Mercurial > hg > truffle
diff src/share/vm/memory/tenuredGeneration.cpp @ 9072:8617e38bb4cb
8008508: CMS does not correctly reduce heap size after a Full GC
Reviewed-by: johnc, ysr
author | jmasa |
---|---|
date | Mon, 11 Feb 2013 10:31:56 -0800 |
parents | db9981fd3124 |
children | de6a9e811145 |
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--- a/src/share/vm/memory/tenuredGeneration.cpp Fri Apr 05 10:20:04 2013 -0700 +++ b/src/share/vm/memory/tenuredGeneration.cpp Mon Feb 11 10:31:56 2013 -0800 @@ -39,7 +39,7 @@ size_t initial_byte_size, int level, GenRemSet* remset) : OneContigSpaceCardGeneration(rs, initial_byte_size, - MinHeapDeltaBytes, level, remset, NULL) + level, remset, NULL) { HeapWord* bottom = (HeapWord*) _virtual_space.low(); HeapWord* end = (HeapWord*) _virtual_space.high(); @@ -86,162 +86,6 @@ return "tenured generation"; } -void TenuredGeneration::compute_new_size() { - assert(_shrink_factor <= 100, "invalid shrink factor"); - size_t current_shrink_factor = _shrink_factor; - _shrink_factor = 0; - - // We don't have floating point command-line arguments - // Note: argument processing ensures that MinHeapFreeRatio < 100. - const double minimum_free_percentage = MinHeapFreeRatio / 100.0; - const double maximum_used_percentage = 1.0 - minimum_free_percentage; - - // Compute some numbers about the state of the heap. - const size_t used_after_gc = used(); - const size_t capacity_after_gc = capacity(); - - const double min_tmp = used_after_gc / maximum_used_percentage; - size_t minimum_desired_capacity = (size_t)MIN2(min_tmp, double(max_uintx)); - // Don't shrink less than the initial generation size - minimum_desired_capacity = MAX2(minimum_desired_capacity, - spec()->init_size()); - assert(used_after_gc <= minimum_desired_capacity, "sanity check"); - - if (PrintGC && Verbose) { - const size_t free_after_gc = free(); - const double free_percentage = ((double)free_after_gc) / capacity_after_gc; - gclog_or_tty->print_cr("TenuredGeneration::compute_new_size: "); - gclog_or_tty->print_cr(" " - " minimum_free_percentage: %6.2f" - " maximum_used_percentage: %6.2f", - minimum_free_percentage, - maximum_used_percentage); - gclog_or_tty->print_cr(" " - " free_after_gc : %6.1fK" - " used_after_gc : %6.1fK" - " capacity_after_gc : %6.1fK", - free_after_gc / (double) K, - used_after_gc / (double) K, - capacity_after_gc / (double) K); - gclog_or_tty->print_cr(" " - " free_percentage: %6.2f", - free_percentage); - } - - if (capacity_after_gc < minimum_desired_capacity) { - // If we have less free space than we want then expand - size_t expand_bytes = minimum_desired_capacity - capacity_after_gc; - // Don't expand unless it's significant - if (expand_bytes >= _min_heap_delta_bytes) { - expand(expand_bytes, 0); // safe if expansion fails - } - if (PrintGC && Verbose) { - gclog_or_tty->print_cr(" expanding:" - " minimum_desired_capacity: %6.1fK" - " expand_bytes: %6.1fK" - " _min_heap_delta_bytes: %6.1fK", - minimum_desired_capacity / (double) K, - expand_bytes / (double) K, - _min_heap_delta_bytes / (double) K); - } - return; - } - - // No expansion, now see if we want to shrink - size_t shrink_bytes = 0; - // We would never want to shrink more than this - size_t max_shrink_bytes = capacity_after_gc - minimum_desired_capacity; - - if (MaxHeapFreeRatio < 100) { - const double maximum_free_percentage = MaxHeapFreeRatio / 100.0; - const double minimum_used_percentage = 1.0 - maximum_free_percentage; - const double max_tmp = used_after_gc / minimum_used_percentage; - size_t maximum_desired_capacity = (size_t)MIN2(max_tmp, double(max_uintx)); - maximum_desired_capacity = MAX2(maximum_desired_capacity, - spec()->init_size()); - if (PrintGC && Verbose) { - gclog_or_tty->print_cr(" " - " maximum_free_percentage: %6.2f" - " minimum_used_percentage: %6.2f", - maximum_free_percentage, - minimum_used_percentage); - gclog_or_tty->print_cr(" " - " _capacity_at_prologue: %6.1fK" - " minimum_desired_capacity: %6.1fK" - " maximum_desired_capacity: %6.1fK", - _capacity_at_prologue / (double) K, - minimum_desired_capacity / (double) K, - maximum_desired_capacity / (double) K); - } - assert(minimum_desired_capacity <= maximum_desired_capacity, - "sanity check"); - - if (capacity_after_gc > maximum_desired_capacity) { - // Capacity too large, compute shrinking size - shrink_bytes = capacity_after_gc - maximum_desired_capacity; - // We don't want shrink all the way back to initSize if people call - // System.gc(), because some programs do that between "phases" and then - // we'd just have to grow the heap up again for the next phase. So we - // damp the shrinking: 0% on the first call, 10% on the second call, 40% - // on the third call, and 100% by the fourth call. But if we recompute - // size without shrinking, it goes back to 0%. - shrink_bytes = shrink_bytes / 100 * current_shrink_factor; - assert(shrink_bytes <= max_shrink_bytes, "invalid shrink size"); - if (current_shrink_factor == 0) { - _shrink_factor = 10; - } else { - _shrink_factor = MIN2(current_shrink_factor * 4, (size_t) 100); - } - if (PrintGC && Verbose) { - gclog_or_tty->print_cr(" " - " shrinking:" - " initSize: %.1fK" - " maximum_desired_capacity: %.1fK", - spec()->init_size() / (double) K, - maximum_desired_capacity / (double) K); - gclog_or_tty->print_cr(" " - " shrink_bytes: %.1fK" - " current_shrink_factor: %d" - " new shrink factor: %d" - " _min_heap_delta_bytes: %.1fK", - shrink_bytes / (double) K, - current_shrink_factor, - _shrink_factor, - _min_heap_delta_bytes / (double) K); - } - } - } - - if (capacity_after_gc > _capacity_at_prologue) { - // We might have expanded for promotions, in which case we might want to - // take back that expansion if there's room after GC. That keeps us from - // stretching the heap with promotions when there's plenty of room. - size_t expansion_for_promotion = capacity_after_gc - _capacity_at_prologue; - expansion_for_promotion = MIN2(expansion_for_promotion, max_shrink_bytes); - // We have two shrinking computations, take the largest - shrink_bytes = MAX2(shrink_bytes, expansion_for_promotion); - assert(shrink_bytes <= max_shrink_bytes, "invalid shrink size"); - if (PrintGC && Verbose) { - gclog_or_tty->print_cr(" " - " aggressive shrinking:" - " _capacity_at_prologue: %.1fK" - " capacity_after_gc: %.1fK" - " expansion_for_promotion: %.1fK" - " shrink_bytes: %.1fK", - capacity_after_gc / (double) K, - _capacity_at_prologue / (double) K, - expansion_for_promotion / (double) K, - shrink_bytes / (double) K); - } - } - // Don't shrink unless it's significant - if (shrink_bytes >= _min_heap_delta_bytes) { - shrink(shrink_bytes); - } - assert(used() == used_after_gc && used_after_gc <= capacity(), - "sanity check"); -} - void TenuredGeneration::gc_prologue(bool full) { _capacity_at_prologue = capacity(); _used_at_prologue = used(); @@ -312,6 +156,19 @@ size, is_tlab); } +void TenuredGeneration::compute_new_size() { + assert_locked_or_safepoint(Heap_lock); + + // Compute some numbers about the state of the heap. + const size_t used_after_gc = used(); + const size_t capacity_after_gc = capacity(); + + CardGeneration::compute_new_size(); + + assert(used() == used_after_gc && used_after_gc <= capacity(), + err_msg("used: " SIZE_FORMAT " used_after_gc: " SIZE_FORMAT + " capacity: " SIZE_FORMAT, used(), used_after_gc, capacity())); +} void TenuredGeneration::update_gc_stats(int current_level, bool full) { // If the next lower level(s) has been collected, gather any statistics