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src/share/vm/gc/shared/cardTableRS.cpp

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   1 /*
   2  * Copyright (c) 2001, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *


 265     // will point off of the left end of the card-table
 266     // for "mr".
 267     cur_entry--;
 268   }
 269   // If the first card of "mr" was dirty, we will have
 270   // been left with a dirty window, co-initial with "mr",
 271   // which we now process.
 272   if (start_of_non_clean < end_of_non_clean) {
 273     const MemRegion mrd(start_of_non_clean, end_of_non_clean);
 274     _dirty_card_closure->do_MemRegion(mrd);
 275   }
 276 }
 277 
 278 // clean (by dirty->clean before) ==> cur_younger_gen
 279 // dirty                          ==> cur_youngergen_and_prev_nonclean_card
 280 // precleaned                     ==> cur_youngergen_and_prev_nonclean_card
 281 // prev-younger-gen               ==> cur_youngergen_and_prev_nonclean_card
 282 // cur-younger-gen                ==> cur_younger_gen
 283 // cur_youngergen_and_prev_nonclean_card ==> no change.
 284 void CardTableRS::write_ref_field_gc_par(void* field, oop new_val) {
 285   jbyte* entry = _ct_bs->byte_for(field);
 286   do {
 287     jbyte entry_val = *entry;
 288     // We put this first because it's probably the most common case.
 289     if (entry_val == clean_card_val()) {
 290       // No threat of contention with cleaning threads.
 291       *entry = cur_youngergen_card_val();
 292       return;
 293     } else if (card_is_dirty_wrt_gen_iter(entry_val)
 294                || is_prev_youngergen_card_val(entry_val)) {
 295       // Mark it as both cur and prev youngergen; card cleaning thread will
 296       // eventually remove the previous stuff.
 297       jbyte new_val = cur_youngergen_and_prev_nonclean_card;
 298       jbyte res = Atomic::cmpxchg(new_val, entry, entry_val);
 299       // Did the CAS succeed?
 300       if (res == entry_val) return;
 301       // Otherwise, retry, to see the new value.
 302       continue;
 303     } else {
 304       assert(entry_val == cur_youngergen_and_prev_nonclean_card
 305              || entry_val == cur_youngergen_card_val(),


   1 /*
   2  * Copyright (c) 2001, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *


 265     // will point off of the left end of the card-table
 266     // for "mr".
 267     cur_entry--;
 268   }
 269   // If the first card of "mr" was dirty, we will have
 270   // been left with a dirty window, co-initial with "mr",
 271   // which we now process.
 272   if (start_of_non_clean < end_of_non_clean) {
 273     const MemRegion mrd(start_of_non_clean, end_of_non_clean);
 274     _dirty_card_closure->do_MemRegion(mrd);
 275   }
 276 }
 277 
 278 // clean (by dirty->clean before) ==> cur_younger_gen
 279 // dirty                          ==> cur_youngergen_and_prev_nonclean_card
 280 // precleaned                     ==> cur_youngergen_and_prev_nonclean_card
 281 // prev-younger-gen               ==> cur_youngergen_and_prev_nonclean_card
 282 // cur-younger-gen                ==> cur_younger_gen
 283 // cur_youngergen_and_prev_nonclean_card ==> no change.
 284 void CardTableRS::write_ref_field_gc_par(void* field, oop new_val) {
 285   volatile jbyte* entry = _ct_bs->byte_for(field);
 286   do {
 287     jbyte entry_val = *entry;
 288     // We put this first because it's probably the most common case.
 289     if (entry_val == clean_card_val()) {
 290       // No threat of contention with cleaning threads.
 291       *entry = cur_youngergen_card_val();
 292       return;
 293     } else if (card_is_dirty_wrt_gen_iter(entry_val)
 294                || is_prev_youngergen_card_val(entry_val)) {
 295       // Mark it as both cur and prev youngergen; card cleaning thread will
 296       // eventually remove the previous stuff.
 297       jbyte new_val = cur_youngergen_and_prev_nonclean_card;
 298       jbyte res = Atomic::cmpxchg(new_val, entry, entry_val);
 299       // Did the CAS succeed?
 300       if (res == entry_val) return;
 301       // Otherwise, retry, to see the new value.
 302       continue;
 303     } else {
 304       assert(entry_val == cur_youngergen_and_prev_nonclean_card
 305              || entry_val == cur_youngergen_card_val(),


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