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src/hotspot/share/memory/metaspace/virtualSpaceNode.cpp
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rev 60538 : imported patch jep387-core.patch
@@ -1,7 +1,8 @@
/*
- * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2020 SAP SE. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
@@ -23,566 +24,497 @@
*/
#include "precompiled.hpp"
#include "logging/log.hpp"
-#include "logging/logStream.hpp"
+
+#include "memory/metaspace/chunkLevel.hpp"
+#include "memory/metaspace/chunkHeaderPool.hpp"
+#include "memory/metaspace/commitLimiter.hpp"
+#include "memory/metaspace/counter.hpp"
+#include "memory/metaspace/freeChunkList.hpp"
+#include "memory/metaspace/internStat.hpp"
#include "memory/metaspace/metachunk.hpp"
-#include "memory/metaspace.hpp"
-#include "memory/metaspace/chunkManager.hpp"
-#include "memory/metaspace/metaDebug.hpp"
#include "memory/metaspace/metaspaceCommon.hpp"
-#include "memory/metaspace/occupancyMap.hpp"
+#include "memory/metaspace/rootChunkArea.hpp"
+#include "memory/metaspace/runningCounters.hpp"
+#include "memory/metaspace/settings.hpp"
#include "memory/metaspace/virtualSpaceNode.hpp"
-#include "memory/virtualspace.hpp"
-#include "runtime/atomic.hpp"
+#include "memory/metaspace.hpp"
+
+#include "runtime/globals.hpp"
+#include "runtime/mutexLocker.hpp"
#include "runtime/os.hpp"
-#include "services/memTracker.hpp"
-#include "utilities/copy.hpp"
+
+#include "utilities/align.hpp"
#include "utilities/debug.hpp"
#include "utilities/globalDefinitions.hpp"
+#include "utilities/ostream.hpp"
namespace metaspace {
-// Decide if large pages should be committed when the memory is reserved.
-static bool should_commit_large_pages_when_reserving(size_t bytes) {
- if (UseLargePages && UseLargePagesInMetaspace && !os::can_commit_large_page_memory()) {
- size_t words = bytes / BytesPerWord;
- bool is_class = false; // We never reserve large pages for the class space.
- if (MetaspaceGC::can_expand(words, is_class) &&
- MetaspaceGC::allowed_expansion() >= words) {
- return true;
- }
- }
+#define LOGFMT "VsListNode @" PTR_FORMAT " base " PTR_FORMAT " "
+#define LOGFMT_ARGS p2i(this), p2i(_base)
- return false;
+#ifdef ASSERT
+void check_pointer_is_aligned_to_commit_granule(const MetaWord* p) {
+ assert(is_aligned(p, Settings::commit_granule_bytes()),
+ "Pointer not aligned to commit granule size: " PTR_FORMAT ".",
+ p2i(p));
+}
+void check_word_size_is_aligned_to_commit_granule(size_t word_size) {
+ assert(is_aligned(word_size, Settings::commit_granule_words()),
+ "Not aligned to commit granule size: " SIZE_FORMAT ".", word_size);
}
+#endif
-// byte_size is the size of the associated virtualspace.
-VirtualSpaceNode::VirtualSpaceNode(bool is_class, size_t bytes) :
- _next(NULL), _is_class(is_class), _rs(), _top(NULL), _container_count(0), _occupancy_map(NULL) {
- assert_is_aligned(bytes, Metaspace::reserve_alignment());
- bool large_pages = should_commit_large_pages_when_reserving(bytes);
- _rs = ReservedSpace(bytes, Metaspace::reserve_alignment(), large_pages);
-
- if (_rs.is_reserved()) {
- assert(_rs.base() != NULL, "Catch if we get a NULL address");
- assert(_rs.size() != 0, "Catch if we get a 0 size");
- assert_is_aligned(_rs.base(), Metaspace::reserve_alignment());
- assert_is_aligned(_rs.size(), Metaspace::reserve_alignment());
-
- MemTracker::record_virtual_memory_type((address)_rs.base(), mtClass);
- }
-}
-
-void VirtualSpaceNode::purge(ChunkManager* chunk_manager) {
- // When a node is purged, lets give it a thorough examination.
- DEBUG_ONLY(verify(true);)
- Metachunk* chunk = first_chunk();
- Metachunk* invalid_chunk = (Metachunk*) top();
- while (chunk < invalid_chunk ) {
- assert(chunk->is_tagged_free(), "Should be tagged free");
- MetaWord* next = ((MetaWord*)chunk) + chunk->word_size();
- chunk_manager->remove_chunk(chunk);
- chunk->remove_sentinel();
- assert(chunk->next() == NULL &&
- chunk->prev() == NULL,
- "Was not removed from its list");
- chunk = (Metachunk*) next;
- }
-}
-
-void VirtualSpaceNode::print_map(outputStream* st, bool is_class) const {
-
- if (bottom() == top()) {
- return;
- }
-
- const size_t spec_chunk_size = is_class ? ClassSpecializedChunk : SpecializedChunk;
- const size_t small_chunk_size = is_class ? ClassSmallChunk : SmallChunk;
- const size_t med_chunk_size = is_class ? ClassMediumChunk : MediumChunk;
-
- int line_len = 100;
- const size_t section_len = align_up(spec_chunk_size * line_len, med_chunk_size);
- line_len = (int)(section_len / spec_chunk_size);
-
- static const int NUM_LINES = 4;
-
- char* lines[NUM_LINES];
- for (int i = 0; i < NUM_LINES; i ++) {
- lines[i] = (char*)os::malloc(line_len, mtInternal);
- }
- int pos = 0;
- const MetaWord* p = bottom();
- const Metachunk* chunk = (const Metachunk*)p;
- const MetaWord* chunk_end = p + chunk->word_size();
- while (p < top()) {
- if (pos == line_len) {
- pos = 0;
- for (int i = 0; i < NUM_LINES; i ++) {
- st->fill_to(22);
- st->print_raw(lines[i], line_len);
- st->cr();
- }
- }
- if (pos == 0) {
- st->print(PTR_FORMAT ":", p2i(p));
+
+// Given an address range, ensure it is committed.
+//
+// The range has to be aligned to granule size.
+//
+// Function will:
+// - check how many granules in that region are uncommitted; If all are committed, it
+// returns true immediately.
+// - check if committing those uncommitted granules would bring us over the commit limit
+// (GC threshold, MaxMetaspaceSize). If true, it returns false.
+// - commit the memory.
+// - mark the range as committed in the commit mask
+//
+// Returns true if success, false if it did hit a commit limit.
+bool VirtualSpaceNode::commit_range(MetaWord* p, size_t word_size) {
+
+ DEBUG_ONLY(check_pointer_is_aligned_to_commit_granule(p);)
+ DEBUG_ONLY(check_word_size_is_aligned_to_commit_granule(word_size);)
+ assert_lock_strong(MetaspaceExpand_lock);
+
+ // First calculate how large the committed regions in this range are
+ const size_t committed_words_in_range = _commit_mask.get_committed_size_in_range(p, word_size);
+ DEBUG_ONLY(check_word_size_is_aligned_to_commit_granule(committed_words_in_range);)
+
+ // By how much words we would increase commit charge
+ // were we to commit the given address range completely.
+ const size_t commit_increase_words = word_size - committed_words_in_range;
+
+ UL2(debug, "committing range " PTR_FORMAT ".." PTR_FORMAT "(" SIZE_FORMAT " words)",
+ p2i(p), p2i(p + word_size), word_size);
+
+ if (commit_increase_words == 0) {
+ UL(debug, "... already fully committed.");
+ return true; // Already fully committed, nothing to do.
}
- if (p == chunk_end) {
- chunk = (Metachunk*)p;
- chunk_end = p + chunk->word_size();
- }
- // line 1: chunk starting points (a dot if that area is a chunk start).
- lines[0][pos] = p == (const MetaWord*)chunk ? '.' : ' ';
-
- // Line 2: chunk type (x=spec, s=small, m=medium, h=humongous), uppercase if
- // chunk is in use.
- const bool chunk_is_free = ((Metachunk*)chunk)->is_tagged_free();
- if (chunk->word_size() == spec_chunk_size) {
- lines[1][pos] = chunk_is_free ? 'x' : 'X';
- } else if (chunk->word_size() == small_chunk_size) {
- lines[1][pos] = chunk_is_free ? 's' : 'S';
- } else if (chunk->word_size() == med_chunk_size) {
- lines[1][pos] = chunk_is_free ? 'm' : 'M';
- } else if (chunk->word_size() > med_chunk_size) {
- lines[1][pos] = chunk_is_free ? 'h' : 'H';
- } else {
- ShouldNotReachHere();
- }
-
- // Line 3: chunk origin
- const ChunkOrigin origin = chunk->get_origin();
- lines[2][pos] = origin == origin_normal ? ' ' : '0' + (int) origin;
-
- // Line 4: Virgin chunk? Virgin chunks are chunks created as a byproduct of padding or splitting,
- // but were never used.
- lines[3][pos] = chunk->get_use_count() > 0 ? ' ' : 'v';
-
- p += spec_chunk_size;
- pos ++;
- }
- if (pos > 0) {
- for (int i = 0; i < NUM_LINES; i ++) {
- st->fill_to(22);
- st->print_raw(lines[i], line_len);
- st->cr();
+
+ // Before committing any more memory, check limits.
+ if (_commit_limiter->possible_expansion_words() < commit_increase_words) {
+ UL(debug, "... cannot commit (limit).");
+ return false;
}
+
+ // Commit...
+ if (os::commit_memory((char*)p, word_size * BytesPerWord, false) == false) {
+ vm_exit_out_of_memory(word_size * BytesPerWord, OOM_MMAP_ERROR, "Failed to commit metaspace.");
}
- for (int i = 0; i < NUM_LINES; i ++) {
- os::free(lines[i]);
+
+ if (AlwaysPreTouch) {
+ os::pretouch_memory(p, p + word_size);
}
-}
+ UL2(debug, "... committed " SIZE_FORMAT " additional words.", commit_increase_words);
-#ifdef ASSERT
+ // ... tell commit limiter...
+ _commit_limiter->increase_committed(commit_increase_words);
-// Verify counters, all chunks in this list node and the occupancy map.
-void VirtualSpaceNode::verify(bool slow) {
- log_trace(gc, metaspace, freelist)("verifying %s virtual space node (%s).",
- (is_class() ? "class space" : "metaspace"), (slow ? "slow" : "quick"));
- // Fast mode: just verify chunk counters and basic geometry
- // Slow mode: verify chunks and occupancy map
- uintx num_in_use_chunks = 0;
- Metachunk* chunk = first_chunk();
- Metachunk* invalid_chunk = (Metachunk*) top();
-
- // Iterate the chunks in this node and verify each chunk.
- while (chunk < invalid_chunk ) {
- if (slow) {
- do_verify_chunk(chunk);
- }
- if (!chunk->is_tagged_free()) {
- num_in_use_chunks ++;
- }
- const size_t s = chunk->word_size();
- // Prevent endless loop on invalid chunk size.
- assert(is_valid_chunksize(is_class(), s), "Invalid chunk size: " SIZE_FORMAT ".", s);
- MetaWord* next = ((MetaWord*)chunk) + s;
- chunk = (Metachunk*) next;
- }
- assert(_container_count == num_in_use_chunks, "Container count mismatch (real: " UINTX_FORMAT
- ", counter: " UINTX_FORMAT ".", num_in_use_chunks, _container_count);
- // Also verify the occupancy map.
- if (slow) {
- occupancy_map()->verify(bottom(), top());
- }
-}
-
-// Verify that all free chunks in this node are ideally merged
-// (there not should be multiple small chunks where a large chunk could exist.)
-void VirtualSpaceNode::verify_free_chunks_are_ideally_merged() {
- Metachunk* chunk = first_chunk();
- Metachunk* invalid_chunk = (Metachunk*) top();
- // Shorthands.
- const size_t size_med = (is_class() ? ClassMediumChunk : MediumChunk) * BytesPerWord;
- const size_t size_small = (is_class() ? ClassSmallChunk : SmallChunk) * BytesPerWord;
- int num_free_chunks_since_last_med_boundary = -1;
- int num_free_chunks_since_last_small_boundary = -1;
- bool error = false;
- char err[256];
- while (!error && chunk < invalid_chunk ) {
- // Test for missed chunk merge opportunities: count number of free chunks since last chunk boundary.
- // Reset the counter when encountering a non-free chunk.
- if (chunk->get_chunk_type() != HumongousIndex) {
- if (chunk->is_tagged_free()) {
- // Count successive free, non-humongous chunks.
- if (is_aligned(chunk, size_small)) {
- if (num_free_chunks_since_last_small_boundary > 0) {
- error = true;
- jio_snprintf(err, sizeof(err), "Missed chunk merge opportunity to merge a small chunk preceding " PTR_FORMAT ".", p2i(chunk));
- } else {
- num_free_chunks_since_last_small_boundary = 0;
- }
- } else if (num_free_chunks_since_last_small_boundary != -1) {
- num_free_chunks_since_last_small_boundary ++;
- }
- if (is_aligned(chunk, size_med)) {
- if (num_free_chunks_since_last_med_boundary > 0) {
- error = true;
- jio_snprintf(err, sizeof(err), "Missed chunk merge opportunity to merge a medium chunk preceding " PTR_FORMAT ".", p2i(chunk));
- } else {
- num_free_chunks_since_last_med_boundary = 0;
- }
- } else if (num_free_chunks_since_last_med_boundary != -1) {
- num_free_chunks_since_last_med_boundary ++;
- }
- } else {
- // Encountering a non-free chunk, reset counters.
- num_free_chunks_since_last_med_boundary = -1;
- num_free_chunks_since_last_small_boundary = -1;
- }
- } else {
- // One cannot merge areas with a humongous chunk in the middle. Reset counters.
- num_free_chunks_since_last_med_boundary = -1;
- num_free_chunks_since_last_small_boundary = -1;
- }
-
- if (error) {
- print_map(tty, is_class());
- fatal("%s", err);
- }
+ // ... update counters in containing vslist ...
+ _total_committed_words_counter->increment_by(commit_increase_words);
- MetaWord* next = ((MetaWord*)chunk) + chunk->word_size();
- chunk = (Metachunk*) next;
+ // ... and update the commit mask.
+ _commit_mask.mark_range_as_committed(p, word_size);
+
+#ifdef ASSERT
+ // The commit boundary maintained in the CommitLimiter should be equal the sum of committed words
+ // in both class and non-class vslist (outside gtests).
+ if (_commit_limiter == CommitLimiter::globalLimiter()) {
+ assert(_commit_limiter->committed_words() == RunningCounters::committed_words(), "counter mismatch");
}
+#endif
+
+ InternalStats::inc_num_space_committed();
+
+ return true;
+
}
-#endif // ASSERT
-void VirtualSpaceNode::inc_container_count() {
+// Given an address range, ensure it is committed.
+//
+// The range does not have to be aligned to granule size. However, the function will always commit
+// whole granules.
+//
+// Function will:
+// - check how many granules in that region are uncommitted; If all are committed, it
+// returns true immediately.
+// - check if committing those uncommitted granules would bring us over the commit limit
+// (GC threshold, MaxMetaspaceSize). If true, it returns false.
+// - commit the memory.
+// - mark the range as committed in the commit mask
+//
+// !! Careful:
+// calling ensure_range_is_committed on a range which contains both committed and uncommitted
+// areas will commit the whole area, thus erase the content in the existing committed parts.
+// Make sure you never call this on an address range containing live data. !!
+//
+// Returns true if success, false if it did hit a commit limit.
+bool VirtualSpaceNode::ensure_range_is_committed(MetaWord* p, size_t word_size) {
+
assert_lock_strong(MetaspaceExpand_lock);
- _container_count++;
+ assert(p != NULL && word_size > 0, "Sanity");
+
+ MetaWord* p_start = align_down(p, Settings::commit_granule_bytes());
+ MetaWord* p_end = align_up(p + word_size, Settings::commit_granule_bytes());
+
+ // Todo: simple for now. Make it more intelligent late
+ return commit_range(p_start, p_end - p_start);
+
}
-void VirtualSpaceNode::dec_container_count() {
+// Given an address range (which has to be aligned to commit granule size):
+// - uncommit it
+// - mark it as uncommitted in the commit mask
+void VirtualSpaceNode::uncommit_range(MetaWord* p, size_t word_size) {
+
+ DEBUG_ONLY(check_pointer_is_aligned_to_commit_granule(p);)
+ DEBUG_ONLY(check_word_size_is_aligned_to_commit_granule(word_size);)
assert_lock_strong(MetaspaceExpand_lock);
- _container_count--;
-}
-VirtualSpaceNode::~VirtualSpaceNode() {
- _rs.release();
- if (_occupancy_map != NULL) {
- delete _occupancy_map;
+ // First calculate how large the committed regions in this range are
+ const size_t committed_words_in_range = _commit_mask.get_committed_size_in_range(p, word_size);
+ DEBUG_ONLY(check_word_size_is_aligned_to_commit_granule(committed_words_in_range);)
+
+ UL2(debug, "uncommitting range " PTR_FORMAT ".." PTR_FORMAT "(" SIZE_FORMAT " words)",
+ p2i(p), p2i(p + word_size), word_size);
+
+ if (committed_words_in_range == 0) {
+ UL(debug, "... already fully uncommitted.");
+ return; // Already fully uncommitted, nothing to do.
}
+
+ // Uncommit...
+ if (os::uncommit_memory((char*)p, word_size * BytesPerWord) == false) {
+ // Note: this can actually happen, since uncommit may increase the number of mappings.
+ fatal("Failed to uncommit metaspace.");
+ }
+
+ UL2(debug, "... uncommitted " SIZE_FORMAT " words.", committed_words_in_range);
+
+ // ... tell commit limiter...
+ _commit_limiter->decrease_committed(committed_words_in_range);
+
+ // ... and global counters...
+ _total_committed_words_counter->decrement_by(committed_words_in_range);
+
+ // ... and update the commit mask.
+ _commit_mask.mark_range_as_uncommitted(p, word_size);
+
#ifdef ASSERT
- size_t word_size = sizeof(*this) / BytesPerWord;
- Copy::fill_to_words((HeapWord*) this, word_size, 0xf1f1f1f1);
+ // The commit boundary maintained in the CommitLimiter should be equal the sum of committed words
+ // in both class and non-class vslist (outside gtests).
+ if (_commit_limiter == CommitLimiter::globalLimiter()) { // We are outside a test scenario
+ assert(_commit_limiter->committed_words() == RunningCounters::committed_words(), "counter mismatch");
+ }
#endif
+
+ InternalStats::inc_num_space_uncommitted();
+
}
-size_t VirtualSpaceNode::used_words_in_vs() const {
- return pointer_delta(top(), bottom(), sizeof(MetaWord));
+//// creation, destruction ////
+
+VirtualSpaceNode::VirtualSpaceNode(ReservedSpace rs, bool owns_rs, CommitLimiter* limiter,
+ SizeCounter* reserve_counter, SizeCounter* commit_counter)
+ : _next(NULL),
+ _rs(rs),
+ _owns_rs(owns_rs),
+ _base((MetaWord*)rs.base()),
+ _word_size(rs.size() / BytesPerWord),
+ _used_words(0),
+ _commit_mask((MetaWord*)rs.base(), rs.size() / BytesPerWord),
+ _root_chunk_area_lut((MetaWord*)rs.base(), rs.size() / BytesPerWord),
+ _commit_limiter(limiter),
+ _total_reserved_words_counter(reserve_counter),
+ _total_committed_words_counter(commit_counter)
+{
+ UL2(debug, "born (word_size " SIZE_FORMAT ").", _word_size);
+
+ // Update reserved counter in vslist
+ _total_reserved_words_counter->increment_by(_word_size);
+
+ assert_is_aligned(_base, chunklevel::MAX_CHUNK_BYTE_SIZE);
+ assert_is_aligned(_word_size, chunklevel::MAX_CHUNK_WORD_SIZE);
+
}
-// Space committed in the VirtualSpace
-size_t VirtualSpaceNode::capacity_words_in_vs() const {
- return pointer_delta(end(), bottom(), sizeof(MetaWord));
-}
-
-size_t VirtualSpaceNode::free_words_in_vs() const {
- return pointer_delta(end(), top(), sizeof(MetaWord));
-}
-
-// Given an address larger than top(), allocate padding chunks until top is at the given address.
-void VirtualSpaceNode::allocate_padding_chunks_until_top_is_at(MetaWord* target_top) {
-
- assert(target_top > top(), "Sanity");
-
- // Padding chunks are added to the freelist.
- ChunkManager* const chunk_manager = Metaspace::get_chunk_manager(is_class());
-
- // shorthands
- const size_t spec_word_size = chunk_manager->specialized_chunk_word_size();
- const size_t small_word_size = chunk_manager->small_chunk_word_size();
- const size_t med_word_size = chunk_manager->medium_chunk_word_size();
-
- while (top() < target_top) {
-
- // We could make this coding more generic, but right now we only deal with two possible chunk sizes
- // for padding chunks, so it is not worth it.
- size_t padding_chunk_word_size = small_word_size;
- if (is_aligned(top(), small_word_size * sizeof(MetaWord)) == false) {
- assert_is_aligned(top(), spec_word_size * sizeof(MetaWord)); // Should always hold true.
- padding_chunk_word_size = spec_word_size;
- }
- MetaWord* here = top();
- assert_is_aligned(here, padding_chunk_word_size * sizeof(MetaWord));
- inc_top(padding_chunk_word_size);
-
- // Create new padding chunk.
- ChunkIndex padding_chunk_type = get_chunk_type_by_size(padding_chunk_word_size, is_class());
- assert(padding_chunk_type == SpecializedIndex || padding_chunk_type == SmallIndex, "sanity");
-
- Metachunk* const padding_chunk =
- ::new (here) Metachunk(padding_chunk_type, is_class(), padding_chunk_word_size, this);
- assert(padding_chunk == (Metachunk*)here, "Sanity");
- DEBUG_ONLY(padding_chunk->set_origin(origin_pad);)
- log_trace(gc, metaspace, freelist)("Created padding chunk in %s at "
- PTR_FORMAT ", size " SIZE_FORMAT_HEX ".",
- (is_class() ? "class space " : "metaspace"),
- p2i(padding_chunk), padding_chunk->word_size() * sizeof(MetaWord));
-
- // Mark chunk start in occupancy map.
- occupancy_map()->set_chunk_starts_at_address((MetaWord*)padding_chunk, true);
-
- // Chunks are born as in-use (see MetaChunk ctor). So, before returning
- // the padding chunk to its chunk manager, mark it as in use (ChunkManager
- // will assert that).
- do_update_in_use_info_for_chunk(padding_chunk, true);
-
- // Return Chunk to freelist.
- inc_container_count();
- chunk_manager->return_single_chunk(padding_chunk);
- // Please note: at this point, ChunkManager::return_single_chunk()
- // may already have merged the padding chunk with neighboring chunks, so
- // it may have vanished at this point. Do not reference the padding
- // chunk beyond this point.
- }
-
- assert(top() == target_top, "Sanity");
-
-} // allocate_padding_chunks_until_top_is_at()
-
-// Allocates the chunk from the virtual space only.
-// This interface is also used internally for debugging. Not all
-// chunks removed here are necessarily used for allocation.
-Metachunk* VirtualSpaceNode::take_from_committed(size_t chunk_word_size) {
- // Non-humongous chunks are to be allocated aligned to their chunk
- // size. So, start addresses of medium chunks are aligned to medium
- // chunk size, those of small chunks to small chunk size and so
- // forth. This facilitates merging of free chunks and reduces
- // fragmentation. Chunk sizes are spec < small < medium, with each
- // larger chunk size being a multiple of the next smaller chunk
- // size.
- // Because of this alignment, me may need to create a number of padding
- // chunks. These chunks are created and added to the freelist.
-
- // The chunk manager to which we will give our padding chunks.
- ChunkManager* const chunk_manager = Metaspace::get_chunk_manager(is_class());
-
- // shorthands
- const size_t spec_word_size = chunk_manager->specialized_chunk_word_size();
- const size_t small_word_size = chunk_manager->small_chunk_word_size();
- const size_t med_word_size = chunk_manager->medium_chunk_word_size();
-
- assert(chunk_word_size == spec_word_size || chunk_word_size == small_word_size ||
- chunk_word_size >= med_word_size, "Invalid chunk size requested.");
-
- // Chunk alignment (in bytes) == chunk size unless humongous.
- // Humongous chunks are aligned to the smallest chunk size (spec).
- const size_t required_chunk_alignment = (chunk_word_size > med_word_size ?
- spec_word_size : chunk_word_size) * sizeof(MetaWord);
-
- // Do we have enough space to create the requested chunk plus
- // any padding chunks needed?
- MetaWord* const next_aligned =
- static_cast<MetaWord*>(align_up(top(), required_chunk_alignment));
- if (!is_available((next_aligned - top()) + chunk_word_size)) {
- return NULL;
- }
-
- // Before allocating the requested chunk, allocate padding chunks if necessary.
- // We only need to do this for small or medium chunks: specialized chunks are the
- // smallest size, hence always aligned. Homungous chunks are allocated unaligned
- // (implicitly, also aligned to smallest chunk size).
- if ((chunk_word_size == med_word_size || chunk_word_size == small_word_size) && next_aligned > top()) {
- log_trace(gc, metaspace, freelist)("Creating padding chunks in %s between %p and %p...",
- (is_class() ? "class space " : "metaspace"),
- top(), next_aligned);
- allocate_padding_chunks_until_top_is_at(next_aligned);
- // Now, top should be aligned correctly.
- assert_is_aligned(top(), required_chunk_alignment);
- }
-
- // Now, top should be aligned correctly.
- assert_is_aligned(top(), required_chunk_alignment);
-
- // Bottom of the new chunk
- MetaWord* chunk_limit = top();
- assert(chunk_limit != NULL, "Not safe to call this method");
-
- // The virtual spaces are always expanded by the
- // commit granularity to enforce the following condition.
- // Without this the is_available check will not work correctly.
- assert(_virtual_space.committed_size() == _virtual_space.actual_committed_size(),
- "The committed memory doesn't match the expanded memory.");
-
- if (!is_available(chunk_word_size)) {
- LogTarget(Trace, gc, metaspace, freelist) lt;
- if (lt.is_enabled()) {
- LogStream ls(lt);
- ls.print("VirtualSpaceNode::take_from_committed() not available " SIZE_FORMAT " words ", chunk_word_size);
- // Dump some information about the virtual space that is nearly full
- print_on(&ls);
- }
- return NULL;
- }
-
- // Take the space (bump top on the current virtual space).
- inc_top(chunk_word_size);
-
- // Initialize the chunk
- ChunkIndex chunk_type = get_chunk_type_by_size(chunk_word_size, is_class());
- Metachunk* result = ::new (chunk_limit) Metachunk(chunk_type, is_class(), chunk_word_size, this);
- assert(result == (Metachunk*)chunk_limit, "Sanity");
- occupancy_map()->set_chunk_starts_at_address((MetaWord*)result, true);
- do_update_in_use_info_for_chunk(result, true);
- inc_container_count();
+// Create a node of a given size (it will create its own space).
+VirtualSpaceNode* VirtualSpaceNode::create_node(size_t word_size,
+ CommitLimiter* limiter, SizeCounter* reserve_words_counter,
+ SizeCounter* commit_words_counter)
+{
-#ifdef ASSERT
- EVERY_NTH(VerifyMetaspaceInterval)
- chunk_manager->locked_verify(true);
- verify(true);
- END_EVERY_NTH
- do_verify_chunk(result);
-#endif
+ DEBUG_ONLY(assert_is_aligned(word_size, chunklevel::MAX_CHUNK_WORD_SIZE);)
- result->inc_use_count();
+ ReservedSpace rs(word_size * BytesPerWord,
+ Settings::virtual_space_node_reserve_alignment_words() * BytesPerWord,
+ false // large
+ );
+
+ if (!rs.is_reserved()) {
+ vm_exit_out_of_memory(word_size * BytesPerWord, OOM_MMAP_ERROR, "Failed to reserve memory for metaspace");
+ }
+
+ assert_is_aligned(rs.base(), chunklevel::MAX_CHUNK_BYTE_SIZE);
+
+ InternalStats::inc_num_vsnodes_births();
+ return new VirtualSpaceNode(rs, true, limiter, reserve_words_counter, commit_words_counter);
- return result;
}
+// Create a node over an existing space
+VirtualSpaceNode* VirtualSpaceNode::create_node(ReservedSpace rs, CommitLimiter* limiter,
+ SizeCounter* reserve_words_counter, SizeCounter* commit_words_counter)
+{
+ InternalStats::inc_num_vsnodes_births();
+ return new VirtualSpaceNode(rs, false, limiter, reserve_words_counter, commit_words_counter);
+}
+
+VirtualSpaceNode::~VirtualSpaceNode() {
-// Expand the virtual space (commit more of the reserved space)
-bool VirtualSpaceNode::expand_by(size_t min_words, size_t preferred_words) {
- size_t min_bytes = min_words * BytesPerWord;
- size_t preferred_bytes = preferred_words * BytesPerWord;
+ DEBUG_ONLY(verify_locked(true);)
- size_t uncommitted = virtual_space()->reserved_size() - virtual_space()->actual_committed_size();
+ UL(debug, ": dies.");
- if (uncommitted < min_bytes) {
- return false;
+ if (_owns_rs) {
+ _rs.release();
}
- size_t commit = MIN2(preferred_bytes, uncommitted);
- bool result = virtual_space()->expand_by(commit, false);
+ // Update counters in vslist
+ size_t committed = committed_words();
+ _total_committed_words_counter->decrement_by(committed);
+ _total_reserved_words_counter->decrement_by(_word_size);
+
+ // ... and tell commit limiter
+ _commit_limiter->decrease_committed(committed);
+
+ InternalStats::inc_num_vsnodes_deaths();
+
+}
+
+//// Chunk allocation, splitting, merging /////
+
+// Allocate a root chunk from this node. Will fail and return NULL if the node is full
+// - if we used up the whole address space of this node's memory region.
+// (in case this node backs compressed class space, this is how we hit
+// CompressedClassSpaceSize).
+// Note that this just returns reserved memory; caller must take care of committing this
+// chunk before using it.
+Metachunk* VirtualSpaceNode::allocate_root_chunk() {
+
+ assert_lock_strong(MetaspaceExpand_lock);
+
+ assert_is_aligned(free_words(), chunklevel::MAX_CHUNK_WORD_SIZE);
+
+ if (free_words() >= chunklevel::MAX_CHUNK_WORD_SIZE) {
+
+ MetaWord* loc = _base + _used_words;
+ _used_words += chunklevel::MAX_CHUNK_WORD_SIZE;
+
+ RootChunkArea* rca = _root_chunk_area_lut.get_area_by_address(loc);
+
+ // Create a root chunk header and initialize it;
+ Metachunk* c = rca->alloc_root_chunk_header(this);
+
+ assert(c->base() == loc && c->vsnode() == this &&
+ c->is_free(), "Sanity");
+
+ DEBUG_ONLY(c->verify(true);)
+
+ UL2(debug, "new root chunk " METACHUNK_FORMAT ".", METACHUNK_FORMAT_ARGS(c));
+
+ return c;
- if (result) {
- log_trace(gc, metaspace, freelist)("Expanded %s virtual space list node by " SIZE_FORMAT " words.",
- (is_class() ? "class" : "non-class"), commit);
- DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_committed_space_expanded));
- } else {
- log_trace(gc, metaspace, freelist)("Failed to expand %s virtual space list node by " SIZE_FORMAT " words.",
- (is_class() ? "class" : "non-class"), commit);
}
- assert(result, "Failed to commit memory");
+ return NULL; // Node is full.
- return result;
}
-Metachunk* VirtualSpaceNode::get_chunk_vs(size_t chunk_word_size) {
+// Given a chunk c, split it recursively until you get a chunk of the given target_level.
+//
+// The resulting target chunk resides at the same address as the original chunk.
+// The resulting splinters are added to freelists.
+void VirtualSpaceNode::split(chunklevel_t target_level, Metachunk* c, FreeChunkListVector* freelists) {
+
assert_lock_strong(MetaspaceExpand_lock);
- Metachunk* result = take_from_committed(chunk_word_size);
- return result;
+
+ // Get the area associated with this chunk and let it handle the splitting
+ RootChunkArea* rca = _root_chunk_area_lut.get_area_by_address(c->base());
+
+ DEBUG_ONLY(rca->verify_area_is_ideally_merged();)
+
+ rca->split(target_level, c, freelists);
+
}
-bool VirtualSpaceNode::initialize() {
+// Given a chunk, attempt to merge it recursively with its neighboring chunks.
+//
+// If successful (merged at least once), returns address of
+// the merged chunk; NULL otherwise.
+//
+// The merged chunks are removed from the freelists.
+//
+// !!! Please note that if this method returns a non-NULL value, the
+// original chunk will be invalid and should not be accessed anymore! !!!
+Metachunk* VirtualSpaceNode::merge(Metachunk* c, FreeChunkListVector* freelists) {
- if (!_rs.is_reserved()) {
- return false;
+ assert(c != NULL && c->is_free(), "Sanity");
+ assert_lock_strong(MetaspaceExpand_lock);
+
+ // Get the rca associated with this chunk and let it handle the merging
+ RootChunkArea* rca = _root_chunk_area_lut.get_area_by_address(c->base());
+
+ Metachunk* c2 = rca->merge(c, freelists);
+
+ DEBUG_ONLY(rca->verify_area_is_ideally_merged();)
+
+ return c2;
+
+}
+
+// Given a chunk c, which must be "in use" and must not be a root chunk, attempt to
+// enlarge it in place by claiming its trailing buddy.
+//
+// This will only work if c is the leader of the buddy pair and the trailing buddy is free.
+//
+// If successful, the follower chunk will be removed from the freelists, the leader chunk c will
+// double in size (level decreased by one).
+//
+// On success, true is returned, false otherwise.
+bool VirtualSpaceNode::attempt_enlarge_chunk(Metachunk* c, FreeChunkListVector* freelists) {
+
+ assert(c != NULL && c->is_in_use() && !c->is_root_chunk(), "Sanity");
+ assert_lock_strong(MetaspaceExpand_lock);
+
+ // Get the rca associated with this chunk and let it handle the merging
+ RootChunkArea* rca = _root_chunk_area_lut.get_area_by_address(c->base());
+
+ bool rc = rca->attempt_enlarge_chunk(c, freelists);
+
+ DEBUG_ONLY(rca->verify_area_is_ideally_merged();)
+
+ if (rc) {
+ InternalStats::inc_num_chunks_enlarged();
}
- // These are necessary restriction to make sure that the virtual space always
- // grows in steps of Metaspace::commit_alignment(). If both base and size are
- // aligned only the middle alignment of the VirtualSpace is used.
- assert_is_aligned(_rs.base(), Metaspace::commit_alignment());
- assert_is_aligned(_rs.size(), Metaspace::commit_alignment());
+ return rc;
- // ReservedSpaces marked as special will have the entire memory
- // pre-committed. Setting a committed size will make sure that
- // committed_size and actual_committed_size agrees.
- size_t pre_committed_size = _rs.special() ? _rs.size() : 0;
+}
- bool result = virtual_space()->initialize_with_granularity(_rs, pre_committed_size,
- Metaspace::commit_alignment());
- if (result) {
- assert(virtual_space()->committed_size() == virtual_space()->actual_committed_size(),
- "Checking that the pre-committed memory was registered by the VirtualSpace");
+// Attempts to purge the node:
+//
+// If all chunks living in this node are free, they will all be removed from
+// the freelist they currently reside in. Then, the node will be deleted.
+//
+// Returns true if the node has been deleted, false if not.
+// !! If this returns true, do not access the node from this point on. !!
+bool VirtualSpaceNode::attempt_purge(FreeChunkListVector* freelists) {
- set_top((MetaWord*)virtual_space()->low());
+ assert_lock_strong(MetaspaceExpand_lock);
+
+ if (!_owns_rs) {
+ // We do not allow purging of nodes if we do not own the
+ // underlying ReservedSpace (CompressClassSpace case).
+ return false;
}
- // Initialize Occupancy Map.
- const size_t smallest_chunk_size = is_class() ? ClassSpecializedChunk : SpecializedChunk;
- _occupancy_map = new OccupancyMap(bottom(), reserved_words(), smallest_chunk_size);
+ // First find out if all areas are empty. Since empty chunks collapse to root chunk
+ // size, if all chunks in this node are free root chunks we are good to go.
+ if (!_root_chunk_area_lut.is_free()) {
+ return false;
+ }
+
+ UL(debug, ": purging.");
+
+ // Okay, we can purge. Before we can do this, we need to remove all chunks from the freelist.
+ for (int narea = 0; narea < _root_chunk_area_lut.number_of_areas(); narea ++) {
+ RootChunkArea* ra = _root_chunk_area_lut.get_area_by_index(narea);
+ Metachunk* c = ra->first_chunk();
+ if (c != NULL) {
+ UL2(trace, "removing chunk from to-be-purged node: "
+ METACHUNK_FULL_FORMAT ".", METACHUNK_FULL_FORMAT_ARGS(c));
+ assert(c->is_free() && c->is_root_chunk(), "Sanity");
+ freelists->remove(c);
+ }
+ }
+
+ // Now, delete the node, then right away return since this object is invalid.
+ delete this;
+
+ return true;
- return result;
}
-void VirtualSpaceNode::print_on(outputStream* st, size_t scale) const {
- size_t used_words = used_words_in_vs();
- size_t commit_words = committed_words();
- size_t res_words = reserved_words();
- VirtualSpace* vs = virtual_space();
- st->print("node @" PTR_FORMAT ": ", p2i(this));
+void VirtualSpaceNode::print_on(outputStream* st) const {
+
+ size_t scale = K;
+
+ st->print("base " PTR_FORMAT ": ", p2i(base()));
st->print("reserved=");
- print_scaled_words(st, res_words, scale);
+ print_scaled_words(st, word_size(), scale);
st->print(", committed=");
- print_scaled_words_and_percentage(st, commit_words, res_words, scale);
+ print_scaled_words_and_percentage(st, committed_words(), word_size(), scale);
st->print(", used=");
- print_scaled_words_and_percentage(st, used_words, res_words, scale);
+ print_scaled_words_and_percentage(st, used_words(), word_size(), scale);
+
st->cr();
- st->print(" [" PTR_FORMAT ", " PTR_FORMAT ", "
- PTR_FORMAT ", " PTR_FORMAT ")",
- p2i(bottom()), p2i(top()), p2i(end()),
- p2i(vs->high_boundary()));
+ _root_chunk_area_lut.print_on(st);
+ _commit_mask.print_on(st);
+
}
-#ifdef ASSERT
-void VirtualSpaceNode::mangle() {
- size_t word_size = capacity_words_in_vs();
- Copy::fill_to_words((HeapWord*) low(), word_size, 0xf1f1f1f1);
+// Returns size, in words, of committed space in this node alone.
+// Note: iterates over commit mask and hence may be a tad expensive on large nodes.
+size_t VirtualSpaceNode::committed_words() const {
+ return _commit_mask.get_committed_size();
}
-#endif // ASSERT
-void VirtualSpaceNode::retire(ChunkManager* chunk_manager) {
- assert(is_class() == chunk_manager->is_class(), "Wrong ChunkManager?");
#ifdef ASSERT
- verify(false);
- EVERY_NTH(VerifyMetaspaceInterval)
- verify(true);
- END_EVERY_NTH
-#endif
- for (int i = (int)MediumIndex; i >= (int)ZeroIndex; --i) {
- ChunkIndex index = (ChunkIndex)i;
- size_t chunk_size = chunk_manager->size_by_index(index);
-
- while (free_words_in_vs() >= chunk_size) {
- Metachunk* chunk = get_chunk_vs(chunk_size);
- // Chunk will be allocated aligned, so allocation may require
- // additional padding chunks. That may cause above allocation to
- // fail. Just ignore the failed allocation and continue with the
- // next smaller chunk size. As the VirtualSpaceNode comitted
- // size should be a multiple of the smallest chunk size, we
- // should always be able to fill the VirtualSpace completely.
- if (chunk == NULL) {
- break;
- }
- chunk_manager->return_single_chunk(chunk);
- }
- }
- assert(free_words_in_vs() == 0, "should be empty now");
+void VirtualSpaceNode::verify(bool slow) const {
+ MutexLocker fcl(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);
+ verify_locked(slow);
}
+// Verify counters and basic structure. Slow mode: verify all chunks in depth
+void VirtualSpaceNode::verify_locked(bool slow) const {
+
+ assert_lock_strong(MetaspaceExpand_lock);
+
+ assert(base() != NULL, "Invalid base");
+ assert(base() == (MetaWord*)_rs.base() &&
+ word_size() == _rs.size() / BytesPerWord,
+ "Sanity");
+ assert_is_aligned(base(), chunklevel::MAX_CHUNK_BYTE_SIZE);
+ assert(used_words() <= word_size(), "Sanity");
+
+ // Since we only ever hand out root chunks from a vsnode, top should always be aligned
+ // to root chunk size.
+ assert_is_aligned(used_words(), chunklevel::MAX_CHUNK_WORD_SIZE);
+
+ _commit_mask.verify(slow);
+ assert(committed_words() <= word_size(), "Sanity");
+ assert_is_aligned(committed_words(), Settings::commit_granule_words());
+ _root_chunk_area_lut.verify(slow);
+
+}
+
+#endif
+
+
} // namespace metaspace
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