Mercurial > hg > nginx
annotate src/core/ngx_rwlock.c @ 7570:d6cf51af8a3d
HTTP/2: fixed possible alert about left open socket on shutdown.
This could happen when graceful shutdown configured by worker_shutdown_timeout
times out and is then followed by another timeout such as proxy_read_timeout.
In this case, the HEADERS frame is added to the output queue, but attempt to
send it fails (due to c->error forcibly set during graceful shutdown timeout).
This triggers request finalization which attempts to close the stream. But the
stream cannot be closed because there is a frame in the output queue, and the
connection cannot be finalized. This leaves the connection open without any
timer events leading to alert.
The fix is to post write event when sending output queue fails on c->error.
That will finalize the connection.
author | Ruslan Ermilov <ru@nginx.com> |
---|---|
date | Mon, 23 Sep 2019 15:45:32 +0300 |
parents | d1816a2696de |
children | 7752d8523066 |
rev | line source |
---|---|
6101 | 1 |
2 /* | |
3 * Copyright (C) Ruslan Ermilov | |
4 * Copyright (C) Nginx, Inc. | |
5 */ | |
6 | |
7 | |
8 #include <ngx_config.h> | |
9 #include <ngx_core.h> | |
10 | |
11 | |
12 #if (NGX_HAVE_ATOMIC_OPS) | |
13 | |
14 | |
15 #define NGX_RWLOCK_SPIN 2048 | |
16 #define NGX_RWLOCK_WLOCK ((ngx_atomic_uint_t) -1) | |
17 | |
18 | |
19 void | |
20 ngx_rwlock_wlock(ngx_atomic_t *lock) | |
21 { | |
22 ngx_uint_t i, n; | |
23 | |
24 for ( ;; ) { | |
25 | |
26 if (*lock == 0 && ngx_atomic_cmp_set(lock, 0, NGX_RWLOCK_WLOCK)) { | |
27 return; | |
28 } | |
29 | |
30 if (ngx_ncpu > 1) { | |
31 | |
32 for (n = 1; n < NGX_RWLOCK_SPIN; n <<= 1) { | |
33 | |
34 for (i = 0; i < n; i++) { | |
35 ngx_cpu_pause(); | |
36 } | |
37 | |
38 if (*lock == 0 | |
39 && ngx_atomic_cmp_set(lock, 0, NGX_RWLOCK_WLOCK)) | |
40 { | |
41 return; | |
42 } | |
43 } | |
44 } | |
45 | |
46 ngx_sched_yield(); | |
47 } | |
48 } | |
49 | |
50 | |
51 void | |
52 ngx_rwlock_rlock(ngx_atomic_t *lock) | |
53 { | |
54 ngx_uint_t i, n; | |
55 ngx_atomic_uint_t readers; | |
56 | |
57 for ( ;; ) { | |
58 readers = *lock; | |
59 | |
60 if (readers != NGX_RWLOCK_WLOCK | |
61 && ngx_atomic_cmp_set(lock, readers, readers + 1)) | |
62 { | |
63 return; | |
64 } | |
65 | |
66 if (ngx_ncpu > 1) { | |
67 | |
68 for (n = 1; n < NGX_RWLOCK_SPIN; n <<= 1) { | |
69 | |
70 for (i = 0; i < n; i++) { | |
71 ngx_cpu_pause(); | |
72 } | |
73 | |
74 readers = *lock; | |
75 | |
76 if (readers != NGX_RWLOCK_WLOCK | |
77 && ngx_atomic_cmp_set(lock, readers, readers + 1)) | |
78 { | |
79 return; | |
80 } | |
81 } | |
82 } | |
83 | |
84 ngx_sched_yield(); | |
85 } | |
86 } | |
87 | |
88 | |
89 void | |
90 ngx_rwlock_unlock(ngx_atomic_t *lock) | |
91 { | |
92 ngx_atomic_uint_t readers; | |
93 | |
94 readers = *lock; | |
95 | |
96 if (readers == NGX_RWLOCK_WLOCK) { | |
7037
12efcdcb8a4b
Added memory barrier semantics to ngx_rwlock_unlock().
Ruslan Ermilov <ru@nginx.com>
parents:
6270
diff
changeset
|
97 (void) ngx_atomic_cmp_set(lock, NGX_RWLOCK_WLOCK, 0); |
6101 | 98 return; |
99 } | |
100 | |
101 for ( ;; ) { | |
102 | |
103 if (ngx_atomic_cmp_set(lock, readers, readers - 1)) { | |
104 return; | |
105 } | |
106 | |
107 readers = *lock; | |
108 } | |
109 } | |
110 | |
111 | |
7038
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
112 void |
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
113 ngx_rwlock_downgrade(ngx_atomic_t *lock) |
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
114 { |
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
115 if (*lock == NGX_RWLOCK_WLOCK) { |
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
116 *lock = 1; |
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
117 } |
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
118 } |
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
119 |
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
120 |
6103
79ddb0bdb273
Upstream: the "zone" directive.
Ruslan Ermilov <ru@nginx.com>
parents:
6101
diff
changeset
|
121 #else |
79ddb0bdb273
Upstream: the "zone" directive.
Ruslan Ermilov <ru@nginx.com>
parents:
6101
diff
changeset
|
122 |
6270
e769cc88f996
Core: read/write locks are also required by the Stream module.
Piotr Sikora <piotrsikora@google.com>
parents:
6103
diff
changeset
|
123 #if (NGX_HTTP_UPSTREAM_ZONE || NGX_STREAM_UPSTREAM_ZONE) |
6103
79ddb0bdb273
Upstream: the "zone" directive.
Ruslan Ermilov <ru@nginx.com>
parents:
6101
diff
changeset
|
124 |
79ddb0bdb273
Upstream: the "zone" directive.
Ruslan Ermilov <ru@nginx.com>
parents:
6101
diff
changeset
|
125 #error ngx_atomic_cmp_set() is not defined! |
79ddb0bdb273
Upstream: the "zone" directive.
Ruslan Ermilov <ru@nginx.com>
parents:
6101
diff
changeset
|
126 |
6101 | 127 #endif |
6103
79ddb0bdb273
Upstream: the "zone" directive.
Ruslan Ermilov <ru@nginx.com>
parents:
6101
diff
changeset
|
128 |
79ddb0bdb273
Upstream: the "zone" directive.
Ruslan Ermilov <ru@nginx.com>
parents:
6101
diff
changeset
|
129 #endif |