details: http://hg.nginx.org/nginx/rev/ccad84a174e0
branches:
changeset: 5980:ccad84a174e0
user: Valentin Bartenev <vbart@nginx.com>
date: Wed Feb 11 17:52:15 2015 +0300
description:
Refactored sendfile() AIO preload.

This reduces layering violation and simplifies the logic of AIO preread, since
it's now triggered by the send chain function itself without falling back to
the copy filter. The context of AIO operation is now stored per file buffer,
which makes it possible to properly handle cases when multiple buffers come
from different locations, each with its own configuration.

diffstat:

src/core/ngx_buf.h | 3 +
src/core/ngx_connection.h | 2 -
src/core/ngx_output_chain.c | 32 ++++++++++
src/event/ngx_event.h | 8 +-
src/http/ngx_http_copy_filter_module.c | 99 +++++++++++--------------------
src/http/ngx_http_request.h | 3 -
src/os/unix/ngx_file_aio_read.c | 42 ++++++++-----
src/os/unix/ngx_files.h | 1 +
src/os/unix/ngx_freebsd_sendfile_chain.c | 77 +++++++++++++++++++-----
src/os/unix/ngx_linux_aio_read.c | 39 ++++++++----
10 files changed, 187 insertions(+), 119 deletions(-)

diffs (truncated from 508 to 300 lines):

diff -r b2920b517490 -r ccad84a174e0 src/core/ngx_buf.h
--- a/src/core/ngx_buf.h Fri Jan 23 15:23:29 2015 +0300
+++ b/src/core/ngx_buf.h Wed Feb 11 17:52:15 2015 +0300
@@ -94,6 +94,9 @@ struct ngx_output_chain_ctx_s {
unsigned aio:1;

ngx_output_chain_aio_pt aio_handler;
+#if (NGX_HAVE_FILE_AIO)
+ ssize_t (*aio_preload)(ngx_buf_t *file);
+#endif
#endif

off_t alignment;
diff -r b2920b517490 -r ccad84a174e0 src/core/ngx_connection.h
--- a/src/core/ngx_connection.h Fri Jan 23 15:23:29 2015 +0300
+++ b/src/core/ngx_connection.h Wed Feb 11 17:52:15 2015 +0300
@@ -181,9 +181,7 @@ struct ngx_connection_s {
#endif

#if (NGX_HAVE_AIO_SENDFILE)
- unsigned aio_sendfile:1;
unsigned busy_count:2;
- ngx_buf_t *busy_sendfile;
#endif

#if (NGX_THREADS)
diff -r b2920b517490 -r ccad84a174e0 src/core/ngx_output_chain.c
--- a/src/core/ngx_output_chain.c Fri Jan 23 15:23:29 2015 +0300
+++ b/src/core/ngx_output_chain.c Wed Feb 11 17:52:15 2015 +0300
@@ -29,6 +29,10 @@

static ngx_inline ngx_int_t
ngx_output_chain_as_is(ngx_output_chain_ctx_t *ctx, ngx_buf_t *buf);
+#if (NGX_HAVE_AIO_SENDFILE)
+static ngx_int_t ngx_output_chain_aio_setup(ngx_output_chain_ctx_t *ctx,
+ ngx_file_t *file);
+#endif
static ngx_int_t ngx_output_chain_add_copy(ngx_pool_t *pool,
ngx_chain_t **chain, ngx_chain_t *in);
static ngx_int_t ngx_output_chain_align_file_buf(ngx_output_chain_ctx_t *ctx,
@@ -252,6 +256,12 @@ ngx_output_chain_as_is(ngx_output_chain_
buf->in_file = 0;
}

+#if (NGX_HAVE_AIO_SENDFILE)
+ if (ctx->aio_preload && buf->in_file) {
+ (void) ngx_output_chain_aio_setup(ctx, buf->file);
+ }
+#endif
+
if (ctx->need_in_memory && !ngx_buf_in_memory(buf)) {
return 0;
}
@@ -264,6 +274,28 @@ ngx_output_chain_as_is(ngx_output_chain_
}


+#if (NGX_HAVE_AIO_SENDFILE)
+
+static ngx_int_t
+ngx_output_chain_aio_setup(ngx_output_chain_ctx_t *ctx, ngx_file_t *file)
+{
+ ngx_event_aio_t *aio;
+
+ if (file->aio == NULL && ngx_file_aio_init(file, ctx->pool) != NGX_OK) {
+ return NGX_ERROR;
+ }
+
+ aio = file->aio;
+
+ aio->data = ctx->filter_ctx;
+ aio->preload_handler = ctx->aio_preload;
+
+ return NGX_OK;
+}
+
+#endif
+
+
static ngx_int_t
ngx_output_chain_add_copy(ngx_pool_t *pool, ngx_chain_t **chain,
ngx_chain_t *in)
diff -r b2920b517490 -r ccad84a174e0 src/event/ngx_event.h
--- a/src/event/ngx_event.h Fri Jan 23 15:23:29 2015 +0300
+++ b/src/event/ngx_event.h Wed Feb 11 17:52:15 2015 +0300
@@ -168,6 +168,10 @@ struct ngx_event_aio_s {
ngx_event_handler_pt handler;
ngx_file_t *file;

+#if (NGX_HAVE_AIO_SENDFILE)
+ ssize_t (*preload_handler)(ngx_buf_t *file);
+#endif
+
ngx_fd_t fd;

#if (NGX_HAVE_EVENTFD)
@@ -181,10 +185,6 @@ struct ngx_event_aio_s {
size_t nbytes;
#endif

-#if (NGX_HAVE_AIO_SENDFILE)
- off_t last_offset;
-#endif
-
ngx_aiocb_t aiocb;
ngx_event_t event;
};
diff -r b2920b517490 -r ccad84a174e0 src/http/ngx_http_copy_filter_module.c
--- a/src/http/ngx_http_copy_filter_module.c Fri Jan 23 15:23:29 2015 +0300
+++ b/src/http/ngx_http_copy_filter_module.c Wed Feb 11 17:52:15 2015 +0300
@@ -20,6 +20,7 @@ static void ngx_http_copy_aio_handler(ng
ngx_file_t *file);
static void ngx_http_copy_aio_event_handler(ngx_event_t *ev);
#if (NGX_HAVE_AIO_SENDFILE)
+static ssize_t ngx_http_copy_aio_sendfile_preload(ngx_buf_t *file);
static void ngx_http_copy_aio_sendfile_event_handler(ngx_event_t *ev);
#endif
#endif
@@ -125,7 +126,9 @@ ngx_http_copy_filter(ngx_http_request_t
ctx->aio_handler = ngx_http_copy_aio_handler;
}
#if (NGX_HAVE_AIO_SENDFILE)
- c->aio_sendfile = (clcf->aio == NGX_HTTP_AIO_SENDFILE);
+ if (clcf->aio == NGX_HTTP_AIO_SENDFILE) {
+ ctx->aio_preload = ngx_http_copy_aio_sendfile_preload;
+ }
#endif
}
#endif
@@ -139,72 +142,19 @@ ngx_http_copy_filter(ngx_http_request_t
ctx->aio = r->aio;
#endif

- for ( ;; ) {
- rc = ngx_output_chain(ctx, in);
+ rc = ngx_output_chain(ctx, in);

- if (ctx->in == NULL) {
- r->buffered &= ~NGX_HTTP_COPY_BUFFERED;
+ if (ctx->in == NULL) {
+ r->buffered &= ~NGX_HTTP_COPY_BUFFERED;

- } else {
- r->buffered |= NGX_HTTP_COPY_BUFFERED;
- }
+ } else {
+ r->buffered |= NGX_HTTP_COPY_BUFFERED;
+ }

- ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0,
- "http copy filter: %i \"%V?%V\"", rc, &r->uri, &r->args);
+ ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0,
+ "http copy filter: %i \"%V?%V\"", rc, &r->uri, &r->args);

-#if (NGX_HAVE_FILE_AIO && NGX_HAVE_AIO_SENDFILE)
-
- if (c->busy_sendfile) {
- ssize_t n;
- off_t offset;
- ngx_file_t *file;
- ngx_http_ephemeral_t *e;
-
- if (r->aio) {
- c->busy_sendfile = NULL;
- return rc;
- }
-
- file = c->busy_sendfile->file;
- offset = c->busy_sendfile->file_pos;
-
- if (file->aio) {
- c->busy_count = (offset == file->aio->last_offset) ?
- c->busy_count + 1 : 0;
- file->aio->last_offset = offset;
-
- if (c->busy_count > 2) {
- ngx_log_error(NGX_LOG_ALERT, c->log, 0,
- "sendfile(%V) returned busy again",
- &file->name);
- c->aio_sendfile = 0;
- }
- }
-
- c->busy_sendfile = NULL;
- e = (ngx_http_ephemeral_t *) &r->uri_start;
-
- n = ngx_file_aio_read(file, &e->aio_preload, 1, offset, r->pool);
-
- if (n > 0) {
- in = NULL;
- continue;
- }
-
- rc = n;
-
- if (rc == NGX_AGAIN) {
- file->aio->data = r;
- file->aio->handler = ngx_http_copy_aio_sendfile_event_handler;
-
- r->main->blocked++;
- r->aio = 1;
- }
- }
-#endif
-
- return rc;
- }
+ return rc;
}


@@ -244,6 +194,29 @@ ngx_http_copy_aio_event_handler(ngx_even

#if (NGX_HAVE_AIO_SENDFILE)

+static ssize_t
+ngx_http_copy_aio_sendfile_preload(ngx_buf_t *file)
+{
+ ssize_t n;
+ static u_char buf[1];
+ ngx_event_aio_t *aio;
+ ngx_http_request_t *r;
+
+ n = ngx_file_aio_read(file->file, buf, 1, file->file_pos, NULL);
+
+ if (n == NGX_AGAIN) {
+ aio = file->file->aio;
+ aio->handler = ngx_http_copy_aio_sendfile_event_handler;
+
+ r = aio->data;
+ r->main->blocked++;
+ r->aio = 1;
+ }
+
+ return n;
+}
+
+
static void
ngx_http_copy_aio_sendfile_event_handler(ngx_event_t *ev)
{
diff -r b2920b517490 -r ccad84a174e0 src/http/ngx_http_request.h
--- a/src/http/ngx_http_request.h Fri Jan 23 15:23:29 2015 +0300
+++ b/src/http/ngx_http_request.h Wed Feb 11 17:52:15 2015 +0300
@@ -574,9 +574,6 @@ struct ngx_http_request_s {

typedef struct {
ngx_http_posted_request_t terminal_posted_request;
-#if (NGX_HAVE_AIO_SENDFILE)
- u_char aio_preload;
-#endif
} ngx_http_ephemeral_t;


diff -r b2920b517490 -r ccad84a174e0 src/os/unix/ngx_file_aio_read.c
--- a/src/os/unix/ngx_file_aio_read.c Fri Jan 23 15:23:29 2015 +0300
+++ b/src/os/unix/ngx_file_aio_read.c Wed Feb 11 17:52:15 2015 +0300
@@ -36,6 +36,28 @@ static ssize_t ngx_file_aio_result(ngx_f
static void ngx_file_aio_event_handler(ngx_event_t *ev);


+ngx_int_t
+ngx_file_aio_init(ngx_file_t *file, ngx_pool_t *pool)
+{
+ ngx_event_aio_t *aio;
+
+ aio = ngx_pcalloc(pool, sizeof(ngx_event_aio_t));
+ if (aio == NULL) {
+ return NGX_ERROR;
+ }
+
+ aio->file = file;
+ aio->fd = file->fd;
+ aio->event.data = aio;
+ aio->event.ready = 1;
+ aio->event.log = file->log;
+
+ file->aio = aio;
+
+ return NGX_OK;
+}
+
+
ssize_t
ngx_file_aio_read(ngx_file_t *file, u_char *buf, size_t size, off_t offset,
ngx_pool_t *pool)
@@ -48,25 +70,11 @@ ngx_file_aio_read(ngx_file_t *file, u_ch
return ngx_read_file(file, buf, size, offset);
}

- aio = file->aio;
-
- if (aio == NULL) {
- aio = ngx_pcalloc(pool, sizeof(ngx_event_aio_t));
- if (aio == NULL) {
- return NGX_ERROR;
- }
-
- aio->file = file;
- aio->fd = file->fd;

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