--- a/hotspot/src/os/linux/vm/globals_linux.hpp Wed Apr 20 20:32:45 2011 -0700
+++ b/hotspot/src/os/linux/vm/globals_linux.hpp Fri Apr 22 09:26:09 2011 -0700
@@ -29,13 +29,19 @@
// Defines Linux specific flags. They are not available on other platforms.
//
#define RUNTIME_OS_FLAGS(develop, develop_pd, product, product_pd, diagnostic, notproduct) \
- product(bool, UseOprofile, false, \
- "enable support for Oprofile profiler") \
- \
- product(bool, UseLinuxPosixThreadCPUClocks, true, \
- "enable fast Linux Posix clocks where available")
-// NB: The default value of UseLinuxPosixThreadCPUClocks may be
-// overridden in Arguments::parse_each_vm_init_arg.
+ product(bool, UseOprofile, false, \
+ "enable support for Oprofile profiler") \
+ \
+ product(bool, UseLinuxPosixThreadCPUClocks, true, \
+ "enable fast Linux Posix clocks where available") \
+/* NB: The default value of UseLinuxPosixThreadCPUClocks may be \
+ overridden in Arguments::parse_each_vm_init_arg. */ \
+ \
+ product(bool, UseHugeTLBFS, false, \
+ "Use MAP_HUGETLB for large pages") \
+ \
+ product(bool, UseSHM, false, \
+ "Use SYSV shared memory for large pages")
//
// Defines Linux-specific default values. The flags are available on all
--- a/hotspot/src/os/linux/vm/os_linux.cpp Wed Apr 20 20:32:45 2011 -0700
+++ b/hotspot/src/os/linux/vm/os_linux.cpp Fri Apr 22 09:26:09 2011 -0700
@@ -2465,16 +2465,40 @@
return res != (uintptr_t) MAP_FAILED;
}
+// Define MAP_HUGETLB here so we can build HotSpot on old systems.
+#ifndef MAP_HUGETLB
+#define MAP_HUGETLB 0x40000
+#endif
+
+// Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
+#ifndef MADV_HUGEPAGE
+#define MADV_HUGEPAGE 14
+#endif
+
bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
bool exec) {
+ if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
+ int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
+ uintptr_t res =
+ (uintptr_t) ::mmap(addr, size, prot,
+ MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_HUGETLB,
+ -1, 0);
+ return res != (uintptr_t) MAP_FAILED;
+ }
+
return commit_memory(addr, size, exec);
}
-void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) { }
+void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
+ if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
+ // We don't check the return value: madvise(MADV_HUGEPAGE) may not
+ // be supported or the memory may already be backed by huge pages.
+ ::madvise(addr, bytes, MADV_HUGEPAGE);
+ }
+}
void os::free_memory(char *addr, size_t bytes) {
- ::mmap(addr, bytes, PROT_READ | PROT_WRITE,
- MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
+ ::madvise(addr, bytes, MADV_DONTNEED);
}
void os::numa_make_global(char *addr, size_t bytes) {
@@ -2812,6 +2836,43 @@
return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
}
+bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
+ bool result = false;
+ void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE,
+ MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
+ -1, 0);
+
+ if (p != (void *) -1) {
+ // We don't know if this really is a huge page or not.
+ FILE *fp = fopen("/proc/self/maps", "r");
+ if (fp) {
+ while (!feof(fp)) {
+ char chars[257];
+ long x = 0;
+ if (fgets(chars, sizeof(chars), fp)) {
+ if (sscanf(chars, "%lx-%*lx", &x) == 1
+ && x == (long)p) {
+ if (strstr (chars, "hugepage")) {
+ result = true;
+ break;
+ }
+ }
+ }
+ }
+ fclose(fp);
+ }
+ munmap (p, page_size);
+ if (result)
+ return true;
+ }
+
+ if (warn) {
+ warning("HugeTLBFS is not supported by the operating system.");
+ }
+
+ return result;
+}
+
/*
* Set the coredump_filter bits to include largepages in core dump (bit 6)
*
@@ -2854,7 +2915,16 @@
static size_t _large_page_size = 0;
bool os::large_page_init() {
- if (!UseLargePages) return false;
+ if (!UseLargePages) {
+ UseHugeTLBFS = false;
+ UseSHM = false;
+ return false;
+ }
+
+ if (FLAG_IS_DEFAULT(UseHugeTLBFS) && FLAG_IS_DEFAULT(UseSHM)) {
+ // Our user has not expressed a preference, so we'll try both.
+ UseHugeTLBFS = UseSHM = true;
+ }
if (LargePageSizeInBytes) {
_large_page_size = LargePageSizeInBytes;
@@ -2899,6 +2969,9 @@
}
}
+ // print a warning if any large page related flag is specified on command line
+ bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
+
const size_t default_page_size = (size_t)Linux::page_size();
if (_large_page_size > default_page_size) {
_page_sizes[0] = _large_page_size;
@@ -2906,6 +2979,14 @@
_page_sizes[2] = 0;
}
+ UseHugeTLBFS = UseHugeTLBFS &&
+ Linux::hugetlbfs_sanity_check(warn_on_failure, _large_page_size);
+
+ if (UseHugeTLBFS)
+ UseSHM = false;
+
+ UseLargePages = UseHugeTLBFS || UseSHM;
+
set_coredump_filter();
// Large page support is available on 2.6 or newer kernel, some vendors
@@ -2922,7 +3003,7 @@
char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) {
// "exec" is passed in but not used. Creating the shared image for
// the code cache doesn't have an SHM_X executable permission to check.
- assert(UseLargePages, "only for large pages");
+ assert(UseLargePages && UseSHM, "only for SHM large pages");
key_t key = IPC_PRIVATE;
char *addr;
@@ -2989,16 +3070,15 @@
return _large_page_size;
}
-// Linux does not support anonymous mmap with large page memory. The only way
-// to reserve large page memory without file backing is through SysV shared
-// memory API. The entire memory region is committed and pinned upfront.
-// Hopefully this will change in the future...
+// HugeTLBFS allows application to commit large page memory on demand;
+// with SysV SHM the entire memory region must be allocated as shared
+// memory.
bool os::can_commit_large_page_memory() {
- return false;
+ return UseHugeTLBFS;
}
bool os::can_execute_large_page_memory() {
- return false;
+ return UseHugeTLBFS;
}
// Reserve memory at an arbitrary address, only if that area is
--- a/hotspot/src/os/linux/vm/os_linux.hpp Wed Apr 20 20:32:45 2011 -0700
+++ b/hotspot/src/os/linux/vm/os_linux.hpp Fri Apr 22 09:26:09 2011 -0700
@@ -86,6 +86,9 @@
static void rebuild_cpu_to_node_map();
static GrowableArray<int>* cpu_to_node() { return _cpu_to_node; }
+
+ static bool hugetlbfs_sanity_check(bool warn, size_t page_size);
+
public:
static void init_thread_fpu_state();
static int get_fpu_control_word();
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Wed Apr 20 20:32:45 2011 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Fri Apr 22 09:26:09 2011 -0700
@@ -1161,6 +1161,7 @@
TraceTime t(system_gc ? "Full GC (System.gc())" : "Full GC",
PrintGC, true, gclog_or_tty);
+ TraceCollectorStats tcs(g1mm()->full_collection_counters());
TraceMemoryManagerStats tms(true /* fullGC */);
double start = os::elapsedTime();
@@ -1339,6 +1340,7 @@
if (PrintHeapAtGC) {
Universe::print_heap_after_gc();
}
+ g1mm()->update_counters();
return true;
}
@@ -1971,6 +1973,10 @@
init_mutator_alloc_region();
+ // Do create of the monitoring and management support so that
+ // values in the heap have been properly initialized.
+ _g1mm = new G1MonitoringSupport(this, &_g1_storage);
+
return JNI_OK;
}
@@ -2113,6 +2119,28 @@
(cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent));
}
+#ifndef PRODUCT
+void G1CollectedHeap::allocate_dummy_regions() {
+ // Let's fill up most of the region
+ size_t word_size = HeapRegion::GrainWords - 1024;
+ // And as a result the region we'll allocate will be humongous.
+ guarantee(isHumongous(word_size), "sanity");
+
+ for (uintx i = 0; i < G1DummyRegionsPerGC; ++i) {
+ // Let's use the existing mechanism for the allocation
+ HeapWord* dummy_obj = humongous_obj_allocate(word_size);
+ if (dummy_obj != NULL) {
+ MemRegion mr(dummy_obj, word_size);
+ CollectedHeap::fill_with_object(mr);
+ } else {
+ // If we can't allocate once, we probably cannot allocate
+ // again. Let's get out of the loop.
+ break;
+ }
+ }
+}
+#endif // !PRODUCT
+
void G1CollectedHeap::increment_full_collections_completed(bool concurrent) {
MonitorLockerEx x(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
@@ -3164,6 +3192,7 @@
TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
TraceTime t(verbose_str, PrintGC && !PrintGCDetails, true, gclog_or_tty);
+ TraceCollectorStats tcs(g1mm()->incremental_collection_counters());
TraceMemoryManagerStats tms(false /* fullGC */);
// If the secondary_free_list is not empty, append it to the
@@ -3338,6 +3367,8 @@
doConcurrentMark();
}
+ allocate_dummy_regions();
+
#if YOUNG_LIST_VERBOSE
gclog_or_tty->print_cr("\nEnd of the pause.\nYoung_list:");
_young_list->print();
@@ -3401,6 +3432,8 @@
if (PrintHeapAtGC) {
Universe::print_heap_after_gc();
}
+ g1mm()->update_counters();
+
if (G1SummarizeRSetStats &&
(G1SummarizeRSetStatsPeriod > 0) &&
(total_collections() % G1SummarizeRSetStatsPeriod == 0)) {
@@ -5314,6 +5347,7 @@
if (new_alloc_region != NULL) {
g1_policy()->update_region_num(true /* next_is_young */);
set_region_short_lived_locked(new_alloc_region);
+ g1mm()->update_eden_counters();
return new_alloc_region;
}
}
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Wed Apr 20 20:32:45 2011 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Fri Apr 22 09:26:09 2011 -0700
@@ -28,7 +28,9 @@
#include "gc_implementation/g1/concurrentMark.hpp"
#include "gc_implementation/g1/g1AllocRegion.hpp"
#include "gc_implementation/g1/g1RemSet.hpp"
+#include "gc_implementation/g1/g1MonitoringSupport.hpp"
#include "gc_implementation/g1/heapRegionSets.hpp"
+#include "gc_implementation/shared/hSpaceCounters.hpp"
#include "gc_implementation/parNew/parGCAllocBuffer.hpp"
#include "memory/barrierSet.hpp"
#include "memory/memRegion.hpp"
@@ -57,6 +59,7 @@
class ConcurrentMark;
class ConcurrentMarkThread;
class ConcurrentG1Refine;
+class GenerationCounters;
typedef OverflowTaskQueue<StarTask> RefToScanQueue;
typedef GenericTaskQueueSet<RefToScanQueue> RefToScanQueueSet;
@@ -236,6 +239,9 @@
// current collection.
HeapRegion* _gc_alloc_region_list;
+ // Helper for monitoring and management support.
+ G1MonitoringSupport* _g1mm;
+
// Determines PLAB size for a particular allocation purpose.
static size_t desired_plab_sz(GCAllocPurpose purpose);
@@ -298,6 +304,14 @@
// started is maintained in _total_full_collections in CollectedHeap.
volatile unsigned int _full_collections_completed;
+ // This is a non-product method that is helpful for testing. It is
+ // called at the end of a GC and artificially expands the heap by
+ // allocating a number of dead regions. This way we can induce very
+ // frequent marking cycles and stress the cleanup / concurrent
+ // cleanup code more (as all the regions that will be allocated by
+ // this method will be found dead by the marking cycle).
+ void allocate_dummy_regions() PRODUCT_RETURN;
+
// These are macros so that, if the assert fires, we get the correct
// line number, file, etc.
@@ -542,6 +556,9 @@
HeapWord* expand_and_allocate(size_t word_size);
public:
+
+ G1MonitoringSupport* g1mm() { return _g1mm; }
+
// Expand the garbage-first heap by at least the given size (in bytes!).
// Returns true if the heap was expanded by the requested amount;
// false otherwise.
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1MonitoringSupport.cpp Fri Apr 22 09:26:09 2011 -0700
@@ -0,0 +1,178 @@
+/*
+ * Copyright (c) 2011, Oracle and/or its affiliates. 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.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "gc_implementation/g1/g1MonitoringSupport.hpp"
+#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
+#include "gc_implementation/g1/g1CollectorPolicy.hpp"
+
+G1MonitoringSupport::G1MonitoringSupport(G1CollectedHeap* g1h,
+ VirtualSpace* g1_storage_addr) :
+ _g1h(g1h),
+ _incremental_collection_counters(NULL),
+ _full_collection_counters(NULL),
+ _non_young_collection_counters(NULL),
+ _old_space_counters(NULL),
+ _young_collection_counters(NULL),
+ _eden_counters(NULL),
+ _from_counters(NULL),
+ _to_counters(NULL),
+ _g1_storage_addr(g1_storage_addr)
+{
+ // Counters for GC collections
+ //
+ // name "collector.0". In a generational collector this would be the
+ // young generation collection.
+ _incremental_collection_counters =
+ new CollectorCounters("G1 incremental collections", 0);
+ // name "collector.1". In a generational collector this would be the
+ // old generation collection.
+ _full_collection_counters =
+ new CollectorCounters("G1 stop-the-world full collections", 1);
+
+ // timer sampling for all counters supporting sampling only update the
+ // used value. See the take_sample() method. G1 requires both used and
+ // capacity updated so sampling is not currently used. It might
+ // be sufficient to update all counters in take_sample() even though
+ // take_sample() only returns "used". When sampling was used, there
+ // were some anomolous values emitted which may have been the consequence
+ // of not updating all values simultaneously (i.e., see the calculation done
+ // in eden_space_used(), is it possbile that the values used to
+ // calculate either eden_used or survivor_used are being updated by
+ // the collector when the sample is being done?).
+ const bool sampled = false;
+
+ // "Generation" and "Space" counters.
+ //
+ // name "generation.1" This is logically the old generation in
+ // generational GC terms. The "1, 1" parameters are for
+ // the n-th generation (=1) with 1 space.
+ // Counters are created from minCapacity, maxCapacity, and capacity
+ _non_young_collection_counters =
+ new GenerationCounters("whole heap", 1, 1, _g1_storage_addr);
+
+ // name "generation.1.space.0"
+ // Counters are created from maxCapacity, capacity, initCapacity,
+ // and used.
+ _old_space_counters = new HSpaceCounters("space", 0,
+ _g1h->max_capacity(), _g1h->capacity(), _non_young_collection_counters);
+
+ // Young collection set
+ // name "generation.0". This is logically the young generation.
+ // The "0, 3" are paremeters for the n-th genertaion (=0) with 3 spaces.
+ // See _non_young_collection_counters for additional counters
+ _young_collection_counters = new GenerationCounters("young", 0, 3, NULL);
+
+ // Replace "max_heap_byte_size() with maximum young gen size for
+ // g1Collectedheap
+ // name "generation.0.space.0"
+ // See _old_space_counters for additional counters
+ _eden_counters = new HSpaceCounters("eden", 0,
+ _g1h->max_capacity(), eden_space_committed(),
+ _young_collection_counters);
+
+ // name "generation.0.space.1"
+ // See _old_space_counters for additional counters
+ // Set the arguments to indicate that this survivor space is not used.
+ _from_counters = new HSpaceCounters("s0", 1, (long) 0, (long) 0,
+ _young_collection_counters);
+
+ // name "generation.0.space.2"
+ // See _old_space_counters for additional counters
+ _to_counters = new HSpaceCounters("s1", 2,
+ _g1h->max_capacity(),
+ survivor_space_committed(),
+ _young_collection_counters);
+}
+
+size_t G1MonitoringSupport::overall_committed() {
+ return g1h()->capacity();
+}
+
+size_t G1MonitoringSupport::overall_used() {
+ return g1h()->used_unlocked();
+}
+
+size_t G1MonitoringSupport::eden_space_committed() {
+ return MAX2(eden_space_used(), (size_t) HeapRegion::GrainBytes);
+}
+
+size_t G1MonitoringSupport::eden_space_used() {
+ size_t young_list_length = g1h()->young_list()->length();
+ size_t eden_used = young_list_length * HeapRegion::GrainBytes;
+ size_t survivor_used = survivor_space_used();
+ eden_used = subtract_up_to_zero(eden_used, survivor_used);
+ return eden_used;
+}
+
+size_t G1MonitoringSupport::survivor_space_committed() {
+ return MAX2(survivor_space_used(),
+ (size_t) HeapRegion::GrainBytes);
+}
+
+size_t G1MonitoringSupport::survivor_space_used() {
+ size_t survivor_num = g1h()->g1_policy()->recorded_survivor_regions();
+ size_t survivor_used = survivor_num * HeapRegion::GrainBytes;
+ return survivor_used;
+}
+
+size_t G1MonitoringSupport::old_space_committed() {
+ size_t committed = overall_committed();
+ size_t eden_committed = eden_space_committed();
+ size_t survivor_committed = survivor_space_committed();
+ committed = subtract_up_to_zero(committed, eden_committed);
+ committed = subtract_up_to_zero(committed, survivor_committed);
+ committed = MAX2(committed, (size_t) HeapRegion::GrainBytes);
+ return committed;
+}
+
+// See the comment near the top of g1MonitoringSupport.hpp for
+// an explanation of these calculations for "used" and "capacity".
+size_t G1MonitoringSupport::old_space_used() {
+ size_t used = overall_used();
+ size_t eden_used = eden_space_used();
+ size_t survivor_used = survivor_space_used();
+ used = subtract_up_to_zero(used, eden_used);
+ used = subtract_up_to_zero(used, survivor_used);
+ return used;
+}
+
+void G1MonitoringSupport::update_counters() {
+ if (UsePerfData) {
+ eden_counters()->update_capacity(eden_space_committed());
+ eden_counters()->update_used(eden_space_used());
+ to_counters()->update_capacity(survivor_space_committed());
+ to_counters()->update_used(survivor_space_used());
+ old_space_counters()->update_capacity(old_space_committed());
+ old_space_counters()->update_used(old_space_used());
+ non_young_collection_counters()->update_all();
+ }
+}
+
+void G1MonitoringSupport::update_eden_counters() {
+ if (UsePerfData) {
+ eden_counters()->update_capacity(eden_space_committed());
+ eden_counters()->update_used(eden_space_used());
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1MonitoringSupport.hpp Fri Apr 22 09:26:09 2011 -0700
@@ -0,0 +1,203 @@
+/*
+ * Copyright (c) 2011, Oracle and/or its affiliates. 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.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1MONITORINGSUPPORT_HPP
+#define SHARE_VM_GC_IMPLEMENTATION_G1_G1MONITORINGSUPPORT_HPP
+
+#include "gc_implementation/shared/hSpaceCounters.hpp"
+
+class G1CollectedHeap;
+class G1SpaceMonitoringSupport;
+
+// Class for monitoring logical spaces in G1.
+// G1 defines a set of regions as a young
+// collection (analogous to a young generation).
+// The young collection is a logical generation
+// with no fixed chunk (see space.hpp) reflecting
+// the address space for the generation. In addition
+// to the young collection there is its complement
+// the non-young collection that is simply the regions
+// not in the young collection. The non-young collection
+// is treated here as a logical old generation only
+// because the monitoring tools expect a generational
+// heap. The monitoring tools expect that a Space
+// (see space.hpp) exists that describe the
+// address space of young collection and non-young
+// collection and such a view is provided here.
+//
+// This class provides interfaces to access
+// the value of variables for the young collection
+// that include the "capacity" and "used" of the
+// young collection along with constant values
+// for the minimum and maximum capacities for
+// the logical spaces. Similarly for the non-young
+// collection.
+//
+// Also provided are counters for G1 concurrent collections
+// and stop-the-world full heap collecitons.
+//
+// Below is a description of how "used" and "capactiy"
+// (or committed) is calculated for the logical spaces.
+//
+// 1) The used space calculation for a pool is not necessarily
+// independent of the others. We can easily get from G1 the overall
+// used space in the entire heap, the number of regions in the young
+// generation (includes both eden and survivors), and the number of
+// survivor regions. So, from that we calculate:
+//
+// survivor_used = survivor_num * region_size
+// eden_used = young_region_num * region_size - survivor_used
+// old_gen_used = overall_used - eden_used - survivor_used
+//
+// Note that survivor_used and eden_used are upper bounds. To get the
+// actual value we would have to iterate over the regions and add up
+// ->used(). But that'd be expensive. So, we'll accept some lack of
+// accuracy for those two. But, we have to be careful when calculating
+// old_gen_used, in case we subtract from overall_used more then the
+// actual number and our result goes negative.
+//
+// 2) Calculating the used space is straightforward, as described
+// above. However, how do we calculate the committed space, given that
+// we allocate space for the eden, survivor, and old gen out of the
+// same pool of regions? One way to do this is to use the used value
+// as also the committed value for the eden and survivor spaces and
+// then calculate the old gen committed space as follows:
+//
+// old_gen_committed = overall_committed - eden_committed - survivor_committed
+//
+// Maybe a better way to do that would be to calculate used for eden
+// and survivor as a sum of ->used() over their regions and then
+// calculate committed as region_num * region_size (i.e., what we use
+// to calculate the used space now). This is something to consider
+// in the future.
+//
+// 3) Another decision that is again not straightforward is what is
+// the max size that each memory pool can grow to. One way to do this
+// would be to use the committed size for the max for the eden and
+// survivors and calculate the old gen max as follows (basically, it's
+// a similar pattern to what we use for the committed space, as
+// described above):
+//
+// old_gen_max = overall_max - eden_max - survivor_max
+//
+// Unfortunately, the above makes the max of each pool fluctuate over
+// time and, even though this is allowed according to the spec, it
+// broke several assumptions in the M&M framework (there were cases
+// where used would reach a value greater than max). So, for max we
+// use -1, which means "undefined" according to the spec.
+//
+// 4) Now, there is a very subtle issue with all the above. The
+// framework will call get_memory_usage() on the three pools
+// asynchronously. As a result, each call might get a different value
+// for, say, survivor_num which will yield inconsistent values for
+// eden_used, survivor_used, and old_gen_used (as survivor_num is used
+// in the calculation of all three). This would normally be
+// ok. However, it's possible that this might cause the sum of
+// eden_used, survivor_used, and old_gen_used to go over the max heap
+// size and this seems to sometimes cause JConsole (and maybe other
+// clients) to get confused. There's not a really an easy / clean
+// solution to this problem, due to the asynchrounous nature of the
+// framework.
+
+class G1MonitoringSupport : public CHeapObj {
+ G1CollectedHeap* _g1h;
+ VirtualSpace* _g1_storage_addr;
+
+ // jstat performance counters
+ // incremental collections both fully and partially young
+ CollectorCounters* _incremental_collection_counters;
+ // full stop-the-world collections
+ CollectorCounters* _full_collection_counters;
+ // young collection set counters. The _eden_counters,
+ // _from_counters, and _to_counters are associated with
+ // this "generational" counter.
+ GenerationCounters* _young_collection_counters;
+ // non-young collection set counters. The _old_space_counters
+ // below are associated with this "generational" counter.
+ GenerationCounters* _non_young_collection_counters;
+ // Counters for the capacity and used for
+ // the whole heap
+ HSpaceCounters* _old_space_counters;
+ // the young collection
+ HSpaceCounters* _eden_counters;
+ // the survivor collection (only one, _to_counters, is actively used)
+ HSpaceCounters* _from_counters;
+ HSpaceCounters* _to_counters;
+
+ // It returns x - y if x > y, 0 otherwise.
+ // As described in the comment above, some of the inputs to the
+ // calculations we have to do are obtained concurrently and hence
+ // may be inconsistent with each other. So, this provides a
+ // defensive way of performing the subtraction and avoids the value
+ // going negative (which would mean a very large result, given that
+ // the parameter are size_t).
+ static size_t subtract_up_to_zero(size_t x, size_t y) {
+ if (x > y) {
+ return x - y;
+ } else {
+ return 0;
+ }
+ }
+
+ public:
+ G1MonitoringSupport(G1CollectedHeap* g1h, VirtualSpace* g1_storage_addr);
+
+ G1CollectedHeap* g1h() { return _g1h; }
+ VirtualSpace* g1_storage_addr() { return _g1_storage_addr; }
+
+ // Performance Counter accessors
+ void update_counters();
+ void update_eden_counters();
+
+ CollectorCounters* incremental_collection_counters() {
+ return _incremental_collection_counters;
+ }
+ CollectorCounters* full_collection_counters() {
+ return _full_collection_counters;
+ }
+ GenerationCounters* non_young_collection_counters() {
+ return _non_young_collection_counters;
+ }
+ HSpaceCounters* old_space_counters() { return _old_space_counters; }
+ HSpaceCounters* eden_counters() { return _eden_counters; }
+ HSpaceCounters* from_counters() { return _from_counters; }
+ HSpaceCounters* to_counters() { return _to_counters; }
+
+ // Monitoring support used by
+ // MemoryService
+ // jstat counters
+ size_t overall_committed();
+ size_t overall_used();
+
+ size_t eden_space_committed();
+ size_t eden_space_used();
+
+ size_t survivor_space_committed();
+ size_t survivor_space_used();
+
+ size_t old_space_committed();
+ size_t old_space_used();
+};
+
+#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1MONITORINGSUPPORT_HPP
--- a/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp Wed Apr 20 20:32:45 2011 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp Fri Apr 22 09:26:09 2011 -0700
@@ -300,6 +300,11 @@
develop(uintx, G1StressConcRegionFreeingDelayMillis, 0, \
"Artificial delay during concurrent region freeing") \
\
+ develop(uintx, G1DummyRegionsPerGC, 0, \
+ "The number of dummy regions G1 will allocate at the end of " \
+ "each evacuation pause in order to artificially fill up the " \
+ "heap and stress the marking implementation.") \
+ \
develop(bool, ReduceInitialCardMarksForG1, false, \
"When ReduceInitialCardMarks is true, this flag setting " \
" controls whether G1 allows the RICM optimization") \
--- a/hotspot/src/share/vm/gc_implementation/parNew/parCardTableModRefBS.cpp Wed Apr 20 20:32:45 2011 -0700
+++ b/hotspot/src/share/vm/gc_implementation/parNew/parCardTableModRefBS.cpp Fri Apr 22 09:26:09 2011 -0700
@@ -33,44 +33,43 @@
#include "runtime/mutexLocker.hpp"
#include "runtime/virtualspace.hpp"
-void CardTableModRefBS::par_non_clean_card_iterate_work(Space* sp, MemRegion mr,
- DirtyCardToOopClosure* dcto_cl,
- MemRegionClosure* cl,
- int n_threads) {
- if (n_threads > 0) {
- assert((n_threads == 1 && ParallelGCThreads == 0) ||
- n_threads <= (int)ParallelGCThreads,
- "# worker threads != # requested!");
- // Make sure the LNC array is valid for the space.
- jbyte** lowest_non_clean;
- uintptr_t lowest_non_clean_base_chunk_index;
- size_t lowest_non_clean_chunk_size;
- get_LNC_array_for_space(sp, lowest_non_clean,
- lowest_non_clean_base_chunk_index,
- lowest_non_clean_chunk_size);
+void CardTableModRefBS::non_clean_card_iterate_parallel_work(Space* sp, MemRegion mr,
+ DirtyCardToOopClosure* dcto_cl,
+ ClearNoncleanCardWrapper* cl,
+ int n_threads) {
+ assert(n_threads > 0, "Error: expected n_threads > 0");
+ assert((n_threads == 1 && ParallelGCThreads == 0) ||
+ n_threads <= (int)ParallelGCThreads,
+ "# worker threads != # requested!");
+ // Make sure the LNC array is valid for the space.
+ jbyte** lowest_non_clean;
+ uintptr_t lowest_non_clean_base_chunk_index;
+ size_t lowest_non_clean_chunk_size;
+ get_LNC_array_for_space(sp, lowest_non_clean,
+ lowest_non_clean_base_chunk_index,
+ lowest_non_clean_chunk_size);
- int n_strides = n_threads * StridesPerThread;
- SequentialSubTasksDone* pst = sp->par_seq_tasks();
- pst->set_n_threads(n_threads);
- pst->set_n_tasks(n_strides);
+ int n_strides = n_threads * StridesPerThread;
+ SequentialSubTasksDone* pst = sp->par_seq_tasks();
+ pst->set_n_threads(n_threads);
+ pst->set_n_tasks(n_strides);
- int stride = 0;
- while (!pst->is_task_claimed(/* reference */ stride)) {
- process_stride(sp, mr, stride, n_strides, dcto_cl, cl,
- lowest_non_clean,
- lowest_non_clean_base_chunk_index,
- lowest_non_clean_chunk_size);
- }
- if (pst->all_tasks_completed()) {
- // Clear lowest_non_clean array for next time.
- intptr_t first_chunk_index = addr_to_chunk_index(mr.start());
- uintptr_t last_chunk_index = addr_to_chunk_index(mr.last());
- for (uintptr_t ch = first_chunk_index; ch <= last_chunk_index; ch++) {
- intptr_t ind = ch - lowest_non_clean_base_chunk_index;
- assert(0 <= ind && ind < (intptr_t)lowest_non_clean_chunk_size,
- "Bounds error");
- lowest_non_clean[ind] = NULL;
- }
+ int stride = 0;
+ while (!pst->is_task_claimed(/* reference */ stride)) {
+ process_stride(sp, mr, stride, n_strides, dcto_cl, cl,
+ lowest_non_clean,
+ lowest_non_clean_base_chunk_index,
+ lowest_non_clean_chunk_size);
+ }
+ if (pst->all_tasks_completed()) {
+ // Clear lowest_non_clean array for next time.
+ intptr_t first_chunk_index = addr_to_chunk_index(mr.start());
+ uintptr_t last_chunk_index = addr_to_chunk_index(mr.last());
+ for (uintptr_t ch = first_chunk_index; ch <= last_chunk_index; ch++) {
+ intptr_t ind = ch - lowest_non_clean_base_chunk_index;
+ assert(0 <= ind && ind < (intptr_t)lowest_non_clean_chunk_size,
+ "Bounds error");
+ lowest_non_clean[ind] = NULL;
}
}
}
@@ -81,7 +80,7 @@
MemRegion used,
jint stride, int n_strides,
DirtyCardToOopClosure* dcto_cl,
- MemRegionClosure* cl,
+ ClearNoncleanCardWrapper* cl,
jbyte** lowest_non_clean,
uintptr_t lowest_non_clean_base_chunk_index,
size_t lowest_non_clean_chunk_size) {
@@ -127,7 +126,11 @@
lowest_non_clean_base_chunk_index,
lowest_non_clean_chunk_size);
- non_clean_card_iterate_work(chunk_mr, cl);
+ // We do not call the non_clean_card_iterate_serial() version because
+ // we want to clear the cards, and the ClearNoncleanCardWrapper closure
+ // itself does the work of finding contiguous dirty ranges of cards to
+ // process (and clear).
+ cl->do_MemRegion(chunk_mr);
// Find the next chunk of the stride.
chunk_card_start += CardsPerStrideChunk * n_strides;
--- a/hotspot/src/share/vm/gc_implementation/shared/generationCounters.cpp Wed Apr 20 20:32:45 2011 -0700
+++ b/hotspot/src/share/vm/gc_implementation/shared/generationCounters.cpp Fri Apr 22 09:26:09 2011 -0700
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2011, Oracle and/or its affiliates. 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
@@ -51,15 +51,18 @@
cname = PerfDataManager::counter_name(_name_space, "minCapacity");
PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_Bytes,
+ _virtual_space == NULL ? 0 :
_virtual_space->committed_size(), CHECK);
cname = PerfDataManager::counter_name(_name_space, "maxCapacity");
PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_Bytes,
+ _virtual_space == NULL ? 0 :
_virtual_space->reserved_size(), CHECK);
cname = PerfDataManager::counter_name(_name_space, "capacity");
_current_size = PerfDataManager::create_variable(SUN_GC, cname,
- PerfData::U_Bytes,
+ PerfData::U_Bytes,
+ _virtual_space == NULL ? 0 :
_virtual_space->committed_size(), CHECK);
}
}
--- a/hotspot/src/share/vm/gc_implementation/shared/generationCounters.hpp Wed Apr 20 20:32:45 2011 -0700
+++ b/hotspot/src/share/vm/gc_implementation/shared/generationCounters.hpp Fri Apr 22 09:26:09 2011 -0700
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2011, Oracle and/or its affiliates. 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
@@ -61,10 +61,11 @@
}
virtual void update_all() {
- _current_size->set_value(_virtual_space->committed_size());
+ _current_size->set_value(_virtual_space == NULL ? 0 :
+ _virtual_space->committed_size());
}
const char* name_space() const { return _name_space; }
+
};
-
#endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_GENERATIONCOUNTERS_HPP
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc_implementation/shared/hSpaceCounters.cpp Fri Apr 22 09:26:09 2011 -0700
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2011, Oracle and/or its affiliates. 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.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "gc_implementation/shared/hSpaceCounters.hpp"
+#include "memory/generation.hpp"
+#include "memory/resourceArea.hpp"
+
+HSpaceCounters::HSpaceCounters(const char* name,
+ int ordinal,
+ size_t max_size,
+ size_t initial_capacity,
+ GenerationCounters* gc) {
+
+ if (UsePerfData) {
+ EXCEPTION_MARK;
+ ResourceMark rm;
+
+ const char* cns =
+ PerfDataManager::name_space(gc->name_space(), "space", ordinal);
+
+ _name_space = NEW_C_HEAP_ARRAY(char, strlen(cns)+1);
+ strcpy(_name_space, cns);
+
+ const char* cname = PerfDataManager::counter_name(_name_space, "name");
+ PerfDataManager::create_string_constant(SUN_GC, cname, name, CHECK);
+
+ cname = PerfDataManager::counter_name(_name_space, "maxCapacity");
+ PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_Bytes,
+ (jlong)max_size, CHECK);
+
+ cname = PerfDataManager::counter_name(_name_space, "capacity");
+ _capacity = PerfDataManager::create_variable(SUN_GC, cname,
+ PerfData::U_Bytes,
+ initial_capacity, CHECK);
+
+ cname = PerfDataManager::counter_name(_name_space, "used");
+ _used = PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes,
+ (jlong) 0, CHECK);
+
+ cname = PerfDataManager::counter_name(_name_space, "initCapacity");
+ PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_Bytes,
+ initial_capacity, CHECK);
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc_implementation/shared/hSpaceCounters.hpp Fri Apr 22 09:26:09 2011 -0700
@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 2011, Oracle and/or its affiliates. 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.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_GC_IMPLEMENTATION_SHARED_HSPACECOUNTERS_HPP
+#define SHARE_VM_GC_IMPLEMENTATION_SHARED_HSPACECOUNTERS_HPP
+
+#ifndef SERIALGC
+#include "gc_implementation/shared/generationCounters.hpp"
+#include "memory/generation.hpp"
+#include "runtime/perfData.hpp"
+#endif
+
+// A HSpaceCounter is a holder class for performance counters
+// that track a collections (logical spaces) in a heap;
+
+class HeapSpaceUsedHelper;
+class G1SpaceMonitoringSupport;
+
+class HSpaceCounters: public CHeapObj {
+ friend class VMStructs;
+
+ private:
+ PerfVariable* _capacity;
+ PerfVariable* _used;
+
+ // Constant PerfData types don't need to retain a reference.
+ // However, it's a good idea to document them here.
+
+ char* _name_space;
+
+ public:
+
+ HSpaceCounters(const char* name, int ordinal, size_t max_size,
+ size_t initial_capacity, GenerationCounters* gc);
+
+ ~HSpaceCounters() {
+ if (_name_space != NULL) FREE_C_HEAP_ARRAY(char, _name_space);
+ }
+
+ inline void update_capacity(size_t v) {
+ _capacity->set_value(v);
+ }
+
+ inline void update_used(size_t v) {
+ _used->set_value(v);
+ }
+
+ debug_only(
+ // for security reasons, we do not allow arbitrary reads from
+ // the counters as they may live in shared memory.
+ jlong used() {
+ return _used->get_value();
+ }
+ jlong capacity() {
+ return _used->get_value();
+ }
+ )
+
+ inline void update_all(size_t capacity, size_t used) {
+ update_capacity(capacity);
+ update_used(used);
+ }
+
+ const char* name_space() const { return _name_space; }
+};
+#endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_HSPACECOUNTERS_HPP
--- a/hotspot/src/share/vm/memory/cardTableModRefBS.cpp Wed Apr 20 20:32:45 2011 -0700
+++ b/hotspot/src/share/vm/memory/cardTableModRefBS.cpp Fri Apr 22 09:26:09 2011 -0700
@@ -456,31 +456,35 @@
}
-void CardTableModRefBS::non_clean_card_iterate(Space* sp,
- MemRegion mr,
- DirtyCardToOopClosure* dcto_cl,
- MemRegionClosure* cl) {
+void CardTableModRefBS::non_clean_card_iterate_possibly_parallel(Space* sp,
+ MemRegion mr,
+ DirtyCardToOopClosure* dcto_cl,
+ ClearNoncleanCardWrapper* cl) {
if (!mr.is_empty()) {
int n_threads = SharedHeap::heap()->n_par_threads();
if (n_threads > 0) {
#ifndef SERIALGC
- par_non_clean_card_iterate_work(sp, mr, dcto_cl, cl, n_threads);
+ non_clean_card_iterate_parallel_work(sp, mr, dcto_cl, cl, n_threads);
#else // SERIALGC
fatal("Parallel gc not supported here.");
#endif // SERIALGC
} else {
- non_clean_card_iterate_work(mr, cl);
+ // We do not call the non_clean_card_iterate_serial() version below because
+ // we want to clear the cards (which non_clean_card_iterate_serial() does not
+ // do for us), and the ClearNoncleanCardWrapper closure itself does the work
+ // of finding contiguous dirty ranges of cards to process (and clear).
+ cl->do_MemRegion(mr);
}
}
}
-// NOTE: For this to work correctly, it is important that
-// we look for non-clean cards below (so as to catch those
-// marked precleaned), rather than look explicitly for dirty
-// cards (and miss those marked precleaned). In that sense,
-// the name precleaned is currently somewhat of a misnomer.
-void CardTableModRefBS::non_clean_card_iterate_work(MemRegion mr,
- MemRegionClosure* cl) {
+// The iterator itself is not MT-aware, but
+// MT-aware callers and closures can use this to
+// accomplish dirty card iteration in parallel. The
+// iterator itself does not clear the dirty cards, or
+// change their values in any manner.
+void CardTableModRefBS::non_clean_card_iterate_serial(MemRegion mr,
+ MemRegionClosure* cl) {
for (int i = 0; i < _cur_covered_regions; i++) {
MemRegion mri = mr.intersection(_covered[i]);
if (mri.word_size() > 0) {
@@ -661,7 +665,7 @@
void CardTableModRefBS::verify_clean_region(MemRegion mr) {
GuaranteeNotModClosure blk(this);
- non_clean_card_iterate_work(mr, &blk);
+ non_clean_card_iterate_serial(mr, &blk);
}
// To verify a MemRegion is entirely dirty this closure is passed to
--- a/hotspot/src/share/vm/memory/cardTableModRefBS.hpp Wed Apr 20 20:32:45 2011 -0700
+++ b/hotspot/src/share/vm/memory/cardTableModRefBS.hpp Fri Apr 22 09:26:09 2011 -0700
@@ -44,6 +44,7 @@
class Generation;
class OopsInGenClosure;
class DirtyCardToOopClosure;
+class ClearNoncleanCardWrapper;
class CardTableModRefBS: public ModRefBarrierSet {
// Some classes get to look at some private stuff.
@@ -165,22 +166,28 @@
// Iterate over the portion of the card-table which covers the given
// region mr in the given space and apply cl to any dirty sub-regions
- // of mr. cl and dcto_cl must either be the same closure or cl must
- // wrap dcto_cl. Both are required - neither may be NULL. Also, dcto_cl
- // may be modified. Note that this function will operate in a parallel
- // mode if worker threads are available.
- void non_clean_card_iterate(Space* sp, MemRegion mr,
- DirtyCardToOopClosure* dcto_cl,
- MemRegionClosure* cl);
+ // of mr. Dirty cards are _not_ cleared by the iterator method itself,
+ // but closures may arrange to do so on their own should they so wish.
+ void non_clean_card_iterate_serial(MemRegion mr, MemRegionClosure* cl);
- // Utility function used to implement the other versions below.
- void non_clean_card_iterate_work(MemRegion mr, MemRegionClosure* cl);
+ // A variant of the above that will operate in a parallel mode if
+ // worker threads are available, and clear the dirty cards as it
+ // processes them.
+ // ClearNoncleanCardWrapper cl must wrap the DirtyCardToOopClosure dcto_cl,
+ // which may itself be modified by the method.
+ void non_clean_card_iterate_possibly_parallel(Space* sp, MemRegion mr,
+ DirtyCardToOopClosure* dcto_cl,
+ ClearNoncleanCardWrapper* cl);
- void par_non_clean_card_iterate_work(Space* sp, MemRegion mr,
- DirtyCardToOopClosure* dcto_cl,
- MemRegionClosure* cl,
- int n_threads);
+ private:
+ // Work method used to implement non_clean_card_iterate_possibly_parallel()
+ // above in the parallel case.
+ void non_clean_card_iterate_parallel_work(Space* sp, MemRegion mr,
+ DirtyCardToOopClosure* dcto_cl,
+ ClearNoncleanCardWrapper* cl,
+ int n_threads);
+ protected:
// Dirty the bytes corresponding to "mr" (not all of which must be
// covered.)
void dirty_MemRegion(MemRegion mr);
@@ -237,7 +244,7 @@
MemRegion used,
jint stride, int n_strides,
DirtyCardToOopClosure* dcto_cl,
- MemRegionClosure* cl,
+ ClearNoncleanCardWrapper* cl,
jbyte** lowest_non_clean,
uintptr_t lowest_non_clean_base_chunk_index,
size_t lowest_non_clean_chunk_size);
@@ -409,14 +416,14 @@
// marking, where a dirty card may cause scanning, and summarization
// marking, of objects that extend onto subsequent cards.)
void mod_card_iterate(MemRegionClosure* cl) {
- non_clean_card_iterate_work(_whole_heap, cl);
+ non_clean_card_iterate_serial(_whole_heap, cl);
}
// Like the "mod_cards_iterate" above, except only invokes the closure
// for cards within the MemRegion "mr" (which is required to be
// card-aligned and sized.)
void mod_card_iterate(MemRegion mr, MemRegionClosure* cl) {
- non_clean_card_iterate_work(mr, cl);
+ non_clean_card_iterate_serial(mr, cl);
}
static uintx ct_max_alignment_constraint();
@@ -493,4 +500,5 @@
void set_CTRS(CardTableRS* rs) { _rs = rs; }
};
+
#endif // SHARE_VM_MEMORY_CARDTABLEMODREFBS_HPP
--- a/hotspot/src/share/vm/memory/cardTableRS.cpp Wed Apr 20 20:32:45 2011 -0700
+++ b/hotspot/src/share/vm/memory/cardTableRS.cpp Fri Apr 22 09:26:09 2011 -0700
@@ -105,107 +105,111 @@
g->younger_refs_iterate(blk);
}
-class ClearNoncleanCardWrapper: public MemRegionClosure {
- MemRegionClosure* _dirty_card_closure;
- CardTableRS* _ct;
- bool _is_par;
-private:
- // Clears the given card, return true if the corresponding card should be
- // processed.
- bool clear_card(jbyte* entry) {
- if (_is_par) {
- while (true) {
- // In the parallel case, we may have to do this several times.
- jbyte entry_val = *entry;
- assert(entry_val != CardTableRS::clean_card_val(),
- "We shouldn't be looking at clean cards, and this should "
- "be the only place they get cleaned.");
- if (CardTableRS::card_is_dirty_wrt_gen_iter(entry_val)
- || _ct->is_prev_youngergen_card_val(entry_val)) {
- jbyte res =
- Atomic::cmpxchg(CardTableRS::clean_card_val(), entry, entry_val);
- if (res == entry_val) {
- break;
- } else {
- assert(res == CardTableRS::cur_youngergen_and_prev_nonclean_card,
- "The CAS above should only fail if another thread did "
- "a GC write barrier.");
- }
- } else if (entry_val ==
- CardTableRS::cur_youngergen_and_prev_nonclean_card) {
- // Parallelism shouldn't matter in this case. Only the thread
- // assigned to scan the card should change this value.
- *entry = _ct->cur_youngergen_card_val();
- break;
- } else {
- assert(entry_val == _ct->cur_youngergen_card_val(),
- "Should be the only possibility.");
- // In this case, the card was clean before, and become
- // cur_youngergen only because of processing of a promoted object.
- // We don't have to look at the card.
- return false;
- }
+inline bool ClearNoncleanCardWrapper::clear_card(jbyte* entry) {
+ if (_is_par) {
+ return clear_card_parallel(entry);
+ } else {
+ return clear_card_serial(entry);
+ }
+}
+
+inline bool ClearNoncleanCardWrapper::clear_card_parallel(jbyte* entry) {
+ while (true) {
+ // In the parallel case, we may have to do this several times.
+ jbyte entry_val = *entry;
+ assert(entry_val != CardTableRS::clean_card_val(),
+ "We shouldn't be looking at clean cards, and this should "
+ "be the only place they get cleaned.");
+ if (CardTableRS::card_is_dirty_wrt_gen_iter(entry_val)
+ || _ct->is_prev_youngergen_card_val(entry_val)) {
+ jbyte res =
+ Atomic::cmpxchg(CardTableRS::clean_card_val(), entry, entry_val);
+ if (res == entry_val) {
+ break;
+ } else {
+ assert(res == CardTableRS::cur_youngergen_and_prev_nonclean_card,
+ "The CAS above should only fail if another thread did "
+ "a GC write barrier.");
}
- return true;
+ } else if (entry_val ==
+ CardTableRS::cur_youngergen_and_prev_nonclean_card) {
+ // Parallelism shouldn't matter in this case. Only the thread
+ // assigned to scan the card should change this value.
+ *entry = _ct->cur_youngergen_card_val();
+ break;
} else {
- jbyte entry_val = *entry;
- assert(entry_val != CardTableRS::clean_card_val(),
- "We shouldn't be looking at clean cards, and this should "
- "be the only place they get cleaned.");
- assert(entry_val != CardTableRS::cur_youngergen_and_prev_nonclean_card,
- "This should be possible in the sequential case.");
- *entry = CardTableRS::clean_card_val();
- return true;
+ assert(entry_val == _ct->cur_youngergen_card_val(),
+ "Should be the only possibility.");
+ // In this case, the card was clean before, and become
+ // cur_youngergen only because of processing of a promoted object.
+ // We don't have to look at the card.
+ return false;
}
}
+ return true;
+}
-public:
- ClearNoncleanCardWrapper(MemRegionClosure* dirty_card_closure,
- CardTableRS* ct) :
+
+inline bool ClearNoncleanCardWrapper::clear_card_serial(jbyte* entry) {
+ jbyte entry_val = *entry;
+ assert(entry_val != CardTableRS::clean_card_val(),
+ "We shouldn't be looking at clean cards, and this should "
+ "be the only place they get cleaned.");
+ assert(entry_val != CardTableRS::cur_youngergen_and_prev_nonclean_card,
+ "This should be possible in the sequential case.");
+ *entry = CardTableRS::clean_card_val();
+ return true;
+}
+
+ClearNoncleanCardWrapper::ClearNoncleanCardWrapper(
+ MemRegionClosure* dirty_card_closure, CardTableRS* ct) :
_dirty_card_closure(dirty_card_closure), _ct(ct) {
_is_par = (SharedHeap::heap()->n_par_threads() > 0);
+}
+
+void ClearNoncleanCardWrapper::do_MemRegion(MemRegion mr) {
+ assert(mr.word_size() > 0, "Error");
+ assert(_ct->is_aligned(mr.start()), "mr.start() should be card aligned");
+ // mr.end() may not necessarily be card aligned.
+ jbyte* cur_entry = _ct->byte_for(mr.last());
+ const jbyte* limit = _ct->byte_for(mr.start());
+ HeapWord* end_of_non_clean = mr.end();
+ HeapWord* start_of_non_clean = end_of_non_clean;
+ while (cur_entry >= limit) {
+ HeapWord* cur_hw = _ct->addr_for(cur_entry);
+ if ((*cur_entry != CardTableRS::clean_card_val()) && clear_card(cur_entry)) {
+ // Continue the dirty range by opening the
+ // dirty window one card to the left.
+ start_of_non_clean = cur_hw;
+ } else {
+ // We hit a "clean" card; process any non-empty
+ // "dirty" range accumulated so far.
+ if (start_of_non_clean < end_of_non_clean) {
+ const MemRegion mrd(start_of_non_clean, end_of_non_clean);
+ _dirty_card_closure->do_MemRegion(mrd);
+ }
+ // Reset the dirty window, while continuing to look
+ // for the next dirty card that will start a
+ // new dirty window.
+ end_of_non_clean = cur_hw;
+ start_of_non_clean = cur_hw;
+ }
+ // Note that "cur_entry" leads "start_of_non_clean" in
+ // its leftward excursion after this point
+ // in the loop and, when we hit the left end of "mr",
+ // will point off of the left end of the card-table
+ // for "mr".
+ cur_entry--;
}
- void do_MemRegion(MemRegion mr) {
- // We start at the high end of "mr", walking backwards
- // while accumulating a contiguous dirty range of cards in
- // [start_of_non_clean, end_of_non_clean) which we then
- // process en masse.
- HeapWord* end_of_non_clean = mr.end();
- HeapWord* start_of_non_clean = end_of_non_clean;
- jbyte* entry = _ct->byte_for(mr.last());
- const jbyte* first_entry = _ct->byte_for(mr.start());
- while (entry >= first_entry) {
- HeapWord* cur = _ct->addr_for(entry);
- if (!clear_card(entry)) {
- // We hit a clean card; process any non-empty
- // dirty range accumulated so far.
- if (start_of_non_clean < end_of_non_clean) {
- MemRegion mr2(start_of_non_clean, end_of_non_clean);
- _dirty_card_closure->do_MemRegion(mr2);
- }
- // Reset the dirty window while continuing to
- // look for the next dirty window to process.
- end_of_non_clean = cur;
- start_of_non_clean = end_of_non_clean;
- }
- // Open the left end of the window one card to the left.
- start_of_non_clean = cur;
- // Note that "entry" leads "start_of_non_clean" in
- // its leftward excursion after this point
- // in the loop and, when we hit the left end of "mr",
- // will point off of the left end of the card-table
- // for "mr".
- entry--;
- }
- // If the first card of "mr" was dirty, we will have
- // been left with a dirty window, co-initial with "mr",
- // which we now process.
- if (start_of_non_clean < end_of_non_clean) {
- MemRegion mr2(start_of_non_clean, end_of_non_clean);
- _dirty_card_closure->do_MemRegion(mr2);
- }
+ // If the first card of "mr" was dirty, we will have
+ // been left with a dirty window, co-initial with "mr",
+ // which we now process.
+ if (start_of_non_clean < end_of_non_clean) {
+ const MemRegion mrd(start_of_non_clean, end_of_non_clean);
+ _dirty_card_closure->do_MemRegion(mrd);
}
-};
+}
+
// clean (by dirty->clean before) ==> cur_younger_gen
// dirty ==> cur_youngergen_and_prev_nonclean_card
// precleaned ==> cur_youngergen_and_prev_nonclean_card
@@ -246,8 +250,8 @@
cl->gen_boundary());
ClearNoncleanCardWrapper clear_cl(dcto_cl, this);
- _ct_bs->non_clean_card_iterate(sp, sp->used_region_at_save_marks(),
- dcto_cl, &clear_cl);
+ _ct_bs->non_clean_card_iterate_possibly_parallel(sp, sp->used_region_at_save_marks(),
+ dcto_cl, &clear_cl);
}
void CardTableRS::clear_into_younger(Generation* gen, bool clear_perm) {
--- a/hotspot/src/share/vm/memory/cardTableRS.hpp Wed Apr 20 20:32:45 2011 -0700
+++ b/hotspot/src/share/vm/memory/cardTableRS.hpp Fri Apr 22 09:26:09 2011 -0700
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2011, Oracle and/or its affiliates. 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
@@ -166,4 +166,21 @@
};
+class ClearNoncleanCardWrapper: public MemRegionClosure {
+ MemRegionClosure* _dirty_card_closure;
+ CardTableRS* _ct;
+ bool _is_par;
+private:
+ // Clears the given card, return true if the corresponding card should be
+ // processed.
+ inline bool clear_card(jbyte* entry);
+ // Work methods called by the clear_card()
+ inline bool clear_card_serial(jbyte* entry);
+ inline bool clear_card_parallel(jbyte* entry);
+
+public:
+ ClearNoncleanCardWrapper(MemRegionClosure* dirty_card_closure, CardTableRS* ct);
+ void do_MemRegion(MemRegion mr);
+};
+
#endif // SHARE_VM_MEMORY_CARDTABLERS_HPP
--- a/hotspot/src/share/vm/services/g1MemoryPool.cpp Wed Apr 20 20:32:45 2011 -0700
+++ b/hotspot/src/share/vm/services/g1MemoryPool.cpp Fri Apr 22 09:26:09 2011 -0700
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2011, Oracle and/or its affiliates. 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
@@ -34,10 +34,10 @@
size_t init_size,
bool support_usage_threshold) :
_g1h(g1h), CollectedMemoryPool(name,
- MemoryPool::Heap,
- init_size,
- undefined_max(),
- support_usage_threshold) {
+ MemoryPool::Heap,
+ init_size,
+ undefined_max(),
+ support_usage_threshold) {
assert(UseG1GC, "sanity");
}
@@ -48,44 +48,27 @@
// See the comment at the top of g1MemoryPool.hpp
size_t G1MemoryPoolSuper::eden_space_used(G1CollectedHeap* g1h) {
- size_t young_list_length = g1h->young_list()->length();
- size_t eden_used = young_list_length * HeapRegion::GrainBytes;
- size_t survivor_used = survivor_space_used(g1h);
- eden_used = subtract_up_to_zero(eden_used, survivor_used);
- return eden_used;
+ return g1h->g1mm()->eden_space_used();
}
// See the comment at the top of g1MemoryPool.hpp
size_t G1MemoryPoolSuper::survivor_space_committed(G1CollectedHeap* g1h) {
- return MAX2(survivor_space_used(g1h), (size_t) HeapRegion::GrainBytes);
+ return g1h->g1mm()->survivor_space_committed();
}
// See the comment at the top of g1MemoryPool.hpp
size_t G1MemoryPoolSuper::survivor_space_used(G1CollectedHeap* g1h) {
- size_t survivor_num = g1h->g1_policy()->recorded_survivor_regions();
- size_t survivor_used = survivor_num * HeapRegion::GrainBytes;
- return survivor_used;
+ return g1h->g1mm()->survivor_space_used();
}
// See the comment at the top of g1MemoryPool.hpp
size_t G1MemoryPoolSuper::old_space_committed(G1CollectedHeap* g1h) {
- size_t committed = overall_committed(g1h);
- size_t eden_committed = eden_space_committed(g1h);
- size_t survivor_committed = survivor_space_committed(g1h);
- committed = subtract_up_to_zero(committed, eden_committed);
- committed = subtract_up_to_zero(committed, survivor_committed);
- committed = MAX2(committed, (size_t) HeapRegion::GrainBytes);
- return committed;
+ return g1h->g1mm()->old_space_committed();
}
// See the comment at the top of g1MemoryPool.hpp
size_t G1MemoryPoolSuper::old_space_used(G1CollectedHeap* g1h) {
- size_t used = overall_used(g1h);
- size_t eden_used = eden_space_used(g1h);
- size_t survivor_used = survivor_space_used(g1h);
- used = subtract_up_to_zero(used, eden_used);
- used = subtract_up_to_zero(used, survivor_used);
- return used;
+ return g1h->g1mm()->old_space_used();
}
G1EdenPool::G1EdenPool(G1CollectedHeap* g1h) :
--- a/hotspot/src/share/vm/services/g1MemoryPool.hpp Wed Apr 20 20:32:45 2011 -0700
+++ b/hotspot/src/share/vm/services/g1MemoryPool.hpp Fri Apr 22 09:26:09 2011 -0700
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2011, Oracle and/or its affiliates. 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
@@ -46,68 +46,9 @@
// get, as this does affect the performance and behavior of G1. Which
// is why we introduce the three memory pools implemented here.
//
-// The above approach inroduces a couple of challenging issues in the
-// implementation of the three memory pools:
-//
-// 1) The used space calculation for a pool is not necessarily
-// independent of the others. We can easily get from G1 the overall
-// used space in the entire heap, the number of regions in the young
-// generation (includes both eden and survivors), and the number of
-// survivor regions. So, from that we calculate:
-//
-// survivor_used = survivor_num * region_size
-// eden_used = young_region_num * region_size - survivor_used
-// old_gen_used = overall_used - eden_used - survivor_used
-//
-// Note that survivor_used and eden_used are upper bounds. To get the
-// actual value we would have to iterate over the regions and add up
-// ->used(). But that'd be expensive. So, we'll accept some lack of
-// accuracy for those two. But, we have to be careful when calculating
-// old_gen_used, in case we subtract from overall_used more then the
-// actual number and our result goes negative.
-//
-// 2) Calculating the used space is straightforward, as described
-// above. However, how do we calculate the committed space, given that
-// we allocate space for the eden, survivor, and old gen out of the
-// same pool of regions? One way to do this is to use the used value
-// as also the committed value for the eden and survivor spaces and
-// then calculate the old gen committed space as follows:
-//
-// old_gen_committed = overall_committed - eden_committed - survivor_committed
+// See comments in g1MonitoringSupport.hpp for additional details
+// on this model.
//
-// Maybe a better way to do that would be to calculate used for eden
-// and survivor as a sum of ->used() over their regions and then
-// calculate committed as region_num * region_size (i.e., what we use
-// to calculate the used space now). This is something to consider
-// in the future.
-//
-// 3) Another decision that is again not straightforward is what is
-// the max size that each memory pool can grow to. One way to do this
-// would be to use the committed size for the max for the eden and
-// survivors and calculate the old gen max as follows (basically, it's
-// a similar pattern to what we use for the committed space, as
-// described above):
-//
-// old_gen_max = overall_max - eden_max - survivor_max
-//
-// Unfortunately, the above makes the max of each pool fluctuate over
-// time and, even though this is allowed according to the spec, it
-// broke several assumptions in the M&M framework (there were cases
-// where used would reach a value greater than max). So, for max we
-// use -1, which means "undefined" according to the spec.
-//
-// 4) Now, there is a very subtle issue with all the above. The
-// framework will call get_memory_usage() on the three pools
-// asynchronously. As a result, each call might get a different value
-// for, say, survivor_num which will yield inconsistent values for
-// eden_used, survivor_used, and old_gen_used (as survivor_num is used
-// in the calculation of all three). This would normally be
-// ok. However, it's possible that this might cause the sum of
-// eden_used, survivor_used, and old_gen_used to go over the max heap
-// size and this seems to sometimes cause JConsole (and maybe other
-// clients) to get confused. There's not a really an easy / clean
-// solution to this problem, due to the asynchrounous nature of the
-// framework.
// This class is shared by the three G1 memory pool classes
@@ -116,22 +57,6 @@
// (see comment above), we put the calculations in this class so that
// we can easily share them among the subclasses.
class G1MemoryPoolSuper : public CollectedMemoryPool {
-private:
- // It returns x - y if x > y, 0 otherwise.
- // As described in the comment above, some of the inputs to the
- // calculations we have to do are obtained concurrently and hence
- // may be inconsistent with each other. So, this provides a
- // defensive way of performing the subtraction and avoids the value
- // going negative (which would mean a very large result, given that
- // the parameter are size_t).
- static size_t subtract_up_to_zero(size_t x, size_t y) {
- if (x > y) {
- return x - y;
- } else {
- return 0;
- }
- }
-
protected:
G1CollectedHeap* _g1h;
@@ -148,13 +73,6 @@
return (size_t) -1;
}
- static size_t overall_committed(G1CollectedHeap* g1h) {
- return g1h->capacity();
- }
- static size_t overall_used(G1CollectedHeap* g1h) {
- return g1h->used_unlocked();
- }
-
static size_t eden_space_committed(G1CollectedHeap* g1h);
static size_t eden_space_used(G1CollectedHeap* g1h);