view src/share/vm/services/dtraceAttacher.cpp @ 452:00b023ae2d78

6722113: CMS: Incorrect overflow handling during precleaning of Reference lists Summary: When we encounter marking stack overflow during precleaning of Reference lists, we were using the overflow list mechanism, which can cause problems on account of mutating the mark word of the header because of conflicts with mutator accesses and updates of that field. Instead we should use the usual mechanism for overflow handling in concurrent phases, namely dirtying of the card on which the overflowed object lies. Since precleaning effectively does a form of discovered list processing, albeit with discovery enabled, we needed to adjust some code to be correct in the face of interleaved processing and discovery. Reviewed-by: apetrusenko, jcoomes
author ysr
date Thu, 20 Nov 2008 12:27:41 -0800
parents a61af66fc99e
children e392695de029
line wrap: on
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/*
 * Copyright 2006-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 */

# include "incls/_precompiled.incl"
# include "incls/_dtraceAttacher.cpp.incl"

#ifdef SOLARIS

class VM_DeoptimizeTheWorld : public VM_Operation {
 public:
  VMOp_Type type() const {
    return VMOp_DeoptimizeTheWorld;
  }
  void doit() {
    CodeCache::mark_all_nmethods_for_deoptimization();
    ResourceMark rm;
    DeoptimizationMarker dm;
    // Deoptimize all activations depending on marked methods
    Deoptimization::deoptimize_dependents();

    // Mark the dependent methods non entrant
    CodeCache::make_marked_nmethods_not_entrant();
  }
};

static void set_bool_flag(const char* flag, bool value) {
  CommandLineFlags::boolAtPut((char*)flag, strlen(flag), &value,
                              ATTACH_ON_DEMAND);
}

// Enable only the "fine grained" flags. Do *not* touch
// the overall "ExtendedDTraceProbes" flag.
void DTrace::enable_dprobes(int probes) {
  bool changed = false;
  if (!DTraceAllocProbes && (probes & DTRACE_ALLOC_PROBES)) {
    set_bool_flag("DTraceAllocProbes", true);
    changed = true;
  }
  if (!DTraceMethodProbes && (probes & DTRACE_METHOD_PROBES)) {
    set_bool_flag("DTraceMethodProbes", true);
    changed = true;
  }
  if (!DTraceMonitorProbes && (probes & DTRACE_MONITOR_PROBES)) {
    set_bool_flag("DTraceMonitorProbes", true);
    changed = true;
  }

  if (changed) {
    // one or more flags changed, need to deoptimize
    VM_DeoptimizeTheWorld op;
    VMThread::execute(&op);
  }
}

// Disable only the "fine grained" flags. Do *not* touch
// the overall "ExtendedDTraceProbes" flag.
void DTrace::disable_dprobes(int probes) {
  bool changed = false;
  if (DTraceAllocProbes && (probes & DTRACE_ALLOC_PROBES)) {
    set_bool_flag("DTraceAllocProbes", false);
    changed = true;
  }
  if (DTraceMethodProbes && (probes & DTRACE_METHOD_PROBES)) {
    set_bool_flag("DTraceMethodProbes", false);
    changed = true;
  }
  if (DTraceMonitorProbes && (probes & DTRACE_MONITOR_PROBES)) {
    set_bool_flag("DTraceMonitorProbes", false);
    changed = true;
  }
  if (changed) {
    // one or more flags changed, need to deoptimize
    VM_DeoptimizeTheWorld op;
    VMThread::execute(&op);
  }
}

// Do clean-up on "all door clients detached" event.
void DTrace::detach_all_clients() {
  /*
   * We restore the state of the fine grained flags
   * to be consistent with overall ExtendedDTraceProbes.
   * This way, we will honour command line setting or the
   * last explicit modification of ExtendedDTraceProbes by
   * a call to set_extended_dprobes.
   */
  if (ExtendedDTraceProbes) {
    enable_dprobes(DTRACE_ALL_PROBES);
  } else {
    disable_dprobes(DTRACE_ALL_PROBES);
  }
}

void DTrace::set_extended_dprobes(bool flag) {
  // explicit setting of ExtendedDTraceProbes flag
  set_bool_flag("ExtendedDTraceProbes", flag);

  // make sure that the fine grained flags reflect the change.
  if (flag) {
    enable_dprobes(DTRACE_ALL_PROBES);
  } else {
    /*
     * FIXME: Revisit this: currently all-client-detach detection
     * does not work and hence disabled. The following scheme does
     * not work. So, we have to disable fine-grained flags here.
     *
     * disable_dprobes call has to be delayed till next "detach all "event.
     * This is to be  done so that concurrent DTrace clients that may
     * have enabled one or more fine grained dprobes and may be running
     * still. On "detach all" clients event, we would sync ExtendedDTraceProbes
     * with  fine grained flags which would take care of disabling fine grained flags.
     */
    disable_dprobes(DTRACE_ALL_PROBES);
  }
}

#endif /* SOLARIS */