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--- libmalloc/libmalloc-317.121.1/src/magazine_medium.c
+++ libmalloc/libmalloc-374.40.6/src/magazine_medium.c
@@ -32,15 +32,29 @@
static MALLOC_INLINE uint64_t
medium_sliding_madvise_granularity(magazine_t *magazine)
{
+ uint64_t granularity = MEDIUM_MADVISE_MIN;
// Use a sliding madvise granularity based on how many bytes the region
// currently has allocated. This way we will advise at a finer granularity
// as the region becomes more and more empty.
// region_trailer_t *t = REGION_TRAILER_FOR_MEDIUM_REGION(region);
- if (magazine->mag_num_bytes_in_objects == 0) {
- return MEDIUM_MADVISE_MIN;
- }
- return MAX(MEDIUM_MADVISE_MIN, 1 << (64 -
- __builtin_clzl(magazine->mag_num_bytes_in_objects >> MEDIUM_MADVISE_SHIFT)));
+ if (magazine->mag_num_bytes_in_objects > 0) {
+ if (magazine_medium_madvise_window_scale_factor == 1) {
+ // NB: This code has a bug causing undefined behavior whenever the result of clzl is > 32
+ // because it's shifting a signed integer. It should be 1ULL << (64 - ...) but
+ // fixing this bug will introduce memory regressions, so for now we've only fixed it on very
+ // large memory configs that are scaling up their window anyways.
+ // See rdar://82128925 for details
+ granularity = MAX(granularity, 1 << (64 -
+ __builtin_clzl(magazine->mag_num_bytes_in_objects >> MEDIUM_MADVISE_SHIFT)));
+ } else {
+ granularity = MAX(granularity, 1ULL << (64 -
+ __builtin_clzl(magazine->mag_num_bytes_in_objects >> MEDIUM_MADVISE_SHIFT)));
+ if (os_mul_overflow(granularity, magazine_medium_madvise_window_scale_factor, &granularity)) {
+ return UINT64_MAX;
+ }
+ }
+ }
+ return granularity;
}
static MALLOC_INLINE void
@@ -866,6 +880,7 @@
medium_advisory_t mat = (medium_advisory_t)pgLo;
mat->next = advisories;
mat->size = pgHi - pgLo;
+ advisories = mat;
}
break;
}
@@ -893,6 +908,7 @@
medium_advisory_t mat = (medium_advisory_t)pgLo;
mat->next = advisories;
mat->size = pgHi - pgLo;
+ advisories = mat;
}
memset(&madv_headers[index], 0, sizeof(uint16_t) * alloc_msize);
@@ -1010,22 +1026,32 @@
// 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 = medium_find_msize_region(rack, depot_ptr, DEPOT_MAGAZINE_INDEX, msize);
+ sparse_region = medium_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_MEDIUM_REGION(sparse_region);
- if (0 >= node->pinned_to_depot) {
+ if (0 == node->pinned_to_depot) {
+ // Found one!
break;
}
- SZONE_MAGAZINE_PTR_UNLOCK(depot_ptr);
- yield();
- SZONE_MAGAZINE_PTR_LOCK(depot_ptr);
+ // 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_MEDIUM_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
@@ -1036,7 +1062,7 @@
// Transfer ownership of the region
MAGAZINE_INDEX_FOR_MEDIUM_REGION(sparse_region) = mag_index;
- node->pinned_to_depot = 0;
+ 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 = medium_free_reattach_region(rack, medium_mag_ptr, sparse_region);
@@ -1127,7 +1153,7 @@
SZONE_MAGAZINE_PTR_LOCK(medium_depot_ptr);
MAGAZINE_INDEX_FOR_MEDIUM_REGION(medium) = DEPOT_MAGAZINE_INDEX;
- REGION_TRAILER_FOR_MEDIUM_REGION(medium)->pinned_to_depot = 0;
+ MALLOC_ASSERT(REGION_TRAILER_FOR_MEDIUM_REGION(medium)->pinned_to_depot == 0);
size_t bytes_inplay = medium_free_reattach_region(rack, medium_depot_ptr, medium);
@@ -1168,7 +1194,6 @@
{
region_trailer_t *node = REGION_TRAILER_FOR_MEDIUM_REGION(region);
msize_t *madvh = MEDIUM_MADVISE_HEADER_FOR_PTR(ptr);
-
msize_t trigger_msize = trigger_level >> SHIFT_MEDIUM_QUANTUM;
size_t free_header_size = sizeof(medium_inplace_free_entry_s) + sizeof(msize_t);
@@ -1217,7 +1242,7 @@
}
msize_t right_dirty_msz = 0;
- if (right_end_idx < src_end_idx) {
+ if (right_end_idx > src_end_idx) {
// Same as above, if we had trailing data coalesced with this entry
// and that was not madvised, consider it, too.
right_dirty_msz = medium_madvise_header_dirty_len(madvh, right_start_idx);
@@ -1230,7 +1255,7 @@
medium_madvise_header_mark_middle(madvh, right_end_idx);
}
- // We absolutely can't madvise lower the the free-list entry pointer plus
+ // We absolutely can't madvise lower than the free-list entry pointer plus
// the header size. When the entry is OOB, there's no header or footer to
// store in memory.
uintptr_t safe_start_ptr = round_page_kernel(rangep + free_header_size);
@@ -1240,21 +1265,33 @@
// If the target region is madvisable, then madvise whatever we can but
// bound it by the safe_start/end pointers to make sure we don't clobber
// the free-list.
- if ((vote_force == 2) || (dirty_msz >= trigger_msize)) {
+ bool should_madvise = (vote_force == 2) || (dirty_msz >= trigger_msize);
+ if (magazine_medium_madvise_window_scale_factor > 1) {
+ // trigger_msize is an unsigned short, but it's possible that trigger level was larger than UINT16_MAX
+ // even after we shifted it. In this case the window rolls around to 0. This is even more likely
+ // if we're scaling the window up. We should fix the truncation bug above, but doing so
+ // will cause a memory regression. For now, we avoid using trigger_msize iff we're scaling
+ // the window up since truncating to 0 would be self-defeating in this case.
+ // See rdar://82128639 for details
+ should_madvise = (vote_force == 2) || (MEDIUM_BYTES_FOR_MSIZE(dirty_msz) >= trigger_level);
+ }
+ if (should_madvise) {
uintptr_t lo = MAX((uintptr_t)MEDIUM_PTR_FOR_META_INDEX(region, range_idx),
safe_start_ptr);
uintptr_t hi = MIN((uintptr_t)MEDIUM_PTR_FOR_META_INDEX(region, range_idx) +
MEDIUM_BYTES_FOR_MSIZE(range_msz), safe_end_ptr);
// The page that contains the freelist entry needs to be marked as not
- // having been madvised.
+ // having been madvised. Note that the quantum is larger than the kernel page size
+ // so if safe_start_ptr and rangep are on different pages, we just mark
+ // the whole block as clean.
if (range_idx < MEDIUM_META_INDEX_FOR_PTR(safe_start_ptr)) {
medium_madvise_header_mark_dirty(madvh, range_idx,
MEDIUM_META_INDEX_FOR_PTR(safe_start_ptr) - range_idx);
}
if (range_idx + range_msz > MEDIUM_META_INDEX_FOR_PTR(safe_end_ptr)) {
medium_madvise_header_mark_dirty(madvh,
- MEDIUM_META_INDEX_FOR_PTR(safe_end_ptr) + 1, range_idx +
+ MEDIUM_META_INDEX_FOR_PTR(safe_end_ptr), range_idx +
range_msz - MEDIUM_META_INDEX_FOR_PTR(safe_end_ptr));
}
@@ -1279,10 +1316,12 @@
// We chose not to madvise, we need to re-mark the region as dirty
// for when we come back to it later.
if (left_dirty_msz < left_msz) {
+ /* The preceding block was clean. */
medium_madvise_header_mark_clean(madvh, range_idx,
left_msz - left_dirty_msz);
}
if (right_dirty_msz < right_msz) {
+ /* The trailing block was clean. */
medium_madvise_header_mark_clean(madvh, right_start_idx +
right_dirty_msz, right_msz - right_dirty_msz);
}
@@ -1865,7 +1904,8 @@
// use is adjusted by the medium_meta_header_set_middle() call below.
medium_meta_header_set_in_use(meta_headers, index + new_msize, leftover_msize);
- if (madv_headers[index] & MEDIUM_IS_ADVISED) {
+ /* Propagate the madvise information from the block we're using to the leftover block. */
+ if (madv_headers[next_index] & MEDIUM_IS_ADVISED) {
medium_madvise_header_mark_clean(madv_headers, index + new_msize, leftover_msize);
} else {
medium_madvise_header_mark_dirty(madv_headers, index + new_msize, leftover_msize);
@@ -1932,6 +1972,12 @@
/* there's some left, so put the remainder back */
leftover = (unsigned char *)ptr + MEDIUM_BYTES_FOR_MSIZE(new_msize);
medium_free_list_add_ptr(rack, medium_mag_ptr, leftover, leftover_msize);
+ msize_t leftover_index = MEDIUM_META_INDEX_FOR_PTR(leftover);
+ if (madv_headers[leftover_index] & MEDIUM_IS_ADVISED) {
+ medium_madvise_header_mark_clean(madv_headers, leftover_index, leftover_msize);
+ } else {
+ medium_madvise_header_mark_dirty(madv_headers, leftover_index, leftover_msize);
+ }
}
medium_meta_header_set_in_use(meta_headers, index, new_msize);
medium_madvise_header_mark_dirty(madv_headers, index, new_msize);
@@ -2260,7 +2306,7 @@
if ((ptr = medium_free_list_get_ptr(rack, *free_list))) {
this_msize = MEDIUM_PTR_SIZE(ptr);
was_madvised = (medium_madvise_header_dirty_len(
- MEDIUM_MADVISE_HEADER_FOR_PTR(ptr), this_msize) == 0);
+ MEDIUM_MADVISE_HEADER_FOR_PTR(ptr), MEDIUM_META_INDEX_FOR_PTR(ptr)) == 0);
medium_free_list_remove_ptr(rack, medium_mag_ptr, *free_list, this_msize);
goto add_leftover_and_proceed;
}