Mercurial > hg > nginx-quic
annotate src/core/ngx_rwlock.c @ 8743:5d09596909c6 stable-1.20
Upstream: fixed timeouts with gRPC, SSL and select (ticket #2229).
With SSL it is possible that an established connection is ready for
reading after the handshake. Further, events might be already disabled
in case of level-triggered event methods. If this happens and
ngx_http_upstream_send_request() blocks waiting for some data from
the upstream, such as flow control in case of gRPC, the connection
will time out due to no read events on the upstream connection.
Fix is to explicitly check the c->read->ready flag if sending request
blocks and post a read event if it is set.
Note that while it is possible to modify ngx_ssl_handshake() to keep
read events active, this won't completely resolve the issue, since
there can be data already received during the SSL handshake
(see 573bd30e46b4).
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Fri, 20 Aug 2021 03:53:56 +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 |