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
|
// SPDX-License-Identifier: GPL-3.0-or-later
#define WEB_SERVER_INTERNALS 1
#include "web_client_cache.h"
// ----------------------------------------------------------------------------
// allocate and free web_clients
static void web_client_zero(struct web_client *w) {
// zero everything about it - but keep the buffers
// remember the pointers to the buffers
BUFFER *b1 = w->response.data;
BUFFER *b2 = w->response.header;
BUFFER *b3 = w->response.header_output;
// empty the buffers
buffer_flush(b1);
buffer_flush(b2);
buffer_flush(b3);
freez(w->user_agent);
// zero everything
memset(w, 0, sizeof(struct web_client));
// restore the pointers of the buffers
w->response.data = b1;
w->response.header = b2;
w->response.header_output = b3;
}
static void web_client_free(struct web_client *w) {
buffer_free(w->response.header_output);
buffer_free(w->response.header);
buffer_free(w->response.data);
freez(w->user_agent);
freez(w);
}
static struct web_client *web_client_alloc(void) {
struct web_client *w = callocz(1, sizeof(struct web_client));
w->response.data = buffer_create(NETDATA_WEB_RESPONSE_INITIAL_SIZE);
w->response.header = buffer_create(NETDATA_WEB_RESPONSE_HEADER_SIZE);
w->response.header_output = buffer_create(NETDATA_WEB_RESPONSE_HEADER_SIZE);
return w;
}
// ----------------------------------------------------------------------------
// web clients caching
// When clients connect and disconnect, avoid allocating and releasing memory.
// Instead, when new clients get connected, reuse any memory previously allocated
// for serving web clients that are now disconnected.
// The size of the cache is adaptive. It caches the structures of 2x
// the number of currently connected clients.
// Comments per server:
// SINGLE-THREADED : 1 cache is maintained
// MULTI-THREADED : 1 cache is maintained
// STATIC-THREADED : 1 cache for each thred of the web server
__thread struct clients_cache web_clients_cache = {
.pid = 0,
.used = NULL,
.used_count = 0,
.avail = NULL,
.avail_count = 0,
.allocated = 0,
.reused = 0
};
inline void web_client_cache_verify(int force) {
#ifdef NETDATA_INTERNAL_CHECKS
static __thread size_t count = 0;
count++;
if(unlikely(force || count > 1000)) {
count = 0;
struct web_client *w;
size_t used = 0, avail = 0;
for(w = web_clients_cache.used; w ; w = w->next) used++;
for(w = web_clients_cache.avail; w ; w = w->next) avail++;
info("web_client_cache has %zu (%zu) used and %zu (%zu) available clients, allocated %zu, reused %zu (hit %zu%%)."
, used, web_clients_cache.used_count
, avail, web_clients_cache.avail_count
, web_clients_cache.allocated
, web_clients_cache.reused
, (web_clients_cache.allocated + web_clients_cache.reused)?(web_clients_cache.reused * 100 / (web_clients_cache.allocated + web_clients_cache.reused)):0
);
}
#else
if(unlikely(force)) {
info("web_client_cache has %zu used and %zu available clients, allocated %zu, reused %zu (hit %zu%%)."
, web_clients_cache.used_count
, web_clients_cache.avail_count
, web_clients_cache.allocated
, web_clients_cache.reused
, (web_clients_cache.allocated + web_clients_cache.reused)?(web_clients_cache.reused * 100 / (web_clients_cache.allocated + web_clients_cache.reused)):0
);
}
#endif
}
// destroy the cache and free all the memory it uses
void web_client_cache_destroy(void) {
#ifdef NETDATA_INTERNAL_CHECKS
if(unlikely(web_clients_cache.pid != 0 && web_clients_cache.pid != gettid()))
error("Oops! wrong thread accessing the cache. Expected %d, found %d", (int)web_clients_cache.pid, (int)gettid());
web_client_cache_verify(1);
#endif
netdata_thread_disable_cancelability();
struct web_client *w, *t;
w = web_clients_cache.used;
while(w) {
t = w;
w = w->next;
web_client_free(t);
}
web_clients_cache.used = NULL;
web_clients_cache.used_count = 0;
w = web_clients_cache.avail;
while(w) {
t = w;
w = w->next;
web_client_free(t);
}
web_clients_cache.avail = NULL;
web_clients_cache.avail_count = 0;
netdata_thread_enable_cancelability();
}
struct web_client *web_client_get_from_cache_or_allocate() {
#ifdef NETDATA_INTERNAL_CHECKS
if(unlikely(web_clients_cache.pid == 0))
web_clients_cache.pid = gettid();
if(unlikely(web_clients_cache.pid != 0 && web_clients_cache.pid != gettid()))
error("Oops! wrong thread accessing the cache. Expected %d, found %d", (int)web_clients_cache.pid, (int)gettid());
#endif
netdata_thread_disable_cancelability();
struct web_client *w = web_clients_cache.avail;
if(w) {
// get it from avail
if (w == web_clients_cache.avail) web_clients_cache.avail = w->next;
if(w->prev) w->prev->next = w->next;
if(w->next) w->next->prev = w->prev;
web_clients_cache.avail_count--;
web_client_zero(w);
web_clients_cache.reused++;
}
else {
// allocate it
w = web_client_alloc();
web_clients_cache.allocated++;
}
// link it to used web clients
if (web_clients_cache.used) web_clients_cache.used->prev = w;
w->next = web_clients_cache.used;
w->prev = NULL;
web_clients_cache.used = w;
web_clients_cache.used_count++;
// initialize it
w->id = web_client_connected();
w->mode = WEB_CLIENT_MODE_NORMAL;
netdata_thread_enable_cancelability();
return w;
}
void web_client_release(struct web_client *w) {
#ifdef NETDATA_INTERNAL_CHECKS
if(unlikely(web_clients_cache.pid != 0 && web_clients_cache.pid != gettid()))
error("Oops! wrong thread accessing the cache. Expected %d, found %d", (int)web_clients_cache.pid, (int)gettid());
if(unlikely(w->running))
error("%llu: releasing web client from %s port %s, but it still running.", w->id, w->client_ip, w->client_port);
#endif
debug(D_WEB_CLIENT_ACCESS, "%llu: Closing web client from %s port %s.", w->id, w->client_ip, w->client_port);
web_server_log_connection(w, "DISCONNECTED");
web_client_request_done(w);
web_client_disconnected();
netdata_thread_disable_cancelability();
if(web_server_mode != WEB_SERVER_MODE_STATIC_THREADED) {
if (w->ifd != -1) close(w->ifd);
if (w->ofd != -1 && w->ofd != w->ifd) close(w->ofd);
w->ifd = w->ofd = -1;
}
// unlink it from the used
if (w == web_clients_cache.used) web_clients_cache.used = w->next;
if(w->prev) w->prev->next = w->next;
if(w->next) w->next->prev = w->prev;
web_clients_cache.used_count--;
if(web_clients_cache.avail_count >= 2 * web_clients_cache.used_count) {
// we have too many of them - free it
web_client_free(w);
}
else {
// link it to the avail
if (web_clients_cache.avail) web_clients_cache.avail->prev = w;
w->next = web_clients_cache.avail;
w->prev = NULL;
web_clients_cache.avail = w;
web_clients_cache.avail_count++;
}
netdata_thread_enable_cancelability();
}
|
