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comparison src/os/unix/ngx_writev_chain.c @ 5913:8e903522c17a

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Introduced the ngx_output_chain_to_iovec() function. It deduplicates code of the send chain functions and uses only preallocated memory, which completely solves the problem mentioned in d1bde5c3c5d2.
author Valentin Bartenev <vbart@nginx.com>
date Tue, 07 Oct 2014 11:38:57 +0400
parents de68ed551bfb
children 2c64b69daec5
comparison
equal deleted inserted replaced
5912:de68ed551bfb 5913:8e903522c17a
11 11
12 12
13 ngx_chain_t * 13 ngx_chain_t *
14 ngx_writev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit) 14 ngx_writev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
15 { 15 {
16 u_char *prev; 16 ssize_t n, sent;
17 ssize_t n, size, sent;
18 off_t send, prev_send; 17 off_t send, prev_send;
19 ngx_uint_t eintr; 18 ngx_uint_t eintr;
20 ngx_err_t err; 19 ngx_err_t err;
21 ngx_array_t vec;
22 ngx_chain_t *cl; 20 ngx_chain_t *cl;
23 ngx_event_t *wev; 21 ngx_event_t *wev;
24 struct iovec *iov, iovs[NGX_IOVS_PREALLOCATE]; 22 ngx_iovec_t vec;
23 struct iovec iovs[NGX_IOVS_PREALLOCATE];
25 24
26 wev = c->write; 25 wev = c->write;
27 26
28 if (!wev->ready) { 27 if (!wev->ready) {
29 return in; 28 return in;
46 limit = NGX_MAX_SIZE_T_VALUE - ngx_pagesize; 45 limit = NGX_MAX_SIZE_T_VALUE - ngx_pagesize;
47 } 46 }
48 47
49 send = 0; 48 send = 0;
50 49
51 vec.elts = iovs; 50 vec.iovs = iovs;
52 vec.size = sizeof(struct iovec);
53 vec.nalloc = NGX_IOVS_PREALLOCATE; 51 vec.nalloc = NGX_IOVS_PREALLOCATE;
54 vec.pool = c->pool;
55 52
56 for ( ;; ) { 53 for ( ;; ) {
57 prev = NULL;
58 iov = NULL;
59 eintr = 0; 54 eintr = 0;
60 prev_send = send; 55 prev_send = send;
61 56
62 vec.nelts = 0;
63
64 /* create the iovec and coalesce the neighbouring bufs */ 57 /* create the iovec and coalesce the neighbouring bufs */
65 58
66 for (cl = in; cl && send < limit; cl = cl->next) { 59 cl = ngx_output_chain_to_iovec(&vec, in, limit - send, c->log);
67 60
68 if (ngx_buf_special(cl->buf)) { 61 if (cl == NGX_CHAIN_ERROR) {
69 continue; 62 return NGX_CHAIN_ERROR;
70 } 63 }
71 64
72 #if 1 65 if (cl && cl->buf->in_file) {
73 if (!ngx_buf_in_memory(cl->buf)) { 66 ngx_log_error(NGX_LOG_ALERT, c->log, 0,
74 ngx_debug_point(); 67 "file buf in writev "
75 } 68 "t:%d r:%d f:%d %p %p-%p %p %O-%O",
76 #endif 69 cl->buf->temporary,
77 70 cl->buf->recycled,
78 size = cl->buf->last - cl->buf->pos; 71 cl->buf->in_file,
79 72 cl->buf->start,
80 if (send + size > limit) { 73 cl->buf->pos,
81 size = (ssize_t) (limit - send); 74 cl->buf->last,
82 } 75 cl->buf->file,
83 76 cl->buf->file_pos,
84 if (prev == cl->buf->pos) { 77 cl->buf->file_last);
85 iov->iov_len += size; 78
86 79 ngx_debug_point();
87 } else { 80
88 if (vec.nelts >= IOV_MAX) { 81 return NGX_CHAIN_ERROR;
89 break; 82 }
90 } 83
91 84 send += vec.size;
92 iov = ngx_array_push(&vec); 85
93 if (iov == NULL) { 86 n = writev(c->fd, vec.iovs, vec.count);
94 return NGX_CHAIN_ERROR;
95 }
96
97 iov->iov_base = (void *) cl->buf->pos;
98 iov->iov_len = size;
99 }
100
101 prev = cl->buf->pos + size;
102 send += size;
103 }
104
105 n = writev(c->fd, vec.elts, vec.nelts);
106 87
107 if (n == -1) { 88 if (n == -1) {
108 err = ngx_errno; 89 err = ngx_errno;
109 90
110 switch (err) { 91 switch (err) {
146 if (send >= limit || in == NULL) { 127 if (send >= limit || in == NULL) {
147 return in; 128 return in;
148 } 129 }
149 } 130 }
150 } 131 }
132
133
134 ngx_chain_t *
135 ngx_output_chain_to_iovec(ngx_iovec_t *vec, ngx_chain_t *in, size_t limit,
136 ngx_log_t *log)
137 {
138 size_t total, size;
139 u_char *prev;
140 ngx_uint_t n;
141 struct iovec *iov;
142
143 iov = NULL;
144 prev = NULL;
145 total = 0;
146 n = 0;
147
148 for ( /* void */ ; in && total < limit; in = in->next) {
149
150 if (ngx_buf_special(in->buf)) {
151 continue;
152 }
153
154 if (in->buf->in_file) {
155 break;
156 }
157
158 if (!ngx_buf_in_memory(in->buf)) {
159 ngx_log_error(NGX_LOG_ALERT, log, 0,
160 "bad buf in output chain "
161 "t:%d r:%d f:%d %p %p-%p %p %O-%O",
162 in->buf->temporary,
163 in->buf->recycled,
164 in->buf->in_file,
165 in->buf->start,
166 in->buf->pos,
167 in->buf->last,
168 in->buf->file,
169 in->buf->file_pos,
170 in->buf->file_last);
171
172 ngx_debug_point();
173
174 return NGX_CHAIN_ERROR;
175 }
176
177 size = in->buf->last - in->buf->pos;
178
179 if (size > limit - total) {
180 size = limit - total;
181 }
182
183 if (prev == in->buf->pos) {
184 iov->iov_len += size;
185
186 } else {
187 if (n == vec->nalloc) {
188 break;
189 }
190
191 iov = &vec->iovs[n++];
192
193 iov->iov_base = (void *) in->buf->pos;
194 iov->iov_len = size;
195 }
196
197 prev = in->buf->pos + size;
198 total += size;
199 }
200
201 vec->count = n;
202 vec->size = total;
203
204 return in;
205 }