Subrequest in limit_rate

Server NGINX
1

Hi all,

Does limit_rate, which is in write filter module, work right when many
subrequests exist?
I meet a problem with limit_rate for many subrequests. Here is the
problem.

  1. limit_rate works like this:
    a) after sending data, it will set wev->delayed which disable data
    sending, and sleep for a while(add_timer);
    b) when timedout, the wev handler will clear wev->delayed, to enable
    data sending.
    For example, the handler may like this;

src/http/ngx_http_upstream.c:ngx_http_upstream_process_downstream()

2361 if (wev->timedout) {

2363 if (wev->delayed) {

2367 wev->delayed = 0;

2389 }

2395 }

  1. but 1 wev (write event) corresponds to 1 connection; while 1
    (downstream) connection may has many subrequests.
    so when wev timedout, wev gets the active request of the connection,
    like this:

src/http/ngx_http_request.c:ngx_http_request_handler()

1724 c = ev->data;

1725 r = c->data;

1726

1733 if (ev->write) {

1734 r->write_event_handler®;

1737 } else {

1738 r->read_event_handler®;

1739 }

  1. The problem is that: the active request of this connection maybe not
    the one who added the timer. which means that the active request of the
    connection changes before timedout. So its write_event_handler maybe not
    the one expected. For example, if the active request’s
    write_event_handler is happened to be ngx_http_request_empty_handler(),
    which is set in ngx_http_core_content_phase(), then the handler doesn’t
    clear the wev->delayed.So the data sending in write filter module will
    never be enabled again.

Is my analysis right? Does limit_rate work right for many subrequests?

I hope I made myself understood.

Thanks,

Wu