--- a/src/hotspot/share/gc/g1/g1AllocRegion.cpp Wed May 02 02:36:17 2018 -0700
+++ b/src/hotspot/share/gc/g1/g1AllocRegion.cpp Wed May 02 13:44:46 2018 +0200
@@ -95,33 +95,40 @@
return result;
}
+size_t G1AllocRegion::retire_internal(HeapRegion* alloc_region, bool fill_up) {
+ // We never have to check whether the active region is empty or not,
+ // and potentially free it if it is, given that it's guaranteed that
+ // it will never be empty.
+ size_t waste = 0;
+ assert_alloc_region(!alloc_region->is_empty(),
+ "the alloc region should never be empty");
+
+ if (fill_up) {
+ waste = fill_up_remaining_space(alloc_region);
+ }
+
+ assert_alloc_region(alloc_region->used() >= _used_bytes_before, "invariant");
+ size_t allocated_bytes = alloc_region->used() - _used_bytes_before;
+ retire_region(alloc_region, allocated_bytes);
+ _used_bytes_before = 0;
+
+ return waste;
+}
+
size_t G1AllocRegion::retire(bool fill_up) {
assert_alloc_region(_alloc_region != NULL, "not initialized properly");
- size_t result = 0;
+ size_t waste = 0;
trace("retiring");
HeapRegion* alloc_region = _alloc_region;
if (alloc_region != _dummy_region) {
- // We never have to check whether the active region is empty or not,
- // and potentially free it if it is, given that it's guaranteed that
- // it will never be empty.
- assert_alloc_region(!alloc_region->is_empty(),
- "the alloc region should never be empty");
-
- if (fill_up) {
- result = fill_up_remaining_space(alloc_region);
- }
-
- assert_alloc_region(alloc_region->used() >= _used_bytes_before, "invariant");
- size_t allocated_bytes = alloc_region->used() - _used_bytes_before;
- retire_region(alloc_region, allocated_bytes);
- _used_bytes_before = 0;
- _alloc_region = _dummy_region;
+ waste = retire_internal(alloc_region, fill_up);
+ reset_alloc_region();
}
trace("retired");
- return result;
+ return waste;
}
HeapWord* G1AllocRegion::new_alloc_region_and_allocate(size_t word_size,
@@ -245,7 +252,8 @@
G1AllocRegion::G1AllocRegion(const char* name,
bool bot_updates)
: _name(name), _bot_updates(bot_updates),
- _alloc_region(NULL), _count(0), _used_bytes_before(0) { }
+ _alloc_region(NULL), _count(0),
+ _used_bytes_before(0) { }
HeapRegion* MutatorAllocRegion::allocate_new_region(size_t word_size,
@@ -258,6 +266,82 @@
_g1h->retire_mutator_alloc_region(alloc_region, allocated_bytes);
}
+void MutatorAllocRegion::init() {
+ assert(_retained_alloc_region == NULL, "Pre-condition");
+ G1AllocRegion::init();
+ _wasted_bytes = 0;
+}
+
+bool MutatorAllocRegion::should_retain(HeapRegion* region) {
+ size_t free_bytes = region->free();
+ if (free_bytes < MinTLABSize) {
+ return false;
+ }
+
+ if (_retained_alloc_region != NULL &&
+ free_bytes < _retained_alloc_region->free()) {
+ return false;
+ }
+
+ return true;
+}
+
+size_t MutatorAllocRegion::retire(bool fill_up) {
+ size_t waste = 0;
+ trace("retiring");
+ HeapRegion* current_region = get();
+ if (current_region != NULL) {
+ // Retain the current region if it fits a TLAB and has more
+ // free than the currently retained region.
+ if (should_retain(current_region)) {
+ trace("mutator retained");
+ if (_retained_alloc_region != NULL) {
+ waste = retire_internal(_retained_alloc_region, true);
+ }
+ _retained_alloc_region = current_region;
+ } else {
+ waste = retire_internal(current_region, fill_up);
+ }
+ reset_alloc_region();
+ }
+
+ _wasted_bytes += waste;
+ trace("retired");
+ return waste;
+}
+
+size_t MutatorAllocRegion::used_in_alloc_regions() {
+ size_t used = 0;
+ HeapRegion* hr = get();
+ if (hr != NULL) {
+ used += hr->used();
+ }
+
+ hr = _retained_alloc_region;
+ if (hr != NULL) {
+ used += hr->used();
+ }
+ return used;
+}
+
+HeapRegion* MutatorAllocRegion::release() {
+ HeapRegion* ret = G1AllocRegion::release();
+
+ // The retained alloc region must be retired and this must be
+ // done after the above call to release the mutator alloc region,
+ // since it might update the _retained_alloc_region member.
+ if (_retained_alloc_region != NULL) {
+ _wasted_bytes += retire_internal(_retained_alloc_region, false);
+ _retained_alloc_region = NULL;
+ }
+ log_debug(gc, alloc, region)("Mutator Allocation stats, regions: %u, wasted size: " SIZE_FORMAT "%s (%4.1f%%)",
+ count(),
+ byte_size_in_proper_unit(_wasted_bytes),
+ proper_unit_for_byte_size(_wasted_bytes),
+ percent_of(_wasted_bytes, count() * HeapRegion::GrainBytes));
+ return ret;
+}
+
HeapRegion* G1GCAllocRegion::allocate_new_region(size_t word_size,
bool force) {
assert(!force, "not supported for GC alloc regions");
--- a/src/hotspot/share/gc/g1/g1AllocRegion.hpp Wed May 02 02:36:17 2018 -0700
+++ b/src/hotspot/share/gc/g1/g1AllocRegion.hpp Wed May 02 13:44:46 2018 +0200
@@ -80,6 +80,20 @@
// whether the _alloc_region is NULL or not.
static HeapRegion* _dummy_region;
+ // After a region is allocated by alloc_new_region, this
+ // method is used to set it as the active alloc_region
+ void update_alloc_region(HeapRegion* alloc_region);
+
+ // Allocate a new active region and use it to perform a word_size
+ // allocation. The force parameter will be passed on to
+ // G1CollectedHeap::allocate_new_alloc_region() and tells it to try
+ // to allocate a new region even if the max has been reached.
+ HeapWord* new_alloc_region_and_allocate(size_t word_size, bool force);
+
+protected:
+ // Reset the alloc region to point a the dummy region.
+ void reset_alloc_region();
+
// Perform a non-MT-safe allocation out of the given region.
inline HeapWord* allocate(HeapRegion* alloc_region,
size_t word_size);
@@ -102,23 +116,14 @@
// the space.
size_t fill_up_remaining_space(HeapRegion* alloc_region);
- // After a region is allocated by alloc_new_region, this
- // method is used to set it as the active alloc_region
- void update_alloc_region(HeapRegion* alloc_region);
-
- // Allocate a new active region and use it to perform a word_size
- // allocation. The force parameter will be passed on to
- // G1CollectedHeap::allocate_new_alloc_region() and tells it to try
- // to allocate a new region even if the max has been reached.
- HeapWord* new_alloc_region_and_allocate(size_t word_size, bool force);
-
-protected:
// Retire the active allocating region. If fill_up is true then make
// sure that the region is full before we retire it so that no one
// else can allocate out of it.
// Returns the number of bytes that have been filled up during retire.
virtual size_t retire(bool fill_up);
+ size_t retire_internal(HeapRegion* alloc_region, bool fill_up);
+
// For convenience as subclasses use it.
static G1CollectedHeap* _g1h;
@@ -177,7 +182,7 @@
inline HeapWord* attempt_allocation_force(size_t word_size);
// Should be called before we start using this object.
- void init();
+ virtual void init();
// This can be used to set the active region to a specific
// region. (Use Example: we try to retain the last old GC alloc
@@ -197,14 +202,49 @@
};
class MutatorAllocRegion : public G1AllocRegion {
+private:
+ // Keeps track of the total waste generated during the current
+ // mutator phase.
+ size_t _wasted_bytes;
+
+ // Retained allocation region. Used to lower the waste generated
+ // during mutation by having two active regions if the free space
+ // in a region about to be retired still could fit a TLAB.
+ HeapRegion* volatile _retained_alloc_region;
+
+ // Decide if the region should be retained, based on the free size
+ // in it and the free size in the currently retained region, if any.
+ bool should_retain(HeapRegion* region);
protected:
virtual HeapRegion* allocate_new_region(size_t word_size, bool force);
virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes);
+ virtual size_t retire(bool fill_up);
public:
MutatorAllocRegion()
- : G1AllocRegion("Mutator Alloc Region", false /* bot_updates */) { }
+ : G1AllocRegion("Mutator Alloc Region", false /* bot_updates */),
+ _wasted_bytes(0),
+ _retained_alloc_region(NULL) { }
+
+ // Returns the combined used memory in the current alloc region and
+ // the retained alloc region.
+ size_t used_in_alloc_regions();
+
+ // Perform an allocation out of the retained allocation region, with the given
+ // minimum and desired size. Returns the actual size allocated (between
+ // minimum and desired size) in actual_word_size if the allocation has been
+ // successful.
+ // Should be called without holding a lock. It will try to allocate lock-free
+ // out of the retained region, or return NULL if it was unable to.
+ inline HeapWord* attempt_retained_allocation(size_t min_word_size,
+ size_t desired_word_size,
+ size_t* actual_word_size);
+
+ // This specialization of release() makes sure that the retained alloc
+ // region is retired and set to NULL.
+ virtual HeapRegion* release();
+
+ virtual void init();
};
-
// Common base class for allocation regions used during GC.
class G1GCAllocRegion : public G1AllocRegion {
protected:
--- a/src/hotspot/share/gc/g1/g1AllocRegion.inline.hpp Wed May 02 02:36:17 2018 -0700
+++ b/src/hotspot/share/gc/g1/g1AllocRegion.inline.hpp Wed May 02 13:44:46 2018 +0200
@@ -36,6 +36,10 @@
} while (0)
+inline void G1AllocRegion::reset_alloc_region() {
+ _alloc_region = _dummy_region;
+}
+
inline HeapWord* G1AllocRegion::allocate(HeapRegion* alloc_region,
size_t word_size) {
assert(alloc_region != NULL, "pre-condition");
@@ -126,4 +130,17 @@
return NULL;
}
+inline HeapWord* MutatorAllocRegion::attempt_retained_allocation(size_t min_word_size,
+ size_t desired_word_size,
+ size_t* actual_word_size) {
+ if (_retained_alloc_region != NULL) {
+ HeapWord* result = par_allocate(_retained_alloc_region, min_word_size, desired_word_size, actual_word_size);
+ if (result != NULL) {
+ trace("alloc retained", min_word_size, desired_word_size, *actual_word_size, result);
+ return result;
+ }
+ }
+ return NULL;
+}
+
#endif // SHARE_VM_GC_G1_G1ALLOCREGION_INLINE_HPP
--- a/src/hotspot/share/gc/g1/g1Allocator.cpp Wed May 02 02:36:17 2018 -0700
+++ b/src/hotspot/share/gc/g1/g1Allocator.cpp Wed May 02 13:44:46 2018 +0200
@@ -157,14 +157,7 @@
size_t G1Allocator::used_in_alloc_regions() {
assert(Heap_lock->owner() != NULL, "Should be owned on this thread's behalf.");
- size_t result = 0;
-
- // Read only once in case it is set to NULL concurrently
- HeapRegion* hr = mutator_alloc_region()->get();
- if (hr != NULL) {
- result += hr->used();
- }
- return result;
+ return mutator_alloc_region()->used_in_alloc_regions();
}
--- a/src/hotspot/share/gc/g1/g1Allocator.hpp Wed May 02 02:36:17 2018 -0700
+++ b/src/hotspot/share/gc/g1/g1Allocator.hpp Wed May 02 13:44:46 2018 +0200
@@ -99,7 +99,9 @@
// Allocate blocks of memory during mutator time.
- inline HeapWord* attempt_allocation(size_t word_size);
+ inline HeapWord* attempt_allocation(size_t min_word_size,
+ size_t desired_word_size,
+ size_t* actual_word_size);
inline HeapWord* attempt_allocation_locked(size_t word_size);
inline HeapWord* attempt_allocation_force(size_t word_size);
--- a/src/hotspot/share/gc/g1/g1Allocator.inline.hpp Wed May 02 02:36:17 2018 -0700
+++ b/src/hotspot/share/gc/g1/g1Allocator.inline.hpp Wed May 02 13:44:46 2018 +0200
@@ -41,8 +41,14 @@
return &_old_gc_alloc_region;
}
-inline HeapWord* G1Allocator::attempt_allocation(size_t word_size) {
- return mutator_alloc_region()->attempt_allocation(word_size);
+inline HeapWord* G1Allocator::attempt_allocation(size_t min_word_size,
+ size_t desired_word_size,
+ size_t* actual_word_size) {
+ HeapWord* result = mutator_alloc_region()->attempt_retained_allocation(min_word_size, desired_word_size, actual_word_size);
+ if (result != NULL) {
+ return result;
+ }
+ return mutator_alloc_region()->attempt_allocation(min_word_size, desired_word_size, actual_word_size);
}
inline HeapWord* G1Allocator::attempt_allocation_locked(size_t word_size) {
--- a/src/hotspot/share/gc/g1/g1CollectedHeap.cpp Wed May 02 02:36:17 2018 -0700
+++ b/src/hotspot/share/gc/g1/g1CollectedHeap.cpp Wed May 02 13:44:46 2018 +0200
@@ -384,11 +384,13 @@
return result;
}
-HeapWord* G1CollectedHeap::allocate_new_tlab(size_t word_size) {
+HeapWord* G1CollectedHeap::allocate_new_tlab(size_t min_size,
+ size_t requested_size,
+ size_t* actual_size) {
assert_heap_not_locked_and_not_at_safepoint();
- assert(!is_humongous(word_size), "we do not allow humongous TLABs");
-
- return attempt_allocation(word_size);
+ assert(!is_humongous(requested_size), "we do not allow humongous TLABs");
+
+ return attempt_allocation(min_size, requested_size, actual_size);
}
HeapWord*
@@ -399,7 +401,8 @@
if (is_humongous(word_size)) {
return attempt_allocation_humongous(word_size);
}
- return attempt_allocation(word_size);
+ size_t dummy = 0;
+ return attempt_allocation(word_size, word_size, &dummy);
}
HeapWord* G1CollectedHeap::attempt_allocation_slow(size_t word_size) {
@@ -492,8 +495,8 @@
// first attempt (without holding the Heap_lock) here and the
// follow-on attempt will be at the start of the next loop
// iteration (after taking the Heap_lock).
-
- result = _allocator->attempt_allocation(word_size);
+ size_t dummy = 0;
+ result = _allocator->attempt_allocation(word_size, word_size, &dummy);
if (result != NULL) {
return result;
}
@@ -722,20 +725,28 @@
}
}
-inline HeapWord* G1CollectedHeap::attempt_allocation(size_t word_size) {
+inline HeapWord* G1CollectedHeap::attempt_allocation(size_t min_word_size,
+ size_t desired_word_size,
+ size_t* actual_word_size) {
assert_heap_not_locked_and_not_at_safepoint();
- assert(!is_humongous(word_size), "attempt_allocation() should not "
+ assert(!is_humongous(desired_word_size), "attempt_allocation() should not "
"be called for humongous allocation requests");
- HeapWord* result = _allocator->attempt_allocation(word_size);
+ HeapWord* result = _allocator->attempt_allocation(min_word_size, desired_word_size, actual_word_size);
if (result == NULL) {
- result = attempt_allocation_slow(word_size);
+ *actual_word_size = desired_word_size;
+ result = attempt_allocation_slow(desired_word_size);
}
+
assert_heap_not_locked();
if (result != NULL) {
- dirty_young_block(result, word_size);
+ assert(*actual_word_size != 0, "Actual size must have been set here");
+ dirty_young_block(result, *actual_word_size);
+ } else {
+ *actual_word_size = 0;
}
+
return result;
}
--- a/src/hotspot/share/gc/g1/g1CollectedHeap.hpp Wed May 02 02:36:17 2018 -0700
+++ b/src/hotspot/share/gc/g1/g1CollectedHeap.hpp Wed May 02 13:44:46 2018 +0200
@@ -420,7 +420,9 @@
// humongous allocation requests should go to mem_allocate() which
// will satisfy them with a special path.
- virtual HeapWord* allocate_new_tlab(size_t word_size);
+ virtual HeapWord* allocate_new_tlab(size_t min_size,
+ size_t requested_size,
+ size_t* actual_size);
virtual HeapWord* mem_allocate(size_t word_size,
bool* gc_overhead_limit_was_exceeded);
@@ -428,7 +430,9 @@
// First-level mutator allocation attempt: try to allocate out of
// the mutator alloc region without taking the Heap_lock. This
// should only be used for non-humongous allocations.
- inline HeapWord* attempt_allocation(size_t word_size);
+ inline HeapWord* attempt_allocation(size_t min_word_size,
+ size_t desired_word_size,
+ size_t* actual_word_size);
// Second-level mutator allocation attempt: take the Heap_lock and
// retry the allocation attempt, potentially scheduling a GC
--- a/src/hotspot/share/gc/parallel/parallelScavengeHeap.cpp Wed May 02 02:36:17 2018 -0700
+++ b/src/hotspot/share/gc/parallel/parallelScavengeHeap.cpp Wed May 02 13:44:46 2018 +0200
@@ -478,8 +478,13 @@
return young_gen()->eden_space()->unsafe_max_tlab_alloc(thr);
}
-HeapWord* ParallelScavengeHeap::allocate_new_tlab(size_t size) {
- return young_gen()->allocate(size);
+HeapWord* ParallelScavengeHeap::allocate_new_tlab(size_t min_size, size_t requested_size, size_t* actual_size) {
+ HeapWord* result = young_gen()->allocate(requested_size);
+ if (result != NULL) {
+ *actual_size = requested_size;
+ }
+
+ return result;
}
void ParallelScavengeHeap::accumulate_statistics_all_tlabs() {
--- a/src/hotspot/share/gc/parallel/parallelScavengeHeap.hpp Wed May 02 02:36:17 2018 -0700
+++ b/src/hotspot/share/gc/parallel/parallelScavengeHeap.hpp Wed May 02 13:44:46 2018 +0200
@@ -85,7 +85,7 @@
protected:
static inline size_t total_invocations();
- HeapWord* allocate_new_tlab(size_t size);
+ HeapWord* allocate_new_tlab(size_t min_size, size_t requested_size, size_t* actual_size);
inline bool should_alloc_in_eden(size_t size) const;
inline void death_march_check(HeapWord* const result, size_t size);
--- a/src/hotspot/share/gc/shared/collectedHeap.cpp Wed May 02 02:36:17 2018 -0700
+++ b/src/hotspot/share/gc/shared/collectedHeap.cpp Wed May 02 13:44:46 2018 +0200
@@ -384,17 +384,24 @@
return NULL;
}
- // Allocate a new TLAB...
- HeapWord* obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
+ // Allocate a new TLAB requesting new_tlab_size. Any size
+ // between minimal and new_tlab_size is accepted.
+ size_t actual_tlab_size = 0;
+ size_t min_tlab_size = ThreadLocalAllocBuffer::compute_min_size(size);
+ HeapWord* obj = Universe::heap()->allocate_new_tlab(min_tlab_size, new_tlab_size, &actual_tlab_size);
if (obj == NULL) {
+ assert(actual_tlab_size == 0, "Allocation failed, but actual size was updated. min: " SIZE_FORMAT ", desired: " SIZE_FORMAT ", actual: " SIZE_FORMAT,
+ min_tlab_size, new_tlab_size, actual_tlab_size);
return NULL;
}
+ assert(actual_tlab_size != 0, "Allocation succeeded but actual size not updated. obj at: " PTR_FORMAT " min: " SIZE_FORMAT ", desired: " SIZE_FORMAT,
+ p2i(obj), min_tlab_size, new_tlab_size);
- AllocTracer::send_allocation_in_new_tlab(klass, obj, new_tlab_size * HeapWordSize, size * HeapWordSize, thread);
+ AllocTracer::send_allocation_in_new_tlab(klass, obj, actual_tlab_size * HeapWordSize, size * HeapWordSize, thread);
if (ZeroTLAB) {
// ..and clear it.
- Copy::zero_to_words(obj, new_tlab_size);
+ Copy::zero_to_words(obj, actual_tlab_size);
} else {
// ...and zap just allocated object.
#ifdef ASSERT
@@ -402,10 +409,10 @@
// ensure that the returned space is not considered parsable by
// any concurrent GC thread.
size_t hdr_size = oopDesc::header_size();
- Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
+ Copy::fill_to_words(obj + hdr_size, actual_tlab_size - hdr_size, badHeapWordVal);
#endif // ASSERT
}
- thread->tlab().fill(obj, obj + size, new_tlab_size);
+ thread->tlab().fill(obj, obj + size, actual_tlab_size);
return obj;
}
@@ -506,7 +513,9 @@
fill_with_object_impl(start, words, zap);
}
-HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {
+HeapWord* CollectedHeap::allocate_new_tlab(size_t min_size,
+ size_t requested_size,
+ size_t* actual_size) {
guarantee(false, "thread-local allocation buffers not supported");
return NULL;
}
--- a/src/hotspot/share/gc/shared/collectedHeap.hpp Wed May 02 02:36:17 2018 -0700
+++ b/src/hotspot/share/gc/shared/collectedHeap.hpp Wed May 02 13:44:46 2018 +0200
@@ -126,7 +126,13 @@
CollectedHeap();
// Create a new tlab. All TLAB allocations must go through this.
- virtual HeapWord* allocate_new_tlab(size_t size);
+ // To allow more flexible TLAB allocations min_size specifies
+ // the minimum size needed, while requested_size is the requested
+ // size based on ergonomics. The actually allocated size will be
+ // returned in actual_size.
+ virtual HeapWord* allocate_new_tlab(size_t min_size,
+ size_t requested_size,
+ size_t* actual_size);
// Accumulate statistics on all tlabs.
virtual void accumulate_statistics_all_tlabs();
--- a/src/hotspot/share/gc/shared/genCollectedHeap.cpp Wed May 02 02:36:17 2018 -0700
+++ b/src/hotspot/share/gc/shared/genCollectedHeap.cpp Wed May 02 13:44:46 2018 +0200
@@ -1146,11 +1146,18 @@
return 0;
}
-HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
+HeapWord* GenCollectedHeap::allocate_new_tlab(size_t min_size,
+ size_t requested_size,
+ size_t* actual_size) {
bool gc_overhead_limit_was_exceeded;
- return mem_allocate_work(size /* size */,
- true /* is_tlab */,
- &gc_overhead_limit_was_exceeded);
+ HeapWord* result = mem_allocate_work(requested_size /* size */,
+ true /* is_tlab */,
+ &gc_overhead_limit_was_exceeded);
+ if (result != NULL) {
+ *actual_size = requested_size;
+ }
+
+ return result;
}
// Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
--- a/src/hotspot/share/gc/shared/genCollectedHeap.hpp Wed May 02 02:36:17 2018 -0700
+++ b/src/hotspot/share/gc/shared/genCollectedHeap.hpp Wed May 02 13:44:46 2018 +0200
@@ -297,7 +297,9 @@
virtual size_t tlab_capacity(Thread* thr) const;
virtual size_t tlab_used(Thread* thr) const;
virtual size_t unsafe_max_tlab_alloc(Thread* thr) const;
- virtual HeapWord* allocate_new_tlab(size_t size);
+ virtual HeapWord* allocate_new_tlab(size_t min_size,
+ size_t requested_size,
+ size_t* actual_size);
// The "requestor" generation is performing some garbage collection
// action for which it would be useful to have scratch space. The
--- a/src/hotspot/share/gc/shared/threadLocalAllocBuffer.hpp Wed May 02 02:36:17 2018 -0700
+++ b/src/hotspot/share/gc/shared/threadLocalAllocBuffer.hpp Wed May 02 13:44:46 2018 +0200
@@ -141,6 +141,9 @@
// Otherwise return 0;
inline size_t compute_size(size_t obj_size);
+ // Compute the minimal needed tlab size for the given object size.
+ static inline size_t compute_min_size(size_t obj_size);
+
// Record slow allocation
inline void record_slow_allocation(size_t obj_size);
--- a/src/hotspot/share/gc/shared/threadLocalAllocBuffer.inline.hpp Wed May 02 02:36:17 2018 -0700
+++ b/src/hotspot/share/gc/shared/threadLocalAllocBuffer.inline.hpp Wed May 02 13:44:46 2018 +0200
@@ -54,18 +54,15 @@
}
inline size_t ThreadLocalAllocBuffer::compute_size(size_t obj_size) {
- const size_t aligned_obj_size = align_object_size(obj_size);
-
// Compute the size for the new TLAB.
// The "last" tlab may be smaller to reduce fragmentation.
// unsafe_max_tlab_alloc is just a hint.
const size_t available_size = Universe::heap()->unsafe_max_tlab_alloc(myThread()) /
HeapWordSize;
- size_t new_tlab_size = MIN3(available_size, desired_size() + aligned_obj_size, max_size());
+ size_t new_tlab_size = MIN3(available_size, desired_size() + align_object_size(obj_size), max_size());
// Make sure there's enough room for object and filler int[].
- const size_t obj_plus_filler_size = aligned_obj_size + alignment_reserve();
- if (new_tlab_size < obj_plus_filler_size) {
+ if (new_tlab_size < compute_min_size(obj_size)) {
// If there isn't enough room for the allocation, return failure.
log_trace(gc, tlab)("ThreadLocalAllocBuffer::compute_size(" SIZE_FORMAT ") returns failure",
obj_size);
@@ -76,6 +73,11 @@
return new_tlab_size;
}
+inline size_t ThreadLocalAllocBuffer::compute_min_size(size_t obj_size) {
+ const size_t aligned_obj_size = align_object_size(obj_size);
+ const size_t size_with_reserve = aligned_obj_size + alignment_reserve();
+ return MAX2(size_with_reserve, MinTLABSize);
+}
void ThreadLocalAllocBuffer::record_slow_allocation(size_t obj_size) {
// Raise size required to bypass TLAB next time. Why? Else there's