Loading...
--- libmalloc/libmalloc-474.0.13/src/magazine_small.c
+++ /dev/null
@@ -1,2483 +0,0 @@
-/*
- * Copyright (c) 2015 Apple Inc. All rights reserved.
- *
- * @APPLE_LICENSE_HEADER_START@
- *
- * This file contains Original Code and/or Modifications of Original Code
- * as defined in and that are subject to the Apple Public Source License
- * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
- *
- * The Original Code and all software distributed under the License are
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
- * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- * Please see the License for the specific language governing rights and
- * limitations under the License.
- *
- * @APPLE_LICENSE_HEADER_END@
- */
-
-#include "internal.h"
-
-
-/********************* SMALL FREE LIST UTILITIES ************************/
-
-#pragma mark meta header helpers
-
-/*
- * Mark a block as free. Only the first quantum of a block is marked thusly,
- * the remainder are marked "middle".
- */
-static MALLOC_INLINE void
-small_meta_header_set_is_free(msize_t *meta_headers, msize_t index, msize_t msize)
-{
- meta_headers[index] = msize | SMALL_IS_FREE;
-}
-
-/*
- * Mark a block as not free, preserving its size.
- */
-static MALLOC_INLINE void
-small_meta_header_set_not_free(msize_t *meta_headers, msize_t index)
-{
- meta_headers[index] &= ~SMALL_IS_FREE;
-}
-
-/*
- * Mark a block as in use. Only the first quantum of a block is marked thusly,
- * the remainder are marked "middle".
- */
-static MALLOC_INLINE void
-small_meta_header_set_in_use(msize_t *meta_headers, msize_t index, msize_t msize)
-{
- meta_headers[index] = msize;
-}
-
-/*
- * Mark a quantum as being the second or later in a block.
- */
-static MALLOC_INLINE void
-small_meta_header_set_middle(msize_t *meta_headers, msize_t index)
-{
- meta_headers[index] = 0;
-}
-
-#pragma mark in-place free list
-
-static MALLOC_INLINE void
-small_inplace_checksum_ptr(rack_t *rack, inplace_linkage_s *linkage, void *ptr)
-{
- uintptr_t checksum = free_list_gen_checksum((uintptr_t)ptr ^ rack->cookie ^ (uintptr_t)rack);
- linkage->checksum = checksum;
- linkage->ptr = ptr;
-}
-
-static MALLOC_INLINE free_list_t
-small_inplace_unchecksum_ptr(rack_t *rack, inplace_linkage_s *linkage)
-{
- if (linkage->checksum != (uint8_t)free_list_gen_checksum((uintptr_t)linkage->ptr ^ rack->cookie ^ (uintptr_t)rack)) {
- free_list_checksum_botch(rack, linkage, linkage->ptr);
- __builtin_trap();
- }
-
- return (free_list_t){ .p = linkage->ptr };
-}
-
-static MALLOC_INLINE free_list_t
-small_inplace_unchecksum_ptr_task(task_t task, memory_reader_t reader,
- print_task_printer_t printer, rack_t *rack, inplace_linkage_s *linkage)
-{
- inplace_linkage_s *mapped_linkage;
- rack_t *mapped_rack;
- if (reader(task, (vm_address_t)linkage, sizeof(*linkage),
- (void **)&mapped_linkage)) {
- printer("Unable to map small linkage pointer %p\n", linkage);
- return (free_list_t){ .p = NULL };
- }
-
- if (reader(task, (vm_address_t)rack,
- sizeof(struct rack_s), (void **)&mapped_rack)) {
- printer("Failed to map small rack\n");
- return (free_list_t){ .p = NULL };
- }
-
- if (mapped_linkage->checksum != (uint8_t)free_list_gen_checksum(
- (uintptr_t)mapped_linkage->ptr ^ mapped_rack->cookie ^ (uintptr_t)rack)) {
- free_list_checksum_botch(rack, linkage, mapped_linkage->ptr);
- __builtin_trap();
- }
-
- return (free_list_t){ .p = mapped_linkage->ptr };
-}
-
-static MALLOC_INLINE free_list_t
-small_inplace_free_entry_get_previous(rack_t *rack, small_inplace_free_entry_t ptr)
-{
- return small_inplace_unchecksum_ptr(rack, &ptr->previous);
-}
-
-static MALLOC_INLINE void
-small_inplace_free_entry_set_previous(rack_t *rack, small_inplace_free_entry_t entry, free_list_t previous)
-{
- small_inplace_checksum_ptr(rack, &entry->previous, previous.p);
-}
-
-static MALLOC_INLINE free_list_t
-small_inplace_free_entry_get_next(rack_t *rack, small_inplace_free_entry_t ptr)
-{
- return small_inplace_unchecksum_ptr(rack, &ptr->next);
-}
-
-static MALLOC_INLINE free_list_t
-small_inplace_free_entry_get_next_task(task_t task, memory_reader_t reader,
- print_task_printer_t printer, rack_t *rack,
- small_inplace_free_entry_t ptr)
-{
- return small_inplace_unchecksum_ptr_task(task, reader, printer, rack,
- &ptr->next);
-}
-
-static MALLOC_INLINE void
-small_inplace_free_entry_set_next(rack_t *rack, small_inplace_free_entry_t entry, free_list_t next)
-{
- small_inplace_checksum_ptr(rack, &entry->next, next.p);
-}
-
-#pragma mark OOB free list
-
-// Returns true if the address and size of the free list entry would result
-// in the free entry being the only data on a given page.
-static MALLOC_INLINE boolean_t
-small_needs_oob_free_entry(void *ptr, msize_t msize)
-{
- return ((trunc_page_quanta((uintptr_t)ptr) == (uintptr_t)ptr) && (SMALL_BYTES_FOR_MSIZE(msize) >= vm_kernel_page_size));
-}
-
-// Returns true if the address given lies within the region's OOB free
-// list entries, rather than a free_list_t in the region's heap space.
-static MALLOC_INLINE boolean_t
-small_is_oob_free_entry(free_list_t ptr)
-{
- small_region_t region = SMALL_REGION_FOR_PTR(ptr.p);
- return (((uintptr_t)ptr.p >= (uintptr_t)®ion->small_oob_free_entries[0]) &&
- ((uintptr_t)ptr.p < (uintptr_t)®ion->small_oob_free_entries[SMALL_OOB_COUNT]));
-}
-
-static MALLOC_INLINE void
-small_oob_free_entry_set_previous(oob_free_entry_t oobe, free_list_t previous)
-{
- oobe->prev = (uintptr_t)previous.p;
-}
-
-static MALLOC_INLINE free_list_t
-small_oob_free_entry_get_previous(oob_free_entry_t oobe)
-{
- return (free_list_t){ .p = (void *)oobe->prev };
-}
-
-static MALLOC_INLINE void
-small_oob_free_entry_set_next(oob_free_entry_t oobe, free_list_t next)
-{
- oobe->next = (uintptr_t)next.p;
-}
-
-static MALLOC_INLINE free_list_t
-small_oob_free_entry_get_next(oob_free_entry_t oobe)
-{
- return (free_list_t){ .p = (void *)oobe->next };
-}
-
-static MALLOC_INLINE free_list_t
-small_oob_free_entry_get_next_task(task_t task, memory_reader_t reader,
- print_task_printer_t printer, oob_free_entry_t oobe)
-{
- oob_free_entry_t mapped_oobe;
- if (reader(task, (vm_address_t)oobe, sizeof(*oobe),
- (void **)&mapped_oobe)) {
- printer("Failed to map small oobe pointer\n");
- return (free_list_t){ .p = NULL };
- }
- return (free_list_t){ .p = (void *)mapped_oobe->next };
-}
-
-static MALLOC_INLINE void *
-small_oob_free_entry_get_ptr(oob_free_entry_t oobe)
-{
- if (!(oobe->ptr & SMALL_IS_OOB)) {
- return NULL;
- }
- small_region_t region = SMALL_REGION_FOR_PTR(oobe);
- uint16_t block = oobe->ptr & ~SMALL_IS_OOB;
- return (void *)((uintptr_t)region + (block << SHIFT_SMALL_QUANTUM));
-}
-
-static MALLOC_INLINE void *
-small_oob_free_entry_get_ptr_task(task_t task, memory_reader_t reader,
- print_task_printer_t printer, oob_free_entry_t oobe)
-{
- // We need to map the oob_free_entry_t to read the pointer value.
- oob_free_entry_t mapped_oobe;
- if (reader(task, (vm_address_t)oobe, sizeof(*oobe),
- (void **)&mapped_oobe)) {
- printer("Failed to map small oobe pointer\n");
- return NULL;
- }
-
- if (!(mapped_oobe->ptr & SMALL_IS_OOB)) {
- return NULL;
- }
-
- // The rest of this code works with target process addresses and returns an
- // address in the target process.
- small_region_t region = SMALL_REGION_FOR_PTR(oobe);
- uint16_t block = mapped_oobe->ptr & ~SMALL_IS_OOB;
- return (void *)((uintptr_t)region + (block << SHIFT_SMALL_QUANTUM));
-}
-
-static MALLOC_INLINE void
-small_oob_free_entry_set_ptr(oob_free_entry_t oobe, void *ptr)
-{
- oobe->ptr = SMALL_IS_OOB | (SMALL_REGION_OFFSET_FOR_PTR(ptr) >> SHIFT_SMALL_QUANTUM);
-}
-
-static MALLOC_INLINE void
-small_oob_free_entry_set_free(oob_free_entry_t oobe)
-{
- oobe->prev = ~0;
- oobe->next = ~0;
- oobe->ptr = 0;
-}
-
-// Finds the first unused OOB free list entry in the pointer's region.
-// Returns NULL if all of the OOB entries are used.
-static MALLOC_INLINE oob_free_entry_t
-small_oob_free_find_empty(void *ptr, msize_t msize)
-{
- small_region_t region = SMALL_REGION_FOR_PTR(ptr);
-
- // There are 61 of these entries at the end of a small region.
- // If this changes, then a linear search through the list may
- // become an unsuitable choice.
- for (int i=0; i < SMALL_OOB_COUNT; i++) {
- if (region->small_oob_free_entries[i].ptr == 0) {
- return ®ion->small_oob_free_entries[i];
- }
- }
-
-#if DEBUG_MALLOC
- malloc_report(ASL_LEVEL_INFO, "used all slots of OOB entries\n");
-#endif
- return NULL;
-}
-
-static MALLOC_INLINE oob_free_entry_t
-small_oob_free_find_ptr(void *ptr, msize_t msize)
-{
- small_region_t region = SMALL_REGION_FOR_PTR(ptr);
-
- // There are 61 of these entries at the end of a small region.
- // If this changes, then a linear search through the list may
- // become an unsuitable choice.
- for (int i=0; i < SMALL_OOB_COUNT; i++) {
- oob_free_entry_t oob = ®ion->small_oob_free_entries[i];
- if (small_oob_free_entry_get_ptr(oob) == ptr &&
- oob->ptr & SMALL_IS_OOB) {
- return ®ion->small_oob_free_entries[i];
- }
- }
-
- return NULL;
-}
-
-#pragma mark generic free list
-
-static MALLOC_INLINE void
-small_free_list_set_previous(rack_t *rack, free_list_t entry, free_list_t previous)
-{
- if (small_is_oob_free_entry(entry)) {
- small_oob_free_entry_set_previous(entry.oob, previous);
- } else {
- small_inplace_free_entry_set_previous(rack, entry.small_inplace, previous);
- }
-}
-
-static MALLOC_INLINE free_list_t
-small_free_list_get_previous(rack_t *rack, free_list_t ptr)
-{
- MALLOC_ASSERT(ptr.p);
- if (small_is_oob_free_entry(ptr)) {
- return small_oob_free_entry_get_previous(ptr.oob);
- } else {
- return small_inplace_free_entry_get_previous(rack, ptr.small_inplace);
- }
-}
-
-static MALLOC_INLINE void
-small_free_list_set_next(rack_t *rack, free_list_t entry, free_list_t next)
-{
- if (small_is_oob_free_entry(entry)) {
- small_oob_free_entry_set_next(entry.oob, next);
- } else {
- small_inplace_free_entry_set_next(rack, entry.small_inplace, next);
- }
-}
-
-static MALLOC_INLINE free_list_t
-small_free_list_get_next(rack_t *rack, free_list_t ptr)
-{
- MALLOC_ASSERT(ptr.p);
- if (small_is_oob_free_entry(ptr)) {
- return small_oob_free_entry_get_next(ptr.oob);
- } else {
- return small_inplace_free_entry_get_next(rack, ptr.small_inplace);
- }
-}
-
-static MALLOC_INLINE free_list_t
-small_free_list_get_next_task(task_t task, memory_reader_t reader,
- print_task_printer_t printer, rack_t *rack, free_list_t ptr)
-{
- MALLOC_ASSERT(ptr.p);
- if (small_is_oob_free_entry(ptr)) {
- return small_oob_free_entry_get_next_task(task, reader, printer, ptr.oob);
- } else {
- return small_inplace_free_entry_get_next_task(task, reader, printer,
- rack, ptr.small_inplace);
- }
-}
-
-static MALLOC_INLINE void *
-small_free_list_get_ptr(free_list_t ptr)
-{
- if (!ptr.p) {
- return NULL;
- } else if (small_is_oob_free_entry(ptr)) {
- return small_oob_free_entry_get_ptr(ptr.oob);
- } else {
- return (void *)ptr.p;
- }
-}
-
-static MALLOC_INLINE void *
-small_free_list_get_ptr_task(task_t task, memory_reader_t reader,
- print_task_printer_t printer, free_list_t ptr)
-{
- if (!ptr.p) {
- return NULL;
- } else if (small_is_oob_free_entry(ptr)) {
- return small_oob_free_entry_get_ptr_task(task, reader, printer, ptr.oob);
- } else {
- return (void *)ptr.p;
- }
-}
-
-// Returns a free_list_t that is either inline or not based on the
-// pointer and msize.
-static MALLOC_INLINE free_list_t
-small_free_list_from_ptr(rack_t *rack, void *ptr, msize_t msize)
-{
- MALLOC_ASSERT(msize);
-
- // The default is to put the free_list_t in the memory that
- // the pointer leads to.
- free_list_t entry;
- entry.p = ptr;
-
- // If the pointer is page aligned, and the msize is greater
- // than a whole page, then we try and put the entry in
- // the out-of-band area instead.
- if (small_needs_oob_free_entry(ptr, msize)) {
- oob_free_entry_t oobe = small_oob_free_find_empty(ptr, msize);
- if (oobe) {
- small_oob_free_entry_set_ptr(oobe, ptr);
- entry.oob = oobe;
- }
- }
-
- return entry;
-}
-
-static MALLOC_INLINE void
-small_free_mark_free(rack_t *rack, free_list_t entry, msize_t msize)
-{
- // Marks both the start and end block of a free-list entry as free.
- void *ptr = small_free_list_get_ptr(entry);
- msize_t *meta_headers = SMALL_META_HEADER_FOR_PTR(ptr);
- uintptr_t start_index = SMALL_META_INDEX_FOR_PTR(ptr);
- uintptr_t end_index = SMALL_META_INDEX_FOR_PTR(ptr + SMALL_BYTES_FOR_MSIZE(msize) - 1);
- MALLOC_ASSERT(start_index <= end_index);
-
- small_meta_header_set_is_free(meta_headers, start_index, msize);
- small_meta_header_set_is_free(meta_headers, end_index, msize);
-}
-
-static MALLOC_INLINE void
-small_free_mark_middle(rack_t *rack, free_list_t entry, msize_t msize)
-{
- // Marks both the start and end block of a free-list entry as "middle" (unfree).
- void *ptr = small_free_list_get_ptr(entry);
- msize_t *meta_headers = SMALL_META_HEADER_FOR_PTR(ptr);
- uintptr_t start_index = SMALL_META_INDEX_FOR_PTR(ptr);
- uintptr_t end_index = SMALL_META_INDEX_FOR_PTR(ptr + SMALL_BYTES_FOR_MSIZE(msize) - 1);
- MALLOC_ASSERT(start_index <= end_index);
- MALLOC_ASSERT((meta_headers[start_index] & ~SMALL_IS_FREE) == msize);
-
- small_meta_header_set_middle(meta_headers, start_index);
- small_meta_header_set_middle(meta_headers, end_index);
-}
-
-static MALLOC_INLINE void
-small_free_mark_unfree(rack_t *rack, free_list_t entry, msize_t msize)
-{
- // Marks both the start and end block of a free-list entry as not free.
- void *ptr = small_free_list_get_ptr(entry);
- msize_t *meta_headers = SMALL_META_HEADER_FOR_PTR(ptr);
- uintptr_t start_index = SMALL_META_INDEX_FOR_PTR(ptr);
- uintptr_t end_index = SMALL_META_INDEX_FOR_PTR(ptr + SMALL_BYTES_FOR_MSIZE(msize) - 1);
- MALLOC_ASSERT(start_index <= end_index);
-
- small_meta_header_set_not_free(meta_headers, start_index);
- small_meta_header_set_not_free(meta_headers, end_index);
-}
-
-static MALLOC_INLINE unsigned int
-small_free_list_count(task_t task, memory_reader_t reader,
- print_task_printer_t printer, rack_t *rack, free_list_t ptr)
-{
- unsigned int count = 0;
- while (ptr.p) {
- count++;
- ptr = small_free_list_get_next_task(task, reader, printer, rack, ptr);
- }
- return count;
-}
-
-/*
- * Adds an item to the proper free list, and also marks the meta-header of the
- * block properly.
- * Assumes szone has been locked
- */
-static free_list_t
-small_free_list_add_ptr(rack_t *rack, magazine_t *small_mag_ptr, void *ptr, msize_t msize)
-{
- grain_t slot = SMALL_FREE_SLOT_FOR_MSIZE(rack, msize);
- free_list_t free_head = small_mag_ptr->mag_free_list[slot];
-
- // This will either return the free_list_t for the current pointer, or attempt
- // to reserve an OOB entry for us.
- free_list_t free_ptr = small_free_list_from_ptr(rack, ptr, msize);
-
-#if DEBUG_MALLOC
- if (LOG(szone, ptr)) {
- malloc_report(ASL_LEVEL_INFO, "in %s, ptr=%p, msize=%d\n", __FUNCTION__, ptr, msize);
- }
- if (((uintptr_t)ptr) & (SMALL_QUANTUM - 1)) {
- malloc_zone_error(rack->debug_flags, true, "small_free_list_add_ptr: Unaligned ptr %p\n", ptr);
- }
-#endif
-
- small_free_list_set_previous(rack, free_ptr, (free_list_t){ .p = NULL });
- small_free_list_set_next(rack, free_ptr, free_head);
-
- // Set the start and end blocks of the meta header as "free". Marking the last block
- // allows coalescing the regions when we free adjacent regions.
- small_free_mark_free(rack, free_ptr, msize);
-
- if (small_free_list_get_ptr(free_head)) {
-#if DEBUG_MALLOC
- if (small_free_list_get_previous(szone, free_head)) {
- malloc_zone_error(rack->debug_flags, true, "small_free_list_add_ptr: Internal invariant broken (free_head->previous != NULL)\n"
- "ptr=%p slot=%d free_head=%p previous=%p\n", ptr, slot, (void *)free_head, free_head->previous.p);
- }
- if (!SMALL_PTR_IS_FREE(small_free_list_get_ptr(free_head))) {
- malloc_zone_error(rack->debug_flags, true, "small_free_list_add_ptr: Internal invariant broken (free_head is not a free pointer)\n"
- "ptr=%p slot=%d free_head=%p\n", ptr, slot, (void *)small_free_list_get_ptr(free_head));
- }
-#endif
- small_free_list_set_previous(rack, free_head, free_ptr);
- } else {
- BITMAPN_SET(small_mag_ptr->mag_bitmap, slot);
- }
-
- small_mag_ptr->mag_free_list[slot] = free_ptr;
- return free_ptr;
-}
-
-/*
- * Removes the item pointed to by ptr in the proper free list.
- * Assumes szone has been locked
- */
-static void
-small_free_list_remove_ptr_no_clear(rack_t *rack, magazine_t *small_mag_ptr, free_list_t entry, msize_t msize)
-{
- grain_t slot = SMALL_FREE_SLOT_FOR_MSIZE(rack, msize);
- free_list_t next, previous;
-
-#if DEBUG_MALLOC
- if (LOG(szone, ptr)) {
- malloc_report(ASL_LEVEL_INFO, "In %s, ptr=%p, msize=%d\n", __FUNCTION__, ptr, msize);
- }
-#endif
-
- previous = small_free_list_get_previous(rack, entry);
- next = small_free_list_get_next(rack, entry);
-
- if (!small_free_list_get_ptr(previous)) {
- // The block to remove is the head of the free list
-#if DEBUG_MALLOC
- if (small_mag_ptr->mag_free_list[slot] != ptr) {
- malloc_zone_error(rack->debug_flags, true,
- "small_free_list_remove_ptr_no_clear: Internal invariant broken (small_mag_ptr->mag_free_list[slot])\n"
- "ptr=%p slot=%d msize=%d small_mag_ptr->mag_free_list[slot]=%p\n", ptr, slot, msize,
- (void *)small_mag_ptr->mag_free_list[slot]);
- return;
- }
-#endif
- small_mag_ptr->mag_free_list[slot] = next;
- if (!small_free_list_get_ptr(next)) {
- BITMAPN_CLR(small_mag_ptr->mag_bitmap, slot);
- }
- } else {
- // Check that the next pointer of "previous" points to "entry".
- free_list_t prev_next = small_free_list_get_next(rack, previous);
- if (small_free_list_get_ptr(prev_next) != small_free_list_get_ptr(entry)) {
- malloc_zone_error(rack->debug_flags, true,
- "small_free_list_remove_ptr_no_clear: Internal invariant broken (next ptr of prev) for %p, prev_next=%p\n",
- small_free_list_get_ptr(entry), small_free_list_get_ptr(prev_next));
- __builtin_unreachable(); // Always crashes in malloc_zone_error().
- }
- small_free_list_set_next(rack, previous, next);
- }
-
- if (small_free_list_get_ptr(next)) {
- // Check that the previous pointer of "next" points to "entry".
- free_list_t next_prev = small_free_list_get_previous(rack, next);
- if (small_free_list_get_ptr(next_prev) != small_free_list_get_ptr(entry)) {
- malloc_zone_error(rack->debug_flags, true,
- "small_free_list_remove_ptr_no_clear: Internal invariant broken (prev ptr of next) for %p, next_prev=%p\n",
- small_free_list_get_ptr(entry), small_free_list_get_ptr(next_prev));
- __builtin_unreachable(); // Always crashes in malloc_zone_error().
- }
- small_free_list_set_previous(rack, next, previous);
- }
-
- if (small_is_oob_free_entry(entry)) {
- small_oob_free_entry_set_free(entry.oob);
- }
-}
-
-static void
-small_free_list_remove_ptr(rack_t *rack, magazine_t *small_mag_ptr, free_list_t entry, msize_t msize)
-{
- // In the general case we want to ensure we marked these entries as "middle"
- // while we are in this function. However, when we're moving free list entries
- // from/to the recirc depot we rely on the metadata bits being intact to
- // reconstruct the free list. In that case we have to be able to skip this
- // metadata manipulation.
- small_free_mark_middle(rack, entry, msize);
- small_free_list_remove_ptr_no_clear(rack, small_mag_ptr, entry, msize);
-}
-
-// Find a free list entry by its pointer address. This should only really be used
-// by small_finalize_region, or similar, where the free_list_t entry of a known
-// pointer is desired. Otherwise it is cheaper to always pull off the free lists.
-static free_list_t
-small_free_list_find_by_ptr(rack_t *rack, magazine_t *small_mag_ptr, void *ptr, msize_t msize)
-{
- if (*SMALL_METADATA_FOR_PTR(ptr) == (SMALL_IS_FREE | msize)) {
- // If the block is marked free, and of size `msize`, then we first must check
- // if the alignment+size is such that we could have use an OOB-entry.
- if (small_needs_oob_free_entry(ptr, msize)) {
- // Scan the OOB entries looking for this address.
- small_region_t region = SMALL_REGION_FOR_PTR(ptr);
- for (int i=0; i<SMALL_OOB_COUNT; i++) {
- if (!region->small_oob_free_entries[i].ptr) {
- continue;
- }
- if (small_oob_free_entry_get_ptr(®ion->small_oob_free_entries[i]) == ptr) {
- return (free_list_t){ .oob = ®ion->small_oob_free_entries[i] };
- }
- }
- }
-
- // Otherwise, the freed pointer will be in place.
- return (free_list_t){ .p = ptr };
- }
-
- malloc_zone_error(rack->debug_flags, true,
- "small_free_list_find_by_ptr: ptr is not free (ptr metadata !SMALL_IS_FREE), "
- "ptr=%p msize=%d metadata=0x%x\n", ptr, msize, *SMALL_METADATA_FOR_PTR(ptr));
- __builtin_trap();
-}
-
-void
-small_finalize_region(rack_t *rack, magazine_t *small_mag_ptr)
-{
- void *last_block, *previous_block;
- msize_t last_msize, previous_msize, last_index;
- free_list_t previous;
-
- // It is possible that the block prior to the last block in the region has
- // been free'd, but was not coalesced with the free bytes at the end of the
- // block, since we treat the bytes at the end of the region as "in use" in
- // the meta headers. Attempt to coalesce the last block with the previous
- // block, so we don't violate the "no consecutive free blocks" invariant.
- //
- // FIXME: If we could calculate the previous small free size in the same
- // manner as tiny_previous_preceding_free, it would eliminate the
- // index & previous msize checks, which are a guard against reading
- // bogus data out of in-use or written-on-freed memory.
- //
- // FIXME: Need to investigate how much work would be required to increase
- // 'mag_bytes_free_at_end' when freeing the preceding block, rather
- // than performing this workaround.
- //
- if (small_mag_ptr->mag_bytes_free_at_end) {
- last_block = SMALL_REGION_HEAP_END(small_mag_ptr->mag_last_region) - small_mag_ptr->mag_bytes_free_at_end;
- last_msize = SMALL_MSIZE_FOR_BYTES(small_mag_ptr->mag_bytes_free_at_end);
-
- last_index = SMALL_META_INDEX_FOR_PTR(last_block);
- previous_msize = SMALL_PREVIOUS_MSIZE(last_block);
-
- if (last_index && (previous_msize <= last_index)) {
- previous_block = (void *)((uintptr_t)last_block - SMALL_BYTES_FOR_MSIZE(previous_msize));
-
- if (SMALL_PTR_IS_FREE(previous_block)) {
- previous = small_free_list_find_by_ptr(rack, small_mag_ptr, previous_block, previous_msize);
- small_free_list_remove_ptr(rack, small_mag_ptr, previous, previous_msize);
- last_block = previous_block;
- last_msize += previous_msize;
- }
- }
-
- // splice last_block into the free list
- small_free_list_add_ptr(rack, small_mag_ptr, last_block, last_msize);
- small_mag_ptr->mag_bytes_free_at_end = 0;
- }
-
-#if CONFIG_ASLR_INTERNAL
- free_list_t next;
-
- if (small_mag_ptr->mag_bytes_free_at_start) {
- last_block = SMALL_REGION_HEAP_BASE(small_mag_ptr->mag_last_region);
- last_msize = SMALL_MSIZE_FOR_BYTES(small_mag_ptr->mag_bytes_free_at_start);
-
- void *next_block = (void *)((uintptr_t)last_block + small_mag_ptr->mag_bytes_free_at_start);
- if (SMALL_PTR_IS_FREE(next_block)) {
- msize_t next_msize = SMALL_PTR_SIZE(next_block);
- next = small_free_list_find_by_ptr(rack, small_mag_ptr, next_block, next_msize);
- small_free_list_remove_ptr(rack, small_mag_ptr, next, next_msize);
- last_msize += next_msize;
- }
-
- // splice last_block into the free list
- small_free_list_add_ptr(rack, small_mag_ptr, last_block, last_msize);
- small_mag_ptr->mag_bytes_free_at_start = 0;
- }
-#endif
-
- // TODO: Will we ever need to coalesce the blocks at the beginning and end when we finalize?
- small_mag_ptr->mag_last_region = NULL;
-}
-
-int
-small_free_detach_region(rack_t *rack, magazine_t *small_mag_ptr, region_t r)
-{
- uintptr_t start = (uintptr_t)SMALL_REGION_HEAP_BASE(r);
- uintptr_t current = start;
- uintptr_t limit = (uintptr_t)SMALL_REGION_HEAP_END(r);
- int total_alloc = 0;
- msize_t *meta_headers = SMALL_META_HEADER_FOR_PTR(start);
-
- while (current < limit) {
- unsigned index = SMALL_META_INDEX_FOR_PTR(current);
- msize_t msize_and_free = meta_headers[index];
- boolean_t is_free = msize_and_free & SMALL_IS_FREE;
- msize_t msize = msize_and_free & ~SMALL_IS_FREE;
-
- if (!msize) {
-#if DEBUG_MALLOC
- boolean_t is_free = msize_and_free & SMALL_IS_FREE;
- malloc_report(ASL_LEVEL_ERR, "*** small_free_detach_region error with %p: msize=%d is_free=%d\n", (void *)current, msize, is_free);
-#endif
- break;
- }
-
- if (is_free) {
- free_list_t entry = small_free_list_find_by_ptr(rack, small_mag_ptr, (void *)current, msize);
- small_free_list_remove_ptr_no_clear(rack, small_mag_ptr, entry, msize);
- } else {
- total_alloc++;
- }
- current += SMALL_BYTES_FOR_MSIZE(msize);
- }
- return total_alloc;
-}
-
-size_t
-small_free_reattach_region(rack_t *rack, magazine_t *small_mag_ptr, region_t r)
-{
- uintptr_t start = (uintptr_t)SMALL_REGION_HEAP_BASE(r);
- uintptr_t current = start;
- uintptr_t limit = (uintptr_t)SMALL_REGION_HEAP_END(r);
- size_t total_alloc = 0;
- msize_t *meta_headers = SMALL_META_HEADER_FOR_PTR(start);
-
- while (current < limit) {
- unsigned index = SMALL_META_INDEX_FOR_PTR(current);
- msize_t msize_and_free = meta_headers[index];
- boolean_t is_free = msize_and_free & SMALL_IS_FREE;
- msize_t msize = msize_and_free & ~SMALL_IS_FREE;
-
- if (!msize) {
-#if DEBUG_MALLOC
- malloc_report(ASL_LEVEL_ERR, "*** small_free_reattach_region error with %p: msize=%d is_free=%d\n", (void *)current, msize, is_free);
-#endif
- break;
- }
- if (is_free) {
- small_free_list_add_ptr(rack, small_mag_ptr, (void *)current, msize);
- } else {
- total_alloc += SMALL_BYTES_FOR_MSIZE(msize);
- }
- current += SMALL_BYTES_FOR_MSIZE(msize);
- }
- return total_alloc;
-}
-
-typedef struct {
- uint16_t pnum, size;
-} small_pg_pair_t;
-
-void
-small_free_scan_madvise_free(rack_t *rack, magazine_t *depot_ptr, region_t r)
-{
- uintptr_t start = (uintptr_t)SMALL_REGION_HEAP_BASE(r);
- uintptr_t current = start;
- uintptr_t limit = (uintptr_t)SMALL_REGION_HEAP_END(r);
- msize_t *meta_headers = SMALL_META_HEADER_FOR_PTR(start);
- small_pg_pair_t advisory[((SMALL_HEAP_SIZE + vm_kernel_page_size - 1) >> vm_kernel_page_shift) >>
- 1]; // 4096bytes stack allocated
- int advisories = 0;
-
- // Scan the metadata identifying blocks which span one or more pages. Mark the pages MADV_FREE taking care to preserve free list
- // management data.
- while (current < limit) {
- unsigned index = SMALL_META_INDEX_FOR_PTR(current);
- msize_t msize_and_free = meta_headers[index];
- boolean_t is_free = msize_and_free & SMALL_IS_FREE;
- msize_t msize = msize_and_free & ~SMALL_IS_FREE;
-
- if (is_free && !msize && (current == start)) {
-#if DEBUG_MALLOC
- // first block is all free
- malloc_report(ASL_LEVEL_ERR, "*** small_free_scan_madvise_free first block is all free! %p: msize=%d is_free=%d\n", (void *)current,
- msize, is_free);
-#endif
- uintptr_t pgLo = round_page_kernel(start + sizeof(free_list_t) + sizeof(msize_t));
- uintptr_t pgHi = trunc_page_kernel(start + SMALL_REGION_SIZE - sizeof(msize_t));
-
- if (pgLo < pgHi) {
- advisory[advisories].pnum = (pgLo - start) >> vm_kernel_page_shift;
- advisory[advisories].size = (pgHi - pgLo) >> vm_kernel_page_shift;
- advisories++;
- }
- break;
- }
- if (!msize) {
-#if DEBUG_MALLOC
- malloc_report(ASL_LEVEL_ERR,
- "*** small_free_scan_madvise_free error with %p: msize=%d is_free=%d\n", (void *)current, msize, is_free);
-#endif
- break;
- }
- if (is_free) {
- uintptr_t pgLo = round_page_kernel(current + sizeof(free_list_t) + sizeof(msize_t));
- uintptr_t pgHi = trunc_page_kernel(current + SMALL_BYTES_FOR_MSIZE(msize) - sizeof(msize_t));
-
- if (pgLo < pgHi) {
- advisory[advisories].pnum = (pgLo - (uintptr_t)r) >> vm_kernel_page_shift;
- advisory[advisories].size = (pgHi - pgLo) >> vm_kernel_page_shift;
- advisories++;
- }
- }
- current += SMALL_BYTES_FOR_MSIZE(msize);
- }
-
- if (advisories > 0) {
- int i;
-
- OSAtomicIncrement32Barrier(&(REGION_TRAILER_FOR_SMALL_REGION(r)->pinned_to_depot));
- SZONE_MAGAZINE_PTR_UNLOCK(depot_ptr);
- for (i = 0; i < advisories; ++i) {
- uintptr_t addr = (advisory[i].pnum << vm_kernel_page_shift) + (uintptr_t)r;
- size_t size = advisory[i].size << vm_kernel_page_shift;
-
- mvm_madvise_free(rack, r, addr, addr + size, NULL, rack->debug_flags & MALLOC_DO_SCRIBBLE);
- }
- SZONE_MAGAZINE_PTR_LOCK(depot_ptr);
- OSAtomicDecrement32Barrier(&(REGION_TRAILER_FOR_SMALL_REGION(r)->pinned_to_depot));
- }
-}
-
-#if CONFIG_RECIRC_DEPOT
-static region_t
-small_find_msize_region(rack_t *rack, magazine_t *small_mag_ptr, mag_index_t mag_index, msize_t msize)
-{
- void *ptr;
- grain_t slot = SMALL_FREE_SLOT_FOR_MSIZE(rack, msize);
- free_list_t *free_list = small_mag_ptr->mag_free_list;
- free_list_t *the_slot = free_list + slot;
- free_list_t *limit;
- unsigned bitmap;
-
- // Assumes we've locked the magazine
- CHECK_MAGAZINE_PTR_LOCKED(szone, small_mag_ptr, __PRETTY_FUNCTION__);
-
- // Look for an exact match by checking the freelist for this msize.
- ptr = small_free_list_get_ptr(*the_slot);
- if (ptr) {
- return SMALL_REGION_FOR_PTR(ptr);
- }
-
- // Mask off the bits representing slots holding free blocks smaller than
- // the size we need.
- //
- // BITMAPN_CTZ implementation
- unsigned idx = slot >> 5;
- bitmap = 0;
- unsigned mask = ~((1 << (slot & 31)) - 1);
- for (; idx < SMALL_FREELIST_BITMAP_WORDS(rack); ++idx) {
- bitmap = small_mag_ptr->mag_bitmap[idx] & mask;
- if (bitmap != 0) {
- break;
- }
- mask = ~0U;
- }
- // Check for fallthrough: No bits set in bitmap
- if ((bitmap == 0) && (idx == SMALL_FREELIST_BITMAP_WORDS(rack))) {
- return NULL;
- }
-
- // Start looking at the first set bit, plus 32 bits for every word of
- // zeroes or entries that were too small.
- slot = BITMAP32_CTZ((&bitmap)) + (idx * 32);
-
- limit = free_list + SMALL_FREE_SLOT_COUNT(rack) - 1;
- free_list += slot;
-
- if (free_list < limit) {
- ptr = small_free_list_get_ptr(*free_list);
- if (ptr) {
- return SMALL_REGION_FOR_PTR(ptr);
- } else {
- /* Shouldn't happen. Fall through to look at last slot. */
-#if DEBUG_MALLOC
- malloc_report(ASL_LEVEL_ERR, "in small_malloc_from_free_list(), mag_bitmap out of sync, slot=%d\n", slot);
-#endif
- }
- }
-
- // We are now looking at the last slot, which contains blocks equal to, or
- // due to coalescing of free blocks, larger than (num_small_slots - 1) * (small quantum size).
- ptr = small_free_list_get_ptr(*limit);
- if (ptr) {
- return SMALL_REGION_FOR_PTR(ptr);
- }
-
- return NULL;
-}
-
-static boolean_t
-small_get_region_from_depot(rack_t *rack, magazine_t *small_mag_ptr, mag_index_t mag_index, msize_t msize)
-{
- magazine_t *depot_ptr = &(rack->magazines[DEPOT_MAGAZINE_INDEX]);
-
-#if DEBUG_MALLOC
- if (DEPOT_MAGAZINE_INDEX == mag_index) {
- malloc_zone_error(rack->debug_flags, true, "small_get_region_from_depot called for magazine index -1\n", NULL, NULL);
- return 0;
- }
-#endif
-
- SZONE_MAGAZINE_PTR_LOCK(depot_ptr);
-
- // Appropriate a Depot'd region that can satisfy requested msize.
- region_trailer_t *node;
- region_t sparse_region;
- msize_t try_msize = msize;
-
- while (1) {
- sparse_region = small_find_msize_region(rack, depot_ptr, DEPOT_MAGAZINE_INDEX, try_msize);
- if (NULL == sparse_region) { // Depot empty?
- SZONE_MAGAZINE_PTR_UNLOCK(depot_ptr);
- return 0;
- }
-
- node = REGION_TRAILER_FOR_SMALL_REGION(sparse_region);
- if (0 == node->pinned_to_depot) {
- // Found one!
- break;
- }
-
- // Try the next msize up - maybe the head of its free list will be in
- // a region we can use. Once we get the region we'll still allocate the
- // original msize.
- try_msize++;
-
- if (try_msize > NUM_SMALL_SLOTS) {
- // Tried all the msizes but couldn't get a usable region. Let's
- // give up for now and we'll allocate a new region from the kernel.
- SZONE_MAGAZINE_PTR_UNLOCK(depot_ptr);
- return 0;
- }
- }
-
- // disconnect node from Depot
- recirc_list_extract(rack, depot_ptr, node);
-
- // Iterate the region pulling its free entries off the (locked) Depot's free list
- int objects_in_use = small_free_detach_region(rack, depot_ptr, sparse_region);
-
- // Transfer ownership of the region
- MAGAZINE_INDEX_FOR_SMALL_REGION(sparse_region) = mag_index;
- MALLOC_ASSERT(node->pinned_to_depot == 0);
-
- // Iterate the region putting its free entries on its new (locked) magazine's free list
- size_t bytes_inplay = small_free_reattach_region(rack, small_mag_ptr, sparse_region);
-
- depot_ptr->mag_num_bytes_in_objects -= bytes_inplay;
- depot_ptr->num_bytes_in_magazine -= SMALL_HEAP_SIZE;
- depot_ptr->mag_num_objects -= objects_in_use;
-
- small_mag_ptr->mag_num_bytes_in_objects += bytes_inplay;
- small_mag_ptr->num_bytes_in_magazine += SMALL_HEAP_SIZE;
- small_mag_ptr->mag_num_objects += objects_in_use;
-
- // connect to magazine as last node
- recirc_list_splice_last(rack, small_mag_ptr, node);
-
- SZONE_MAGAZINE_PTR_UNLOCK(depot_ptr);
-
- MAGMALLOC_DEPOTREGION(SMALL_SZONE_FROM_RACK(rack), (int)mag_index, (void *)sparse_region, SMALL_REGION_SIZE,
- (int)BYTES_USED_FOR_SMALL_REGION(sparse_region)); // DTrace USDT Probe
-
- return 1;
-}
-#endif // CONFIG_RECIRC_DEPOT
-
-#if CONFIG_MADVISE_PRESSURE_RELIEF
-void
-small_madvise_pressure_relief(rack_t *rack)
-{
- mag_index_t mag_index;
- magazine_t *small_depot_ptr = &rack->magazines[DEPOT_MAGAZINE_INDEX];
-
- for (mag_index = 0; mag_index < rack->num_magazines; mag_index++) {
- size_t index;
- for (index = 0; index < rack->region_generation->num_regions_allocated; ++index) {
- rack_region_lock(rack);
-
- region_t small = rack->region_generation->hashed_regions[index];
- if (!small || small == HASHRING_REGION_DEALLOCATED) {
- rack_region_unlock(rack);
- continue;
- }
-
- region_trailer_t *trailer = REGION_TRAILER_FOR_SMALL_REGION(small);
- // Make sure that the owning magazine doesn't try and take this out
- // from under our feet.
- trailer->dispose_flags |= RACK_DISPOSE_DELAY;
- rack_region_unlock(rack);
-
- magazine_t *mag_ptr = mag_lock_zine_for_region_trailer(rack->magazines,
- trailer, MAGAZINE_INDEX_FOR_SMALL_REGION(small));
-
- // If acquiring the region lock was enough to prevent the owning
- // magazine from deallocating the region, free it now so we don't
- // do wasted work.
- if (rack_region_maybe_dispose(rack, small, SMALL_REGION_SIZE, trailer)) {
- SZONE_MAGAZINE_PTR_UNLOCK(mag_ptr);
- continue;
- }
-
- /* Ordering is important here, the magazine of a region may potentially change
- * during mag_lock_zine_for_region_trailer, so src_mag_index must be taken
- * after we've obtained the lock.
- */
- mag_index_t src_mag_index = MAGAZINE_INDEX_FOR_SMALL_REGION(small);
-
- /* We can (and must) ignore magazines that are already in the recirc depot. */
- if (src_mag_index == DEPOT_MAGAZINE_INDEX) {
- SZONE_MAGAZINE_PTR_UNLOCK(mag_ptr);
- continue;
- }
-
- if (REGION_TRAILER_FOR_SMALL_REGION(small)->pinned_to_depot > 0) {
- SZONE_MAGAZINE_PTR_UNLOCK(mag_ptr);
- continue;
- }
-
- if (small == mag_ptr->mag_last_region && (mag_ptr->mag_bytes_free_at_end || mag_ptr->mag_bytes_free_at_start)) {
- small_finalize_region(rack, mag_ptr);
- }
-
- /* Because this region is currently in use, we can't safely madvise it while
- * it's attached to the magazine. For this operation we have to remove it from
- * the current mag, attach it to the depot and then madvise.
- */
-
- recirc_list_extract(rack, mag_ptr, REGION_TRAILER_FOR_SMALL_REGION(small));
- int objects_in_use = small_free_detach_region(rack, mag_ptr, small);
-
- SZONE_MAGAZINE_PTR_LOCK(small_depot_ptr);
- MAGAZINE_INDEX_FOR_SMALL_REGION(small) = DEPOT_MAGAZINE_INDEX;
- MALLOC_ASSERT(REGION_TRAILER_FOR_SMALL_REGION(small)->pinned_to_depot == 0);
-
- size_t bytes_inplay = small_free_reattach_region(rack, small_depot_ptr, small);
-
- /* Fix up the metadata of the target magazine while the region is in the depot. */
- mag_ptr->mag_num_bytes_in_objects -= bytes_inplay;
- mag_ptr->num_bytes_in_magazine -= SMALL_HEAP_SIZE;
- mag_ptr->mag_num_objects -= objects_in_use;
-
- /* Now we can drop the magazine lock of the source mag. */
- SZONE_MAGAZINE_PTR_UNLOCK(mag_ptr);
-
- small_depot_ptr->mag_num_bytes_in_objects += bytes_inplay;
- small_depot_ptr->num_bytes_in_magazine += SMALL_HEAP_SIZE;
- small_depot_ptr->mag_num_objects -= objects_in_use;
-
- recirc_list_splice_last(rack, small_depot_ptr, REGION_TRAILER_FOR_SMALL_REGION(small));
-
- /* Actually do the scan, done holding the depot lock, the call will drop the lock
- * around the actual madvise syscalls.
- */
- small_free_scan_madvise_free(rack, small_depot_ptr, small);
-
- /* Now the region is in the recirc depot, the next allocations to require more
- * blocks will come along and take one of these regions back out of the depot.
- * As OS X madvise's reuse on an per-region basis, we leave as many of these
- * regions in the depot as possible after memory pressure.
- */
- SZONE_MAGAZINE_PTR_UNLOCK(small_depot_ptr);
- }
- }
-}
-#endif // CONFIG_MADVISE_PRESSURE_RELIEF
-
-#if CONFIG_AGGRESSIVE_MADVISE || CONFIG_RECIRC_DEPOT
-static MALLOC_INLINE void
-small_madvise_free_range_no_lock(rack_t *rack,
- magazine_t *small_mag_ptr,
- region_t region,
- free_list_t freee,
- msize_t fmsize,
- void *headptr,
- size_t headsize)
-{
- void *ptr = small_free_list_get_ptr(freee);
- region_trailer_t *node = REGION_TRAILER_FOR_SMALL_REGION(region);
-
- // Lock on small_magazines[mag_index] is already held here.
- // Calculate the first page in the coalesced block that would be safe to mark MADV_FREE
- size_t free_header_size = sizeof(free_list_t) + sizeof(msize_t);
-
- // If the free_list_t entry is out-of-line then we don't need to reserve any space
- // at the start of the region.
- if (small_is_oob_free_entry(freee)) {
- free_header_size = 0;
- }
-
- uintptr_t safe_ptr = (uintptr_t)ptr + free_header_size;
- uintptr_t round_safe = round_page_kernel(safe_ptr);
-
- // Calculate the last page in the coalesced block that would be safe to mark MADV_FREE
- uintptr_t safe_extent = (uintptr_t)ptr + SMALL_BYTES_FOR_MSIZE(fmsize);
- uintptr_t trunc_extent = trunc_page_kernel(safe_extent);
-
- // The newly freed block may complete a span of bytes that cover one or more pages. Mark the span with MADV_FREE.
- if (round_safe < trunc_extent) { // Coalesced area covers a page (perhaps many)
- // Extend the freed block by the free region header and tail sizes to include pages
- // we may have coalesced that no longer host free region tails and headers.
- // This may extend over in-use ranges, but the MIN/MAX clamping below will fix that up.
- uintptr_t lo = trunc_page_kernel((uintptr_t)headptr);
- uintptr_t hi = round_page_kernel((uintptr_t)headptr + headsize + free_header_size);
-
- uintptr_t free_lo = MAX(round_safe, lo);
- uintptr_t free_hi = MIN(trunc_extent, hi);
-
- if (free_lo < free_hi) {
- // Before unlocking, ensure that the metadata for the freed region
- // makes it look not free but includes the length. This ensures that
- // any code that inspects the metadata while we are unlocked sees
- // a valid state and will not try to use or coalesce freed memory
- // into it.
- small_free_mark_unfree(rack, freee, fmsize);
- small_free_list_remove_ptr_no_clear(rack, small_mag_ptr, freee, fmsize);
- OSAtomicIncrement32Barrier(&(node->pinned_to_depot));
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- mvm_madvise_free(rack, region, free_lo, free_hi, &rack->last_madvise, rack->debug_flags & MALLOC_DO_SCRIBBLE);
- SZONE_MAGAZINE_PTR_LOCK(small_mag_ptr);
- OSAtomicDecrement32Barrier(&(node->pinned_to_depot));
- small_free_list_add_ptr(rack, small_mag_ptr, ptr, fmsize);
- }
- }
-}
-#endif // CONFIG_AGGRESSIVE_MADVISE || CONFIG_RECIRC_DEPOT
-
-#if CONFIG_RECIRC_DEPOT
-static region_t
-small_free_try_depot_unmap_no_lock(rack_t *rack, magazine_t *depot_ptr, region_trailer_t *node)
-{
- if (0 < node->bytes_used || 0 < node->pinned_to_depot || depot_ptr->recirculation_entries < recirc_retained_regions) {
- return NULL;
- }
-
- // disconnect first node from Depot
- recirc_list_extract(rack, depot_ptr, node);
-
- // Iterate the region pulling its free entries off the (locked) Depot's free list
- region_t sparse_region = SMALL_REGION_FOR_PTR(node);
- int objects_in_use = small_free_detach_region(rack, depot_ptr, sparse_region);
-
- if (0 == objects_in_use) {
- if (!rack_region_remove(rack, sparse_region, node)) {
- return NULL;
- }
- depot_ptr->num_bytes_in_magazine -= SMALL_HEAP_SIZE;
-
- // Caller will transfer ownership of the region back to the OS with no locks held
- MAGMALLOC_DEALLOCREGION(SMALL_SZONE_FROM_RACK(rack), (void *)sparse_region, (int)SMALL_REGION_SIZE); // DTrace USDT Probe
- return sparse_region;
-
- } else {
- malloc_zone_error(rack->debug_flags, true,
- "small_free_try_depot_unmap_no_lock objects_in_use not zero: %d\n", objects_in_use);
- return NULL;
- }
-}
-
-static boolean_t
-small_free_do_recirc_to_depot(rack_t *rack, magazine_t *small_mag_ptr, mag_index_t mag_index)
-{
- // The entire magazine crossed the "emptiness threshold". Transfer a region
- // from this magazine to the Depot. Choose a region that itself has crossed the emptiness threshold (i.e
- // is at least fraction "f" empty.) Such a region will be marked "suitable" on the recirculation list.
- region_trailer_t *node = small_mag_ptr->firstNode;
-
- while (node && (!node->recirc_suitable || node->pinned_to_depot)) {
- node = node->next;
- }
-
- if (NULL == node) {
-#if DEBUG_MALLOC
- malloc_report(ASL_LEVEL_ERR, "*** small_free_do_recirc_to_depot end of list\n");
-#endif
- return TRUE; // Caller must SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- }
-
- region_t sparse_region = SMALL_REGION_FOR_PTR(node);
-
- // Deal with unclaimed memory -- mag_bytes_free_at_end or mag_bytes_free_at start
- if (sparse_region == small_mag_ptr->mag_last_region &&
- (small_mag_ptr->mag_bytes_free_at_end || small_mag_ptr->mag_bytes_free_at_start)) {
- small_finalize_region(rack, small_mag_ptr);
- }
-
- // disconnect "suitable" node from magazine
- recirc_list_extract(rack, small_mag_ptr, node);
-
- // Iterate the region pulling its free entries off its (locked) magazine's free list
- int objects_in_use = small_free_detach_region(rack, small_mag_ptr, sparse_region);
- magazine_t *depot_ptr = &(rack->magazines[DEPOT_MAGAZINE_INDEX]);
-
- // hand over the region to the (locked) Depot
- SZONE_MAGAZINE_PTR_LOCK(depot_ptr);
- // this will cause small_free_list_add_ptr called by small_free_reattach_region to use
- // the depot as its target magazine, rather than magazine formerly associated with sparse_region
- MAGAZINE_INDEX_FOR_SMALL_REGION(sparse_region) = DEPOT_MAGAZINE_INDEX;
- node->pinned_to_depot = 0;
-
- // Iterate the region putting its free entries on Depot's free list
- size_t bytes_inplay = small_free_reattach_region(rack, depot_ptr, sparse_region);
-
- small_mag_ptr->mag_num_bytes_in_objects -= bytes_inplay;
- small_mag_ptr->num_bytes_in_magazine -= SMALL_HEAP_SIZE;
- small_mag_ptr->mag_num_objects -= objects_in_use;
-
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr); // Unlock the originating magazine
-
- depot_ptr->mag_num_bytes_in_objects += bytes_inplay;
- depot_ptr->num_bytes_in_magazine += SMALL_HEAP_SIZE;
- depot_ptr->mag_num_objects += objects_in_use;
-
- // connect to Depot as last node
- recirc_list_splice_last(rack, depot_ptr, node);
-
- MAGMALLOC_RECIRCREGION(SMALL_SZONE_FROM_RACK(rack), (int)mag_index, (void *)sparse_region, SMALL_REGION_SIZE,
- (int)BYTES_USED_FOR_SMALL_REGION(sparse_region)); // DTrace USDT Probe
-
-#if CONFIG_AGGRESSIVE_MADVISE
- if (!aggressive_madvise_enabled)
-#endif
- {
- // Mark free'd dirty pages with MADV_FREE to reduce memory pressure
- small_free_scan_madvise_free(rack, depot_ptr, sparse_region);
- }
-
- // If the region is entirely empty vm_deallocate() it outside the depot lock
- region_t r_dealloc = small_free_try_depot_unmap_no_lock(rack, depot_ptr, node);
- SZONE_MAGAZINE_PTR_UNLOCK(depot_ptr);
- if (r_dealloc) {
- mvm_deallocate_pages(r_dealloc, SMALL_REGION_SIZE,
- MALLOC_FIX_GUARD_PAGE_FLAGS(rack->debug_flags));
- }
- return FALSE; // Caller need not unlock the originating magazine
-}
-
-static MALLOC_INLINE boolean_t
-small_free_try_recirc_to_depot(rack_t *rack,
- magazine_t *small_mag_ptr,
- mag_index_t mag_index,
- region_t region,
- free_list_t freee,
- msize_t msize,
- void *headptr,
- size_t headsize)
-{
- region_trailer_t *node = REGION_TRAILER_FOR_SMALL_REGION(region);
- size_t bytes_used = node->bytes_used;
-
- if (DEPOT_MAGAZINE_INDEX != mag_index) {
- // Emptiness discriminant
- if (small_region_below_recirc_threshold(region)) {
- /* Region has crossed threshold from density to sparsity. Mark it "suitable" on the
- * recirculation candidates list. */
- node->recirc_suitable = TRUE;
- } else {
- /* After this free, we've found the region is still dense, so it must have been even more so before
- * the free. That implies the region is already correctly marked. Do nothing. */
- }
-
- // Has the entire magazine crossed the "emptiness threshold"? If so, transfer a region
- // from this magazine to the Depot. Choose a region that itself has crossed the emptiness threshold (i.e
- // is at least fraction "f" empty.) Such a region will be marked "suitable" on the recirculation list.
- if (small_magazine_below_recirc_threshold(small_mag_ptr)) {
- return small_free_do_recirc_to_depot(rack, small_mag_ptr, mag_index);
- }
- } else {
-#if CONFIG_AGGRESSIVE_MADVISE
- if (!aggressive_madvise_enabled)
-#endif
- {
- // We are free'ing into the depot, so madvise as we do so unless we were madvising every incoming
- // allocation anyway.
- small_madvise_free_range_no_lock(rack, small_mag_ptr, region, freee, msize, headptr, headsize);
- }
-
- if (0 < bytes_used || 0 < node->pinned_to_depot) {
- /* Depot'd region is still live. Leave it in place on the Depot's recirculation list
- * so as to avoid thrashing between the Depot's free list and a magazines's free list
- * with detach_region/reattach_region */
- } else {
- /* Depot'd region is just now empty. Consider return to OS. */
- region_t r_dealloc = small_free_try_depot_unmap_no_lock(rack, small_mag_ptr, node);
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- if (r_dealloc) {
- mvm_deallocate_pages(r_dealloc, SMALL_REGION_SIZE, MALLOC_FIX_GUARD_PAGE_FLAGS(rack->debug_flags));
- }
- return FALSE; // Caller need not unlock
- }
- }
- return TRUE; // Caller must do SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr)
-}
-#endif // CONFIG_RECIRC_DEPOT
-
-static MALLOC_INLINE boolean_t
-small_free_no_lock(rack_t *rack, magazine_t *small_mag_ptr, mag_index_t mag_index, region_t region, void *ptr, msize_t msize)
-{
- msize_t *meta_headers = SMALL_META_HEADER_FOR_PTR(ptr);
- unsigned index = SMALL_META_INDEX_FOR_PTR(ptr);
- size_t original_size = SMALL_BYTES_FOR_MSIZE(msize);
- void *next_block = ptr + original_size;
- msize_t next_index = index + msize;
-
- MALLOC_TRACE(TRACE_small_free, (uintptr_t)rack, (uintptr_t)small_mag_ptr, (uintptr_t)ptr, SMALL_BYTES_FOR_MSIZE(msize));
-
-#if CONFIG_AGGRESSIVE_MADVISE || CONFIG_RECIRC_DEPOT
- void *original_ptr = ptr;
-#endif // CONFIG_AGGRESSIVE_MADVISE || CONFIG_RECIRC_DEPOT
-
-#if DEBUG_MALLOC
- if (LOG(szone, ptr)) {
- malloc_report(ASL_LEVEL_ERR, "in small_free_no_lock(), ptr=%p, msize=%d\n", ptr, msize);
- }
- if (!msize) {
- malloc_zone_error(rack->debug_flags, true, "trying to free small block that is too small in small_free_no_lock(), ptr=%p, msize=%d\n",
- ptr, msize);
- }
-#endif
-
- // Check that the region cookie is intact.
- region_check_cookie(region, ®ION_COOKIE_FOR_SMALL_REGION(region));
-
- // We try to coalesce this block with the preceeding one
- if (index > 0 && (meta_headers[index - 1] & SMALL_IS_FREE)) {
- msize_t previous_msize = meta_headers[index - 1] & ~SMALL_IS_FREE;
- grain_t previous_index = index - previous_msize;
-
- // Check if the metadata for the start of the block is also free.
- if (meta_headers[previous_index] == (previous_msize | SMALL_IS_FREE)) {
- void *previous_ptr = (void *)((uintptr_t)ptr - SMALL_BYTES_FOR_MSIZE(previous_msize));
- free_list_t previous = small_free_list_find_by_ptr(rack, small_mag_ptr, previous_ptr, previous_msize);
- small_free_list_remove_ptr(rack, small_mag_ptr, previous, previous_msize);
- ptr = previous_ptr;
- small_meta_header_set_middle(meta_headers, index); // This block is now a middle block.
- msize += previous_msize;
- index -= previous_msize;
- } else {
- _os_set_crash_log_message("small free list metadata inconsistency (headers[previous] != previous size)");
- __builtin_trap();
- }
- }
-
- // Try to coalesce with this block with the next block
- if ((next_block < SMALL_REGION_HEAP_END(region)) && (meta_headers[next_index] & SMALL_IS_FREE)) {
- msize_t next_msize = meta_headers[next_index] & ~SMALL_IS_FREE;
- free_list_t next = small_free_list_find_by_ptr(rack, small_mag_ptr, next_block, next_msize);
- small_free_list_remove_ptr(rack, small_mag_ptr, next, next_msize);
- msize += next_msize;
- }
-
- if (rack->debug_flags & MALLOC_DO_SCRIBBLE) {
- if (!msize) {
- malloc_zone_error(rack->debug_flags, true, "incorrect size information for %p - block header was damaged\n", ptr);
- } else {
- memset(ptr, SCRABBLE_BYTE, SMALL_BYTES_FOR_MSIZE(msize));
- }
- }
-
- free_list_t freee = small_free_list_add_ptr(rack, small_mag_ptr, ptr, msize);
-
- // use original_size and not msize to avoid double counting the coalesced blocks
- small_mag_ptr->mag_num_bytes_in_objects -= original_size;
-
- // Update this region's bytes in use count
- region_trailer_t *trailer = REGION_TRAILER_FOR_SMALL_REGION(region);
- size_t bytes_used = trailer->bytes_used - original_size;
- trailer->bytes_used = (unsigned int)bytes_used;
-
-#if CONFIG_AGGRESSIVE_MADVISE
- if (aggressive_madvise_enabled) {
- small_madvise_free_range_no_lock(rack, small_mag_ptr, region, freee, msize, original_ptr, original_size);
- }
-#endif
-
- // Caller must do SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr) if this function
- // returns TRUE.
- boolean_t needs_unlock = TRUE;
-
-#if CONFIG_RECIRC_DEPOT
- needs_unlock = small_free_try_recirc_to_depot(rack, small_mag_ptr, mag_index, region, freee, msize, original_ptr, original_size);
-#endif // CONFIG_RECIRC_DEPOT
- return needs_unlock;
-}
-
-// Allocates from the last region or a freshly allocated region
-static void *
-small_malloc_from_region_no_lock(rack_t *rack,
- magazine_t *small_mag_ptr,
- mag_index_t mag_index,
- msize_t msize,
- void *aligned_address)
-{
- void *ptr;
-
- // Before anything we transform the mag_bytes_free_at_end or mag_bytes_free_at_start - if any - to a regular free block
- /* FIXME: last_block needs to be coalesced with previous entry if free, <rdar://5462322> */
- if (small_mag_ptr->mag_bytes_free_at_end || small_mag_ptr->mag_bytes_free_at_start) {
- small_finalize_region(rack, small_mag_ptr);
- }
-
- small_region_t region = (small_region_t)aligned_address;
-
- // Tag the region at "aligned_address" as belonging to us,
- // and so put it under the protection of the magazine lock we are holding.
- // Do this before advertising "aligned_address" on the hash ring(!)
- MAGAZINE_INDEX_FOR_SMALL_REGION(region) = mag_index;
-
- // Insert the new region into the hash ring
- rack_region_insert(rack, region);
-
- small_mag_ptr->mag_last_region = region;
- BYTES_USED_FOR_SMALL_REGION(region) = SMALL_BYTES_FOR_MSIZE(msize);
-
-#if CONFIG_ASLR_INTERNAL
- int offset_msize = malloc_entropy[1] & SMALL_ENTROPY_MASK;
-#if DEBUG_MALLOC
- if (getenv("MallocASLRForce")) {
- offset_msize = strtol(getenv("MallocASLRForce"), NULL, 0) & SMALL_ENTROPY_MASK;
- }
- if (getenv("MallocASLRPrint")) {
- malloc_report(ASL_LEVEL_INFO, "Region: %p offset: %d\n", region, offset_msize);
- }
-#endif
-#else
- int offset_msize = 0;
-#endif
- ptr = (void *)(SMALL_REGION_HEAP_BASE(region) + SMALL_BYTES_FOR_MSIZE(offset_msize));
- small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(ptr), offset_msize, msize);
- small_mag_ptr->mag_num_objects++;
- small_mag_ptr->mag_num_bytes_in_objects += SMALL_BYTES_FOR_MSIZE(msize);
- small_mag_ptr->num_bytes_in_magazine += SMALL_HEAP_SIZE;
-
- // add a big free block at the end
- small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(ptr), offset_msize + msize, NUM_SMALL_BLOCKS - msize - offset_msize);
- small_mag_ptr->mag_bytes_free_at_end = SMALL_BYTES_FOR_MSIZE(NUM_SMALL_BLOCKS - msize - offset_msize);
-
-#if CONFIG_ASLR_INTERNAL
- // add a big free block at the start
- small_mag_ptr->mag_bytes_free_at_start = SMALL_BYTES_FOR_MSIZE(offset_msize);
- if (offset_msize) {
- small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(ptr), 0, offset_msize);
- }
-#else
- small_mag_ptr->mag_bytes_free_at_start = 0;
-#endif
-
- // connect to magazine as last node
- recirc_list_splice_last(rack, small_mag_ptr, REGION_TRAILER_FOR_SMALL_REGION(region));
-
- return ptr;
-}
-
-void *
-small_memalign(szone_t *szone, size_t alignment, size_t size, size_t span)
-{
- msize_t mspan = SMALL_MSIZE_FOR_BYTES(span + SMALL_QUANTUM - 1);
- void *p = small_malloc_should_clear(&szone->small_rack, mspan, 0);
-
- if (NULL == p) {
- return NULL;
- }
-
- size_t offset = ((uintptr_t)p) & (alignment - 1); // p % alignment
- size_t pad = (0 == offset) ? 0 : alignment - offset; // p + pad achieves desired alignment
-
- msize_t msize = SMALL_MSIZE_FOR_BYTES(size + SMALL_QUANTUM - 1);
- msize_t mpad = SMALL_MSIZE_FOR_BYTES(pad + SMALL_QUANTUM - 1);
- msize_t mwaste = mspan - msize - mpad; // excess blocks
-
- if (mpad > 0) {
- void *q = (void *)(((uintptr_t)p) + pad);
-
- // Mark q as block header and in-use, thus creating two blocks.
- magazine_t *small_mag_ptr = mag_lock_zine_for_region_trailer(szone->small_rack.magazines,
- REGION_TRAILER_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(p)),
- MAGAZINE_INDEX_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(p)));
- small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(p), SMALL_META_INDEX_FOR_PTR(p), mpad);
- small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(q), SMALL_META_INDEX_FOR_PTR(q), msize + mwaste);
- small_mag_ptr->mag_num_objects++;
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
-
- // Give up mpad blocks beginning at p to the small free list
- free_small(&szone->small_rack, p, SMALL_REGION_FOR_PTR(p), SMALL_BYTES_FOR_MSIZE(mpad));
-
- p = q; // advance p to the desired alignment
- }
- if (mwaste > 0) {
- void *q = (void *)(((uintptr_t)p) + SMALL_BYTES_FOR_MSIZE(msize));
- // Mark q as block header and in-use, thus creating two blocks.
- magazine_t *small_mag_ptr = mag_lock_zine_for_region_trailer(szone->small_rack.magazines,
- REGION_TRAILER_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(p)),
- MAGAZINE_INDEX_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(p)));
- small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(p), SMALL_META_INDEX_FOR_PTR(p), msize);
- small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(q), SMALL_META_INDEX_FOR_PTR(q), mwaste);
- small_mag_ptr->mag_num_objects++;
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
-
- // Give up mwaste blocks beginning at q to the small free list
- free_small(&szone->small_rack, q, SMALL_REGION_FOR_PTR(q), SMALL_BYTES_FOR_MSIZE(mwaste));
- }
-
- return p; // p has the desired size and alignment, and can later be free()'d
-}
-
-boolean_t
-small_claimed_address(rack_t *rack, void *ptr)
-{
- region_t r = small_region_for_ptr_no_lock(rack, ptr);
- return r && ptr >= SMALL_REGION_HEAP_BASE(r)
- && ptr < SMALL_REGION_HEAP_END(r);
-}
-
-void *
-small_try_shrink_in_place(rack_t *rack, void *ptr, size_t old_size, size_t new_good_size)
-{
- msize_t new_msize = SMALL_MSIZE_FOR_BYTES(new_good_size);
- msize_t mshrinkage = SMALL_MSIZE_FOR_BYTES(old_size) - new_msize;
-
- if (mshrinkage) {
- void *q = (void *)((uintptr_t)ptr + SMALL_BYTES_FOR_MSIZE(new_msize));
- magazine_t *small_mag_ptr = mag_lock_zine_for_region_trailer(rack->magazines,
- REGION_TRAILER_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr)),
- MAGAZINE_INDEX_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr)));
-
- // Mark q as block header and in-use, thus creating two blocks.
- small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(ptr), SMALL_META_INDEX_FOR_PTR(ptr), new_msize);
- small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(q), SMALL_META_INDEX_FOR_PTR(q), mshrinkage);
- small_mag_ptr->mag_num_objects++;
-
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- free_small(rack, q, SMALL_REGION_FOR_PTR(q), 0);
- }
-
- return ptr;
-}
-
-boolean_t
-small_try_realloc_in_place(rack_t *rack, void *ptr, size_t old_size, size_t new_size)
-{
- // returns 1 on success
- msize_t *meta_headers = SMALL_META_HEADER_FOR_PTR(ptr);
- unsigned index;
- msize_t old_msize, new_msize;
- unsigned next_index;
- void *next_block;
- msize_t next_msize_and_free;
- boolean_t is_free;
- msize_t next_msize, leftover_msize;
- void *leftover;
-
- index = SMALL_META_INDEX_FOR_PTR(ptr);
- old_msize = SMALL_MSIZE_FOR_BYTES(old_size);
- new_msize = SMALL_MSIZE_FOR_BYTES(new_size + SMALL_QUANTUM - 1);
- next_index = index + old_msize;
-
- if (next_index >= NUM_SMALL_BLOCKS) {
- return 0;
- }
- next_block = (char *)ptr + old_size;
-
-#if DEBUG_MALLOC
- if ((uintptr_t)next_block & (SMALL_QUANTUM - 1)) {
- malloc_zone_error(rack->debug_flags, true, "internal invariant broken in realloc(next_block) for %p\n", next_block);
- }
- if (meta_headers[index] != old_msize) {
- malloc_report(ASL_LEVEL_ERR, "*** small_try_realloc_in_place incorrect old %d %d\n", meta_headers[index], old_msize);
- }
-#endif
-
- magazine_t *small_mag_ptr = mag_lock_zine_for_region_trailer(rack->magazines,
- REGION_TRAILER_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr)),
- MAGAZINE_INDEX_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr)));
- if (DEPOT_MAGAZINE_INDEX == MAGAZINE_INDEX_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr))) {
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- return 0;
- }
-
- msize_t coalesced_msize = new_msize - old_msize;
-#if CONFIG_SMALL_CACHE
- void *last_free_ptr = small_mag_ptr->mag_last_free;
- msize_t last_free_msize = small_mag_ptr->mag_last_free_msize;
- if (last_free_ptr == next_block && old_msize + last_free_msize >= new_msize) {
- /*
- * There is a block in mag_last_free and it's immediately after
- * this block and it's large enough. We can use some or all of it.
- */
- leftover_msize = last_free_msize - coalesced_msize;
- if (leftover_msize) {
- small_mag_ptr->mag_last_free_msize -= coalesced_msize;
- small_mag_ptr->mag_last_free += new_size - old_size;
- // The block in mag_last_free is still marked as header and in-use, so copy that
- // state to the block that remains. The state for the block that we're going to
- // use is adjusted by the small_meta_header_set_middle() call below.
- small_meta_header_set_in_use(meta_headers, index + new_msize, leftover_msize);
- } else {
- // Using the whole block.
- small_mag_ptr->mag_last_free = NULL;
- small_mag_ptr->mag_last_free_msize = 0;
- small_mag_ptr->mag_last_free_rgn = NULL;
- }
- small_meta_header_set_in_use(meta_headers, index, new_msize);
- small_meta_header_set_middle(meta_headers, next_index);
- } else {
-#endif // CONFIG_SMALL_CACHE
- /*
- * Try to expand into unused space immediately after this block.
- */
- msize_t unused_msize = SMALL_MSIZE_FOR_BYTES(small_mag_ptr->mag_bytes_free_at_end);
- void *unused_start = SMALL_REGION_HEAP_END(SMALL_REGION_FOR_PTR(ptr)) - small_mag_ptr->mag_bytes_free_at_end;
- if (small_mag_ptr->mag_last_region == SMALL_REGION_FOR_PTR(ptr)
- && coalesced_msize < unused_msize && unused_start == ptr + old_size) {
- // Extend the in-use for this block to the new size
- small_meta_header_set_in_use(meta_headers, index, new_msize);
-
- // Clear the in-use size for the start of the area we extended into
- small_meta_header_set_middle(meta_headers, next_index);
-
- // Reduce mag_bytes_free_at_end and update its in-use size.
- small_mag_ptr->mag_bytes_free_at_end -= SMALL_BYTES_FOR_MSIZE(coalesced_msize);
- small_meta_header_set_in_use(meta_headers, index + new_msize, SMALL_MSIZE_FOR_BYTES(small_mag_ptr->mag_bytes_free_at_end));
- } else {
- /*
- * Look for a free block immediately afterwards. If it's large enough, we can consume (part of)
- * it.
- */
- next_msize_and_free = meta_headers[next_index];
- is_free = next_msize_and_free & SMALL_IS_FREE;
- if (!is_free) {
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- return 0; // next_block is in use;
- }
-
- next_msize = next_msize_and_free & ~SMALL_IS_FREE;
- if (old_msize + next_msize < new_msize) {
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- return 0; // even with next block, not enough
- }
-
- // The following block is big enough; pull it from its freelist and chop off enough to satisfy
- // our needs.
- free_list_t freee = small_free_list_find_by_ptr(rack, small_mag_ptr, next_block, next_msize);
- small_free_list_remove_ptr(rack, small_mag_ptr, freee, next_msize);
- small_meta_header_set_middle(meta_headers, next_index);
- leftover_msize = old_msize + next_msize - new_msize;
- if (leftover_msize) {
- /* there's some left, so put the remainder back */
- leftover = (unsigned char *)ptr + SMALL_BYTES_FOR_MSIZE(new_msize);
- small_free_list_add_ptr(rack, small_mag_ptr, leftover, leftover_msize);
- }
- small_meta_header_set_in_use(meta_headers, index, new_msize);
- }
-#if CONFIG_SMALL_CACHE
- }
-#endif // CONFIG_SMALL_CACHE
-#if DEBUG_MALLOC
- if (SMALL_BYTES_FOR_MSIZE(new_msize) > szone->large_threshold) {
- malloc_report(ASL_LEVEL_ERR, "*** realloc in place for %p exceeded msize=%d\n", new_msize);
- }
-
- if (LOG(szone, ptr)) {
- malloc_report(ASL_LEVEL_INFO, "in small_try_realloc_in_place(), ptr=%p, msize=%d\n", ptr, *SMALL_METADATA_FOR_PTR(ptr));
- }
-#endif
- small_mag_ptr->mag_num_bytes_in_objects += SMALL_BYTES_FOR_MSIZE(new_msize - old_msize);
-
- // Update this region's bytes in use count
- region_trailer_t *node = REGION_TRAILER_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr));
- size_t bytes_used = node->bytes_used + SMALL_BYTES_FOR_MSIZE(new_msize - old_msize);
- node->bytes_used = (unsigned int)bytes_used;
-
- // Emptiness discriminant
- if (bytes_used < DENSITY_THRESHOLD(SMALL_HEAP_SIZE)) {
- /* After this reallocation the region is still sparse, so it must have been even more so before
- * the reallocation. That implies the region is already correctly marked. Do nothing. */
- } else {
- /* Region has crossed threshold from sparsity to density. Mark it not "suitable" on the
- * recirculation candidates list. */
- node->recirc_suitable = FALSE;
- }
-
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- CHECK(szone, __PRETTY_FUNCTION__);
- return 1;
-}
-
-static char *small_check_fail_msg = "check: incorrect small region ";
-
-#define SMALL_CHECK_FAIL(fmt, ...) \
- malloc_zone_check_fail(small_check_fail_msg, \
- "%ld, counter=%d\n" fmt, region_index, counter, __VA_ARGS__);
-
-boolean_t
-small_check_region(rack_t *rack, region_t region, size_t region_index,
- unsigned counter)
-{
- unsigned char *ptr = SMALL_REGION_HEAP_BASE(region);
- msize_t *meta_headers = SMALL_META_HEADER_FOR_PTR(ptr);
- unsigned char *region_end = SMALL_REGION_HEAP_END(region);
- msize_t prev_free = 0;
- unsigned index;
- msize_t msize_and_free;
- msize_t msize;
- free_list_t free_head, previous, next;
- msize_t *follower;
- mag_index_t mag_index = MAGAZINE_INDEX_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr));
- magazine_t *small_mag_ptr = &(rack->magazines[mag_index]);
-
- // Assumes locked
- CHECK_MAGAZINE_PTR_LOCKED(szone, small_mag_ptr, __PRETTY_FUNCTION__);
-
- if (region == small_mag_ptr->mag_last_region) {
- ptr += small_mag_ptr->mag_bytes_free_at_start;
- region_end -= small_mag_ptr->mag_bytes_free_at_end;
- }
-
- while (ptr < region_end) {
- index = SMALL_META_INDEX_FOR_PTR(ptr);
- msize_and_free = meta_headers[index];
- if (!(msize_and_free & SMALL_IS_FREE)) {
- // block is in use
- msize = msize_and_free;
- if (!msize) {
- SMALL_CHECK_FAIL("*** invariant broken: null msize ptr=%p num_small_regions=%d end=%p\n", ptr,
- (int)rack->num_regions, region_end);
- return 0;
- }
-#if !CONFIG_RELAXED_INVARIANT_CHECKS
- if (SMALL_BYTES_FOR_MSIZE(msize) > szone->large_threshold) {
- SMALL_CHECK_FAIL("*** invariant broken for %p this small msize=%d - size is too large\n", ptr, msize_and_free);
- return 0;
- }
-#endif // CONFIG_RELAXED_INVARIANT_CHECKS
- ptr += SMALL_BYTES_FOR_MSIZE(msize);
- prev_free = 0;
- } else {
- // free pointer
- msize = msize_and_free & ~SMALL_IS_FREE;
- free_head = (free_list_t){ .p = ptr };
- follower = (msize_t *)FOLLOWING_SMALL_PTR(ptr, msize);
- if (!msize) {
- SMALL_CHECK_FAIL("*** invariant broken for free block %p this msize=%d\n", ptr, msize);
- return 0;
- }
-#if !CONFIG_RELAXED_INVARIANT_CHECKS
- if (prev_free) {
- SMALL_CHECK_FAIL("*** invariant broken for %p (2 free in a row)\n", ptr);
- return 0;
- }
-#endif
-
- // <rdar://problem/24680189> check for possible OOB entry if needed
- if (small_needs_oob_free_entry(ptr, msize)) {
- oob_free_entry_t oob = small_oob_free_find_ptr(ptr, msize);
- if (oob) {
- free_head.oob = oob;
- }
- }
-
- previous = small_free_list_get_previous(rack, free_head);
- next = small_free_list_get_next(rack, free_head);
- if (previous.p && !SMALL_PTR_IS_FREE(small_free_list_get_ptr(previous))) {
- SMALL_CHECK_FAIL("*** invariant broken for %p (previous %p is not a free pointer)\n", ptr, small_free_list_get_ptr(previous));
- return 0;
- }
- if (next.p && !SMALL_PTR_IS_FREE(small_free_list_get_ptr(next))) {
- SMALL_CHECK_FAIL("*** invariant broken for %p (next %p is not a free pointer)\n", ptr, small_free_list_get_ptr(next));
- return 0;
- }
- if (SMALL_PREVIOUS_MSIZE(follower) != msize) {
- SMALL_CHECK_FAIL("*** invariant broken for small free %p followed by %p in region [%p-%p] "
- "(end marker incorrect) should be %d; in fact %d\n",
- ptr, follower, SMALL_REGION_HEAP_BASE(region), region_end, msize, SMALL_PREVIOUS_MSIZE(follower));
- return 0;
- }
- ptr = (unsigned char *)follower;
- prev_free = SMALL_IS_FREE;
- }
- }
- return 1;
-}
-
-kern_return_t
-small_in_use_enumerator(task_t task,
- void *context,
- unsigned type_mask,
- szone_t *szone,
- memory_reader_t reader,
- vm_range_recorder_t recorder)
-{
- size_t num_regions;
- size_t index;
- region_t *regions;
- vm_range_t buffer[MAX_RECORDER_BUFFER];
- unsigned count = 0;
- kern_return_t err;
- region_t region;
- vm_range_t range;
- vm_range_t admin_range;
- vm_range_t ptr_range;
- unsigned char *mapped_region;
- msize_t *block_header;
- unsigned block_index;
- unsigned block_limit;
- msize_t msize_and_free;
- msize_t msize;
- magazine_t *small_mag_base = NULL;
-
- region_hash_generation_t *srg_ptr;
- err = reader(task, (vm_address_t)szone->small_rack.region_generation, sizeof(region_hash_generation_t), (void **)&srg_ptr);
- if (err) {
- return err;
- }
-
- num_regions = srg_ptr->num_regions_allocated;
- err = reader(task, (vm_address_t)srg_ptr->hashed_regions, sizeof(region_t) * num_regions, (void **)®ions);
- if (err) {
- return err;
- }
-
- if (type_mask & MALLOC_PTR_IN_USE_RANGE_TYPE) {
- // Map in all active magazines. Do this outside the iteration over regions.
- err = reader(task, (vm_address_t)(szone->small_rack.magazines), szone->small_rack.num_magazines * sizeof(magazine_t),
- (void **)&small_mag_base);
- if (err) {
- return err;
- }
- }
-
- for (index = 0; index < num_regions; ++index) {
- region = regions[index];
- if (HASHRING_OPEN_ENTRY != region && HASHRING_REGION_DEALLOCATED != region) {
- range.address = (vm_address_t)SMALL_REGION_HEAP_BASE(region);
- range.size = SMALL_HEAP_SIZE;
- if (type_mask & MALLOC_ADMIN_REGION_RANGE_TYPE) {
- admin_range.address = SMALL_REGION_METADATA(region);
- admin_range.size = SMALL_METADATA_SIZE;
- recorder(task, context, MALLOC_ADMIN_REGION_RANGE_TYPE, &admin_range, 1);
- }
- if (type_mask & (MALLOC_PTR_REGION_RANGE_TYPE | MALLOC_ADMIN_REGION_RANGE_TYPE)) {
- ptr_range.address = range.address;
- ptr_range.size = SMALL_HEAP_SIZE;
- recorder(task, context, MALLOC_PTR_REGION_RANGE_TYPE, &ptr_range, 1);
- }
- if (type_mask & MALLOC_PTR_IN_USE_RANGE_TYPE) {
- err = reader(task, (vm_address_t)region, (vm_size_t)SMALL_REGION_SIZE, (void **)&mapped_region);
- if (err) {
- return err;
- }
-
- mag_index_t mag_index = MAGAZINE_INDEX_FOR_SMALL_REGION(mapped_region);
- magazine_t *small_mag_ptr = small_mag_base + mag_index;
-
- int cached_free_blocks = 0;
-#if CONFIG_SMALL_CACHE
- // Each magazine could have a pointer to a cached free block from
- // this region. Count the regions that have such a pointer.
- for (mag_index = 0; mag_index < szone->small_rack.num_magazines; mag_index++) {
- if (region == (small_mag_base + mag_index)->mag_last_free_rgn) {
- cached_free_blocks++;
- }
- }
-#endif // CONFIG_SMALL_CACHE
-
- block_header = SMALL_META_HEADER_FOR_REGION(mapped_region);
- block_index = 0;
- block_limit = NUM_SMALL_BLOCKS;
- if (region == small_mag_ptr->mag_last_region) {
- block_index += SMALL_MSIZE_FOR_BYTES(small_mag_ptr->mag_bytes_free_at_start);
- block_limit -= SMALL_MSIZE_FOR_BYTES(small_mag_ptr->mag_bytes_free_at_end);
- }
-
- for (;block_index < block_limit; block_index += msize) {
- msize_and_free = block_header[block_index];
- msize = msize_and_free & ~SMALL_IS_FREE;
- if (!msize) {
- return KERN_FAILURE; // Somethings amiss. Avoid looping at this block_index.
- }
- if (!(msize_and_free & SMALL_IS_FREE)) {
- void *ptr = SMALL_REGION_HEAP_BASE(region) + SMALL_BYTES_FOR_MSIZE(block_index);
-#if CONFIG_SMALL_CACHE
- // If there are still magazines that have cached free
- // blocks in this region, check whether this is one of
- // them and don't return the block pointer if it is.
- boolean_t block_cached = false;
- if (cached_free_blocks) {
- for (mag_index = 0; mag_index < szone->small_rack.num_magazines; mag_index++) {
- if (ptr == (small_mag_base + mag_index)->mag_last_free) {
- block_cached = true;
- cached_free_blocks--;
- break;
- }
- }
- }
- if (block_cached) {
- continue;
- }
-#endif // CONFIG_SMALL_CACHE
- // Block in use
- buffer[count].address = (vm_address_t)ptr;
- buffer[count].size = SMALL_BYTES_FOR_MSIZE(msize);
- count++;
- if (count >= MAX_RECORDER_BUFFER) {
- recorder(task, context, MALLOC_PTR_IN_USE_RANGE_TYPE, buffer, count);
- count = 0;
- }
- }
- }
- if (count) {
- recorder(task, context, MALLOC_PTR_IN_USE_RANGE_TYPE, buffer, count);
- count = 0;
- }
- }
- }
- }
- return 0;
-}
-
-static void *
-small_malloc_from_free_list(rack_t *rack, magazine_t *small_mag_ptr, mag_index_t mag_index, msize_t msize)
-{
- msize_t this_msize;
- grain_t slot = SMALL_FREE_SLOT_FOR_MSIZE(rack, msize);
- free_list_t *free_list = small_mag_ptr->mag_free_list;
- free_list_t *the_slot = free_list + slot;
- free_list_t *limit;
- unsigned bitmap;
- msize_t leftover_msize;
- void *leftover_ptr;
- void *ptr;
-
- // Assumes we've locked the region
- CHECK_MAGAZINE_PTR_LOCKED(szone, small_mag_ptr, __PRETTY_FUNCTION__);
-
- // Look for an exact match by checking the freelist for this msize.
- if (small_free_list_get_ptr(*the_slot)) {
- ptr = small_free_list_get_ptr(*the_slot);
- this_msize = msize;
- small_free_list_remove_ptr(rack, small_mag_ptr, *the_slot, msize);
- goto return_small_alloc;
- }
-
- // Mask off the bits representing slots holding free blocks smaller than
- // the size we need. If there are no larger free blocks, try allocating
- // from the free space at the end of the small region.
- //
- // BITMAPN_CTZ implementation
- unsigned idx = slot >> 5;
- bitmap = 0;
- unsigned mask = ~((1 << (slot & 31)) - 1);
- for (; idx < SMALL_FREELIST_BITMAP_WORDS(rack); ++idx) {
- bitmap = small_mag_ptr->mag_bitmap[idx] & mask;
- if (bitmap != 0) {
- break;
- }
- mask = ~0U;
- }
- // Check for fallthrough: No bits set in bitmap
- if ((bitmap == 0) && (idx == SMALL_FREELIST_BITMAP_WORDS(rack))) {
- goto try_small_from_end;
- }
-
- // Start looking at the first set bit, plus 32 bits for every word of
- // zeroes or entries that were too small.
- slot = BITMAP32_CTZ((&bitmap)) + (idx * 32);
-
- // FIXME: Explain use of - 1 here, last slot has special meaning
- limit = free_list + SMALL_FREE_SLOT_COUNT(rack) - 1;
- free_list += slot;
-
- // Attempt to pull off the free_list slot that we now think is full.
- if ((ptr = small_free_list_get_ptr(*free_list))) {
- this_msize = SMALL_PTR_SIZE(ptr);
- small_free_list_remove_ptr(rack, small_mag_ptr, *free_list, this_msize);
- goto add_leftover_and_proceed;
- }
-
-#if DEBUG_MALLOC
- malloc_report(ASL_LEVEL_ERR, "in small_malloc_from_free_list(), mag_bitmap out of sync, slot=%d\n", slot);
-#endif
-
-try_small_from_end:
- // Let's see if we can use small_mag_ptr->mag_bytes_free_at_end
- if (small_mag_ptr->mag_bytes_free_at_end >= SMALL_BYTES_FOR_MSIZE(msize)) {
- ptr = SMALL_REGION_HEAP_END(small_mag_ptr->mag_last_region) - small_mag_ptr->mag_bytes_free_at_end;
- small_mag_ptr->mag_bytes_free_at_end -= SMALL_BYTES_FOR_MSIZE(msize);
- if (small_mag_ptr->mag_bytes_free_at_end) {
- // let's mark this block as in use to serve as boundary
- small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(ptr),
- SMALL_META_INDEX_FOR_PTR((unsigned char *)ptr + SMALL_BYTES_FOR_MSIZE(msize)),
- SMALL_MSIZE_FOR_BYTES(small_mag_ptr->mag_bytes_free_at_end));
- }
- this_msize = msize;
- goto return_small_alloc;
- }
-#if CONFIG_ASLR_INTERNAL
- // Try from start if nothing left at end
- if (small_mag_ptr->mag_bytes_free_at_start >= SMALL_BYTES_FOR_MSIZE(msize)) {
- ptr = SMALL_REGION_HEAP_BASE(small_mag_ptr->mag_last_region) + small_mag_ptr->mag_bytes_free_at_start -
- SMALL_BYTES_FOR_MSIZE(msize);
- small_mag_ptr->mag_bytes_free_at_start -= SMALL_BYTES_FOR_MSIZE(msize);
- if (small_mag_ptr->mag_bytes_free_at_start) {
- // let's mark this block as in use to serve as boundary
- small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(ptr), 0,
- SMALL_MSIZE_FOR_BYTES(small_mag_ptr->mag_bytes_free_at_start));
- }
- this_msize = msize;
- goto return_small_alloc;
- }
-#endif
- return NULL;
-
-add_leftover_and_proceed:
- if (this_msize > msize) {
- leftover_msize = this_msize - msize;
- leftover_ptr = (unsigned char *)ptr + SMALL_BYTES_FOR_MSIZE(msize);
-#if DEBUG_MALLOC
- if (LOG(szone, ptr)) {
- malloc_report(ASL_LEVEL_INFO, "in small_malloc_from_free_list(), adding leftover ptr=%p, this_msize=%d\n", ptr, this_msize);
- }
-#endif
- small_free_list_add_ptr(rack, small_mag_ptr, leftover_ptr, leftover_msize);
- this_msize = msize;
- }
-
-return_small_alloc:
- small_mag_ptr->mag_num_objects++;
- small_mag_ptr->mag_num_bytes_in_objects += SMALL_BYTES_FOR_MSIZE(this_msize);
-
- // Check that the region cookie is intact and update the region's bytes in use count
- small_region_t region = SMALL_REGION_FOR_PTR(ptr);
- region_check_cookie(region, ®ION_COOKIE_FOR_SMALL_REGION(region));
-
- region_trailer_t *trailer = REGION_TRAILER_FOR_SMALL_REGION(region);
- size_t bytes_used = trailer->bytes_used + SMALL_BYTES_FOR_MSIZE(this_msize);
- trailer->bytes_used = (unsigned int)bytes_used;
-
- // Emptiness discriminant
- if (bytes_used < DENSITY_THRESHOLD(SMALL_HEAP_SIZE)) {
- /* After this allocation the region is still sparse, so it must have been even more so before
- * the allocation. That implies the region is already correctly marked. Do nothing. */
- } else {
- /* Region has crossed threshold from sparsity to density. Mark in not "suitable" on the
- * recirculation candidates list. */
- trailer->recirc_suitable = FALSE;
- }
-#if DEBUG_MALLOC
- if (LOG(szone, ptr)) {
- malloc_report(ASL_LEVEL_INFO, "in small_malloc_from_free_list(), ptr=%p, this_msize=%d, msize=%d\n", ptr, this_msize, msize);
- }
-#endif
- small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(ptr), SMALL_META_INDEX_FOR_PTR(ptr), this_msize);
- return ptr;
-}
-
-void *
-small_malloc_should_clear(rack_t *rack, msize_t msize, boolean_t cleared_requested)
-{
- void *ptr;
- mag_index_t mag_index = rack_get_thread_index(rack) % rack->num_magazines;
- magazine_t *small_mag_ptr = &(rack->magazines[mag_index]);
-
- MALLOC_TRACE(TRACE_small_malloc, (uintptr_t)rack, SMALL_BYTES_FOR_MSIZE(msize), (uintptr_t)small_mag_ptr, cleared_requested);
-
- SZONE_MAGAZINE_PTR_LOCK(small_mag_ptr);
-
-#if CONFIG_SMALL_CACHE
- ptr = small_mag_ptr->mag_last_free;
-
- if (small_mag_ptr->mag_last_free_msize == msize) {
- // we have a winner
- small_mag_ptr->mag_last_free = NULL;
- small_mag_ptr->mag_last_free_msize = 0;
- small_mag_ptr->mag_last_free_rgn = NULL;
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- CHECK(szone, __PRETTY_FUNCTION__);
- if (cleared_requested) {
- memset(ptr, 0, SMALL_BYTES_FOR_MSIZE(msize));
- }
- return ptr;
- }
-#endif /* CONFIG_SMALL_CACHE */
-
- while (1) {
- ptr = small_malloc_from_free_list(rack, small_mag_ptr, mag_index, msize);
- if (ptr) {
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- CHECK(szone, __PRETTY_FUNCTION__);
- if (cleared_requested) {
- memset(ptr, 0, SMALL_BYTES_FOR_MSIZE(msize));
- }
- return ptr;
- }
-
-#if CONFIG_RECIRC_DEPOT
- if (small_get_region_from_depot(rack, small_mag_ptr, mag_index, msize)) {
- ptr = small_malloc_from_free_list(rack, small_mag_ptr, mag_index, msize);
- if (ptr) {
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- CHECK(szone, __PRETTY_FUNCTION__);
- if (cleared_requested) {
- memset(ptr, 0, SMALL_BYTES_FOR_MSIZE(msize));
- }
- return ptr;
- }
- }
-#endif // CONFIG_RECIRC_DEPOT
-
- // The magazine is exhausted. A new region (heap) must be allocated to satisfy this call to malloc().
- // The allocation, an mmap() system call, will be performed outside the magazine spin locks by the first
- // thread that suffers the exhaustion. That thread sets "alloc_underway" and enters a critical section.
- // Threads arriving here later are excluded from the critical section, yield the CPU, and then retry the
- // allocation. After some time the magazine is resupplied, the original thread leaves with its allocation,
- // and retry-ing threads succeed in the code just above.
- if (!small_mag_ptr->alloc_underway) {
- void *fresh_region;
-
- // time to create a new region (do this outside the magazine lock)
- small_mag_ptr->alloc_underway = TRUE;
- OSMemoryBarrier();
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- fresh_region = mvm_allocate_pages(SMALL_REGION_SIZE,
- SMALL_BLOCKS_ALIGN,
- MALLOC_FIX_GUARD_PAGE_FLAGS(rack->debug_flags),
- VM_MEMORY_MALLOC_SMALL);
- SZONE_MAGAZINE_PTR_LOCK(small_mag_ptr);
-
- // DTrace USDT Probe
- MAGMALLOC_ALLOCREGION(SMALL_SZONE_FROM_RACK(rack), (int)mag_index, fresh_region, SMALL_REGION_SIZE);
-
- if (!fresh_region) { // out of memory!
- small_mag_ptr->alloc_underway = FALSE;
- OSMemoryBarrier();
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- return NULL;
- }
-
- region_set_cookie(®ION_COOKIE_FOR_SMALL_REGION(fresh_region));
- ptr = small_malloc_from_region_no_lock(rack, small_mag_ptr, mag_index, msize, fresh_region);
-
- // we don't clear because this freshly allocated space is pristine
- small_mag_ptr->alloc_underway = FALSE;
- OSMemoryBarrier();
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- CHECK(szone, __PRETTY_FUNCTION__);
- return ptr;
- } else {
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- yield();
- SZONE_MAGAZINE_PTR_LOCK(small_mag_ptr);
- }
- }
- /* NOTREACHED */
-}
-
-size_t
-small_size(rack_t *rack, const void *ptr)
-{
- if (small_region_for_ptr_no_lock(rack, ptr)) {
- if (SMALL_META_INDEX_FOR_PTR(ptr) >= NUM_SMALL_BLOCKS) {
- return 0;
- }
- msize_t msize_and_free = *SMALL_METADATA_FOR_PTR(ptr);
- if (msize_and_free & SMALL_IS_FREE) {
- return 0;
- }
-#if CONFIG_SMALL_CACHE
- {
- mag_index_t mag_index = MAGAZINE_INDEX_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr));
- if (DEPOT_MAGAZINE_INDEX != mag_index) {
- magazine_t *small_mag_ptr = &(rack->magazines[mag_index]);
-
- if (ptr == small_mag_ptr->mag_last_free) {
- return 0;
- }
- } else {
- for (mag_index = 0; mag_index < rack->num_magazines; mag_index++) {
- magazine_t *small_mag_ptr = &(rack->magazines[mag_index]);
-
- if (ptr == small_mag_ptr->mag_last_free) {
- return 0;
- }
- }
- }
- }
-#endif
- return SMALL_BYTES_FOR_MSIZE(msize_and_free);
- }
-
- return 0;
-}
-
-static MALLOC_NOINLINE void
-free_small_botch(rack_t *rack, void *ptr)
-{
- malloc_zone_error(rack->debug_flags, true, "double free for ptr %p\n", ptr);
-}
-
-void
-free_small(rack_t *rack, void *ptr, region_t small_region, size_t known_size)
-{
- msize_t msize;
- mag_index_t mag_index = MAGAZINE_INDEX_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr));
- magazine_t *small_mag_ptr = &(rack->magazines[mag_index]);
-
- // ptr is known to be in small_region
- if (known_size) {
- msize = SMALL_MSIZE_FOR_BYTES(known_size + SMALL_QUANTUM - 1);
- } else {
- msize = SMALL_PTR_SIZE(ptr);
- if (SMALL_PTR_IS_FREE(ptr)) {
- free_small_botch(rack, ptr);
- return;
- }
- }
-
- SZONE_MAGAZINE_PTR_LOCK(small_mag_ptr);
-
-#if CONFIG_SMALL_CACHE
- // Depot does not participate in CONFIG_SMALL_CACHE since it can't be directly malloc()'d
- if (DEPOT_MAGAZINE_INDEX != mag_index) {
- void *ptr2 = small_mag_ptr->mag_last_free; // Might be NULL
- msize_t msize2 = small_mag_ptr->mag_last_free_msize;
- region_t rgn2 = small_mag_ptr->mag_last_free_rgn;
-
- /* check that we don't already have this pointer in the cache */
- if (ptr == ptr2) {
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- free_small_botch(rack, ptr);
- return;
- }
-
- if ((rack->debug_flags & MALLOC_DO_SCRIBBLE) && msize) {
- memset(ptr, SCRABBLE_BYTE, SMALL_BYTES_FOR_MSIZE(msize));
- }
-
- small_mag_ptr->mag_last_free = ptr;
- small_mag_ptr->mag_last_free_msize = msize;
- small_mag_ptr->mag_last_free_rgn = small_region;
-
- if (!ptr2) {
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- CHECK(szone, __PRETTY_FUNCTION__);
- return;
- }
-
- msize = msize2;
- ptr = ptr2;
- small_region = rgn2;
- }
-#endif /* CONFIG_SMALL_CACHE */
-
- // Now in the time it took to acquire the lock, the region may have migrated
- // from one magazine to another. I.e. trailer->mag_index is volatile.
- // In which case the magazine lock we obtained (namely magazines[mag_index].mag_lock)
- // is stale. If so, keep on tryin' ...
- region_trailer_t *trailer = REGION_TRAILER_FOR_SMALL_REGION(small_region);
- mag_index_t refreshed_index;
-
- while (mag_index != (refreshed_index = trailer->mag_index)) { // Note assignment
-
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
-
- mag_index = refreshed_index;
- small_mag_ptr = &(rack->magazines[mag_index]);
- SZONE_MAGAZINE_PTR_LOCK(small_mag_ptr);
- }
-
- if (small_free_no_lock(rack, small_mag_ptr, mag_index, small_region, ptr, msize)) {
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- }
-
- CHECK(szone, __PRETTY_FUNCTION__);
-}
-
-void
-print_small_free_list(task_t task, memory_reader_t reader,
- print_task_printer_t printer, rack_t *rack)
-{
- free_list_t ptr;
- _SIMPLE_STRING b = _simple_salloc();
- mag_index_t mag_index;
-
- if (b) {
- rack_t *mapped_rack;
- magazine_t *mapped_magazines;
- if (reader(task, (vm_address_t)rack, sizeof(struct rack_s),
- (void **)&mapped_rack)) {
- printer("Failed to map small rack\n");
- return;
- }
- if (reader(task, (vm_address_t)mapped_rack->magazines,
- mapped_rack->num_magazines * sizeof(magazine_t),
- (void **)&mapped_magazines)) {
- printer("Failed to map small rack magazines\n");
- return;
- }
-
- _simple_sappend(b, "small free sizes:\n");
- grain_t free_slots = SMALL_FREE_SLOT_COUNT(mapped_rack);
- for (mag_index = -1; mag_index < mapped_rack->num_magazines;
- mag_index++) {
- grain_t slot = 0;
- if (mag_index == -1) {
- _simple_sprintf(b, "\tRecirc depot: ");
- } else {
- _simple_sprintf(b, "\tMagazine %d: ", mag_index);
- }
- while (slot < free_slots) {
- ptr = mapped_magazines[mag_index].mag_free_list[slot];
- if (small_free_list_get_ptr_task(task, reader, printer, ptr)) {
- _simple_sprintf(b, "%s%y[%d]; ", (slot == free_slots - 1) ?
- ">=" : "", (slot + 1) * SMALL_QUANTUM,
- small_free_list_count(task, reader, printer,
- rack, ptr));
- }
- slot++;
- }
- _simple_sappend(b, "\n");
- }
- printer("%s\n", _simple_string(b));
- _simple_sfree(b);
- }
-}
-
-void
-print_small_region(task_t task, memory_reader_t reader,
- print_task_printer_t printer, szone_t *szone, int level,
- region_t region, size_t bytes_at_start, size_t bytes_at_end)
-{
- unsigned counts[1024];
- unsigned in_use = 0;
- uintptr_t start = (uintptr_t)SMALL_REGION_HEAP_BASE(region);
- uintptr_t current = start + bytes_at_start;
- uintptr_t limit = (uintptr_t)SMALL_REGION_HEAP_END(region) - bytes_at_end;
- uintptr_t mapped_start;
- msize_t msize_and_free;
- msize_t msize;
- unsigned ci;
- _SIMPLE_STRING b;
- uintptr_t pgTot = 0;
-
- if (reader(task, (vm_address_t)start, SMALL_REGION_SIZE,
- (void **)&mapped_start)) {
- printer("Failed to map small region at %p\n", start);
- return;
- }
- off_t start_offset = mapped_start - start;
- region_t mapped_region = (region_t)mapped_start;
-
- if (region == HASHRING_REGION_DEALLOCATED) {
- if ((b = _simple_salloc()) != NULL) {
- _simple_sprintf(b, "Small region [unknown address] was returned to the OS\n");
- printer("%s\n", _simple_string(b));
- _simple_sfree(b);
- }
- return;
- }
-
- memset(counts, 0, sizeof(counts));
- while (current < limit) {
- msize_and_free = *(uintptr_t *)((char *)SMALL_METADATA_FOR_PTR(current) + start_offset);
- msize = msize_and_free & ~SMALL_IS_FREE;
- if (!msize) {
- printer("*** error with %p: msize=%d, free: %x\n", (void *)current,
- (unsigned)msize, msize_and_free & SMALL_IS_FREE);
- break;
- }
- if (!(msize_and_free & SMALL_IS_FREE)) {
- // block in use
- if (msize < 1024) {
- counts[msize]++;
- }
- in_use++;
- } else {
- uintptr_t pgLo = round_page_quanta(current +
- sizeof(free_list_t) + sizeof(msize_t));
- uintptr_t pgHi = trunc_page_quanta(current +
- SMALL_BYTES_FOR_MSIZE(msize) - sizeof(msize_t));
-
- if (pgLo < pgHi) {
- pgTot += (pgHi - pgLo);
- }
- }
- current += SMALL_BYTES_FOR_MSIZE(msize);
- }
-
- if ((b = _simple_salloc()) != NULL) {
- mag_index_t mag_index = MAGAZINE_INDEX_FOR_SMALL_REGION(mapped_region);
- _simple_sprintf(b, "Small region %p [%p-%p, %y] \t", region, (void *)start,
- SMALL_REGION_HEAP_END(region), (int)SMALL_REGION_SIZE);
- if (mag_index == DEPOT_MAGAZINE_INDEX) {
- _simple_sprintf(b, "Recirc depot \t");
- } else {
- _simple_sprintf(b, "Magazine=%d \t", mag_index);
- }
- _simple_sprintf(b, "Allocations in use=%d \t Bytes in use=%ly (%d%%) \t",
- in_use, BYTES_USED_FOR_SMALL_REGION(mapped_region),
- (int)(100.0F * BYTES_USED_FOR_SMALL_REGION(mapped_region))/SMALL_REGION_SIZE);
- if (bytes_at_end || bytes_at_start) {
- _simple_sprintf(b, "Untouched=%ly ", bytes_at_end + bytes_at_start);
- }
- if (mag_index == DEPOT_MAGAZINE_INDEX) {
- _simple_sprintf(b, "Advised MADV_FREE=%ly", pgTot);
- } else {
- _simple_sprintf(b, "Fragments subject to reclamation=%ly", pgTot);
-#if CONFIG_RECIRC_DEPOT
- _simple_sprintf(b, small_region_below_recirc_threshold(mapped_region) ?
- "\tEmpty enough to be moved to recirc depot" :
- "\tNot empty enough to be moved to recirc depot");
-#endif // CONFIG_RECIRC_DEPOT
- }
- if (level >= MALLOC_VERBOSE_PRINT_LEVEL && in_use) {
- _simple_sappend(b, "\n\tSizes in use: ");
- for (ci = 0; ci < 1024; ci++) {
- if (counts[ci]) {
- _simple_sprintf(b, "%y[%d] ", SMALL_BYTES_FOR_MSIZE(ci),
- counts[ci]);
- }
- }
- }
- printer("%s\n", _simple_string(b));
- _simple_sfree(b);
- }
-}
-
-static char *small_freelist_fail_msg = "check: small free list incorrect";
-
-#define SMALL_FREELIST_FAIL(fmt, ...) \
- malloc_zone_check_fail(small_freelist_fail_msg, \
- " (slot=%u), counter=%d\n" fmt, slot, counter, __VA_ARGS__);
-
-boolean_t
-small_free_list_check(rack_t *rack, grain_t slot, unsigned counter)
-{
- mag_index_t mag_index;
-
- for (mag_index = -1; mag_index < rack->num_magazines; mag_index++) {
- magazine_t *small_mag_ptr = &(rack->magazines[mag_index]);
- SZONE_MAGAZINE_PTR_LOCK(small_mag_ptr);
-
- unsigned count = 0;
- free_list_t current = rack->magazines[mag_index].mag_free_list[slot];
- free_list_t previous = (free_list_t){ .p = NULL };
- msize_t msize_and_free;
- void *ptr = NULL;
-
- while ((ptr = small_free_list_get_ptr(current))) {
- msize_and_free = *SMALL_METADATA_FOR_PTR(ptr);
- if (!(msize_and_free & SMALL_IS_FREE)) {
- SMALL_FREELIST_FAIL("*** in-use ptr in free list slot=%u count=%d ptr=%p\n", slot, count, ptr);
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- return 0;
- }
- if (((uintptr_t)ptr) & (SMALL_QUANTUM - 1)) {
- SMALL_FREELIST_FAIL("*** unaligned ptr in free list slot=%u count=%d ptr=%p\n", slot, count, ptr);
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- return 0;
- }
- if (!small_region_for_ptr_no_lock(rack, ptr)) {
- SMALL_FREELIST_FAIL("*** ptr not in szone slot=%d count=%d ptr=%p\n", slot, count, ptr);
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- return 0;
- }
- if (small_free_list_get_previous(rack, current).p != previous.p) {
- SMALL_FREELIST_FAIL("*** previous incorrectly set slot=%u count=%d ptr=%p\n", slot, count, ptr);
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- return 0;
- }
- previous = current;
- current = small_free_list_get_next(rack, current);
- count++;
- }
-
- SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
- }
- return 1;
-}