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6896603: CMS/GCH: collection_attempt_is_safe() ergo should use more recent data

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Deprecated HandlePromotionFailure, removing the ability to turn off that feature, did away with one epoch look-ahead when deciding if a scavenge is likely to fail, relying on current data.

Reviewed-by: jmasa, johnc, poonam
This commit is contained in:
Y. Srinivas Ramakrishna 2010-10-23 23:03:49 -07:00
parent 554e77efb4
commit cbc7f8756a
14 changed files with 101 additions and 222 deletions
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84
hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp
View File

@ -354,12 +354,8 @@ void CMSStats::adjust_cms_free_adjustment_factor(bool fail, size_t free) {
double CMSStats::time_until_cms_gen_full() const { double CMSStats::time_until_cms_gen_full() const {
size_t cms_free = _cms_gen->cmsSpace()->free(); size_t cms_free = _cms_gen->cmsSpace()->free();
GenCollectedHeap* gch = GenCollectedHeap::heap(); GenCollectedHeap* gch = GenCollectedHeap::heap();
size_t expected_promotion = gch->get_gen(0)->capacity(); size_t expected_promotion = MIN2(gch->get_gen(0)->capacity(),
if (HandlePromotionFailure) { (size_t) _cms_gen->gc_stats()->avg_promoted()->padded_average());
expected_promotion = MIN2(
(size_t) _cms_gen->gc_stats()->avg_promoted()->padded_average(),
expected_promotion);
}
if (cms_free > expected_promotion) { if (cms_free > expected_promotion) {
// Start a cms collection if there isn't enough space to promote // Start a cms collection if there isn't enough space to promote
// for the next minor collection. Use the padded average as // for the next minor collection. Use the padded average as
@ -865,57 +861,18 @@ size_t ConcurrentMarkSweepGeneration::max_available() const {
return free() + _virtual_space.uncommitted_size(); return free() + _virtual_space.uncommitted_size();
} }
bool ConcurrentMarkSweepGeneration::promotion_attempt_is_safe( bool ConcurrentMarkSweepGeneration::promotion_attempt_is_safe(size_t max_promotion_in_bytes) const {
size_t max_promotion_in_bytes, size_t available = max_available();
bool younger_handles_promotion_failure) const { size_t av_promo = (size_t)gc_stats()->avg_promoted()->padded_average();
bool res = (available >= av_promo) || (available >= max_promotion_in_bytes);
// This is the most conservative test. Full promotion is if (PrintGC && Verbose) {
// guaranteed if this is used. The multiplicative factor is to gclog_or_tty->print_cr(
// account for the worst case "dilatation". "CMS: promo attempt is%s safe: available("SIZE_FORMAT") %s av_promo("SIZE_FORMAT"),"
double adjusted_max_promo_bytes = _dilatation_factor * max_promotion_in_bytes; "max_promo("SIZE_FORMAT")",
if (adjusted_max_promo_bytes > (double)max_uintx) { // larger than size_t res? "":" not", available, res? ">=":"<",
adjusted_max_promo_bytes = (double)max_uintx; av_promo, max_promotion_in_bytes);
} }
bool result = (max_contiguous_available() >= (size_t)adjusted_max_promo_bytes); return res;
if (younger_handles_promotion_failure && !result) {
// Full promotion is not guaranteed because fragmentation
// of the cms generation can prevent the full promotion.
result = (max_available() >= (size_t)adjusted_max_promo_bytes);
if (!result) {
// With promotion failure handling the test for the ability
// to support the promotion does not have to be guaranteed.
// Use an average of the amount promoted.
result = max_available() >= (size_t)
gc_stats()->avg_promoted()->padded_average();
if (PrintGC && Verbose && result) {
gclog_or_tty->print_cr(
"\nConcurrentMarkSweepGeneration::promotion_attempt_is_safe"
" max_available: " SIZE_FORMAT
" avg_promoted: " SIZE_FORMAT,
max_available(), (size_t)
gc_stats()->avg_promoted()->padded_average());
}
} else {
if (PrintGC && Verbose) {
gclog_or_tty->print_cr(
"\nConcurrentMarkSweepGeneration::promotion_attempt_is_safe"
" max_available: " SIZE_FORMAT
" adj_max_promo_bytes: " SIZE_FORMAT,
max_available(), (size_t)adjusted_max_promo_bytes);
}
}
} else {
if (PrintGC && Verbose) {
gclog_or_tty->print_cr(
"\nConcurrentMarkSweepGeneration::promotion_attempt_is_safe"
" contiguous_available: " SIZE_FORMAT
" adj_max_promo_bytes: " SIZE_FORMAT,
max_contiguous_available(), (size_t)adjusted_max_promo_bytes);
}
}
return result;
} }
// At a promotion failure dump information on block layout in heap // At a promotion failure dump information on block layout in heap
@ -6091,23 +6048,14 @@ void CMSCollector::sweep(bool asynch) {
assert(_collectorState == Resizing, "Change of collector state to" assert(_collectorState == Resizing, "Change of collector state to"
" Resizing must be done under the freelistLocks (plural)"); " Resizing must be done under the freelistLocks (plural)");
// Now that sweeping has been completed, if the GCH's // Now that sweeping has been completed, we clear
// incremental_collection_will_fail flag is set, clear it, // the incremental_collection_failed flag,
// thus inviting a younger gen collection to promote into // thus inviting a younger gen collection to promote into
// this generation. If such a promotion may still fail, // this generation. If such a promotion may still fail,
// the flag will be set again when a young collection is // the flag will be set again when a young collection is
// attempted. // attempted.
// I think the incremental_collection_will_fail flag's use
// is specific to a 2 generation collection policy, so i'll
// assert that that's the configuration we are operating within.
// The use of the flag can and should be generalized appropriately
// in the future to deal with a general n-generation system.
GenCollectedHeap* gch = GenCollectedHeap::heap(); GenCollectedHeap* gch = GenCollectedHeap::heap();
assert(gch->collector_policy()->is_two_generation_policy(), gch->clear_incremental_collection_failed(); // Worth retrying as fresh space may have been freed up
"Resetting of incremental_collection_will_fail flag"
" may be incorrect otherwise");
gch->clear_incremental_collection_will_fail();
gch->update_full_collections_completed(_collection_count_start); gch->update_full_collections_completed(_collection_count_start);
} }

3
hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.hpp
View File

@ -1185,8 +1185,7 @@ class ConcurrentMarkSweepGeneration: public CardGeneration {
virtual void par_promote_alloc_done(int thread_num); virtual void par_promote_alloc_done(int thread_num);
virtual void par_oop_since_save_marks_iterate_done(int thread_num); virtual void par_oop_since_save_marks_iterate_done(int thread_num);
virtual bool promotion_attempt_is_safe(size_t promotion_in_bytes, virtual bool promotion_attempt_is_safe(size_t promotion_in_bytes) const;
bool younger_handles_promotion_failure) const;
// Inform this (non-young) generation that a promotion failure was // Inform this (non-young) generation that a promotion failure was
// encountered during a collection of a younger generation that // encountered during a collection of a younger generation that

17
hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.cpp
View File

@ -846,7 +846,7 @@ void ParNewGeneration::collect(bool full,
// from this generation, pass on collection; let the next generation // from this generation, pass on collection; let the next generation
// do it. // do it.
if (!collection_attempt_is_safe()) { if (!collection_attempt_is_safe()) {
gch->set_incremental_collection_will_fail(); gch->set_incremental_collection_failed(); // slight lie, in that we did not even attempt one
return; return;
} }
assert(to()->is_empty(), "Else not collection_attempt_is_safe"); assert(to()->is_empty(), "Else not collection_attempt_is_safe");
@ -935,8 +935,6 @@ void ParNewGeneration::collect(bool full,
assert(to()->is_empty(), "to space should be empty now"); assert(to()->is_empty(), "to space should be empty now");
} else { } else {
assert(HandlePromotionFailure,
"Should only be here if promotion failure handling is on");
assert(_promo_failure_scan_stack.is_empty(), "post condition"); assert(_promo_failure_scan_stack.is_empty(), "post condition");
_promo_failure_scan_stack.clear(true); // Clear cached segments. _promo_failure_scan_stack.clear(true); // Clear cached segments.
@ -947,7 +945,7 @@ void ParNewGeneration::collect(bool full,
// All the spaces are in play for mark-sweep. // All the spaces are in play for mark-sweep.
swap_spaces(); // Make life simpler for CMS || rescan; see 6483690. swap_spaces(); // Make life simpler for CMS || rescan; see 6483690.
from()->set_next_compaction_space(to()); from()->set_next_compaction_space(to());
gch->set_incremental_collection_will_fail(); gch->set_incremental_collection_failed();
// Inform the next generation that a promotion failure occurred. // Inform the next generation that a promotion failure occurred.
_next_gen->promotion_failure_occurred(); _next_gen->promotion_failure_occurred();
@ -1092,11 +1090,6 @@ oop ParNewGeneration::copy_to_survivor_space_avoiding_promotion_undo(
old, m, sz); old, m, sz);
if (new_obj == NULL) { if (new_obj == NULL) {
if (!HandlePromotionFailure) {
// A failed promotion likely means the MaxLiveObjectEvacuationRatio flag
// is incorrectly set. In any case, its seriously wrong to be here!
vm_exit_out_of_memory(sz*wordSize, "promotion");
}
// promotion failed, forward to self // promotion failed, forward to self
_promotion_failed = true; _promotion_failed = true;
new_obj = old; new_obj = old;
@ -1206,12 +1199,6 @@ oop ParNewGeneration::copy_to_survivor_space_with_undo(
old, m, sz); old, m, sz);
if (new_obj == NULL) { if (new_obj == NULL) {
if (!HandlePromotionFailure) {
// A failed promotion likely means the MaxLiveObjectEvacuationRatio
// flag is incorrectly set. In any case, its seriously wrong to be
// here!
vm_exit_out_of_memory(sz*wordSize, "promotion");
}
// promotion failed, forward to self // promotion failed, forward to self
forward_ptr = old->forward_to_atomic(old); forward_ptr = old->forward_to_atomic(old);
new_obj = old; new_obj = old;

8
hotspot/src/share/vm/memory/collectorPolicy.cpp
View File

@ -659,9 +659,6 @@ HeapWord* GenCollectorPolicy::satisfy_failed_allocation(size_t size,
} }
return result; // could be null if we are out of space return result; // could be null if we are out of space
} else if (!gch->incremental_collection_will_fail()) { } else if (!gch->incremental_collection_will_fail()) {
// The gc_prologues have not executed yet. The value
// for incremental_collection_will_fail() is the remanent
// of the last collection.
// Do an incremental collection. // Do an incremental collection.
gch->do_collection(false /* full */, gch->do_collection(false /* full */,
false /* clear_all_soft_refs */, false /* clear_all_soft_refs */,
@ -739,9 +736,8 @@ bool GenCollectorPolicy::should_try_older_generation_allocation(
GenCollectedHeap* gch = GenCollectedHeap::heap(); GenCollectedHeap* gch = GenCollectedHeap::heap();
size_t gen0_capacity = gch->get_gen(0)->capacity_before_gc(); size_t gen0_capacity = gch->get_gen(0)->capacity_before_gc();
return (word_size > heap_word_size(gen0_capacity)) return (word_size > heap_word_size(gen0_capacity))
|| (GC_locker::is_active_and_needs_gc()) || GC_locker::is_active_and_needs_gc()
|| ( gch->last_incremental_collection_failed() || gch->incremental_collection_failed();
&& gch->incremental_collection_will_fail());
} }

56
hotspot/src/share/vm/memory/defNewGeneration.cpp
View File

@ -510,7 +510,7 @@ void DefNewGeneration::collect(bool full,
// from this generation, pass on collection; let the next generation // from this generation, pass on collection; let the next generation
// do it. // do it.
if (!collection_attempt_is_safe()) { if (!collection_attempt_is_safe()) {
gch->set_incremental_collection_will_fail(); gch->set_incremental_collection_failed(); // Slight lie: we did not even attempt one
return; return;
} }
assert(to()->is_empty(), "Else not collection_attempt_is_safe"); assert(to()->is_empty(), "Else not collection_attempt_is_safe");
@ -596,9 +596,8 @@ void DefNewGeneration::collect(bool full,
if (PrintGC && !PrintGCDetails) { if (PrintGC && !PrintGCDetails) {
gch->print_heap_change(gch_prev_used); gch->print_heap_change(gch_prev_used);
} }
assert(!gch->incremental_collection_failed(), "Should be clear");
} else { } else {
assert(HandlePromotionFailure,
"Should not be here unless promotion failure handling is on");
assert(_promo_failure_scan_stack.is_empty(), "post condition"); assert(_promo_failure_scan_stack.is_empty(), "post condition");
_promo_failure_scan_stack.clear(true); // Clear cached segments. _promo_failure_scan_stack.clear(true); // Clear cached segments.
@ -613,7 +612,7 @@ void DefNewGeneration::collect(bool full,
// and from-space. // and from-space.
swap_spaces(); // For uniformity wrt ParNewGeneration. swap_spaces(); // For uniformity wrt ParNewGeneration.
from()->set_next_compaction_space(to()); from()->set_next_compaction_space(to());
gch->set_incremental_collection_will_fail(); gch->set_incremental_collection_failed();
// Inform the next generation that a promotion failure occurred. // Inform the next generation that a promotion failure occurred.
_next_gen->promotion_failure_occurred(); _next_gen->promotion_failure_occurred();
@ -700,12 +699,6 @@ oop DefNewGeneration::copy_to_survivor_space(oop old) {
if (obj == NULL) { if (obj == NULL) {
obj = _next_gen->promote(old, s); obj = _next_gen->promote(old, s);
if (obj == NULL) { if (obj == NULL) {
if (!HandlePromotionFailure) {
// A failed promotion likely means the MaxLiveObjectEvacuationRatio flag
// is incorrectly set. In any case, its seriously wrong to be here!
vm_exit_out_of_memory(s*wordSize, "promotion");
}
handle_promotion_failure(old); handle_promotion_failure(old);
return old; return old;
} }
@ -812,31 +805,7 @@ bool DefNewGeneration::collection_attempt_is_safe() {
assert(_next_gen != NULL, assert(_next_gen != NULL,
"This must be the youngest gen, and not the only gen"); "This must be the youngest gen, and not the only gen");
} }
return _next_gen->promotion_attempt_is_safe(used());
// Decide if there's enough room for a full promotion
// When using extremely large edens, we effectively lose a
// large amount of old space. Use the "MaxLiveObjectEvacuationRatio"
// flag to reduce the minimum evacuation space requirements. If
// there is not enough space to evacuate eden during a scavenge,
// the VM will immediately exit with an out of memory error.
// This flag has not been tested
// with collectors other than simple mark & sweep.
//
// Note that with the addition of promotion failure handling, the
// VM will not immediately exit but will undo the young generation
// collection. The parameter is left here for compatibility.
const double evacuation_ratio = MaxLiveObjectEvacuationRatio / 100.0;
// worst_case_evacuation is based on "used()". For the case where this
// method is called after a collection, this is still appropriate because
// the case that needs to be detected is one in which a full collection
// has been done and has overflowed into the young generation. In that
// case a minor collection will fail (the overflow of the full collection
// means there is no space in the old generation for any promotion).
size_t worst_case_evacuation = (size_t)(used() * evacuation_ratio);
return _next_gen->promotion_attempt_is_safe(worst_case_evacuation,
HandlePromotionFailure);
} }
void DefNewGeneration::gc_epilogue(bool full) { void DefNewGeneration::gc_epilogue(bool full) {
@ -845,14 +814,17 @@ void DefNewGeneration::gc_epilogue(bool full) {
// a minimum at the end of a collection. If it is not, then // a minimum at the end of a collection. If it is not, then
// the heap is approaching full. // the heap is approaching full.
GenCollectedHeap* gch = GenCollectedHeap::heap(); GenCollectedHeap* gch = GenCollectedHeap::heap();
clear_should_allocate_from_space(); if (full) {
if (collection_attempt_is_safe()) { assert(!GC_locker::is_active(), "We should not be executing here");
gch->clear_incremental_collection_will_fail(); if (!collection_attempt_is_safe()) {
} else { gch->set_incremental_collection_failed(); // Slight lie: a full gc left us in that state
gch->set_incremental_collection_will_fail(); set_should_allocate_from_space(); // we seem to be running out of space
if (full) { // we seem to be running out of space } else {
set_should_allocate_from_space(); gch->clear_incremental_collection_failed(); // We just did a full collection
clear_should_allocate_from_space(); // if set
} }
} else {
assert(!gch->incremental_collection_failed(), "Error");
} }
if (ZapUnusedHeapArea) { if (ZapUnusedHeapArea) {

14
hotspot/src/share/vm/memory/defNewGeneration.hpp
View File

@ -82,12 +82,6 @@ protected:
Stack<oop> _objs_with_preserved_marks; Stack<oop> _objs_with_preserved_marks;
Stack<markOop> _preserved_marks_of_objs; Stack<markOop> _preserved_marks_of_objs;
// Returns true if the collection can be safely attempted.
// If this method returns false, a collection is not
// guaranteed to fail but the system may not be able
// to recover from the failure.
bool collection_attempt_is_safe();
// Promotion failure handling // Promotion failure handling
OopClosure *_promo_failure_scan_stack_closure; OopClosure *_promo_failure_scan_stack_closure;
void set_promo_failure_scan_stack_closure(OopClosure *scan_stack_closure) { void set_promo_failure_scan_stack_closure(OopClosure *scan_stack_closure) {
@ -304,6 +298,14 @@ protected:
// GC support // GC support
virtual void compute_new_size(); virtual void compute_new_size();
// Returns true if the collection is likely to be safely
// completed. Even if this method returns true, a collection
// may not be guaranteed to succeed, and the system should be
// able to safely unwind and recover from that failure, albeit
// at some additional cost. Override superclass's implementation.
virtual bool collection_attempt_is_safe();
virtual void collect(bool full, virtual void collect(bool full,
bool clear_all_soft_refs, bool clear_all_soft_refs,
size_t size, size_t size,

14
hotspot/src/share/vm/memory/genCollectedHeap.cpp
View File

@ -142,8 +142,7 @@ jint GenCollectedHeap::initialize() {
} }
_perm_gen = perm_gen_spec->init(heap_rs, PermSize, rem_set()); _perm_gen = perm_gen_spec->init(heap_rs, PermSize, rem_set());
clear_incremental_collection_will_fail(); clear_incremental_collection_failed();
clear_last_incremental_collection_failed();
#ifndef SERIALGC #ifndef SERIALGC
// If we are running CMS, create the collector responsible // If we are running CMS, create the collector responsible
@ -1347,17 +1346,6 @@ class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
}; };
void GenCollectedHeap::gc_epilogue(bool full) { void GenCollectedHeap::gc_epilogue(bool full) {
// Remember if a partial collection of the heap failed, and
// we did a complete collection.
if (full && incremental_collection_will_fail()) {
set_last_incremental_collection_failed();
} else {
clear_last_incremental_collection_failed();
}
// Clear the flag, if set; the generation gc_epilogues will set the
// flag again if the condition persists despite the collection.
clear_incremental_collection_will_fail();
#ifdef COMPILER2 #ifdef COMPILER2
assert(DerivedPointerTable::is_empty(), "derived pointer present"); assert(DerivedPointerTable::is_empty(), "derived pointer present");
size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr())); size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));

39
hotspot/src/share/vm/memory/genCollectedHeap.hpp
View File

@ -62,11 +62,10 @@ public:
// The generational collector policy. // The generational collector policy.
GenCollectorPolicy* _gen_policy; GenCollectorPolicy* _gen_policy;
// If a generation would bail out of an incremental collection, // Indicates that the most recent previous incremental collection failed.
// it sets this flag. If the flag is set, satisfy_failed_allocation // The flag is cleared when an action is taken that might clear the
// will attempt allocating in all generations before doing a full GC. // condition that caused that incremental collection to fail.
bool _incremental_collection_will_fail; bool _incremental_collection_failed;
bool _last_incremental_collection_failed;
// In support of ExplicitGCInvokesConcurrent functionality // In support of ExplicitGCInvokesConcurrent functionality
unsigned int _full_collections_completed; unsigned int _full_collections_completed;
@ -469,26 +468,26 @@ public:
// call to "save_marks". // call to "save_marks".
bool no_allocs_since_save_marks(int level); bool no_allocs_since_save_marks(int level);
// If a generation bails out of an incremental collection, // Returns true if an incremental collection is likely to fail.
// it sets this flag.
bool incremental_collection_will_fail() { bool incremental_collection_will_fail() {
return _incremental_collection_will_fail; // Assumes a 2-generation system; the first disjunct remembers if an
} // incremental collection failed, even when we thought (second disjunct)
void set_incremental_collection_will_fail() { // that it would not.
_incremental_collection_will_fail = true; assert(heap()->collector_policy()->is_two_generation_policy(),
} "the following definition may not be suitable for an n(>2)-generation system");
void clear_incremental_collection_will_fail() { return incremental_collection_failed() || !get_gen(0)->collection_attempt_is_safe();
_incremental_collection_will_fail = false;
} }
bool last_incremental_collection_failed() const { // If a generation bails out of an incremental collection,
return _last_incremental_collection_failed; // it sets this flag.
bool incremental_collection_failed() const {
return _incremental_collection_failed;
} }
void set_last_incremental_collection_failed() { void set_incremental_collection_failed() {
_last_incremental_collection_failed = true; _incremental_collection_failed = true;
} }
void clear_last_incremental_collection_failed() { void clear_incremental_collection_failed() {
_last_incremental_collection_failed = false; _incremental_collection_failed = false;
} }
// Promotion of obj into gen failed. Try to promote obj to higher non-perm // Promotion of obj into gen failed. Try to promote obj to higher non-perm

15
hotspot/src/share/vm/memory/generation.cpp
View File

@ -165,15 +165,16 @@ size_t Generation::max_contiguous_available() const {
return max; return max;
} }
bool Generation::promotion_attempt_is_safe(size_t promotion_in_bytes, bool Generation::promotion_attempt_is_safe(size_t max_promotion_in_bytes) const {
bool not_used) const { size_t available = max_contiguous_available();
bool res = (available >= max_promotion_in_bytes);
if (PrintGC && Verbose) { if (PrintGC && Verbose) {
gclog_or_tty->print_cr("Generation::promotion_attempt_is_safe" gclog_or_tty->print_cr(
" contiguous_available: " SIZE_FORMAT "Generation: promo attempt is%s safe: available("SIZE_FORMAT") %s max_promo("SIZE_FORMAT")",
" promotion_in_bytes: " SIZE_FORMAT, res? "":" not", available, res? ">=":"<",
max_contiguous_available(), promotion_in_bytes); max_promotion_in_bytes);
} }
return max_contiguous_available() >= promotion_in_bytes; return res;
} }
// Ignores "ref" and calls allocate(). // Ignores "ref" and calls allocate().

22
hotspot/src/share/vm/memory/generation.hpp
View File

@ -173,15 +173,11 @@ class Generation: public CHeapObj {
// The largest number of contiguous free bytes in this or any higher generation. // The largest number of contiguous free bytes in this or any higher generation.
virtual size_t max_contiguous_available() const; virtual size_t max_contiguous_available() const;
// Returns true if promotions of the specified amount can // Returns true if promotions of the specified amount are
// be attempted safely (without a vm failure). // likely to succeed without a promotion failure.
// Promotion of the full amount is not guaranteed but // Promotion of the full amount is not guaranteed but
// can be attempted. // might be attempted in the worst case.
// younger_handles_promotion_failure virtual bool promotion_attempt_is_safe(size_t max_promotion_in_bytes) const;
// is true if the younger generation handles a promotion
// failure.
virtual bool promotion_attempt_is_safe(size_t promotion_in_bytes,
bool younger_handles_promotion_failure) const;
// For a non-young generation, this interface can be used to inform a // For a non-young generation, this interface can be used to inform a
// generation that a promotion attempt into that generation failed. // generation that a promotion attempt into that generation failed.
@ -358,6 +354,16 @@ class Generation: public CHeapObj {
return (full || should_allocate(word_size, is_tlab)); return (full || should_allocate(word_size, is_tlab));
} }
// Returns true if the collection is likely to be safely
// completed. Even if this method returns true, a collection
// may not be guaranteed to succeed, and the system should be
// able to safely unwind and recover from that failure, albeit
// at some additional cost.
virtual bool collection_attempt_is_safe() {
guarantee(false, "Are you sure you want to call this method?");
return true;
}
// Perform a garbage collection. // Perform a garbage collection.
// If full is true attempt a full garbage collection of this generation. // If full is true attempt a full garbage collection of this generation.
// Otherwise, attempting to (at least) free enough space to support an // Otherwise, attempting to (at least) free enough space to support an

35
hotspot/src/share/vm/memory/tenuredGeneration.cpp
View File

@ -419,29 +419,16 @@ void TenuredGeneration::retire_alloc_buffers_before_full_gc() {}
void TenuredGeneration::verify_alloc_buffers_clean() {} void TenuredGeneration::verify_alloc_buffers_clean() {}
#endif // SERIALGC #endif // SERIALGC
bool TenuredGeneration::promotion_attempt_is_safe( bool TenuredGeneration::promotion_attempt_is_safe(size_t max_promotion_in_bytes) const {
size_t max_promotion_in_bytes, size_t available = max_contiguous_available();
bool younger_handles_promotion_failure) const { size_t av_promo = (size_t)gc_stats()->avg_promoted()->padded_average();
bool res = (available >= av_promo) || (available >= max_promotion_in_bytes);
bool result = max_contiguous_available() >= max_promotion_in_bytes; if (PrintGC && Verbose) {
gclog_or_tty->print_cr(
if (younger_handles_promotion_failure && !result) { "Tenured: promo attempt is%s safe: available("SIZE_FORMAT") %s av_promo("SIZE_FORMAT"),"
result = max_contiguous_available() >= "max_promo("SIZE_FORMAT")",
(size_t) gc_stats()->avg_promoted()->padded_average(); res? "":" not", available, res? ">=":"<",
if (PrintGC && Verbose && result) { av_promo, max_promotion_in_bytes);
gclog_or_tty->print_cr("TenuredGeneration::promotion_attempt_is_safe"
" contiguous_available: " SIZE_FORMAT
" avg_promoted: " SIZE_FORMAT,
max_contiguous_available(),
gc_stats()->avg_promoted()->padded_average());
}
} else {
if (PrintGC && Verbose) {
gclog_or_tty->print_cr("TenuredGeneration::promotion_attempt_is_safe"
" contiguous_available: " SIZE_FORMAT
" promotion_in_bytes: " SIZE_FORMAT,
max_contiguous_available(), max_promotion_in_bytes);
}
} }
return result; return res;
} }

3
hotspot/src/share/vm/memory/tenuredGeneration.hpp
View File

@ -101,8 +101,7 @@ class TenuredGeneration: public OneContigSpaceCardGeneration {
virtual void update_gc_stats(int level, bool full); virtual void update_gc_stats(int level, bool full);
virtual bool promotion_attempt_is_safe(size_t max_promoted_in_bytes, virtual bool promotion_attempt_is_safe(size_t max_promoted_in_bytes) const;
bool younger_handles_promotion_failure) const;
void verify_alloc_buffers_clean(); void verify_alloc_buffers_clean();
}; };

6
hotspot/src/share/vm/runtime/arguments.cpp
View File

@ -185,6 +185,10 @@ static ObsoleteFlag obsolete_jvm_flags[] = {
JDK_Version::jdk_update(6,18), JDK_Version::jdk(7) }, JDK_Version::jdk_update(6,18), JDK_Version::jdk(7) },
{ "UseDepthFirstScavengeOrder", { "UseDepthFirstScavengeOrder",
JDK_Version::jdk_update(6,22), JDK_Version::jdk(7) }, JDK_Version::jdk_update(6,22), JDK_Version::jdk(7) },
{ "HandlePromotionFailure",
JDK_Version::jdk_update(6,24), JDK_Version::jdk(8) },
{ "MaxLiveObjectEvacuationRatio",
JDK_Version::jdk_update(6,24), JDK_Version::jdk(8) },
{ NULL, JDK_Version(0), JDK_Version(0) } { NULL, JDK_Version(0), JDK_Version(0) }
}; };
@ -1722,8 +1726,6 @@ bool Arguments::check_vm_args_consistency() {
status = false; status = false;
} }
status = status && verify_percentage(MaxLiveObjectEvacuationRatio,
"MaxLiveObjectEvacuationRatio");
status = status && verify_percentage(AdaptiveSizePolicyWeight, status = status && verify_percentage(AdaptiveSizePolicyWeight,
"AdaptiveSizePolicyWeight"); "AdaptiveSizePolicyWeight");
status = status && verify_percentage(AdaptivePermSizeWeight, "AdaptivePermSizeWeight"); status = status && verify_percentage(AdaptivePermSizeWeight, "AdaptivePermSizeWeight");

7
hotspot/src/share/vm/runtime/globals.hpp
View File

@ -1786,10 +1786,6 @@ class CommandLineFlags {
notproduct(bool, GCALotAtAllSafepoints, false, \ notproduct(bool, GCALotAtAllSafepoints, false, \
"Enforce ScavengeALot/GCALot at all potential safepoints") \ "Enforce ScavengeALot/GCALot at all potential safepoints") \
\ \
product(bool, HandlePromotionFailure, true, \
"The youngest generation collection does not require " \
"a guarantee of full promotion of all live objects.") \
\
product(bool, PrintPromotionFailure, false, \ product(bool, PrintPromotionFailure, false, \
"Print additional diagnostic information following " \ "Print additional diagnostic information following " \
" promotion failure") \ " promotion failure") \
@ -3003,9 +2999,6 @@ class CommandLineFlags {
product(intx, NewRatio, 2, \ product(intx, NewRatio, 2, \
"Ratio of new/old generation sizes") \ "Ratio of new/old generation sizes") \
\ \
product(uintx, MaxLiveObjectEvacuationRatio, 100, \
"Max percent of eden objects that will be live at scavenge") \
\
product_pd(uintx, NewSizeThreadIncrease, \ product_pd(uintx, NewSizeThreadIncrease, \
"Additional size added to desired new generation size per " \ "Additional size added to desired new generation size per " \
"non-daemon thread (in bytes)") \ "non-daemon thread (in bytes)") \