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src/hotspot/share/memory/metaspace/chunkManager.cpp
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rev 57511 : [mq]: metaspace-improvement
*** 21,641 ****
* questions.
*
*/
#include "precompiled.hpp"
#include "logging/log.hpp"
! #include "logging/logStream.hpp"
! #include "memory/binaryTreeDictionary.inline.hpp"
! #include "memory/freeList.inline.hpp"
#include "memory/metaspace/chunkManager.hpp"
#include "memory/metaspace/metachunk.hpp"
- #include "memory/metaspace/metaDebug.hpp"
- #include "memory/metaspace/metaspaceCommon.hpp"
#include "memory/metaspace/metaspaceStatistics.hpp"
- #include "memory/metaspace/occupancyMap.hpp"
#include "memory/metaspace/virtualSpaceNode.hpp"
#include "runtime/mutexLocker.hpp"
#include "utilities/debug.hpp"
#include "utilities/globalDefinitions.hpp"
- #include "utilities/ostream.hpp"
namespace metaspace {
- ChunkManager::ChunkManager(bool is_class)
- : _is_class(is_class), _free_chunks_total(0), _free_chunks_count(0) {
- _free_chunks[SpecializedIndex].set_size(get_size_for_nonhumongous_chunktype(SpecializedIndex, is_class));
- _free_chunks[SmallIndex].set_size(get_size_for_nonhumongous_chunktype(SmallIndex, is_class));
- _free_chunks[MediumIndex].set_size(get_size_for_nonhumongous_chunktype(MediumIndex, is_class));
- }
! void ChunkManager::remove_chunk(Metachunk* chunk) {
! size_t word_size = chunk->word_size();
! ChunkIndex index = list_index(word_size);
! if (index != HumongousIndex) {
! free_chunks(index)->remove_chunk(chunk);
! } else {
! humongous_dictionary()->remove_chunk(chunk);
! }
!
! // Chunk has been removed from the chunks free list, update counters.
! account_for_removed_chunk(chunk);
}
- bool ChunkManager::attempt_to_coalesce_around_chunk(Metachunk* chunk, ChunkIndex target_chunk_type) {
- assert_lock_strong(MetaspaceExpand_lock);
- assert(chunk != NULL, "invalid chunk pointer");
- // Check for valid merge combinations.
- assert((chunk->get_chunk_type() == SpecializedIndex &&
- (target_chunk_type == SmallIndex || target_chunk_type == MediumIndex)) ||
- (chunk->get_chunk_type() == SmallIndex && target_chunk_type == MediumIndex),
- "Invalid chunk merge combination.");
-
- const size_t target_chunk_word_size =
- get_size_for_nonhumongous_chunktype(target_chunk_type, this->is_class());
-
- // [ prospective merge region )
- MetaWord* const p_merge_region_start =
- (MetaWord*) align_down(chunk, target_chunk_word_size * sizeof(MetaWord));
- MetaWord* const p_merge_region_end =
- p_merge_region_start + target_chunk_word_size;
-
- // We need the VirtualSpaceNode containing this chunk and its occupancy map.
- VirtualSpaceNode* const vsn = chunk->container();
- OccupancyMap* const ocmap = vsn->occupancy_map();
-
- // The prospective chunk merge range must be completely contained by the
- // committed range of the virtual space node.
- if (p_merge_region_start < vsn->bottom() || p_merge_region_end > vsn->top()) {
- return false;
- }
-
- // Only attempt to merge this range if at its start a chunk starts and at its end
- // a chunk ends. If a chunk (can only be humongous) straddles either start or end
- // of that range, we cannot merge.
- if (!ocmap->chunk_starts_at_address(p_merge_region_start)) {
- return false;
- }
- if (p_merge_region_end < vsn->top() &&
- !ocmap->chunk_starts_at_address(p_merge_region_end)) {
- return false;
- }
-
- // Now check if the prospective merge area contains live chunks. If it does we cannot merge.
- if (ocmap->is_region_in_use(p_merge_region_start, target_chunk_word_size)) {
- return false;
- }
-
- // Success! Remove all chunks in this region...
- log_trace(gc, metaspace, freelist)("%s: coalescing chunks in area [%p-%p)...",
- (is_class() ? "class space" : "metaspace"),
- p_merge_region_start, p_merge_region_end);
-
- const int num_chunks_removed =
- remove_chunks_in_area(p_merge_region_start, target_chunk_word_size);
-
- // ... and create a single new bigger chunk.
- Metachunk* const p_new_chunk =
- ::new (p_merge_region_start) Metachunk(target_chunk_type, is_class(), target_chunk_word_size, vsn);
- assert(p_new_chunk == (Metachunk*)p_merge_region_start, "Sanity");
- p_new_chunk->set_origin(origin_merge);
-
- log_trace(gc, metaspace, freelist)("%s: created coalesced chunk at %p, size " SIZE_FORMAT_HEX ".",
- (is_class() ? "class space" : "metaspace"),
- p_new_chunk, p_new_chunk->word_size() * sizeof(MetaWord));
-
- // Fix occupancy map: remove old start bits of the small chunks and set new start bit.
- ocmap->wipe_chunk_start_bits_in_region(p_merge_region_start, target_chunk_word_size);
- ocmap->set_chunk_starts_at_address(p_merge_region_start, true);
-
- // Mark chunk as free. Note: it is not necessary to update the occupancy
- // map in-use map, because the old chunks were also free, so nothing
- // should have changed.
- p_new_chunk->set_is_tagged_free(true);
-
- // Add new chunk to its freelist.
- ChunkList* const list = free_chunks(target_chunk_type);
- list->return_chunk_at_head(p_new_chunk);
-
- // And adjust ChunkManager:: _free_chunks_count (_free_chunks_total
- // should not have changed, because the size of the space should be the same)
- _free_chunks_count -= num_chunks_removed;
- _free_chunks_count ++;
-
- // VirtualSpaceNode::chunk_count does not have to be modified:
- // it means "number of active (non-free) chunks", so merging free chunks
- // should not affect that count.
-
- // At the end of a chunk merge, run verification tests.
#ifdef ASSERT
!
! EVERY_NTH(VerifyMetaspaceInterval)
! locked_verify(true);
! vsn->verify(true);
! END_EVERY_NTH
!
! g_internal_statistics.num_chunk_merges ++;
!
! #endif
!
! return true;
! }
!
! // Remove all chunks in the given area - the chunks are supposed to be free -
! // from their corresponding freelists. Mark them as invalid.
! // - This does not correct the occupancy map.
! // - This does not adjust the counters in ChunkManager.
! // - Does not adjust container count counter in containing VirtualSpaceNode
! // Returns number of chunks removed.
! int ChunkManager::remove_chunks_in_area(MetaWord* p, size_t word_size) {
! assert(p != NULL && word_size > 0, "Invalid range.");
! const size_t smallest_chunk_size = get_size_for_nonhumongous_chunktype(SpecializedIndex, is_class());
! assert_is_aligned(word_size, smallest_chunk_size);
!
! Metachunk* const start = (Metachunk*) p;
! const Metachunk* const end = (Metachunk*)(p + word_size);
! Metachunk* cur = start;
! int num_removed = 0;
! while (cur < end) {
! Metachunk* next = (Metachunk*)(((MetaWord*)cur) + cur->word_size());
! DEBUG_ONLY(do_verify_chunk(cur));
! assert(cur->get_chunk_type() != HumongousIndex, "Unexpected humongous chunk found at %p.", cur);
! assert(cur->is_tagged_free(), "Chunk expected to be free (%p)", cur);
! log_trace(gc, metaspace, freelist)("%s: removing chunk %p, size " SIZE_FORMAT_HEX ".",
! (is_class() ? "class space" : "metaspace"),
! cur, cur->word_size() * sizeof(MetaWord));
! cur->remove_sentinel();
! // Note: cannot call ChunkManager::remove_chunk, because that
! // modifies the counters in ChunkManager, which we do not want. So
! // we call remove_chunk on the freelist directly (see also the
! // splitting function which does the same).
! ChunkList* const list = free_chunks(list_index(cur->word_size()));
! list->remove_chunk(cur);
! num_removed ++;
! cur = next;
}
- return num_removed;
- }
-
- // Update internal accounting after a chunk was added
- void ChunkManager::account_for_added_chunk(const Metachunk* c) {
- assert_lock_strong(MetaspaceExpand_lock);
- _free_chunks_count ++;
- _free_chunks_total += c->word_size();
- }
-
- // Update internal accounting after a chunk was removed
- void ChunkManager::account_for_removed_chunk(const Metachunk* c) {
- assert_lock_strong(MetaspaceExpand_lock);
- assert(_free_chunks_count >= 1,
- "ChunkManager::_free_chunks_count: about to go negative (" SIZE_FORMAT ").", _free_chunks_count);
- assert(_free_chunks_total >= c->word_size(),
- "ChunkManager::_free_chunks_total: about to go negative"
- "(now: " SIZE_FORMAT ", decrement value: " SIZE_FORMAT ").", _free_chunks_total, c->word_size());
- _free_chunks_count --;
- _free_chunks_total -= c->word_size();
- }
-
- ChunkIndex ChunkManager::list_index(size_t size) {
- return get_chunk_type_by_size(size, is_class());
- }
-
- size_t ChunkManager::size_by_index(ChunkIndex index) const {
- index_bounds_check(index);
- assert(index != HumongousIndex, "Do not call for humongous chunks.");
- return get_size_for_nonhumongous_chunktype(index, is_class());
- }
-
- #ifdef ASSERT
- void ChunkManager::verify(bool slow) const {
- MutexLocker cl(MetaspaceExpand_lock,
- Mutex::_no_safepoint_check_flag);
- locked_verify(slow);
}
- void ChunkManager::locked_verify(bool slow) const {
- log_trace(gc, metaspace, freelist)("verifying %s chunkmanager (%s).",
- (is_class() ? "class space" : "metaspace"), (slow ? "slow" : "quick"));
-
- assert_lock_strong(MetaspaceExpand_lock);
! size_t chunks_counted = 0;
! size_t wordsize_chunks_counted = 0;
! for (ChunkIndex i = ZeroIndex; i < NumberOfFreeLists; i = next_chunk_index(i)) {
! const ChunkList* list = _free_chunks + i;
! if (list != NULL) {
! Metachunk* chunk = list->head();
! while (chunk) {
! if (slow) {
! do_verify_chunk(chunk);
! }
! assert(chunk->is_tagged_free(), "Chunk should be tagged as free.");
! chunks_counted ++;
! wordsize_chunks_counted += chunk->size();
! chunk = chunk->next();
}
}
}
! chunks_counted += humongous_dictionary()->total_free_blocks();
! wordsize_chunks_counted += humongous_dictionary()->total_size();
!
! assert(chunks_counted == _free_chunks_count && wordsize_chunks_counted == _free_chunks_total,
! "freelist accounting mismatch: "
! "we think: " SIZE_FORMAT " chunks, total " SIZE_FORMAT " words, "
! "reality: " SIZE_FORMAT " chunks, total " SIZE_FORMAT " words.",
! _free_chunks_count, _free_chunks_total,
! chunks_counted, wordsize_chunks_counted);
! }
! #endif // ASSERT
!
! void ChunkManager::locked_print_free_chunks(outputStream* st) {
! assert_lock_strong(MetaspaceExpand_lock);
! st->print_cr("Free chunk total " SIZE_FORMAT " count " SIZE_FORMAT,
! _free_chunks_total, _free_chunks_count);
! }
!
! ChunkList* ChunkManager::free_chunks(ChunkIndex index) {
! assert(index == SpecializedIndex || index == SmallIndex || index == MediumIndex,
! "Bad index: %d", (int)index);
! return &_free_chunks[index];
! }
!
! ChunkList* ChunkManager::find_free_chunks_list(size_t word_size) {
! ChunkIndex index = list_index(word_size);
! assert(index < HumongousIndex, "No humongous list");
! return free_chunks(index);
! }
!
! // Helper for chunk splitting: given a target chunk size and a larger free chunk,
! // split up the larger chunk into n smaller chunks, at least one of which should be
! // the target chunk of target chunk size. The smaller chunks, including the target
! // chunk, are returned to the freelist. The pointer to the target chunk is returned.
! // Note that this chunk is supposed to be removed from the freelist right away.
! Metachunk* ChunkManager::split_chunk(size_t target_chunk_word_size, Metachunk* larger_chunk) {
! assert(larger_chunk->word_size() > target_chunk_word_size, "Sanity");
!
! const ChunkIndex larger_chunk_index = larger_chunk->get_chunk_type();
! const ChunkIndex target_chunk_index = get_chunk_type_by_size(target_chunk_word_size, is_class());
!
! MetaWord* const region_start = (MetaWord*)larger_chunk;
! const size_t region_word_len = larger_chunk->word_size();
! MetaWord* const region_end = region_start + region_word_len;
! VirtualSpaceNode* const vsn = larger_chunk->container();
! OccupancyMap* const ocmap = vsn->occupancy_map();
!
! // Any larger non-humongous chunk size is a multiple of any smaller chunk size.
! // Since non-humongous chunks are aligned to their chunk size, the larger chunk should start
! // at an address suitable to place the smaller target chunk.
! assert_is_aligned(region_start, target_chunk_word_size);
!
! // Remove old chunk.
! free_chunks(larger_chunk_index)->remove_chunk(larger_chunk);
! larger_chunk->remove_sentinel();
!
! // Prevent access to the old chunk from here on.
! larger_chunk = NULL;
! // ... and wipe it.
! DEBUG_ONLY(memset(region_start, 0xfe, region_word_len * BytesPerWord));
!
! // In its place create first the target chunk...
! MetaWord* p = region_start;
! Metachunk* target_chunk = ::new (p) Metachunk(target_chunk_index, is_class(), target_chunk_word_size, vsn);
! assert(target_chunk == (Metachunk*)p, "Sanity");
! target_chunk->set_origin(origin_split);
!
! // Note: we do not need to mark its start in the occupancy map
! // because it coincides with the old chunk start.
!
! // Mark chunk as free and return to the freelist.
! do_update_in_use_info_for_chunk(target_chunk, false);
! free_chunks(target_chunk_index)->return_chunk_at_head(target_chunk);
!
! // This chunk should now be valid and can be verified.
! DEBUG_ONLY(do_verify_chunk(target_chunk));
!
! // In the remaining space create the remainder chunks.
! p += target_chunk->word_size();
! assert(p < region_end, "Sanity");
!
! while (p < region_end) {
!
! // Find the largest chunk size which fits the alignment requirements at address p.
! ChunkIndex this_chunk_index = prev_chunk_index(larger_chunk_index);
! size_t this_chunk_word_size = 0;
! for(;;) {
! this_chunk_word_size = get_size_for_nonhumongous_chunktype(this_chunk_index, is_class());
! if (is_aligned(p, this_chunk_word_size * BytesPerWord)) {
break;
- } else {
- this_chunk_index = prev_chunk_index(this_chunk_index);
- assert(this_chunk_index >= target_chunk_index, "Sanity");
}
}
-
- assert(this_chunk_word_size >= target_chunk_word_size, "Sanity");
- assert(is_aligned(p, this_chunk_word_size * BytesPerWord), "Sanity");
- assert(p + this_chunk_word_size <= region_end, "Sanity");
-
- // Create splitting chunk.
- Metachunk* this_chunk = ::new (p) Metachunk(this_chunk_index, is_class(), this_chunk_word_size, vsn);
- assert(this_chunk == (Metachunk*)p, "Sanity");
- this_chunk->set_origin(origin_split);
- ocmap->set_chunk_starts_at_address(p, true);
- do_update_in_use_info_for_chunk(this_chunk, false);
-
- // This chunk should be valid and can be verified.
- DEBUG_ONLY(do_verify_chunk(this_chunk));
-
- // Return this chunk to freelist and correct counter.
- free_chunks(this_chunk_index)->return_chunk_at_head(this_chunk);
- _free_chunks_count ++;
-
- log_trace(gc, metaspace, freelist)("Created chunk at " PTR_FORMAT ", word size "
- SIZE_FORMAT_HEX " (%s), in split region [" PTR_FORMAT "..." PTR_FORMAT ").",
- p2i(this_chunk), this_chunk->word_size(), chunk_size_name(this_chunk_index),
- p2i(region_start), p2i(region_end));
-
- p += this_chunk_word_size;
-
}
! // Note: at this point, the VirtualSpaceNode is invalid since we split a chunk and
! // did not yet hand out part of that split; so, vsn->verify_free_chunks_are_ideally_merged()
! // would assert. Instead, do all verifications in the caller.
!
! DEBUG_ONLY(g_internal_statistics.num_chunk_splits ++);
!
! return target_chunk;
! }
!
! Metachunk* ChunkManager::free_chunks_get(size_t word_size) {
! assert_lock_strong(MetaspaceExpand_lock);
!
! Metachunk* chunk = NULL;
! bool we_did_split_a_chunk = false;
! if (list_index(word_size) != HumongousIndex) {
! ChunkList* free_list = find_free_chunks_list(word_size);
! assert(free_list != NULL, "Sanity check");
! chunk = free_list->head();
! if (chunk == NULL) {
! // Split large chunks into smaller chunks if there are no smaller chunks, just large chunks.
! // This is the counterpart of the coalescing-upon-chunk-return.
! ChunkIndex target_chunk_index = get_chunk_type_by_size(word_size, is_class());
! // Is there a larger chunk we could split?
! Metachunk* larger_chunk = NULL;
! ChunkIndex larger_chunk_index = next_chunk_index(target_chunk_index);
! while (larger_chunk == NULL && larger_chunk_index < NumberOfFreeLists) {
! larger_chunk = free_chunks(larger_chunk_index)->head();
! if (larger_chunk == NULL) {
! larger_chunk_index = next_chunk_index(larger_chunk_index);
! }
}
! if (larger_chunk != NULL) {
! assert(larger_chunk->word_size() > word_size, "Sanity");
! assert(larger_chunk->get_chunk_type() == larger_chunk_index, "Sanity");
! // We found a larger chunk. Lets split it up:
! // - remove old chunk
! // - in its place, create new smaller chunks, with at least one chunk
! // being of target size, the others sized as large as possible. This
! // is to make sure the resulting chunks are "as coalesced as possible"
! // (similar to VirtualSpaceNode::retire()).
! // Note: during this operation both ChunkManager and VirtualSpaceNode
! // are temporarily invalid, so be careful with asserts.
! log_trace(gc, metaspace, freelist)("%s: splitting chunk " PTR_FORMAT
! ", word size " SIZE_FORMAT_HEX " (%s), to get a chunk of word size " SIZE_FORMAT_HEX " (%s)...",
! (is_class() ? "class space" : "metaspace"), p2i(larger_chunk), larger_chunk->word_size(),
! chunk_size_name(larger_chunk_index), word_size, chunk_size_name(target_chunk_index));
- chunk = split_chunk(word_size, larger_chunk);
! // This should have worked.
! assert(chunk != NULL, "Sanity");
! assert(chunk->word_size() == word_size, "Sanity");
! assert(chunk->is_tagged_free(), "Sanity");
! we_did_split_a_chunk = true;
!
! }
! }
! if (chunk == NULL) {
! return NULL;
! }
! // Remove the chunk as the head of the list.
! free_list->remove_chunk(chunk);
! log_trace(gc, metaspace, freelist)("ChunkManager::free_chunks_get: free_list: " PTR_FORMAT " chunks left: " SSIZE_FORMAT ".",
! p2i(free_list), free_list->count());
! } else {
! chunk = humongous_dictionary()->get_chunk(word_size);
! if (chunk == NULL) {
! return NULL;
}
-
- log_trace(gc, metaspace, alloc)("Free list allocate humongous chunk size " SIZE_FORMAT " for requested size " SIZE_FORMAT " waste " SIZE_FORMAT,
- chunk->word_size(), word_size, chunk->word_size() - word_size);
}
! // Chunk has been removed from the chunk manager; update counters.
! account_for_removed_chunk(chunk);
! do_update_in_use_info_for_chunk(chunk, true);
! chunk->container()->inc_container_count();
! chunk->inc_use_count();
!
! // Remove it from the links to this freelist
! chunk->set_next(NULL);
! chunk->set_prev(NULL);
!
! // Run some verifications (some more if we did a chunk split)
! #ifdef ASSERT
!
! EVERY_NTH(VerifyMetaspaceInterval)
! // Be extra verify-y when chunk split happened.
! locked_verify(true);
! VirtualSpaceNode* const vsn = chunk->container();
! vsn->verify(true);
! if (we_did_split_a_chunk) {
! vsn->verify_free_chunks_are_ideally_merged();
}
- END_EVERY_NTH
-
- g_internal_statistics.num_chunks_removed_from_freelist ++;
! #endif
- return chunk;
}
- Metachunk* ChunkManager::chunk_freelist_allocate(size_t word_size) {
- assert_lock_strong(MetaspaceExpand_lock);
-
- // Take from the beginning of the list
- Metachunk* chunk = free_chunks_get(word_size);
- if (chunk == NULL) {
- return NULL;
- }
! assert((word_size <= chunk->word_size()) ||
! (list_index(chunk->word_size()) == HumongousIndex),
! "Non-humongous variable sized chunk");
! LogTarget(Trace, gc, metaspace, freelist) lt;
! if (lt.is_enabled()) {
! size_t list_count;
! if (list_index(word_size) < HumongousIndex) {
! ChunkList* list = find_free_chunks_list(word_size);
! list_count = list->count();
! } else {
! list_count = humongous_dictionary()->total_count();
! }
! LogStream ls(lt);
! ls.print("ChunkManager::chunk_freelist_allocate: " PTR_FORMAT " chunk " PTR_FORMAT " size " SIZE_FORMAT " count " SIZE_FORMAT " ",
! p2i(this), p2i(chunk), chunk->word_size(), list_count);
! ResourceMark rm;
! locked_print_free_chunks(&ls);
! }
! return chunk;
}
! void ChunkManager::return_single_chunk(Metachunk* chunk) {
!
! #ifdef ASSERT
! EVERY_NTH(VerifyMetaspaceInterval)
! this->locked_verify(false);
! do_verify_chunk(chunk);
! END_EVERY_NTH
! #endif
!
! const ChunkIndex index = chunk->get_chunk_type();
! assert_lock_strong(MetaspaceExpand_lock);
! DEBUG_ONLY(g_internal_statistics.num_chunks_added_to_freelist ++;)
! assert(chunk != NULL, "Expected chunk.");
! assert(chunk->container() != NULL, "Container should have been set.");
! assert(chunk->is_tagged_free() == false, "Chunk should be in use.");
! index_bounds_check(index);
!
! // Note: mangle *before* returning the chunk to the freelist or dictionary. It does not
! // matter for the freelist (non-humongous chunks), but the humongous chunk dictionary
! // keeps tree node pointers in the chunk payload area which mangle will overwrite.
! DEBUG_ONLY(chunk->mangle(badMetaWordVal);)
!
! // may need node for verification later after chunk may have been merged away.
! DEBUG_ONLY(VirtualSpaceNode* vsn = chunk->container(); )
!
! if (index != HumongousIndex) {
! // Return non-humongous chunk to freelist.
! ChunkList* list = free_chunks(index);
! assert(list->size() == chunk->word_size(), "Wrong chunk type.");
! list->return_chunk_at_head(chunk);
! log_trace(gc, metaspace, freelist)("returned one %s chunk at " PTR_FORMAT " to freelist.",
! chunk_size_name(index), p2i(chunk));
! } else {
! // Return humongous chunk to dictionary.
! assert(chunk->word_size() > free_chunks(MediumIndex)->size(), "Wrong chunk type.");
! assert(chunk->word_size() % free_chunks(SpecializedIndex)->size() == 0,
! "Humongous chunk has wrong alignment.");
! _humongous_dictionary.return_chunk(chunk);
! log_trace(gc, metaspace, freelist)("returned one %s chunk at " PTR_FORMAT " (word size " SIZE_FORMAT ") to freelist.",
! chunk_size_name(index), p2i(chunk), chunk->word_size());
! }
! chunk->container()->dec_container_count();
! do_update_in_use_info_for_chunk(chunk, false);
!
! // Chunk has been added; update counters.
! account_for_added_chunk(chunk);
!
! // Attempt coalesce returned chunks with its neighboring chunks:
! // if this chunk is small or special, attempt to coalesce to a medium chunk.
! if (index == SmallIndex || index == SpecializedIndex) {
! if (!attempt_to_coalesce_around_chunk(chunk, MediumIndex)) {
! // This did not work. But if this chunk is special, we still may form a small chunk?
! if (index == SpecializedIndex) {
! if (!attempt_to_coalesce_around_chunk(chunk, SmallIndex)) {
! // give up.
! }
! }
! }
! }
!
! // From here on do not access chunk anymore, it may have been merged with another chunk.
- #ifdef ASSERT
- EVERY_NTH(VerifyMetaspaceInterval)
- this->locked_verify(true);
- vsn->verify(true);
- vsn->verify_free_chunks_are_ideally_merged();
- END_EVERY_NTH
- #endif
! }
! void ChunkManager::return_chunk_list(Metachunk* chunks) {
! if (chunks == NULL) {
! return;
! }
! LogTarget(Trace, gc, metaspace, freelist) log;
! if (log.is_enabled()) { // tracing
! log.print("returning list of chunks...");
! }
! unsigned num_chunks_returned = 0;
! size_t size_chunks_returned = 0;
! Metachunk* cur = chunks;
! while (cur != NULL) {
! // Capture the next link before it is changed
! // by the call to return_chunk_at_head();
! Metachunk* next = cur->next();
! if (log.is_enabled()) { // tracing
! num_chunks_returned ++;
! size_chunks_returned += cur->word_size();
! }
! return_single_chunk(cur);
! cur = next;
! }
! if (log.is_enabled()) { // tracing
! log.print("returned %u chunks to freelist, total word size " SIZE_FORMAT ".",
! num_chunks_returned, size_chunks_returned);
}
- }
- void ChunkManager::collect_statistics(ChunkManagerStatistics* out) const {
- MutexLocker cl(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);
- for (ChunkIndex i = ZeroIndex; i < NumberOfInUseLists; i = next_chunk_index(i)) {
- out->chunk_stats(i).add(num_free_chunks(i), size_free_chunks_in_bytes(i) / sizeof(MetaWord));
- }
}
} // namespace metaspace
--- 21,264 ----
* questions.
*
*/
#include "precompiled.hpp"
+
#include "logging/log.hpp"
! #include "memory/metaspace/constants.hpp"
! #include "memory/metaspace/chunkAllocSequence.hpp"
! #include "memory/metaspace/chunkLevel.hpp"
#include "memory/metaspace/chunkManager.hpp"
#include "memory/metaspace/metachunk.hpp"
#include "memory/metaspace/metaspaceStatistics.hpp"
#include "memory/metaspace/virtualSpaceNode.hpp"
+ #include "memory/metaspace/virtualSpaceList.hpp"
#include "runtime/mutexLocker.hpp"
#include "utilities/debug.hpp"
#include "utilities/globalDefinitions.hpp"
namespace metaspace {
! // Return a single chunk to the freelist and adjust accounting. No merge is attempted.
! void ChunkManager::return_chunk_simple(Metachunk* c) {
! DEBUG_ONLY(c->verify(false));
! const chklvl_t lvl = c->level();
! _chunks[lvl].add(c);
! _total_word_size.increment_by(c->word_size());
! }
!
! // Take a single chunk from the given freelist and adjust counters. Returns NULL
! // if there is no fitting chunk for this level.
! Metachunk* ChunkManager::remove_first_chunk_at_level(chklvl_t l) {
! DEBUG_ONLY(chklvl::check_valid_level(l);)
! Metachunk* c = _chunks[l].remove_first();
! if (c != NULL) {
! _total_word_size.decrement_by(c->word_size());
! }
! return c;
! }
!
! // Creates a chunk manager with a given name (which is for debug purposes only)
! // and an associated space list which will be used to request new chunks from
! // (see get_chunk())
! ChunkManager::ChunkManager(const char* name, VirtualSpaceList* space_list)
! : _vslist(space_list),
! _name(name),
! _chunks()
! {
! }
!
! // Given a chunk we are about to handout to the caller, make sure it is committed
! // according to constants::committed_words_on_fresh_chunks
! bool ChunkManager::commit_chunk_before_handout(Metachunk* c) {
! const size_t must_be_committed = MIN2(c->word_size(), constants::committed_words_on_fresh_chunks);
! return c->ensure_committed(must_be_committed);
}
#ifdef ASSERT
! // Given a splinters array returned from a split operation, check that it meets expectations
! static void check_splinters_array(Metachunk* splinters[chklvl::NUM_CHUNK_LEVELS], chklvl_t min, chklvl_t max) {
! // The array shall contain splinters in the range [min, max] and nothing outside. The chunk levels for
! // the chunks must match too.
! for (chklvl_t l = chklvl::ROOT_CHUNK_LEVEL; l <= chklvl::HIGHEST_CHUNK_LEVEL; l ++) {
! if (l >= min && l < max) {
! assert(splinters[l] != NULL, "Missing splinters");
! assert(splinters[l]->level() == l, "Unexpected level");
! splinters[l]->verify(false);
! } else {
! assert(splinters[l] == NULL, "Unexpected splinters");
! }
}
}
+ #endif
! // Given a chunk which must be outside of a freelist and must be free, split it to
! // meet a target level and return it. Splinters are added to the freelist.
! Metachunk* ChunkManager::split_chunk_and_add_splinters(Metachunk* c, chklvl_t target_level) {
!
! assert(c->is_free() && c->level() > target_level, "Invalid chunk for splitting");
! DEBUG_ONLY(chklvl::check_valid_level(target_level);)
!
! const chklvl_t orig_level = c->level();
! Metachunk* splinters[chklvl::NUM_CHUNK_LEVELS] = { 0 };
! c = c->vsnode()->split(target_level, c, splinters);
!
! // Splitting should never fail.
! assert(c != NULL, "Split failed");
! assert(c->level() == target_level, "Sanity");
! DEBUG_ONLY(c->verify(false));
! DEBUG_ONLY(check_splinters_array(splinters, orig_level + 1, target_level);)
!
! // Return splinters to freelist.
! for (chklvl_t l = orig_level + 1; l <= target_level; l ++) {
! return_chunk_simple(splinters[l]);
! }
!
! return c;
! }
!
! // Get a chunk and be smart about it.
! // - 1) Attempt to find a free chunk of exactly the pref_level level
! // - 2) Failing that, attempt to find a chunk smaller or equal the minimal level.
! // - 3) Failing that, attempt to find a free chunk of larger size and split it.
! // - 4) Failing that, attempt to allocate a new chunk from the connected virtual space.
! // - Failing that, give up and return NULL.
! // Note: this is not guaranteed to return a *committed* chunk. The chunk manager will
! // attempt to commit the returned chunk according to constants::committed_words_on_fresh_chunks;
! // but this may fail if we hit a commit limit. In that case, a partly uncommit chunk
! // will be returned, and the commit is attempted again when we allocate from the chunk's
! // uncommitted area. See also Metachunk::allocate.
! Metachunk* ChunkManager::get_chunk(chklvl_t min_level, chklvl_t pref_level) {
!
! assert_lock_strong(MetaspaceExpand_lock);
! DEBUG_ONLY(chklvl::check_valid_level(min_level);)
! DEBUG_ONLY(chklvl::check_valid_level(pref_level);)
!
! Metachunk* c = NULL;
!
! // 1) Attempt to find a free chunk of exactly the pref_level level
! c = remove_first_chunk_at_level(pref_level);
!
! // 2) Failing that, attempt to find a chunk smaller or equal the minimal level.
! if (c == NULL) {
! for (chklvl_t lvl = pref_level + 1; lvl <= min_level; lvl ++) {
! c = remove_first_chunk_at_level(lvl);
! if (c != NULL) {
! break;
}
}
}
! // 3) Failing that, attempt to find a free chunk of larger size and split it.
! if (c == NULL) {
! for (chklvl_t lvl = pref_level - 1; lvl >= chklvl::ROOT_CHUNK_LEVEL; lvl --) {
! c = remove_first_chunk_at_level(lvl);
! if (c != NULL) {
! // Split chunk; add splinters to freelist
! c = split_chunk_and_add_splinters(c, pref_level);
break;
}
}
}
! // 4) Failing that, attempt to allocate a new chunk from the connected virtual space.
! if (c == NULL) {
! c = _vslist->allocate_root_chunk();
! // This should always work. Note that getting the root chunk may not mean we committed memory.
! assert(c != NULL, "Unexpected");
! // Split this root chunk to the desired chunk size.
! c = split_chunk_and_add_splinters(c, pref_level);
! }
! // Note that we should at this point have a chunk; should always work. If we hit
! // a commit limit in the meantime, the chunk may still be uncommitted, but the chunk
! // itself should exist now.
! assert(c != NULL, "Unexpected");
! // Before returning the chunk, attempt to commit it according to the handout rules.
! // If that fails, we ignore the error and return the uncommitted chunk.
! if (commit_chunk_before_handout(c) == false) {
! log_info(gc, metaspace)("Failed to commit chunk prior to handout.");
}
! DEBUG_ONLY(verify(false);)
! return c;
! } // ChunkManager::get_chunk
! // Return a single chunk to the ChunkManager and adjust accounting. May merge chunk
! // with neighbors.
! // Happens after a Classloader was unloaded and releases its metaspace chunks.
! // !! Note: this may invalidate the chunk. Do not access the chunk after
! // this function returns !!
! void ChunkManager::return_chunk(Metachunk* c) {
! assert_lock_strong(MetaspaceExpand_lock);
! DEBUG_ONLY(c->verify(false);)
! const chklvl_t orig_lvl = c->level();
! int num_merged[chklvl::NUM_CHUNK_LEVELS] = { 0 };
! Metachunk* c2 = c->vsnode()->merge(c, num_merged);
! if (c2 != NULL) {
! DEBUG_ONLY(c2->verify(false));
! // We did merge chunks and now have a bigger chunk.
! assert(c2->level() < orig_lvl, "Sanity");
! // Adjust counters - the merged-in chunks have been removed from the free lists, but the counters
! // in this chunk manager must be adjusted too.
! size_t size_chunks_removed = 0;
! for (chklvl_t l = chklvl::ROOT_CHUNK_LEVEL; l <= chklvl::HIGHEST_CHUNK_LEVEL; l ++) {
! if (num_merged[l] > 0) {
! // Since we have a binary tree, we should exactly see one merge per level.
! assert(num_merged[l] == 1, "sanity");
! _chunks[l].dec_counter_by(1);
! size_chunks_removed += chklvl::word_size_for_level(l);
}
}
+ _total_word_size.decrement_by(size_chunks_removed);
! c = c2;
}
! return_chunk_simple(c);
}
! ChunkManager* ChunkManager::_chunkmanager_class = NULL;
! ChunkManager* ChunkManager::_chunkmanager_nonclass = NULL;
! void ChunkManager::set_chunkmanager_class(ChunkManager* cm) {
! assert(_chunkmanager_class == NULL, "Sanity");
! _chunkmanager_class = cm;
}
! void ChunkManager::set_chunkmanager_nonclass(ChunkManager* cm) {
! assert(_chunkmanager_nonclass == NULL, "Sanity");
! _chunkmanager_nonclass = cm;
! }
! // Update statistics.
! void ChunkManager::add_to_statistics(ChunkManagerStatistics* out) const {
! for (chklvl_t l = chklvl::ROOT_CHUNK_LEVEL; l <= chklvl::HIGHEST_CHUNK_LEVEL; l ++) {
! out->num_chunks[l] += _chunks[l].size();
}
}
} // namespace metaspace
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