/* ---------------------------------------------------------------------------- Copyright (c) 2018, 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. -----------------------------------------------------------------------------*/ #pragma once #ifndef MIMALLOC_TYPES_H #define MIMALLOC_TYPES_H #include // ptrdiff_t #include // uintptr_t, uint16_t, etc #include // _Atomic // Minimal alignment necessary. On most platforms 16 bytes are needed // due to SSE registers for example. This must be at least `MI_INTPTR_SIZE` #define MI_MAX_ALIGN_SIZE 16 // sizeof(max_align_t) // ------------------------------------------------------ // Variants // ------------------------------------------------------ // Define NDEBUG in the release version to disable assertions. // #define NDEBUG // Define MI_STAT as 1 to maintain statistics; set it to 2 to have detailed statistics (but costs some performance). // #define MI_STAT 1 // Define MI_SECURE to enable security mitigations // #define MI_SECURE 1 // guard page around metadata // #define MI_SECURE 2 // guard page around each mimalloc page // #define MI_SECURE 3 // encode free lists (detect corrupted free list (buffer overflow), and invalid pointer free) // #define MI_SECURE 4 // checks for double free. (may be more expensive) #if !defined(MI_SECURE) #define MI_SECURE 0 #endif // Define MI_DEBUG for debug mode // #define MI_DEBUG 1 // basic assertion checks and statistics, check double free, corrupted free list, and invalid pointer free. // #define MI_DEBUG 2 // + internal assertion checks // #define MI_DEBUG 3 // + extensive internal invariant checking (cmake -DMI_DEBUG_FULL=ON) #if !defined(MI_DEBUG) #if !defined(NDEBUG) || defined(_DEBUG) #define MI_DEBUG 2 #else #define MI_DEBUG 0 #endif #endif // Reserve extra padding at the end of each block to be more resilient against heap block overflows. // The padding can detect byte-precise buffer overflow on free. #if !defined(MI_PADDING) && (MI_DEBUG>=1) #define MI_PADDING 1 #endif // Encoded free lists allow detection of corrupted free lists // and can detect buffer overflows, modify after free, and double `free`s. #if (MI_SECURE>=3 || MI_DEBUG>=1 || MI_PADDING > 0) #define MI_ENCODE_FREELIST 1 #endif // ------------------------------------------------------ // Platform specific values // ------------------------------------------------------ // ------------------------------------------------------ // Size of a pointer. // We assume that `sizeof(void*)==sizeof(intptr_t)` // and it holds for all platforms we know of. // // However, the C standard only requires that: // p == (void*)((intptr_t)p)) // but we also need: // i == (intptr_t)((void*)i) // or otherwise one might define an intptr_t type that is larger than a pointer... // ------------------------------------------------------ #if INTPTR_MAX == 9223372036854775807LL # define MI_INTPTR_SHIFT (3) #elif INTPTR_MAX == 2147483647LL # define MI_INTPTR_SHIFT (2) #else #error platform must be 32 or 64 bits #endif #define MI_INTPTR_SIZE (1<= 655360) #error "define more bins" #endif // Used as a special value to encode block sizes in 32 bits. #define MI_HUGE_BLOCK_SIZE ((uint32_t)MI_HUGE_OBJ_SIZE_MAX) // The free lists use encoded next fields // (Only actually encodes when MI_ENCODED_FREELIST is defined.) typedef uintptr_t mi_encoded_t; // free lists contain blocks typedef struct mi_block_s { mi_encoded_t next; } mi_block_t; // The delayed flags are used for efficient multi-threaded free-ing typedef enum mi_delayed_e { MI_USE_DELAYED_FREE = 0, // push on the owning heap thread delayed list MI_DELAYED_FREEING = 1, // temporary: another thread is accessing the owning heap MI_NO_DELAYED_FREE = 2, // optimize: push on page local thread free queue if another block is already in the heap thread delayed free list MI_NEVER_DELAYED_FREE = 3 // sticky, only resets on page reclaim } mi_delayed_t; // The `in_full` and `has_aligned` page flags are put in a union to efficiently // test if both are false (`full_aligned == 0`) in the `mi_free` routine. typedef union mi_page_flags_s { uint8_t full_aligned; struct { uint8_t in_full : 1; uint8_t has_aligned : 1; } x; } mi_page_flags_t; // Thread free list. // We use the bottom 2 bits of the pointer for mi_delayed_t flags typedef uintptr_t mi_thread_free_t; // A page contains blocks of one specific size (`block_size`). // Each page has three list of free blocks: // `free` for blocks that can be allocated, // `local_free` for freed blocks that are not yet available to `mi_malloc` // `thread_free` for freed blocks by other threads // The `local_free` and `thread_free` lists are migrated to the `free` list // when it is exhausted. The separate `local_free` list is necessary to // implement a monotonic heartbeat. The `thread_free` list is needed for // avoiding atomic operations in the common case. // // // `used - |thread_free|` == actual blocks that are in use (alive) // `used - |thread_free| + |free| + |local_free| == capacity` // // We don't count `freed` (as |free|) but use `used` to reduce // the number of memory accesses in the `mi_page_all_free` function(s). // // Notes: // - Access is optimized for `mi_free` and `mi_page_alloc` (in `alloc.c`) // - Using `uint16_t` does not seem to slow things down // - The size is 8 words on 64-bit which helps the page index calculations // (and 10 words on 32-bit, and encoded free lists add 2 words. Sizes 10 // and 12 are still good for address calculation) // - To limit the structure size, the `xblock_size` is 32-bits only; for // blocks > MI_HUGE_BLOCK_SIZE the size is determined from the segment page size // - `thread_free` uses the bottom bits as a delayed-free flags to optimize // concurrent frees where only the first concurrent free adds to the owning // heap `thread_delayed_free` list (see `alloc.c:mi_free_block_mt`). // The invariant is that no-delayed-free is only set if there is // at least one block that will be added, or as already been added, to // the owning heap `thread_delayed_free` list. This guarantees that pages // will be freed correctly even if only other threads free blocks. typedef struct mi_page_s { // "owned" by the segment uint8_t segment_idx; // index in the segment `pages` array, `page == &segment->pages[page->segment_idx]` uint8_t segment_in_use:1; // `true` if the segment allocated this page uint8_t is_reset:1; // `true` if the page memory was reset uint8_t is_committed:1; // `true` if the page virtual memory is committed uint8_t is_zero_init:1; // `true` if the page was zero initialized // layout like this to optimize access in `mi_malloc` and `mi_free` uint16_t capacity; // number of blocks committed, must be the first field, see `segment.c:page_clear` uint16_t reserved; // number of blocks reserved in memory mi_page_flags_t flags; // `in_full` and `has_aligned` flags (8 bits) uint8_t is_zero:1; // `true` if the blocks in the free list are zero initialized uint8_t retire_expire:7; // expiration count for retired blocks mi_block_t* free; // list of available free blocks (`malloc` allocates from this list) #ifdef MI_ENCODE_FREELIST uintptr_t keys[2]; // two random keys to encode the free lists (see `_mi_block_next`) #endif uint32_t used; // number of blocks in use (including blocks in `local_free` and `thread_free`) uint32_t xblock_size; // size available in each block (always `>0`) mi_block_t* local_free; // list of deferred free blocks by this thread (migrates to `free`) volatile _Atomic(mi_thread_free_t) xthread_free; // list of deferred free blocks freed by other threads volatile _Atomic(uintptr_t) xheap; struct mi_page_s* next; // next page owned by this thread with the same `block_size` struct mi_page_s* prev; // previous page owned by this thread with the same `block_size` } mi_page_t; typedef enum mi_page_kind_e { MI_PAGE_SMALL, // small blocks go into 64kb pages inside a segment MI_PAGE_MEDIUM, // medium blocks go into 512kb pages inside a segment MI_PAGE_LARGE, // larger blocks go into a single page spanning a whole segment MI_PAGE_HUGE // huge blocks (>512kb) are put into a single page in a segment of the exact size (but still 2mb aligned) } mi_page_kind_t; // Segments are large allocated memory blocks (2mb on 64 bit) from // the OS. Inside segments we allocated fixed size _pages_ that // contain blocks. typedef struct mi_segment_s { // memory fields size_t memid; // id for the os-level memory manager bool mem_is_fixed; // `true` if we cannot decommit/reset/protect in this memory (i.e. when allocated using large OS pages) bool mem_is_committed; // `true` if the whole segment is eagerly committed // segment fields struct mi_segment_s* next; // must be the first segment field -- see `segment.c:segment_alloc` struct mi_segment_s* prev; struct mi_segment_s* abandoned_next; size_t abandoned; // abandoned pages (i.e. the original owning thread stopped) (`abandoned <= used`) size_t abandoned_visits; // count how often this segment is visited in the abandoned list (to force reclaim it it is too long) size_t used; // count of pages in use (`used <= capacity`) size_t capacity; // count of available pages (`#free + used`) size_t segment_size;// for huge pages this may be different from `MI_SEGMENT_SIZE` size_t segment_info_size; // space we are using from the first page for segment meta-data and possible guard pages. uintptr_t cookie; // verify addresses in secure mode: `_mi_ptr_cookie(segment) == segment->cookie` // layout like this to optimize access in `mi_free` size_t page_shift; // `1 << page_shift` == the page sizes == `page->block_size * page->reserved` (unless the first page, then `-segment_info_size`). volatile _Atomic(uintptr_t) thread_id; // unique id of the thread owning this segment mi_page_kind_t page_kind; // kind of pages: small, large, or huge mi_page_t pages[1]; // up to `MI_SMALL_PAGES_PER_SEGMENT` pages } mi_segment_t; // ------------------------------------------------------ // Heaps // Provide first-class heaps to allocate from. // A heap just owns a set of pages for allocation and // can only be allocate/reallocate from the thread that created it. // Freeing blocks can be done from any thread though. // Per thread, the segments are shared among its heaps. // Per thread, there is always a default heap that is // used for allocation; it is initialized to statically // point to an empty heap to avoid initialization checks // in the fast path. // ------------------------------------------------------ // Thread local data typedef struct mi_tld_s mi_tld_t; // Pages of a certain block size are held in a queue. typedef struct mi_page_queue_s { mi_page_t* first; mi_page_t* last; size_t block_size; } mi_page_queue_t; #define MI_BIN_FULL (MI_BIN_HUGE+1) // Random context typedef struct mi_random_cxt_s { uint32_t input[16]; uint32_t output[16]; int output_available; } mi_random_ctx_t; // In debug mode there is a padding stucture at the end of the blocks to check for buffer overflows #if (MI_PADDING) typedef struct mi_padding_s { uint32_t canary; // encoded block value to check validity of the padding (in case of overflow) uint32_t delta; // padding bytes before the block. (mi_usable_size(p) - delta == exact allocated bytes) } mi_padding_t; #define MI_PADDING_SIZE (sizeof(mi_padding_t)) #define MI_PADDING_WSIZE ((MI_PADDING_SIZE + MI_INTPTR_SIZE - 1) / MI_INTPTR_SIZE) #else #define MI_PADDING_SIZE 0 #define MI_PADDING_WSIZE 0 #endif #define MI_PAGES_DIRECT (MI_SMALL_WSIZE_MAX + MI_PADDING_WSIZE + 1) // A heap owns a set of pages. struct mi_heap_s { mi_tld_t* tld; mi_page_t* pages_free_direct[MI_PAGES_DIRECT]; // optimize: array where every entry points a page with possibly free blocks in the corresponding queue for that size. mi_page_queue_t pages[MI_BIN_FULL + 1]; // queue of pages for each size class (or "bin") volatile _Atomic(mi_block_t*) thread_delayed_free; uintptr_t thread_id; // thread this heap belongs too uintptr_t cookie; // random cookie to verify pointers (see `_mi_ptr_cookie`) uintptr_t keys[2]; // two random keys used to encode the `thread_delayed_free` list mi_random_ctx_t random; // random number context used for secure allocation size_t page_count; // total number of pages in the `pages` queues. size_t page_retired_min; // smallest retired index (retired pages are fully free, but still in the page queues) size_t page_retired_max; // largest retired index into the `pages` array. mi_heap_t* next; // list of heaps per thread bool no_reclaim; // `true` if this heap should not reclaim abandoned pages }; // ------------------------------------------------------ // Debug // ------------------------------------------------------ #define MI_DEBUG_UNINIT (0xD0) #define MI_DEBUG_FREED (0xDF) #define MI_DEBUG_PADDING (0xDE) #if (MI_DEBUG) // use our own assertion to print without memory allocation void _mi_assert_fail(const char* assertion, const char* fname, unsigned int line, const char* func ); #define mi_assert(expr) ((expr) ? (void)0 : _mi_assert_fail(#expr,__FILE__,__LINE__,__func__)) #else #define mi_assert(x) #endif #if (MI_DEBUG>1) #define mi_assert_internal mi_assert #else #define mi_assert_internal(x) #endif #if (MI_DEBUG>2) #define mi_assert_expensive mi_assert #else #define mi_assert_expensive(x) #endif // ------------------------------------------------------ // Statistics // ------------------------------------------------------ #ifndef MI_STAT #if (MI_DEBUG>0) #define MI_STAT 2 #else #define MI_STAT 0 #endif #endif typedef struct mi_stat_count_s { int64_t allocated; int64_t freed; int64_t peak; int64_t current; } mi_stat_count_t; typedef struct mi_stat_counter_s { int64_t total; int64_t count; } mi_stat_counter_t; typedef struct mi_stats_s { mi_stat_count_t segments; mi_stat_count_t pages; mi_stat_count_t reserved; mi_stat_count_t committed; mi_stat_count_t reset; mi_stat_count_t page_committed; mi_stat_count_t segments_abandoned; mi_stat_count_t pages_abandoned; mi_stat_count_t threads; mi_stat_count_t huge; mi_stat_count_t giant; mi_stat_count_t malloc; mi_stat_count_t segments_cache; mi_stat_counter_t pages_extended; mi_stat_counter_t mmap_calls; mi_stat_counter_t commit_calls; mi_stat_counter_t page_no_retire; mi_stat_counter_t searches; mi_stat_counter_t huge_count; mi_stat_counter_t giant_count; #if MI_STAT>1 mi_stat_count_t normal[MI_BIN_HUGE+1]; #endif } mi_stats_t; void _mi_stat_increase(mi_stat_count_t* stat, size_t amount); void _mi_stat_decrease(mi_stat_count_t* stat, size_t amount); void _mi_stat_counter_increase(mi_stat_counter_t* stat, size_t amount); #if (MI_STAT) #define mi_stat_increase(stat,amount) _mi_stat_increase( &(stat), amount) #define mi_stat_decrease(stat,amount) _mi_stat_decrease( &(stat), amount) #define mi_stat_counter_increase(stat,amount) _mi_stat_counter_increase( &(stat), amount) #else #define mi_stat_increase(stat,amount) (void)0 #define mi_stat_decrease(stat,amount) (void)0 #define mi_stat_counter_increase(stat,amount) (void)0 #endif #define mi_heap_stat_increase(heap,stat,amount) mi_stat_increase( (heap)->tld->stats.stat, amount) #define mi_heap_stat_decrease(heap,stat,amount) mi_stat_decrease( (heap)->tld->stats.stat, amount) // ------------------------------------------------------ // Thread Local data // ------------------------------------------------------ typedef int64_t mi_msecs_t; // Queue of segments typedef struct mi_segment_queue_s { mi_segment_t* first; mi_segment_t* last; } mi_segment_queue_t; // OS thread local data typedef struct mi_os_tld_s { size_t region_idx; // start point for next allocation mi_stats_t* stats; // points to tld stats } mi_os_tld_t; // Segments thread local data typedef struct mi_segments_tld_s { mi_segment_queue_t small_free; // queue of segments with free small pages mi_segment_queue_t medium_free; // queue of segments with free medium pages mi_page_queue_t pages_reset; // queue of freed pages that can be reset size_t count; // current number of segments; size_t peak_count; // peak number of segments size_t current_size; // current size of all segments size_t peak_size; // peak size of all segments size_t cache_count; // number of segments in the cache size_t cache_size; // total size of all segments in the cache mi_segment_t* cache; // (small) cache of segments mi_stats_t* stats; // points to tld stats mi_os_tld_t* os; // points to os stats } mi_segments_tld_t; // Thread local data struct mi_tld_s { unsigned long long heartbeat; // monotonic heartbeat count bool recurse; // true if deferred was called; used to prevent infinite recursion. mi_heap_t* heap_backing; // backing heap of this thread (cannot be deleted) mi_heap_t* heaps; // list of heaps in this thread (so we can abandon all when the thread terminates) mi_segments_tld_t segments; // segment tld mi_os_tld_t os; // os tld mi_stats_t stats; // statistics }; #endif