1 /*
2 * Copyright (c) 2013, 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 *
23 */
24
25 #ifndef SHARE_VM_GC_G1_G1FROMCARDCACHE_HPP
26 #define SHARE_VM_GC_G1_G1FROMCARDCACHE_HPP
27
28 #include "memory/allocation.hpp"
29 #include "utilities/ostream.hpp"
30
31 // G1FromCardCache remembers the most recently processed card on the heap on
32 // a per-region and per-thread basis.
33 class G1FromCardCache : public AllStatic {
34 private:
35 // Array of card indices. Indexed by heap region (rows) and thread (columns) to minimize
36 // thread contention.
37 // This order minimizes the time to clear all entries for a given region during region
38 // freeing. I.e. a single clear of a single memory area instead of multiple separate
39 // accesses with a large stride per region.
40 static uintptr_t** _cache;
41 static uint _max_regions;
42 static size_t _static_mem_size;
43 #ifdef ASSERT
44 static uint _max_workers;
45
46 static void check_bounds(uint worker_id, uint region_idx) {
47 assert(worker_id < _max_workers, "Worker_id %u is larger than maximum %u", worker_id, _max_workers);
48 assert(region_idx < _max_regions, "Region_idx %u is larger than maximum %u", region_idx, _max_regions);
49 }
50 #endif
51
52 public:
53 static const uintptr_t InvalidCard = UINTPTR_MAX;
54
55 static void clear(uint region_idx);
56
57 // Returns true if the given card is in the cache at the given location, or
58 // replaces the card at that location and returns false.
59 static bool contains_or_replace(uint worker_id, uint region_idx, uintptr_t card) {
60 uintptr_t card_in_cache = at(worker_id, region_idx);
61 if (card_in_cache == card) {
62 return true;
63 } else {
64 set(worker_id, region_idx, card);
65 return false;
66 }
67 }
68
69 static uintptr_t at(uint worker_id, uint region_idx) {
70 DEBUG_ONLY(check_bounds(worker_id, region_idx);)
71 return _cache[region_idx][worker_id];
72 }
73
74 static void set(uint worker_id, uint region_idx, uintptr_t val) {
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1 /*
2 * Copyright (c) 2013, 2018, 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 *
23 */
24
25 #ifndef SHARE_VM_GC_G1_G1FROMCARDCACHE_HPP
26 #define SHARE_VM_GC_G1_G1FROMCARDCACHE_HPP
27
28 #include "memory/allocation.hpp"
29 #include "utilities/ostream.hpp"
30
31 // G1FromCardCache remembers the most recently processed card on the heap on
32 // a per-region and per-thread basis.
33 class G1FromCardCache : public AllStatic {
34 private:
35 // Array of card indices. Indexed by heap region (rows) and thread (columns) to minimize
36 // thread contention.
37 // This order minimizes the time to clear all entries for a given region during region
38 // freeing. I.e. a single clear of a single memory area instead of multiple separate
39 // accesses with a large stride per region.
40 static uintptr_t** _cache;
41 static uint _max_regions;
42 static size_t _static_mem_size;
43 #ifdef ASSERT
44 static uint _max_workers;
45
46 static void check_bounds(uint worker_id, uint region_idx) {
47 assert(worker_id < _max_workers, "Worker_id %u is larger than maximum %u", worker_id, _max_workers);
48 assert(region_idx < _max_regions, "Region_idx %u is larger than maximum %u", region_idx, _max_regions);
49 }
50 #endif
51
52 // This card index indicates "no card for that entry" yet. This allows us to use the OS
53 // lazy backing of memory with zero-filled pages to avoid initial actual memory use.
54 // This means that the heap must not contain card zero.
55 static const uintptr_t InvalidCard = 0;
56
57 public:
58 static void clear(uint region_idx);
59
60 // Returns true if the given card is in the cache at the given location, or
61 // replaces the card at that location and returns false.
62 static bool contains_or_replace(uint worker_id, uint region_idx, uintptr_t card) {
63 uintptr_t card_in_cache = at(worker_id, region_idx);
64 if (card_in_cache == card) {
65 return true;
66 } else {
67 set(worker_id, region_idx, card);
68 return false;
69 }
70 }
71
72 static uintptr_t at(uint worker_id, uint region_idx) {
73 DEBUG_ONLY(check_bounds(worker_id, region_idx);)
74 return _cache[region_idx][worker_id];
75 }
76
77 static void set(uint worker_id, uint region_idx, uintptr_t val) {
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