1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
|
/* A handle to a source of mapped memory
(C) 2021 Niall Douglas <http://www.nedproductions.biz/> (10 commits)
File Created: Aug 2021
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License in the accompanying file
Licence.txt or at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
Distributed under the Boost Software License, Version 1.0.
(See accompanying file Licence.txt or copy at
http://www.boost.org/LICENSE_1_0.txt)
*/
#include "../../map_handle.hpp"
#include "../../utils.hpp"
#include <chrono>
#include <mutex>
#include <quickcpplib/algorithm/bitwise_trie.hpp>
LLFIO_V2_NAMESPACE_BEGIN
namespace detail
{
struct map_handle_cache_item_t
{
map_handle_cache_item_t *trie_parent{nullptr};
map_handle_cache_item_t *trie_child[2];
map_handle_cache_item_t *trie_sibling[2];
size_t trie_key{0}; // allocation size shifted right by map_handle_cache_page_size_shift
size_t page_size{0};
void *addr{nullptr};
std::chrono::steady_clock::time_point when_added{std::chrono::steady_clock::now()};
map_handle_cache_item_t(size_t key, size_t _page_size, void *_addr)
: trie_key(key)
, page_size(_page_size)
, addr(_addr)
{
}
};
struct map_handle_cache_base_t
{
std::mutex lock;
size_t trie_count{0};
map_handle_cache_item_t *trie_children[8 * sizeof(size_t)];
bool trie_nobbledir{0};
size_t bytes_in_cache{0};
};
static const size_t page_size_shift = [] { return QUICKCPPLIB_NAMESPACE::algorithm::bitwise_trie::detail::bitscanr(utils::page_size()); }();
class map_handle_cache_t : protected QUICKCPPLIB_NAMESPACE::algorithm::bitwise_trie::bitwise_trie<map_handle_cache_base_t, map_handle_cache_item_t>
{
using _base = QUICKCPPLIB_NAMESPACE::algorithm::bitwise_trie::bitwise_trie<map_handle_cache_base_t, map_handle_cache_item_t>;
using _lock_guard = std::unique_lock<std::mutex>;
public:
std::atomic<unsigned> do_not_store_failed_count{0};
using _base::size;
void *get(size_t bytes, size_t page_size)
{
const auto _bytes = bytes >> page_size_shift;
_lock_guard g(lock);
auto it = _base::find_equal_or_larger(_bytes, 7 /* 99% close to the key after page size shift */);
for(; it != _base::end() && page_size != it->page_size && _bytes == it->trie_key; ++it)
{
}
if(it == _base::end() || page_size != it->page_size || _bytes != it->trie_key)
{
return nullptr;
}
auto *p = *it;
_base::erase(it);
_base::bytes_in_cache -= bytes;
assert(bytes == p->trie_key << page_size_shift);
g.unlock();
void *ret = p->addr;
delete p;
return ret;
}
void add(size_t bytes, size_t page_size, void *addr)
{
const auto _bytes = bytes >> page_size_shift;
auto *p = new map_handle_cache_item_t(_bytes, page_size, addr);
_lock_guard g(lock);
_base::insert(p);
_base::bytes_in_cache += bytes;
}
map_handle::cache_statistics trim_cache(std::chrono::steady_clock::time_point older_than)
{
_lock_guard g(lock);
map_handle::cache_statistics ret;
if(older_than != std::chrono::steady_clock::time_point())
{
for(auto it = _base::begin(); it != _base::end();)
{
if(it->when_added < older_than)
{
auto *p = *it;
it = _base::erase(it);
const auto _bytes = p->trie_key << page_size_shift;
_base::bytes_in_cache -= _bytes;
ret.bytes_just_trimmed += _bytes;
ret.items_just_trimmed++;
delete p;
}
else
{
++it;
}
}
}
ret.items_in_cache = _base::size();
ret.bytes_in_cache = _base::bytes_in_cache;
return ret;
}
};
extern inline QUICKCPPLIB_SYMBOL_EXPORT map_handle_cache_t &map_handle_cache()
{
static map_handle_cache_t v;
return v;
}
} // namespace detail
result<map_handle> map_handle::_recycled_map(size_type bytes, section_handle::flag _flag) noexcept
{
if(bytes == 0u)
{
return errc::argument_out_of_domain;
}
result<map_handle> ret(map_handle(nullptr, _flag));
native_handle_type &nativeh = ret.value()._v;
OUTCOME_TRY(auto &&pagesize, detail::pagesize_from_flags(ret.value()._flag));
bytes = utils::round_up_to_page_size(bytes, pagesize);
LLFIO_LOG_FUNCTION_CALL(&ret);
void *addr = detail::map_handle_cache().get(bytes, pagesize);
if(addr == nullptr)
{
return _new_map(bytes, _flag);
}
#ifdef _WIN32
{
DWORD allocation = MEM_COMMIT, prot;
size_t commitsize;
OUTCOME_TRY(win32_map_flags(nativeh, allocation, prot, commitsize, true, _flag));
if(VirtualAlloc(addr, bytes, allocation, prot) == nullptr)
{
return win32_error();
}
// Windows has no way of getting the kernel to prefault maps on creation, so ...
if(_flag & section_handle::flag::prefault)
{
using namespace windows_nt_kernel;
// Start an asynchronous prefetch, so it might fault the whole lot in at once
buffer_type b{static_cast<byte *>(addr), bytes};
(void) prefetch(span<buffer_type>(&b, 1));
volatile auto *a = static_cast<volatile char *>(addr);
for(size_t n = 0; n < bytes; n += pagesize)
{
a[n];
}
}
}
#else
int flags = MAP_FIXED;
#ifdef MAP_POPULATE
if(_flag & section_handle::flag::prefault)
{
flags |= MAP_POPULATE;
}
#endif
#ifdef MAP_PREFAULT_READ
if(_flag & section_handle::flag::prefault)
flags |= MAP_PREFAULT_READ;
#endif
OUTCOME_TRY(do_mmap(nativeh, addr, flags, nullptr, pagesize, bytes, 0, _flag));
#endif
ret.value()._addr = static_cast<byte *>(addr);
ret.value()._reservation = bytes;
ret.value()._length = bytes;
ret.value()._pagesize = pagesize;
nativeh._init = -2; // otherwise appears closed
nativeh.behaviour |= native_handle_type::disposition::allocation;
return ret;
}
bool map_handle::_recycle_map() noexcept
{
try
{
LLFIO_LOG_FUNCTION_CALL(this);
auto &c = detail::map_handle_cache();
#ifdef _WIN32
if(!win32_release_nonfile_allocations(_addr, _length, MEM_DECOMMIT))
{
return false;
}
#else
if(memory_accounting() == memory_accounting_kind::commit_charge)
{
if(!do_mmap(_v, _addr, MAP_FIXED, nullptr, _pagesize, _length, 0, section_handle::flag::none | section_handle::flag::nocommit))
{
return false;
}
}
else
{
#ifdef __linux__
if(c.do_not_store_failed_count.load(std::memory_order_relaxed) < 10)
{
auto r = do_not_store({_addr, _length});
if(!r)
{
c.do_not_store_failed_count.fetch_add(1, std::memory_order_relaxed);
}
}
#endif
}
#endif
c.add(_length, _pagesize, _addr);
return true; // cached
}
catch(...)
{
return false;
}
}
map_handle::cache_statistics map_handle::trim_cache(std::chrono::steady_clock::time_point older_than) noexcept
{
return detail::map_handle_cache().trim_cache(older_than);
}
LLFIO_V2_NAMESPACE_END
|
