segment-map.c | Explore in Territory

/* ----------------------------------------------------------------------------
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.
-----------------------------------------------------------------------------*/

/* -----------------------------------------------------------
  The following functions are to reliably find the segment or
  block that encompasses any pointer p (or NULL if it is not
  in any of our segments).
  We maintain a bitmap of all memory with 1 bit per MI_SEGMENT_SIZE (64MiB)
  set to 1 if it contains the segment meta data.
----------------------------------------------------------- */
#include "mimalloc.h"
#include "mimalloc/internal.h"
#include "mimalloc/atomic.h"

#if (MI_INTPTR_SIZE==8)
#define MI_MAX_ADDRESS …
#else
#define MI_MAX_ADDRESS …
#endif

#define MI_SEGMENT_MAP_BITS …
#define MI_SEGMENT_MAP_SIZE …
#define MI_SEGMENT_MAP_WSIZE …

static _Atomic(uintptr_t) mi_segment_map[MI_SEGMENT_MAP_WSIZE + 1];  // 2KiB per TB with 64MiB segments

static size_t mi_segment_map_index_of(const mi_segment_t* segment, size_t* bitidx) { … }

void _mi_segment_map_allocated_at(const mi_segment_t* segment) { … }

void _mi_segment_map_freed_at(const mi_segment_t* segment) { … }

// Determine the segment belonging to a pointer or NULL if it is not in a valid segment.
static mi_segment_t* _mi_segment_of(const void* p) { … }

// Is this a valid pointer in our heap?
static bool  mi_is_valid_pointer(const void* p) { … }

mi_decl_nodiscard mi_decl_export bool mi_is_in_heap_region(const void* p) mi_attr_noexcept { … }

/*
// Return the full segment range belonging to a pointer
static void* mi_segment_range_of(const void* p, size_t* size) {
  mi_segment_t* segment = _mi_segment_of(p);
  if (segment == NULL) {
    if (size != NULL) *size = 0;
    return NULL;
  }
  else {
    if (size != NULL) *size = segment->segment_size;
    return segment;
  }
  mi_assert_expensive(page == NULL || mi_segment_is_valid(_mi_page_segment(page),tld));
  mi_assert_internal(page == NULL || (mi_segment_page_size(_mi_page_segment(page)) - (MI_SECURE == 0 ? 0 : _mi_os_page_size())) >= block_size);
  mi_reset_delayed(tld);
  mi_assert_internal(page == NULL || mi_page_not_in_queue(page, tld));
  return page;
}
*/
cpython/Objects/mimalloc/segment-map.c
