Mercurial > hg > nginx
annotate src/os/unix/ngx_gcc_atomic_sparc64.h @ 7142:b9d919b53593 stable-1.12
Stream: relaxed next upstream condition (ticket #1317).
When switching to a next upstream, some buffers could be stuck in the middle
of the filter chain. A condition existed that raised an error when this
happened. As it turned out, this condition prevented switching to a next
upstream if ssl preread was used with the TCP protocol (see the ticket).
In fact, the condition does not make sense for TCP, since after successful
connection to an upstream switching to another upstream never happens. As for
UDP, the issue with stuck buffers is unlikely to happen, but is still possible.
Specifically, if a filter delays sending data to upstream.
The condition can be relaxed to only check the "buffered" bitmask of the
upstream connection. The new condition is simpler and fixes the ticket issue
as well. Additionally, the upstream_out chain is now reset for UDP prior to
connecting to a new upstream to prevent repeating the client data twice.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Mon, 11 Sep 2017 15:32:31 +0300 |
parents | 67653855682e |
children |
rev | line source |
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561 | 1 |
2 /* | |
3 * Copyright (C) Igor Sysoev | |
4412 | 4 * Copyright (C) Nginx, Inc. |
561 | 5 */ |
6 | |
7 | |
8 /* | |
9 * "casa [r1] 0x80, r2, r0" and | |
10 * "casxa [r1] 0x80, r2, r0" do the following: | |
11 * | |
12 * if ([r1] == r2) { | |
13 * swap(r0, [r1]); | |
14 * } else { | |
15 * r0 = [r1]; | |
16 * } | |
17 * | |
4572
67653855682e
Fixed spelling in multiline C comments.
Ruslan Ermilov <ru@nginx.com>
parents:
4412
diff
changeset
|
18 * so "r0 == r2" means that the operation was successful. |
561 | 19 * |
20 * | |
21 * The "r" means the general register. | |
22 * The "+r" means the general register used for both input and output. | |
23 */ | |
24 | |
25 | |
26 #if (NGX_PTR_SIZE == 4) | |
27 #define NGX_CASA "casa" | |
28 #else | |
29 #define NGX_CASA "casxa" | |
30 #endif | |
31 | |
32 | |
33 static ngx_inline ngx_atomic_uint_t | |
34 ngx_atomic_cmp_set(ngx_atomic_t *lock, ngx_atomic_uint_t old, | |
35 ngx_atomic_uint_t set) | |
36 { | |
37 __asm__ volatile ( | |
38 | |
39 NGX_CASA " [%1] 0x80, %2, %0" | |
40 | |
41 : "+r" (set) : "r" (lock), "r" (old) : "memory"); | |
42 | |
43 return (set == old); | |
577 | 44 } |
561 | 45 |
46 | |
47 static ngx_inline ngx_atomic_int_t | |
48 ngx_atomic_fetch_add(ngx_atomic_t *value, ngx_atomic_int_t add) | |
49 { | |
50 ngx_atomic_uint_t old, res; | |
51 | |
52 old = *value; | |
53 | |
54 for ( ;; ) { | |
55 | |
56 res = old + add; | |
57 | |
58 __asm__ volatile ( | |
59 | |
60 NGX_CASA " [%1] 0x80, %2, %0" | |
61 | |
62 : "+r" (res) : "r" (value), "r" (old) : "memory"); | |
63 | |
64 if (res == old) { | |
65 return res; | |
66 } | |
67 | |
68 old = res; | |
69 } | |
70 } | |
563 | 71 |
72 | |
73 #if (NGX_SMP) | |
74 #define ngx_memory_barrier() \ | |
75 __asm__ volatile ( \ | |
76 "membar #LoadLoad | #LoadStore | #StoreStore | #StoreLoad" \ | |
77 ::: "memory") | |
78 #else | |
79 #define ngx_memory_barrier() __asm__ volatile ("" ::: "memory") | |
80 #endif | |
611 | 81 |
82 #define ngx_cpu_pause() |