info_t info) {
+ return ((info&1) != 0);
+}
+
+static size_t mi_block_count(mi_block_info_t info) {
+ return (info>>1);
+}
+
+static mi_block_info_t mi_block_info_create(size_t bcount, bool in_use) {
+ return (((mi_block_info_t)bcount << 1) | (in_use ? 1 : 0));
+}
+
+
+/* -----------------------------------------------------------
+ Thread safe allocation in an arena
+----------------------------------------------------------- */
+
+static void* mi_arena_allocx(mi_arena_t* arena, size_t start_idx, size_t end_idx, size_t needed_bcount, bool* is_zero, size_t* block_index)
+{
+ // Scan linearly through all block info's
+ // Skipping used ranges, coalescing free ranges on demand.
+ mi_assert_internal(needed_bcount > 0);
+ mi_assert_internal(start_idx <= arena->block_count);
+ mi_assert_internal(end_idx <= arena->block_count);
+ _Atomic(mi_block_info_t)* block = &arena->blocks[start_idx];
+ _Atomic(mi_block_info_t)* end = &arena->blocks[end_idx];
+ while (block < end) {
+ mi_block_info_t binfo = mi_atomic_read_relaxed(block);
+ size_t bcount = mi_block_count(binfo);
+ if (mi_block_is_in_use(binfo)) {
+ // in-use, skip ahead
+ mi_assert_internal(bcount > 0);
+ block += bcount;
+ }
+ else {
+ // free blocks
+ if (bcount==0) {
+ // optimization:
+ // use 0 initialized blocks at the end, to use single atomic operation
+ // initially to reduce contention (as we don't need to split)
+ if (block + needed_bcount > end) {
+ return NULL; // does not fit
+ }
+ else if (!mi_atomic_cas_weak(block, mi_block_info_create(needed_bcount, true), binfo)) {
+ // ouch, someone else was quicker. Try again..
+ continue;
+ }
+ else {
+ // we got it: return a pointer to the claimed memory
+ ptrdiff_t idx = (block - arena->blocks);
+ *is_zero = arena->is_zero_init;
+ *block_index = idx;
+ return (arena->start + (idx*MI_ARENA_BLOCK_SIZE));
+ }
+ }
+
+ mi_assert_internal(bcount>0);
+ if (needed_bcount > bcount) {
+#if 0 // MI_NO_ARENA_COALESCE
+ block += bcount; // too small, skip to the next range
+ continue;
+#else
+ // too small, try to coalesce
+ _Atomic(mi_block_info_t)* block_next = block + bcount;
+ if (block_next >= end) {
+ return NULL; // does not fit
+ }
+ mi_block_info_t binfo_next = mi_atomic_read(block_next);
+ size_t bcount_next = mi_block_count(binfo_next);
+ if (mi_block_is_in_use(binfo_next)) {
+ // next block is in use, cannot coalesce
+ block += (bcount + bcount_next); // skip ahea over both blocks
+ }
+ else {
+ // next block is free, try to coalesce
+ // first set the next one to being used to prevent dangling ranges
+ if (!mi_atomic_cas_strong(block_next, mi_block_info_create(bcount_next, true), binfo_next)) {
+ // someone else got in before us.. try again
+ continue;
+ }
+ else {
+ if (!mi_atomic_cas_strong(block, mi_block_info_create(bcount + bcount_next, true), binfo)) { // use strong to increase success chance
+ // someone claimed/coalesced the block in the meantime
+ // first free the next block again..
+ bool ok = mi_atomic_cas_strong(block_next, mi_block_info_create(bcount_next, false), binfo_next); // must be strong
+ mi_assert(ok); UNUSED(ok);
+ // and try again
+ continue;
+ }
+ else {
+ // coalesced! try again
+ // todo: we could optimize here to immediately claim the block if the
+ // coalesced size is a fit instead of retrying. Keep it simple for now.
+ continue;
+ }
+ }
+ }
+#endif
+ }
+ else { // needed_bcount <= bcount
+ mi_assert_internal(needed_bcount <= bcount);
+ // it fits, claim the whole block
+ if (!mi_atomic_cas_weak(block, mi_block_info_create(bcount, true), binfo)) {
+ // ouch, someone else was quicker. Try again..
+ continue;
+ }
+ else {
+ // got it, now split off the needed part
+ if (needed_bcount < bcount) {
+ mi_atomic_write(block + needed_bcount, mi_block_info_create(bcount - needed_bcount, false));
+ mi_atomic_write(block, mi_block_info_create(needed_bcount, true));
+ }
+ // return a pointer to the claimed memory
+ ptrdiff_t idx = (block - arena->blocks);
+ *is_zero = false;
+ *block_index = idx;
+ return (arena->start + (idx*MI_ARENA_BLOCK_SIZE));
+ }
+ }
+ }
+ }
+ // no success
+ return NULL;
+}
+
+// Try to reduce search time by starting from bottom and wrap around.
+static void* mi_arena_alloc(mi_arena_t* arena, size_t needed_bcount, bool* is_zero, size_t* block_index)
+{
+ uintptr_t bottom = mi_atomic_read_relaxed(&arena->block_bottom);
+ void* p = mi_arena_allocx(arena, bottom, arena->block_count, needed_bcount, is_zero, block_index);
+ if (p == NULL && bottom > 0) {
+ // try again from the start
+ p = mi_arena_allocx(arena, 0, bottom, needed_bcount, is_zero, block_index);
+ }
+ if (p != NULL) {
+ mi_atomic_write(&arena->block_bottom, *block_index);
+ }
+ return p;
+}
+
+/* -----------------------------------------------------------
+ Arena Allocation
+----------------------------------------------------------- */
+
+void* _mi_arena_alloc_aligned(size_t size, size_t alignment, bool* commit, bool* large, bool* is_zero, size_t* memid, mi_os_tld_t* tld) {
+ mi_assert_internal(memid != NULL && tld != NULL);
+ mi_assert_internal(size > 0);
+ *memid = MI_MEMID_OS;
+ *is_zero = false;
+ bool default_large = false;
+ if (large==NULL) large = &default_large; // ensure `large != NULL`
+
+ // try to allocate in an arena if the alignment is small enough
+ // and if there is not too much waste around the `MI_ARENA_BLOCK_SIZE`.
+ if (alignment <= MI_SEGMENT_ALIGN &&
+ size >= 3*(MI_ARENA_BLOCK_SIZE/4) && // > 48MiB (not more than 25% waste)
+ !(size > MI_ARENA_BLOCK_SIZE && size < 3*(MI_ARENA_BLOCK_SIZE/2)) // ! <64MiB - 96MiB>
+ )
+ {
+ size_t asize = _mi_align_up(size, MI_ARENA_BLOCK_SIZE);
+ size_t bcount = asize / MI_ARENA_BLOCK_SIZE;
+
+ mi_assert_internal(size <= bcount*MI_ARENA_BLOCK_SIZE);
+ for (size_t i = 0; i < MI_MAX_ARENAS; i++) {
+ mi_arena_t* arena = (mi_arena_t*)mi_atomic_read_ptr_relaxed(mi_atomic_cast(void*, &mi_arenas[i]));
+ if (arena==NULL) break;
+ size_t block_index = SIZE_MAX;
+ void* p = mi_arena_alloc(arena, bcount, is_zero, &block_index);
+ if (p != NULL) {
+ mi_assert_internal(block_index != SIZE_MAX);
+ #if MI_DEBUG>=1
+ _Atomic(mi_block_info_t)* block = &arena->blocks[block_index];
+ mi_block_info_t binfo = mi_atomic_read(block);
+ mi_assert_internal(mi_block_is_in_use(binfo));
+ mi_assert_internal(mi_block_count(binfo)*MI_ARENA_BLOCK_SIZE >= size);
+ #endif
+ *memid = mi_memid_create(i, block_index);
+ *commit = true; // TODO: support commit on demand?
+ *large = arena->is_large;
+ mi_assert_internal((uintptr_t)p % alignment == 0);
+ return p;
+ }
+ }
+ }
+
+ // fall back to the OS
+ *is_zero = true;
+ *memid = MI_MEMID_OS;
+ return _mi_os_alloc_aligned(size, alignment, *commit, large, tld);
+}
+
+void* _mi_arena_alloc(size_t size, bool* commit, bool* large, bool* is_zero, size_t* memid, mi_os_tld_t* tld)
+{
+ return _mi_arena_alloc_aligned(size, MI_ARENA_BLOCK_SIZE, commit, large, is_zero, memid, tld);
+}
+
+/* -----------------------------------------------------------
+ Arena free
+----------------------------------------------------------- */
+
+void _mi_arena_free(void* p, size_t size, size_t memid, mi_stats_t* stats) {
+ mi_assert_internal(size > 0 && stats != NULL);
+ if (p==NULL) return;
+ if (size==0) return;
+ if (memid == MI_MEMID_OS) {
+ // was a direct OS allocation, pass through
+ _mi_os_free(p, size, stats);
+ }
+ else {
+ mi_assert_internal(memid != 0);
+ // allocated in an arena
+ size_t arena_idx;
+ size_t block_idx;
+ mi_memid_indices(memid, &arena_idx, &block_idx);
+ mi_assert_internal(arena_idx < MI_MAX_ARENAS);
+ mi_arena_t* arena = (mi_arena_t*)mi_atomic_read_ptr_relaxed(mi_atomic_cast(void*, &mi_arenas[arena_idx]));
+ mi_assert_internal(arena != NULL);
+ if (arena == NULL) {
+ _mi_fatal_error("trying to free from non-existent arena: %p, size %zu, memid: 0x%zx\n", p, size, memid);
+ return;
+ }
+ mi_assert_internal(arena->block_count > block_idx);
+ if (arena->block_count <= block_idx) {
+ _mi_fatal_error("trying to free from non-existent block: %p, size %zu, memid: 0x%zx\n", p, size, memid);
+ return;
+ }
+ _Atomic(mi_block_info_t)* block = &arena->blocks[block_idx];
+ mi_block_info_t binfo = mi_atomic_read_relaxed(block);
+ mi_assert_internal(mi_block_is_in_use(binfo));
+ mi_assert_internal(mi_block_count(binfo)*MI_ARENA_BLOCK_SIZE >= size);
+ if (!mi_block_is_in_use(binfo)) {
+ _mi_fatal_error("trying to free an already freed block: %p, size %zu\n", p, size);
+ return;
+ };
+ bool ok = mi_atomic_cas_strong(block, mi_block_info_create(mi_block_count(binfo), false), binfo);
+ mi_assert_internal(ok);
+ if (!ok) {
+ _mi_warning_message("unable to free arena block: %p, info 0x%zx", p, binfo);
+ }
+ if (block_idx < mi_atomic_read_relaxed(&arena->block_bottom)) {
+ mi_atomic_write(&arena->block_bottom, block_idx);
+ }
+ }
+}
+
+/* -----------------------------------------------------------
+ Add an arena.
+----------------------------------------------------------- */
+
+static bool mi_arena_add(mi_arena_t* arena) {
+ mi_assert_internal(arena != NULL);
+ mi_assert_internal((uintptr_t)arena->start % MI_SEGMENT_ALIGN == 0);
+ mi_assert_internal(arena->block_count > 0);
+ mi_assert_internal(mi_mem_is_zero(arena->blocks,arena->block_count*sizeof(mi_block_info_t)));
+
+ uintptr_t i = mi_atomic_addu(&mi_arena_count,1);
+ if (i >= MI_MAX_ARENAS) {
+ mi_atomic_subu(&mi_arena_count, 1);
+ return false;
+ }
+ mi_atomic_write_ptr(mi_atomic_cast(void*,&mi_arenas[i]), arena);
+ return true;
+}
+
+
+/* -----------------------------------------------------------
+ Reserve a huge page arena.
+ TODO: improve OS api to just reserve and claim a huge
+ page area at once, (and return the total size).
+----------------------------------------------------------- */
+
+#include
+
+void* _mi_os_try_alloc_from_huge_reserved(size_t size, size_t try_alignment);
+
+int mi_reserve_huge_os_pages(size_t pages, double max_secs, size_t* pages_reserved) mi_attr_noexcept {
+ size_t pages_reserved_default = 0;
+ if (pages_reserved==NULL) pages_reserved = &pages_reserved_default;
+ int err = _mi_os_reserve_huge_os_pages(pages, max_secs, pages_reserved);
+ if (*pages_reserved==0) return err;
+ size_t hsize = (*pages_reserved) * GiB;
+ void* p = _mi_os_try_alloc_from_huge_reserved(hsize, MI_SEGMENT_ALIGN);
+ mi_assert_internal(p != NULL);
+ if (p == NULL) return ENOMEM;
+ size_t bcount = hsize / MI_ARENA_BLOCK_SIZE;
+ size_t asize = sizeof(mi_arena_t) + (bcount*sizeof(mi_block_info_t)); // one too much
+ mi_arena_t* arena = (mi_arena_t*)_mi_os_alloc(asize, &_mi_heap_default->tld->stats);
+ if (arena == NULL) return ENOMEM;
+ arena->block_count = bcount;
+ arena->start = (uint8_t*)p;
+ arena->block_bottom = 0;
+ arena->is_large = true;
+ arena->is_zero_init = true;
+ memset(arena->blocks, 0, bcount * sizeof(mi_block_info_t));
+ //mi_atomic_write(&arena->blocks[0], mi_block_info_create(bcount, false));
+ mi_arena_add(arena);
+ return 0;
+}
\ No newline at end of file