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--- libmalloc/libmalloc-792.60.6/src/magazine_tiny.c
+++ libmalloc/libmalloc-317.140.5/src/magazine_tiny.c
@@ -38,6 +38,25 @@
// reduce the msize part below zero (not checked).
#define TINY_MAG_LAST_FREE_PTR_DEC_MSIZE(x, msize_delta) (x) = ((void *)(x) - (msize_delta))
+static MALLOC_INLINE MALLOC_ALWAYS_INLINE
+mag_index_t
+tiny_mag_get_thread_index(void)
+{
+#if CONFIG_TINY_USES_HYPER_SHIFT
+ if (os_likely(_os_cpu_number_override == -1)) {
+ return _malloc_cpu_number() >> hyper_shift;
+ } else {
+ return _os_cpu_number_override >> hyper_shift;
+ }
+#else // CONFIG_SMALL_USES_HYPER_SHIFT
+ if (os_likely(_os_cpu_number_override == -1)) {
+ return _malloc_cpu_number();
+ } else {
+ return _os_cpu_number_override;
+ }
+#endif // CONFIG_SMALL_USES_HYPER_SHIFT
+}
+
static inline grain_t
tiny_slot_from_msize(msize_t msize)
{
@@ -62,11 +81,7 @@
if (BITARRAY_BIT(prev_header, prev_index)) {
return 1;
}
- msize_t *prev_msize_ptr = &TINY_PREVIOUS_MSIZE(ptr);
- // This is a speculative read of potentially in-use app memory, we need
- // to use _malloc_read_uint16_via_rsp to avoid triggering warnings in
- // memory diagnostic tools.
- return _malloc_read_uint16_via_rsp(prev_msize_ptr);
+ return TINY_PREVIOUS_MSIZE(ptr);
}
// don't read possibly unmapped memory before the beginning of the region
return 0;
@@ -182,160 +197,6 @@
BITARRAY_CLR(block_header, index);
BITARRAY_CLR(in_use, index);
}
-
-static MALLOC_INLINE void
-zero_tiny_free_inline_meta(void *ptr, msize_t msize)
-{
- if (malloc_zero_policy == MALLOC_ZERO_ON_FREE) {
- *((tiny_free_list_t *)ptr) = (tiny_free_list_t){ 0 };
- if (msize > 1) {
- TINY_FREE_SIZE(ptr) = 0;
- void *follower = FOLLOWING_TINY_PTR(ptr, msize);
- TINY_PREVIOUS_MSIZE(follower) = 0;
- } else if (msize == 0) {
- TINY_FREE_SIZE(ptr) = 0;
- }
- }
-}
-
-static MALLOC_INLINE void
-zero_tiny_free_inline_meta_following(void *ptr, msize_t msize)
-{
- if (malloc_zero_policy == MALLOC_ZERO_ON_FREE) {
- if (msize > 1) {
- void *follower = FOLLOWING_TINY_PTR(ptr, msize);
- TINY_PREVIOUS_MSIZE(follower) = 0;
- }
- }
-}
-
-static MALLOC_COLD MALLOC_NOINLINE void
-tiny_zero_corruption_abort(void *ptr, msize_t msize)
-{
- uint8_t *bytes = ptr;
- size_t size = TINY_BYTES_FOR_MSIZE(msize);
- uint8_t *start = bytes, *end = bytes + size;
- // scan to the first non-NUL byte
- while (*bytes == '\0') {
- bytes++;
- }
-
- unsigned int offset = (unsigned int)(bytes - start);
- malloc_zone_error(MALLOC_ABORT_ON_CORRUPTION, true,
- "Corruption detected in block %p of size %u at offset %u, "
- "first 32 bytes at that offset are "
- "%02X %02X %02X %02X %02X %02X %02X %02X | "
- "%02X %02X %02X %02X %02X %02X %02X %02X | "
- "%02X %02X %02X %02X %02X %02X %02X %02X | "
- "%02X %02X %02X %02X %02X %02X %02X %02X\n",
- ptr, (unsigned int)size, offset,
- (bytes + 0) < end ? *(bytes + 0) : 0,
- (bytes + 1) < end ? *(bytes + 1) : 0,
- (bytes + 2) < end ? *(bytes + 2) : 0,
- (bytes + 3) < end ? *(bytes + 3) : 0,
- (bytes + 4) < end ? *(bytes + 4) : 0,
- (bytes + 5) < end ? *(bytes + 5) : 0,
- (bytes + 6) < end ? *(bytes + 6) : 0,
- (bytes + 7) < end ? *(bytes + 7) : 0,
- (bytes + 8) < end ? *(bytes + 8) : 0,
- (bytes + 9) < end ? *(bytes + 9) : 0,
- (bytes + 10) < end ? *(bytes + 10) : 0,
- (bytes + 11) < end ? *(bytes + 11) : 0,
- (bytes + 12) < end ? *(bytes + 12) : 0,
- (bytes + 13) < end ? *(bytes + 13) : 0,
- (bytes + 14) < end ? *(bytes + 14) : 0,
- (bytes + 15) < end ? *(bytes + 15) : 0,
- (bytes + 16) < end ? *(bytes + 16) : 0,
- (bytes + 17) < end ? *(bytes + 17) : 0,
- (bytes + 18) < end ? *(bytes + 18) : 0,
- (bytes + 19) < end ? *(bytes + 19) : 0,
- (bytes + 20) < end ? *(bytes + 20) : 0,
- (bytes + 21) < end ? *(bytes + 21) : 0,
- (bytes + 22) < end ? *(bytes + 22) : 0,
- (bytes + 23) < end ? *(bytes + 23) : 0,
- (bytes + 24) < end ? *(bytes + 24) : 0,
- (bytes + 25) < end ? *(bytes + 25) : 0,
- (bytes + 26) < end ? *(bytes + 26) : 0,
- (bytes + 27) < end ? *(bytes + 27) : 0,
- (bytes + 28) < end ? *(bytes + 28) : 0,
- (bytes + 29) < end ? *(bytes + 29) : 0,
- (bytes + 30) < end ? *(bytes + 30) : 0,
- (bytes + 31) < end ? *(bytes + 31) : 0);
-}
-
-static MALLOC_INLINE void
-tiny_check_zero_or_clear(void *ptr, msize_t msize, boolean_t clear)
-{
- switch (malloc_zero_policy) {
- case MALLOC_ZERO_ON_FREE:
- if (zero_on_free_should_sample() &&
- _malloc_memcmp_zero_aligned8(ptr, TINY_BYTES_FOR_MSIZE(msize))) {
- tiny_zero_corruption_abort(ptr, msize);
- }
- break;
- case MALLOC_ZERO_NONE:
- if (!clear) {
- break;
- }
- MALLOC_FALLTHROUGH;
- case MALLOC_ZERO_ON_ALLOC:
- memset(ptr, '\0', TINY_BYTES_FOR_MSIZE(msize));
- break;
- }
-}
-
-// Check the inline metadata of a free block that hasn't already been verified:
-// - the previous freelist pointer
-// - agreement of the inline msizes
-//
-// Then clear all the inline metadata.
-static MALLOC_NOINLINE void
-_tiny_check_and_zero_inline_meta_from_freelist(rack_t *rack, void *ptr,
- msize_t msize)
-{
- tiny_free_list_t *free_ptr = ptr;
-
- // check the previous pointer
- (void)free_list_unchecksum_ptr(rack, &free_ptr->previous);
- // zero both pointers
- *free_ptr = (tiny_free_list_t){ 0 };
-
- // check agreement between msizes and zero
- if (msize > 1) {
- msize_t leading_free_size = TINY_FREE_SIZE(ptr);
- void *follower = FOLLOWING_TINY_PTR(ptr, msize);
- msize_t trailing_free_size = TINY_PREVIOUS_MSIZE(follower);
-
- if (leading_free_size != trailing_free_size) {
- malloc_zone_error(MALLOC_ABORT_ON_CORRUPTION, true,
- "Corruption of free object %p: msizes %u/%u disagree\n",
- ptr, leading_free_size, trailing_free_size);
- } else if (leading_free_size != msize) {
- malloc_zone_error(MALLOC_ABORT_ON_CORRUPTION, true,
- "Corruption at %p: unexpected msizes %u/%u\n",
- ptr, leading_free_size, msize);
- }
-
- TINY_FREE_SIZE(ptr) = 0;
- TINY_PREVIOUS_MSIZE(follower) = 0;
- } else if (msize == 0 && TINY_FREE_SIZE(ptr) != 0) {
- malloc_zone_error(MALLOC_ABORT_ON_CORRUPTION, true,
- "Corruption at %p: unexpected nonzero msize %u\n", ptr,
- TINY_FREE_SIZE(ptr));
- }
-}
-
-static MALLOC_ALWAYS_INLINE MALLOC_INLINE void
-tiny_check_and_zero_inline_meta_from_freelist(rack_t *rack, void *ptr,
- msize_t msize)
-{
- if (malloc_zero_policy != MALLOC_ZERO_ON_FREE) {
- return;
- }
-
- _tiny_check_and_zero_inline_meta_from_freelist(rack, ptr, msize);
-}
-
static MALLOC_INLINE void
set_tiny_meta_header_free(const void *ptr, msize_t msize)
@@ -728,9 +589,6 @@
if (previous_block) {
set_tiny_meta_header_middle(last_block);
tiny_free_list_remove_ptr(rack, tiny_mag_ptr, previous_block, previous_msize);
- // zero out the trailing inline msize of the previous block to
- // connect its zero prefix to the last block
- zero_tiny_free_inline_meta_following(previous_block, previous_msize);
last_block = previous_block;
last_msize += previous_msize;
}
@@ -756,9 +614,6 @@
msize_t next_msize = get_tiny_free_size(next_block);
set_tiny_meta_header_middle(next_block);
tiny_free_list_remove_ptr(rack, tiny_mag_ptr, next_block, next_msize);
- // zero inline metadata of next_block to continue the zero prefix of
- // the big starting free block
- zero_tiny_free_inline_meta(next_block, next_msize);
last_msize += next_msize;
}
@@ -1018,11 +873,6 @@
continue;
}
- if (REGION_TRAILER_FOR_TINY_REGION(tiny)->pinned_to_depot > 0) {
- SZONE_MAGAZINE_PTR_UNLOCK(mag_ptr);
- continue;
- }
-
if (tiny == mag_ptr->mag_last_region && (mag_ptr->mag_bytes_free_at_end || mag_ptr->mag_bytes_free_at_start)) {
tiny_finalize_region(rack, mag_ptr);
}
@@ -1037,7 +887,7 @@
SZONE_MAGAZINE_PTR_LOCK(tiny_depot_ptr);
MAGAZINE_INDEX_FOR_TINY_REGION(tiny) = DEPOT_MAGAZINE_INDEX;
- MALLOC_ASSERT(REGION_TRAILER_FOR_TINY_REGION(tiny)->pinned_to_depot == 0);
+ REGION_TRAILER_FOR_TINY_REGION(tiny)->pinned_to_depot = 0;
size_t bytes_inplay = tiny_free_reattach_region(rack, tiny_depot_ptr, tiny);
@@ -1126,6 +976,11 @@
{
magazine_t *depot_ptr = &(rack->magazines[DEPOT_MAGAZINE_INDEX]);
+ /* FIXME: Would Uniprocessor benefit from recirc and MADV_FREE? */
+ if (rack->num_magazines == 1) { // Uniprocessor, single magazine, so no recirculation necessary
+ return 0;
+ }
+
#if DEBUG_MALLOC
if (DEPOT_MAGAZINE_INDEX == mag_index) {
malloc_zone_error(rack->debug_flags, true, "tiny_get_region_from_depot called for magazine index -1\n");
@@ -1138,32 +993,22 @@
// 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 = tiny_find_msize_region(rack, depot_ptr, DEPOT_MAGAZINE_INDEX, try_msize);
+ sparse_region = tiny_find_msize_region(rack, depot_ptr, DEPOT_MAGAZINE_INDEX, msize);
if (NULL == sparse_region) { // Depot empty?
SZONE_MAGAZINE_PTR_UNLOCK(depot_ptr);
return 0;
}
node = REGION_TRAILER_FOR_TINY_REGION(sparse_region);
- if (0 == node->pinned_to_depot) {
- // Found one!
+ if (0 >= node->pinned_to_depot) {
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_TINY_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;
- }
+ SZONE_MAGAZINE_PTR_UNLOCK(depot_ptr);
+ yield();
+ SZONE_MAGAZINE_PTR_LOCK(depot_ptr);
}
// disconnect node from Depot
@@ -1174,7 +1019,7 @@
// Transfer ownership of the region
MAGAZINE_INDEX_FOR_TINY_REGION(sparse_region) = mag_index;
- MALLOC_ASSERT(node->pinned_to_depot == 0);
+ node->pinned_to_depot = 0;
// Iterate the region putting its free entries on its new (locked) magazine's free list
size_t bytes_inplay = tiny_free_reattach_region(rack, tiny_mag_ptr, sparse_region);
@@ -1332,7 +1177,11 @@
region_trailer_t *node = REGION_TRAILER_FOR_TINY_REGION(region);
size_t bytes_used = node->bytes_used;
- if (DEPOT_MAGAZINE_INDEX != mag_index) {
+ /* FIXME: Would Uniprocessor benefit from recirc and MADV_FREE? */
+ if (rack->num_magazines == 1) { // Uniprocessor, single magazine, so no recirculation necessary
+ /* NOTHING */
+ return TRUE; // Caller must do SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr)
+ } else if (DEPOT_MAGAZINE_INDEX != mag_index) {
// Emptiness discriminant
if (tiny_region_below_recirc_threshold(region)) {
/* Region has crossed threshold from density to sparsity. Mark it "suitable" on the
@@ -1378,12 +1227,8 @@
}
#endif // CONFIG_RECIRC_DEPOT
-#define TINY_FREE_FLAG_PARTIAL 0x1
-#define TINY_FREE_FLAG_FROM_CACHE 0x2
-
boolean_t
-tiny_free_no_lock(rack_t *rack, magazine_t *tiny_mag_ptr, mag_index_t mag_index,
- region_t region, void *ptr, msize_t msize, uint32_t flags)
+tiny_free_no_lock(rack_t *rack, magazine_t *tiny_mag_ptr, mag_index_t mag_index, region_t region, void *ptr, msize_t msize, boolean_t partial_free)
{
void *original_ptr = ptr;
size_t original_size = TINY_BYTES_FOR_MSIZE(msize);
@@ -1420,15 +1265,9 @@
// clear the meta_header since this is no longer the start of a block
set_tiny_meta_header_middle(ptr);
tiny_free_list_remove_ptr(rack, tiny_mag_ptr, previous, previous_msize);
-
- // zero out the trailing inline msize of the block to connect the zero
- // prefix of this block to the newly free block
- zero_tiny_free_inline_meta_following(previous, previous_msize);
-
ptr = previous;
msize += previous_msize;
}
-
// We try to coalesce with the next block
if ((next_block < TINY_REGION_HEAP_END(region)) && tiny_meta_header_is_free(next_block)) {
next_msize = get_tiny_free_size(next_block);
@@ -1465,12 +1304,6 @@
// clear the meta_header to enable coalescing backwards
set_tiny_meta_header_middle(big_free_block);
-
- // zero out inline metadata to continue the zero prefix of the
- // previous block - must happen before set_tiny_meta_header_free()
- // reinitializes the new inline metadata
- zero_tiny_free_inline_meta(big_free_block, next_msize);
-
set_tiny_meta_header_free(ptr, msize);
uint16_t next_block_index = TINY_INDEX_FOR_PTR(big_free_block) + 1;
@@ -1487,21 +1320,13 @@
}
tiny_free_list_remove_ptr(rack, tiny_mag_ptr, next_block, next_msize);
set_tiny_meta_header_middle(next_block); // clear the meta_header to enable coalescing backwards
- // zero out inline metadata to continue the zero prefix of the previous
- // block
- zero_tiny_free_inline_meta(next_block, next_msize);
msize += next_msize;
}
- if (malloc_zero_policy != MALLOC_ZERO_ON_FREE) {
- // The tiny cache already scribbles free blocks as they go through the
- // cache, so we do not need to do it here.
- //
- // XXX This should probably also be conditional on CONFIG_TINY_CACHE
- if ((rack->debug_flags & MALLOC_DO_SCRIBBLE) &&
- !(flags & TINY_FREE_FLAG_FROM_CACHE)) {
- memset(ptr, SCRABBLE_BYTE, TINY_BYTES_FOR_MSIZE(msize));
- }
+ // The tiny cache already scribbles free blocks as they go through the
+ // cache whenever msize < TINY_QUANTUM , so we do not need to do it here.
+ if ((rack->debug_flags & MALLOC_DO_SCRIBBLE) && msize && (msize >= TINY_QUANTUM)) {
+ memset(ptr, SCRABBLE_BYTE, TINY_BYTES_FOR_MSIZE(msize));
}
tiny_free_list_add_ptr(rack, tiny_mag_ptr, ptr, msize);
@@ -1519,7 +1344,7 @@
// posix_memalign and then free some range of bytes at the start and/or
// the end. In that case, we aren't changing the number of allocated objects.
// Similarly for realloc() in the case where we shrink in place.
- if (!(flags & TINY_FREE_FLAG_PARTIAL)) {
+ if (!partial_free) {
trailer->objects_in_use--;
tiny_mag_ptr->mag_num_objects--;
}
@@ -1758,8 +1583,7 @@
// 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 set_tiny_meta_header_middle() call below.
- void *leftover_ptr = ((char *)next_block) + TINY_BYTES_FOR_MSIZE(coalesced_msize);
- set_tiny_meta_header_in_use(leftover_ptr, leftover_msize);
+ set_tiny_meta_header_in_use(next_block + TINY_BYTES_FOR_MSIZE(coalesced_msize), leftover_msize);
} else {
// Using the whole block.
tiny_mag_ptr->mag_last_free = NULL;
@@ -1768,7 +1592,6 @@
trailer->objects_in_use--;
}
set_tiny_meta_header_middle(next_block);
- tiny_check_zero_or_clear(last_free_ptr, coalesced_msize, false);
coalesced_msize = 0; // No net change in memory use
} else {
#endif // CONFIG_TINY_CACHE
@@ -1793,7 +1616,6 @@
// Mark the first block of the remaining free area as a header and in-use.
set_tiny_meta_header_in_use_1(ptr + TINY_BYTES_FOR_MSIZE(new_msize));
}
- tiny_check_zero_or_clear(unused_start, coalesced_msize, false);
} else {
/*
* Look for a free block immediately afterwards. If it's large
@@ -1815,10 +1637,6 @@
*/
tiny_free_list_remove_ptr(rack, tiny_mag_ptr, next_block, next_msize);
set_tiny_meta_header_middle(next_block); // clear the meta_header to enable coalescing backwards
-
- tiny_check_and_zero_inline_meta_from_freelist(rack, next_block, next_msize);
- tiny_check_zero_or_clear(next_block, coalesced_msize, false);
-
leftover_msize = next_msize - coalesced_msize;
if (leftover_msize) {
/* there's some left, so put the remainder back */
@@ -2218,7 +2036,6 @@
}
#endif
tiny_update_region_free_list_for_remove(slot, ptr, next);
- tiny_check_and_zero_inline_meta_from_freelist(rack, ptr, msize);
goto return_tiny_alloc;
}
@@ -2250,14 +2067,7 @@
BITMAPV_CLR(tiny_mag_ptr->mag_bitmap, slot);
}
this_msize = get_tiny_free_size(ptr);
- if (os_unlikely(this_msize < msize)) {
- malloc_zone_error(MALLOC_ABORT_ON_CORRUPTION, true,
- "Corruption of tiny freelist %p: size too small (%u/%u)\n",
- ptr, this_msize, msize);
-
- }
tiny_update_region_free_list_for_remove(slot, ptr, next);
- tiny_check_and_zero_inline_meta_from_freelist(rack, ptr, this_msize);
goto add_leftover_and_proceed;
}
#if DEBUG_MALLOC
@@ -2272,27 +2082,18 @@
ptr = limit->p;
if (ptr) {
this_msize = get_tiny_free_size(ptr);
- if (os_unlikely(this_msize < msize)) {
- malloc_zone_error(MALLOC_ABORT_ON_CORRUPTION, true,
- "Corruption of tiny freelist %p: size too small (%u/%u)\n",
- ptr, this_msize, msize);
- }
next = free_list_unchecksum_ptr(rack, &ptr->next);
if (this_msize - msize > NUM_TINY_SLOTS) {
// the leftover will go back to the free list, so we optimize by
// modifying the free list rather than a pop and push of the head
leftover_msize = this_msize - msize;
leftover_ptr = (tiny_free_list_t *)((unsigned char *)ptr + TINY_BYTES_FOR_MSIZE(msize));
-
- tiny_free_list_t tmp_ptr = *ptr;
- tiny_check_and_zero_inline_meta_from_freelist(rack, ptr, this_msize);
-
limit->p = leftover_ptr;
if (next) {
next->previous.u = free_list_checksum_ptr(rack, leftover_ptr);
}
- leftover_ptr->previous = tmp_ptr.previous;
- leftover_ptr->next = tmp_ptr.next;
+ leftover_ptr->previous = ptr->previous;
+ leftover_ptr->next = ptr->next;
set_tiny_meta_header_free(leftover_ptr, leftover_msize);
#if DEBUG_MALLOC
if (LOG(szone, ptr)) {
@@ -2310,7 +2111,6 @@
}
limit->p = next;
tiny_update_region_free_list_for_remove(slot, ptr, next);
- tiny_check_and_zero_inline_meta_from_freelist(rack, ptr, this_msize);
goto add_leftover_and_proceed;
/* NOTREACHED */
}
@@ -2355,8 +2155,6 @@
add_leftover_and_proceed:
if (!this_msize || (this_msize > msize)) {
- // XXX This works even when (this_msize == 0) because the unsigned
- // subtraction wraps around to the correct result
leftover_msize = this_msize - msize;
leftover_ptr = (tiny_free_list_t *)((unsigned char *)ptr + TINY_BYTES_FOR_MSIZE(msize));
#if DEBUG_MALLOC
@@ -2407,7 +2205,7 @@
tiny_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;
+ mag_index_t mag_index = tiny_mag_get_thread_index() % rack->num_magazines;
magazine_t *tiny_mag_ptr = &(rack->magazines[mag_index]);
MALLOC_TRACE(TRACE_tiny_malloc, (uintptr_t)rack, TINY_BYTES_FOR_MSIZE(msize), (uintptr_t)tiny_mag_ptr, cleared_requested);
@@ -2436,9 +2234,9 @@
tiny_mag_ptr->mag_last_free_rgn = NULL;
SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
CHECK(szone, __PRETTY_FUNCTION__);
-
- tiny_check_zero_or_clear(ptr, msize, cleared_requested);
-
+ if (cleared_requested) {
+ memset(ptr, 0, TINY_BYTES_FOR_MSIZE(msize));
+ }
#if DEBUG_MALLOC
if (LOG(szone, ptr)) {
malloc_report(ASL_LEVEL_INFO, "in tiny_malloc_should_clear(), tiny cache ptr=%p, msize=%d\n", ptr, msize);
@@ -2453,7 +2251,9 @@
if (ptr) {
SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
CHECK(szone, __PRETTY_FUNCTION__);
- tiny_check_zero_or_clear(ptr, msize, cleared_requested);
+ if (cleared_requested) {
+ memset(ptr, 0, TINY_BYTES_FOR_MSIZE(msize));
+ }
return ptr;
}
@@ -2463,7 +2263,9 @@
if (ptr) {
SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
CHECK(szone, __PRETTY_FUNCTION__);
- tiny_check_zero_or_clear(ptr, msize, cleared_requested);
+ if (cleared_requested) {
+ memset(ptr, 0, TINY_BYTES_FOR_MSIZE(msize));
+ }
return ptr;
}
}
@@ -2471,17 +2273,16 @@
// 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 accquires the magazine_alloc_lock, then drops the
- // magazine lock to allow freeing threads to proceed. Allocating thrads that arrive later are excluded
- // from the critial section by the alloc lock. When those are unblocked, they succeed in the code above.
- //
- // Note that we need to trylock the alloc lock to avoid a deadlock, since we can't block on the alloc
- // lock while holding the magazine lock
- if (os_likely(_malloc_lock_trylock(&tiny_mag_ptr->magazine_alloc_lock))) {
- // We got the alloc lock, so we are the thread that should allocate a new region
+ // 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 (!tiny_mag_ptr->alloc_underway) {
void *fresh_region;
// time to create a new region (do this outside the magazine lock)
+ tiny_mag_ptr->alloc_underway = TRUE;
+ OSMemoryBarrier();
SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
fresh_region = mvm_allocate_pages(TINY_REGION_SIZE,
TINY_BLOCKS_ALIGN,
@@ -2493,30 +2294,24 @@
MAGMALLOC_ALLOCREGION(TINY_SZONE_FROM_RACK(rack), (int)mag_index, fresh_region, TINY_REGION_SIZE);
if (!fresh_region) { // out of memory!
+ tiny_mag_ptr->alloc_underway = FALSE;
+ OSMemoryBarrier();
SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
- _malloc_lock_unlock(&tiny_mag_ptr->magazine_alloc_lock);
return NULL;
}
region_set_cookie(®ION_COOKIE_FOR_TINY_REGION(fresh_region));
ptr = tiny_malloc_from_region_no_lock(rack, tiny_mag_ptr, mag_index, msize, fresh_region);
- // we don't clear or zero-check because this freshly allocated space
- // is pristine
+ // we don't clear because this freshly allocated space is pristine
+ tiny_mag_ptr->alloc_underway = FALSE;
+ OSMemoryBarrier();
SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
- _malloc_lock_unlock(&tiny_mag_ptr->magazine_alloc_lock);
CHECK(szone, __PRETTY_FUNCTION__);
return ptr;
} else {
- // We failed to get the alloc lock, so someone else is allocating.
- // Drop the magazine lock...
SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
-
- // Wait for the other thread on the alloc lock
- _malloc_lock_lock(&tiny_mag_ptr->magazine_alloc_lock);
- _malloc_lock_unlock(&tiny_mag_ptr->magazine_alloc_lock);
-
- // Reacquire the magazine lock to go around the loop again
+ yield();
SZONE_MAGAZINE_PTR_LOCK(tiny_mag_ptr);
}
}
@@ -2578,7 +2373,6 @@
boolean_t is_free;
mag_index_t mag_index = MAGAZINE_INDEX_FOR_TINY_REGION(tiny_region);
magazine_t *tiny_mag_ptr = &(rack->magazines[mag_index]);
- uint32_t flags = 0;
MALLOC_TRACE(TRACE_tiny_free, (uintptr_t)rack, (uintptr_t)ptr, (uintptr_t)tiny_mag_ptr, known_size);
@@ -2599,10 +2393,6 @@
}
#endif
- if (malloc_zero_policy == MALLOC_ZERO_ON_FREE) {
- memset(ptr, '\0', TINY_BYTES_FOR_MSIZE(msize));
- }
-
SZONE_MAGAZINE_PTR_LOCK(tiny_mag_ptr);
#if CONFIG_TINY_CACHE
@@ -2620,10 +2410,8 @@
return;
}
- if (malloc_zero_policy != MALLOC_ZERO_ON_FREE) {
- if ((rack->debug_flags & MALLOC_DO_SCRIBBLE) && msize) {
- memset(ptr, SCRABBLE_BYTE, TINY_BYTES_FOR_MSIZE(msize));
- }
+ if ((rack->debug_flags & MALLOC_DO_SCRIBBLE) && msize) {
+ memset(ptr, SCRABBLE_BYTE, TINY_BYTES_FOR_MSIZE(msize));
}
tiny_mag_ptr->mag_last_free = ptr;
@@ -2639,7 +2427,6 @@
msize = msize2;
ptr = ptr2;
tiny_region = rgn2;
- flags |= TINY_FREE_FLAG_FROM_CACHE;
}
}
#endif /* CONFIG_TINY_CACHE */
@@ -2658,12 +2445,8 @@
SZONE_MAGAZINE_PTR_LOCK(tiny_mag_ptr);
}
- if (partial_free) {
- flags |= TINY_FREE_FLAG_PARTIAL;
- }
-
if (tiny_free_no_lock(rack, tiny_mag_ptr, mag_index, tiny_region, ptr,
- msize, flags)) {
+ msize, partial_free)) {
SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
}
@@ -2675,8 +2458,7 @@
{
msize_t msize = TINY_MSIZE_FOR_BYTES(size + TINY_QUANTUM - 1);
unsigned found = 0;
-
- mag_index_t mag_index = rack_get_thread_index(&szone->tiny_rack) % szone->tiny_rack.num_magazines;
+ mag_index_t mag_index = tiny_mag_get_thread_index() % szone->tiny_rack.num_magazines;
magazine_t *tiny_mag_ptr = &(szone->tiny_rack.magazines[mag_index]);
// make sure to return objects at least one quantum in size
@@ -2751,10 +2533,7 @@
if (is_free) {
break; // a double free; let the standard free deal with it
}
- if (malloc_zero_policy == MALLOC_ZERO_ON_FREE) {
- memset(ptr, '\0', TINY_BYTES_FOR_MSIZE(msize));
- }
- if (!tiny_free_no_lock(&szone->tiny_rack, tiny_mag_ptr, mag_index, tiny_region, ptr, msize, 0)) {
+ if (!tiny_free_no_lock(&szone->tiny_rack, tiny_mag_ptr, mag_index, tiny_region, ptr, msize, false)) {
// Arrange to re-acquire magazine lock
tiny_mag_ptr = NULL;
tiny_region = NULL;
@@ -2982,39 +2761,3 @@
}
return 1;
}
-
-boolean_t
-tiny_check(rack_t *rack, unsigned counter)
-{
- size_t index;
-
- /* check tiny regions - chould check region count */
- for (index = 0; index < rack->region_generation->num_regions_allocated; ++index) {
- region_t tiny = rack->region_generation->hashed_regions[index];
-
- if (HASHRING_REGION_DEALLOCATED == tiny) {
- continue;
- }
-
- if (tiny) {
- magazine_t *tiny_mag_ptr = mag_lock_zine_for_region_trailer(rack->magazines,
- REGION_TRAILER_FOR_TINY_REGION(tiny),
- MAGAZINE_INDEX_FOR_TINY_REGION(tiny));
-
- if (!tiny_check_region(rack, tiny, index, counter)) {
- SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
- return 0;
- }
- SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
- }
- }
-
- /* check tiny free lists */
- for (index = 0; index < NUM_TINY_SLOTS; ++index) {
- if (!tiny_free_list_check(rack, (grain_t)index, counter)) {
- return 0;
- }
- }
-
- return 1;
-}