Tue, 07 Jul 2009 14:23:00 -0400
6855834: G1: minimize the output when -XX:+PrintHeapAtGC is set
Summary: Changing the behavior of -XX:+PrintHeapAtGC for G1 from printing lengthy, per-region information to instead printing a concise summary.
Reviewed-by: ysr, apetrusenko, jcoomes
duke@435 | 1 | /* |
duke@435 | 2 | * Copyright 1997-2005 Sun Microsystems, Inc. All Rights Reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
duke@435 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
duke@435 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
duke@435 | 21 | * have any questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
duke@435 | 25 | # include "incls/_precompiled.incl" |
duke@435 | 26 | # include "incls/_sweeper.cpp.incl" |
duke@435 | 27 | |
duke@435 | 28 | long NMethodSweeper::_traversals = 0; // No. of stack traversals performed |
duke@435 | 29 | CodeBlob* NMethodSweeper::_current = NULL; // Current nmethod |
duke@435 | 30 | int NMethodSweeper::_seen = 0 ; // No. of blobs we have currently processed in current pass of CodeCache |
duke@435 | 31 | int NMethodSweeper::_invocations = 0; // No. of invocations left until we are completed with this pass |
duke@435 | 32 | |
duke@435 | 33 | jint NMethodSweeper::_locked_seen = 0; |
duke@435 | 34 | jint NMethodSweeper::_not_entrant_seen_on_stack = 0; |
duke@435 | 35 | bool NMethodSweeper::_rescan = false; |
duke@435 | 36 | |
duke@435 | 37 | void NMethodSweeper::sweep() { |
duke@435 | 38 | assert(SafepointSynchronize::is_at_safepoint(), "must be executed at a safepoint"); |
duke@435 | 39 | if (!MethodFlushing) return; |
duke@435 | 40 | |
duke@435 | 41 | // No need to synchronize access, since this is always executed at a |
duke@435 | 42 | // safepoint. If we aren't in the middle of scan and a rescan |
duke@435 | 43 | // hasn't been requested then just return. |
duke@435 | 44 | if (_current == NULL && !_rescan) return; |
duke@435 | 45 | |
duke@435 | 46 | // Make sure CompiledIC_lock in unlocked, since we might update some |
duke@435 | 47 | // inline caches. If it is, we just bail-out and try later. |
duke@435 | 48 | if (CompiledIC_lock->is_locked() || Patching_lock->is_locked()) return; |
duke@435 | 49 | |
duke@435 | 50 | // Check for restart |
duke@435 | 51 | assert(CodeCache::find_blob_unsafe(_current) == _current, "Sweeper nmethod cached state invalid"); |
duke@435 | 52 | if (_current == NULL) { |
duke@435 | 53 | _seen = 0; |
duke@435 | 54 | _invocations = NmethodSweepFraction; |
duke@435 | 55 | _current = CodeCache::first(); |
duke@435 | 56 | _traversals += 1; |
duke@435 | 57 | if (PrintMethodFlushing) { |
duke@435 | 58 | tty->print_cr("### Sweep: stack traversal %d", _traversals); |
duke@435 | 59 | } |
duke@435 | 60 | Threads::nmethods_do(); |
duke@435 | 61 | |
duke@435 | 62 | // reset the flags since we started a scan from the beginning. |
duke@435 | 63 | _rescan = false; |
duke@435 | 64 | _locked_seen = 0; |
duke@435 | 65 | _not_entrant_seen_on_stack = 0; |
duke@435 | 66 | } |
duke@435 | 67 | |
duke@435 | 68 | if (PrintMethodFlushing && Verbose) { |
duke@435 | 69 | tty->print_cr("### Sweep at %d out of %d. Invocations left: %d", _seen, CodeCache::nof_blobs(), _invocations); |
duke@435 | 70 | } |
duke@435 | 71 | |
duke@435 | 72 | // We want to visit all nmethods after NmethodSweepFraction invocations. |
duke@435 | 73 | // If invocation is 1 we do the rest |
duke@435 | 74 | int todo = CodeCache::nof_blobs(); |
duke@435 | 75 | if (_invocations != 1) { |
duke@435 | 76 | todo = (CodeCache::nof_blobs() - _seen) / _invocations; |
duke@435 | 77 | _invocations--; |
duke@435 | 78 | } |
duke@435 | 79 | |
duke@435 | 80 | for(int i = 0; i < todo && _current != NULL; i++) { |
duke@435 | 81 | CodeBlob* next = CodeCache::next(_current); // Read next before we potentially delete current |
duke@435 | 82 | if (_current->is_nmethod()) { |
duke@435 | 83 | process_nmethod((nmethod *)_current); |
duke@435 | 84 | } |
duke@435 | 85 | _seen++; |
duke@435 | 86 | _current = next; |
duke@435 | 87 | } |
duke@435 | 88 | // Because we could stop on a codeBlob other than an nmethod we skip forward |
duke@435 | 89 | // to the next nmethod (if any). codeBlobs other than nmethods can be freed |
duke@435 | 90 | // async to us and make _current invalid while we sleep. |
duke@435 | 91 | while (_current != NULL && !_current->is_nmethod()) { |
duke@435 | 92 | _current = CodeCache::next(_current); |
duke@435 | 93 | } |
duke@435 | 94 | |
duke@435 | 95 | if (_current == NULL && !_rescan && (_locked_seen || _not_entrant_seen_on_stack)) { |
duke@435 | 96 | // we've completed a scan without making progress but there were |
duke@435 | 97 | // nmethods we were unable to process either because they were |
duke@435 | 98 | // locked or were still on stack. We don't have to aggresively |
duke@435 | 99 | // clean them up so just stop scanning. We could scan once more |
duke@435 | 100 | // but that complicates the control logic and it's unlikely to |
duke@435 | 101 | // matter much. |
duke@435 | 102 | if (PrintMethodFlushing) { |
duke@435 | 103 | tty->print_cr("### Couldn't make progress on some nmethods so stopping sweep"); |
duke@435 | 104 | } |
duke@435 | 105 | } |
duke@435 | 106 | } |
duke@435 | 107 | |
duke@435 | 108 | |
duke@435 | 109 | void NMethodSweeper::process_nmethod(nmethod *nm) { |
duke@435 | 110 | // Skip methods that are currently referenced by the VM |
duke@435 | 111 | if (nm->is_locked_by_vm()) { |
duke@435 | 112 | // But still remember to clean-up inline caches for alive nmethods |
duke@435 | 113 | if (nm->is_alive()) { |
duke@435 | 114 | // Clean-up all inline caches that points to zombie/non-reentrant methods |
duke@435 | 115 | nm->cleanup_inline_caches(); |
duke@435 | 116 | } else { |
duke@435 | 117 | _locked_seen++; |
duke@435 | 118 | } |
duke@435 | 119 | return; |
duke@435 | 120 | } |
duke@435 | 121 | |
duke@435 | 122 | if (nm->is_zombie()) { |
duke@435 | 123 | // If it is first time, we see nmethod then we mark it. Otherwise, |
duke@435 | 124 | // we reclame it. When we have seen a zombie method twice, we know that |
duke@435 | 125 | // there are no inline caches that referes to it. |
duke@435 | 126 | if (nm->is_marked_for_reclamation()) { |
duke@435 | 127 | assert(!nm->is_locked_by_vm(), "must not flush locked nmethods"); |
duke@435 | 128 | nm->flush(); |
duke@435 | 129 | } else { |
duke@435 | 130 | nm->mark_for_reclamation(); |
duke@435 | 131 | _rescan = true; |
duke@435 | 132 | } |
duke@435 | 133 | } else if (nm->is_not_entrant()) { |
duke@435 | 134 | // If there is no current activations of this method on the |
duke@435 | 135 | // stack we can safely convert it to a zombie method |
duke@435 | 136 | if (nm->can_not_entrant_be_converted()) { |
duke@435 | 137 | nm->make_zombie(); |
duke@435 | 138 | _rescan = true; |
duke@435 | 139 | } else { |
duke@435 | 140 | // Still alive, clean up its inline caches |
duke@435 | 141 | nm->cleanup_inline_caches(); |
duke@435 | 142 | // we coudn't transition this nmethod so don't immediately |
duke@435 | 143 | // request a rescan. If this method stays on the stack for a |
duke@435 | 144 | // long time we don't want to keep rescanning at every safepoint. |
duke@435 | 145 | _not_entrant_seen_on_stack++; |
duke@435 | 146 | } |
duke@435 | 147 | } else if (nm->is_unloaded()) { |
duke@435 | 148 | // Unloaded code, just make it a zombie |
duke@435 | 149 | if (nm->is_osr_only_method()) { |
duke@435 | 150 | // No inline caches will ever point to osr methods, so we can just remove it |
duke@435 | 151 | nm->flush(); |
duke@435 | 152 | } else { |
duke@435 | 153 | nm->make_zombie(); |
duke@435 | 154 | _rescan = true; |
duke@435 | 155 | } |
duke@435 | 156 | } else { |
duke@435 | 157 | assert(nm->is_alive(), "should be alive"); |
duke@435 | 158 | // Clean-up all inline caches that points to zombie/non-reentrant methods |
duke@435 | 159 | nm->cleanup_inline_caches(); |
duke@435 | 160 | } |
duke@435 | 161 | } |