wow, makes me want to rebuild all my server nodes to include this patch.<br><br><div class="gmail_quote">On Fri, Sep 9, 2011 at 8:32 PM, Maxim Dounin <span dir="ltr"><<a href="mailto:mdounin@mdounin.ru">mdounin@mdounin.ru</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"># HG changeset patch<br>
# User Maxim Dounin <<a href="mailto:mdounin@mdounin.ru">mdounin@mdounin.ru</a>><br>
# Date 1315564269 -14400<br>
# Node ID b667ed67c0b9046b94291fa6f52e850006011718<br>
# Parent 014764a85840606c90317e9f44f2b9fa139cbc8b<br>
Buffers reuse in chunked filter.<br>
<br>
There were 2 buffers allocated on each buffer chain sent through chunked<br>
filter (one buffer for chunk size, another one for trailing CRLF, about<br>
120 bytes in total on 32-bit platforms). This resulted in large memory<br>
consumption with long-lived requests sending many buffer chains. Usual<br>
example of problematic scenario is streaming though proxy with<br>
proxy_buffering set to off.<br>
<br>
Introduced buffers reuse reduces memory consumption in the above problematic<br>
scenario.<br>
<br>
See here for initial report:<br>
<a href="http://mailman.nginx.org/pipermail/nginx/2010-April/019814.html" target="_blank">http://mailman.nginx.org/pipermail/nginx/2010-April/019814.html</a><br>
<br>
diff --git a/src/http/modules/ngx_http_chunked_filter_module.c b/src/http/modules/ngx_http_chunked_filter_module.c<br>
--- a/src/http/modules/ngx_http_chunked_filter_module.c<br>
+++ b/src/http/modules/ngx_http_chunked_filter_module.c<br>
@@ -9,6 +9,12 @@<br>
#include <ngx_http.h><br>
<br>
<br>
+typedef struct {<br>
+ ngx_chain_t *free;<br>
+ ngx_chain_t *busy;<br>
+} ngx_http_chunked_filter_ctx_t;<br>
+<br>
+<br>
static ngx_int_t ngx_http_chunked_filter_init(ngx_conf_t *cf);<br>
<br>
<br>
@@ -50,7 +56,8 @@ static ngx_http_output_body_filter_pt<br>
static ngx_int_t<br>
ngx_http_chunked_header_filter(ngx_http_request_t *r)<br>
{<br>
- ngx_http_core_loc_conf_t *clcf;<br>
+ ngx_http_core_loc_conf_t *clcf;<br>
+ ngx_http_chunked_filter_ctx_t *ctx;<br>
<br>
if (r->headers_out.status == NGX_HTTP_NOT_MODIFIED<br>
|| r->headers_out.status == NGX_HTTP_NO_CONTENT<br>
@@ -70,6 +77,14 @@ ngx_http_chunked_header_filter(ngx_http_<br>
if (clcf->chunked_transfer_encoding) {<br>
r->chunked = 1;<br>
<br>
+ ctx = ngx_pcalloc(r->pool,<br>
+ sizeof(ngx_http_chunked_filter_ctx_t));<br>
+ if (ctx == NULL) {<br>
+ return NGX_ERROR;<br>
+ }<br>
+<br>
+ ngx_http_set_ctx(r, ctx, ngx_http_chunked_filter_module);<br>
+<br>
} else {<br>
r->keepalive = 0;<br>
}<br>
@@ -83,17 +98,21 @@ ngx_http_chunked_header_filter(ngx_http_<br>
static ngx_int_t<br>
ngx_http_chunked_body_filter(ngx_http_request_t *r, ngx_chain_t *in)<br>
{<br>
- u_char *chunk;<br>
- off_t size;<br>
- ngx_buf_t *b;<br>
- ngx_chain_t out, tail, *cl, *tl, **ll;<br>
+ u_char *chunk;<br>
+ off_t size;<br>
+ ngx_int_t rc;<br>
+ ngx_buf_t *b;<br>
+ ngx_chain_t *out, *cl, *tl, **ll;<br>
+ ngx_http_chunked_filter_ctx_t *ctx;<br>
<br>
if (in == NULL || !r->chunked || r->header_only) {<br>
return ngx_http_next_body_filter(r, in);<br>
}<br>
<br>
- out.buf = NULL;<br>
- ll = &out.next;<br>
+ ctx = ngx_http_get_module_ctx(r, ngx_http_chunked_filter_module);<br>
+<br>
+ out = NULL;<br>
+ ll = &out;<br>
<br>
size = 0;<br>
cl = in;<br>
@@ -127,31 +146,46 @@ ngx_http_chunked_body_filter(ngx_http_re<br>
}<br>
<br>
if (size) {<br>
- b = ngx_calloc_buf(r->pool);<br>
- if (b == NULL) {<br>
+ tl = ngx_chain_get_free_buf(r->pool, &ctx->free);<br>
+ if (tl == NULL) {<br>
return NGX_ERROR;<br>
}<br>
<br>
- /* the "0000000000000000" is 64-bit hexadimal string */<br>
+ b = tl->buf;<br>
+ chunk = b->start;<br>
<br>
- chunk = ngx_palloc(r->pool, sizeof("0000000000000000" CRLF) - 1);<br>
if (chunk == NULL) {<br>
- return NGX_ERROR;<br>
+ /* the "0000000000000000" is 64-bit hexadecimal string */<br>
+<br>
+ chunk = ngx_palloc(r->pool, sizeof("0000000000000000" CRLF) - 1);<br>
+ if (chunk == NULL) {<br>
+ return NGX_ERROR;<br>
+ }<br>
+<br>
+ b->start = chunk;<br>
+ b->end = chunk + sizeof("0000000000000000" CRLF) - 1;<br>
}<br>
<br>
+ b->tag = (ngx_buf_tag_t) &ngx_http_chunked_filter_module;<br>
+ b->memory = 0;<br>
b->temporary = 1;<br>
b->pos = chunk;<br>
b->last = ngx_sprintf(chunk, "%xO" CRLF, size);<br>
<br>
- out.buf = b;<br>
+ tl->next = out;<br>
+ out = tl;<br>
}<br>
<br>
if (cl->buf->last_buf) {<br>
- b = ngx_calloc_buf(r->pool);<br>
- if (b == NULL) {<br>
+ tl = ngx_chain_get_free_buf(r->pool, &ctx->free);<br>
+ if (tl == NULL) {<br>
return NGX_ERROR;<br>
}<br>
+<br>
+ b = tl->buf;<br>
<br>
+ b->tag = (ngx_buf_tag_t) &ngx_http_chunked_filter_module;<br>
+ b->temporary = 0;<br>
b->memory = 1;<br>
b->last_buf = 1;<br>
b->pos = (u_char *) CRLF "0" CRLF CRLF;<br>
@@ -159,35 +193,38 @@ ngx_http_chunked_body_filter(ngx_http_re<br>
<br>
cl->buf->last_buf = 0;<br>
<br>
+ *ll = tl;<br>
+<br>
if (size == 0) {<br>
b->pos += 2;<br>
- out.buf = b;<br>
- out.next = NULL;<br>
-<br>
- return ngx_http_next_body_filter(r, &out);<br>
}<br>
<br>
- } else {<br>
- if (size == 0) {<br>
- *ll = NULL;<br>
- return ngx_http_next_body_filter(r, out.next);<br>
- }<br>
-<br>
- b = ngx_calloc_buf(r->pool);<br>
- if (b == NULL) {<br>
+ } else if (size > 0) {<br>
+ tl = ngx_chain_get_free_buf(r->pool, &ctx->free);<br>
+ if (tl == NULL) {<br>
return NGX_ERROR;<br>
}<br>
<br>
+ b = tl->buf;<br>
+<br>
+ b->tag = (ngx_buf_tag_t) &ngx_http_chunked_filter_module;<br>
+ b->temporary = 0;<br>
b->memory = 1;<br>
b->pos = (u_char *) CRLF;<br>
b->last = b->pos + 2;<br>
+<br>
+ *ll = tl;<br>
+<br>
+ } else {<br>
+ *ll = NULL;<br>
}<br>
<br>
- tail.buf = b;<br>
- tail.next = NULL;<br>
- *ll = &tail;<br>
+ rc = ngx_http_next_body_filter(r, out);<br>
<br>
- return ngx_http_next_body_filter(r, &out);<br>
+ ngx_chain_update_chains(&ctx->free, &ctx->busy, &out,<br>
+ (ngx_buf_tag_t) &ngx_http_chunked_filter_module);<br>
+<br>
+ return rc;<br>
}<br>
<br>
<br>
<br>
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</blockquote></div><br>