Commit 484aba50 authored by Jim Jagielski's avatar Jim Jagielski
Browse files

Merge r1840010 from trunk:

On the trunk:

mod_http2: connection IO event handling reworked. Instead of reacting on 
     incoming bytes, the state machine now acts on incoming frames that are 
     affecting it. This reduces state transitions. 


Submitted by: icing
Reviewed by: icing, ylavic, jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1840757 13f79535-47bb-0310-9956-ffa450edef68
parent 72eb47da
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+0 −6
Original line number Diff line number Diff line
@@ -123,12 +123,6 @@ RELEASE SHOWSTOPPERS:
PATCHES ACCEPTED TO BACKPORT FROM TRUNK:
  [ start all new proposals below, under PATCHES PROPOSED. ]

   *) mod_http2: connection IO event handling reworked. Instead of reacting on 
      incoming bytes, the state machine now acts on incoming frames that are 
      affecting it.
      trunk: http://svn.apache.org/r1840010
      2.4.x: https://svn.apache.org/repos/asf/httpd/httpd/patches/2.4.x/mod-http2-con-io-events.patch
      +1: icing, ylavic, jim


PATCHES PROPOSED TO BACKPORT FROM TRUNK:
+151 −87
Original line number Diff line number Diff line
@@ -235,6 +235,7 @@ static int on_data_chunk_recv_cb(nghttp2_session *ngh2, uint8_t flags,
    stream = h2_session_stream_get(session, stream_id);
    if (stream) {
        status = h2_stream_recv_DATA(stream, flags, data, len);
        dispatch_event(session, H2_SESSION_EV_STREAM_CHANGE, 0, "stream data rcvd");
    }
    else {
        ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, session->c, APLOGNO(03064)
@@ -317,9 +318,9 @@ static int on_header_cb(nghttp2_session *ngh2, const nghttp2_frame *frame,
}

/**
 * nghttp2 session has received a complete frame. Most, it uses
 * for processing of internal state. HEADER and DATA frames however
 * we need to handle ourself.
 * nghttp2 session has received a complete frame. Most are used by nghttp2
 * for processing of internal state. Some, like HEADER and DATA frames,
 * we need to act on.
 */
static int on_frame_recv_cb(nghttp2_session *ng2s,
                            const nghttp2_frame *frame,
@@ -378,6 +379,9 @@ static int on_frame_recv_cb(nghttp2_session *ng2s,
                          "h2_stream(%ld-%d): WINDOW_UPDATE incr=%d", 
                          session->id, (int)frame->hd.stream_id,
                          frame->window_update.window_size_increment);
            if (nghttp2_session_want_write(session->ngh2)) {
                dispatch_event(session, H2_SESSION_EV_FRAME_RCVD, 0, "window update");
            }
            break;
        case NGHTTP2_RST_STREAM:
            ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, session->c, APLOGNO(03067)
@@ -404,6 +408,12 @@ static int on_frame_recv_cb(nghttp2_session *ng2s,
                               frame->goaway.error_code, NULL);
            }
            break;
        case NGHTTP2_SETTINGS:
            if (APLOGctrace2(session->c)) {
                ap_log_cerror(APLOG_MARK, APLOG_TRACE2, 0, session->c,
                              H2_SSSN_MSG(session, "SETTINGS, len=%ld"), (long)frame->hd.length);
            }
            break;
        default:
            if (APLOGctrace2(session->c)) {
                char buffer[256];
@@ -415,7 +425,40 @@ static int on_frame_recv_cb(nghttp2_session *ng2s,
            }
            break;
    }
    return (APR_SUCCESS == rv)? 0 : NGHTTP2_ERR_PROTO;
    
    if (session->state == H2_SESSION_ST_IDLE) {
        /* We received a frame, but session is in state IDLE. That means the frame
         * did not really progress any of the (possibly) open streams. It was a meta
         * frame, e.g. SETTINGS/WINDOW_UPDATE/unknown/etc.
         * Remember: IDLE means we cannot send because either there are no streams open or
         * all open streams are blocked on exhausted WINDOWs for outgoing data.
         * The more frames we receive that do not change this, the less interested we
         * become in serving this connection. This is expressed in increasing "idle_delays".
         * Eventually, the connection will timeout and we'll close it. */
        session->idle_frames = H2MIN(session->idle_frames + 1, session->frames_received);
            ap_log_cerror( APLOG_MARK, APLOG_TRACE2, 0, session->c,
                          H2_SSSN_MSG(session, "session has %ld idle frames"), 
                          (long)session->idle_frames);
        if (session->idle_frames > 10) {
            apr_size_t busy_frames = H2MAX(session->frames_received - session->idle_frames, 1);
            int idle_ratio = (int)(session->idle_frames / busy_frames); 
            if (idle_ratio > 100) {
                session->idle_delay = apr_time_from_msec(H2MIN(1000, idle_ratio));
            }
            else if (idle_ratio > 10) {
                session->idle_delay = apr_time_from_msec(10);
            }
            else if (idle_ratio > 1) {
                session->idle_delay = apr_time_from_msec(1);
            }
            else {
                session->idle_delay = 0;
            }
        }
    }
    
    if (APR_SUCCESS != rv) return NGHTTP2_ERR_PROTO;
    return 0;
}

static int h2_session_continue_data(h2_session *session) {
@@ -1603,23 +1646,57 @@ static void update_child_status(h2_session *session, int status, const char *msg

static void transit(h2_session *session, const char *action, h2_session_state nstate)
{
    apr_time_t timeout;
    int ostate, loglvl;
    const char *s;
    
    if (session->state != nstate) {
        int loglvl = APLOG_DEBUG;
        if ((session->state == H2_SESSION_ST_BUSY && nstate == H2_SESSION_ST_WAIT)
            || (session->state == H2_SESSION_ST_WAIT && nstate == H2_SESSION_ST_BUSY)){
        ostate = session->state;
        session->state = nstate;
        
        loglvl = APLOG_DEBUG;
        if ((ostate == H2_SESSION_ST_BUSY && nstate == H2_SESSION_ST_WAIT)
            || (ostate == H2_SESSION_ST_WAIT && nstate == H2_SESSION_ST_BUSY)){
            loglvl = APLOG_TRACE1;
        }
        ap_log_cerror(APLOG_MARK, loglvl, 0, session->c, 
                      H2_SSSN_LOG(APLOGNO(03078), session, 
                      "transit [%s] -- %s --> [%s]"), 
                      h2_session_state_str(session->state), action, 
                      h2_session_state_str(ostate), action, 
                      h2_session_state_str(nstate));
        session->state = nstate;
        
        switch (session->state) {
            case H2_SESSION_ST_IDLE:
                update_child_status(session, (session->open_streams == 0? 
                                              SERVER_BUSY_KEEPALIVE
                                              : SERVER_BUSY_READ), "idle");
                if (!session->remote.emitted_count) {
                    /* on fresh connections, with async mpm, do not return
                     * to mpm for a second. This gives the first request a better
                     * chance to arrive (und connection leaving IDLE state).
                     * If we return to mpm right away, this connection has the
                     * same chance of being cleaned up by the mpm as connections
                     * that already served requests - not fair. */
                    session->idle_sync_until = apr_time_now() + apr_time_from_sec(1);
                    s = "timeout";
                    timeout = H2MAX(session->s->timeout, session->s->keep_alive_timeout);
                    update_child_status(session, SERVER_BUSY_READ, "idle");
                    ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, session->c, 
                                  H2_SSSN_LOG("", session, "enter idle, timeout = %d sec"), 
                                  (int)apr_time_sec(H2MAX(session->s->timeout, session->s->keep_alive_timeout)));
                }
                else if (session->open_streams) {
                    s = "timeout";
                    timeout = session->s->keep_alive_timeout;
                    update_child_status(session, SERVER_BUSY_KEEPALIVE, "idle");
                }
                else {
                    /* normal keepalive setup */
                    s = "keepalive";
                    timeout = session->s->keep_alive_timeout;
                    update_child_status(session, SERVER_BUSY_KEEPALIVE, "idle");
                }
                session->idle_until = apr_time_now() + timeout; 
                ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, session->c, 
                              H2_SSSN_LOG("", session, "enter idle, %s = %d sec"), 
                              s, (int)apr_time_sec(timeout));
                break;
            case H2_SESSION_ST_DONE:
                update_child_status(session, SERVER_CLOSING, "done");
@@ -1726,8 +1803,6 @@ static void h2_session_ev_no_io(h2_session *session, int arg, const char *msg)
                     * This means we only wait for WINDOW_UPDATE from the 
                     * client and can block on READ. */
                    transit(session, "no io (flow wait)", H2_SESSION_ST_IDLE);
                    session->idle_until = apr_time_now() + session->s->timeout;
                    session->keep_sync_until = session->idle_until;
                    /* Make sure we have flushed all previously written output
                     * so that the client will react. */
                    if (h2_conn_io_flush(&session->io) != APR_SUCCESS) {
@@ -1738,12 +1813,7 @@ static void h2_session_ev_no_io(h2_session *session, int arg, const char *msg)
            }
            else if (session->local.accepting) {
                /* When we have no streams, but accept new, switch to idle */
                apr_time_t now = apr_time_now();
                transit(session, "no io (keepalive)", H2_SESSION_ST_IDLE);
                session->idle_until = (session->remote.emitted_count? 
                                       session->s->keep_alive_timeout : 
                                       session->s->timeout) + now;
                session->keep_sync_until = now + apr_time_from_sec(1);
            }
            else {
                /* We are no longer accepting new streams and there are
@@ -1758,12 +1828,25 @@ static void h2_session_ev_no_io(h2_session *session, int arg, const char *msg)
    }
}

static void h2_session_ev_data_read(h2_session *session, int arg, const char *msg)
static void h2_session_ev_frame_rcvd(h2_session *session, int arg, const char *msg)
{
    switch (session->state) {
        case H2_SESSION_ST_IDLE:
        case H2_SESSION_ST_WAIT:
            transit(session, "data read", H2_SESSION_ST_BUSY);
            transit(session, "frame received", H2_SESSION_ST_BUSY);
            break;
        default:
            /* nop */
            break;
    }
}

static void h2_session_ev_stream_change(h2_session *session, int arg, const char *msg)
{
    switch (session->state) {
        case H2_SESSION_ST_IDLE:
        case H2_SESSION_ST_WAIT:
            transit(session, "stream change", H2_SESSION_ST_BUSY);
            break;
        default:
            /* nop */
@@ -1803,16 +1886,6 @@ static void h2_session_ev_pre_close(h2_session *session, int arg, const char *ms
static void ev_stream_open(h2_session *session, h2_stream *stream)
{
    h2_iq_append(session->in_process, stream->id);
    switch (session->state) {
        case H2_SESSION_ST_IDLE:
            if (session->open_streams == 1) {
                /* enter timeout, since we have a stream again */
                session->idle_until = (session->s->timeout + apr_time_now());
            }
            break;
        default:
            break;
    }
}

static void ev_stream_closed(h2_session *session, h2_stream *stream)
@@ -1825,11 +1898,6 @@ static void ev_stream_closed(h2_session *session, h2_stream *stream)
    }
    switch (session->state) {
        case H2_SESSION_ST_IDLE:
            if (session->open_streams == 0) {
                /* enter keepalive timeout, since we no longer have streams */
                session->idle_until = (session->s->keep_alive_timeout
                                       + apr_time_now());
            }
            break;
        default:
            break;
@@ -1887,6 +1955,7 @@ static void on_stream_state_enter(void *ctx, h2_stream *stream)
        default:
            break;
    }
    dispatch_event(session, H2_SESSION_EV_STREAM_CHANGE, 0, "stream state change");
}

static void on_stream_event(void *ctx, h2_stream *stream, 
@@ -1945,8 +2014,8 @@ static void dispatch_event(h2_session *session, h2_session_event_t ev,
        case H2_SESSION_EV_NO_IO:
            h2_session_ev_no_io(session, arg, msg);
            break;
        case H2_SESSION_EV_DATA_READ:
            h2_session_ev_data_read(session, arg, msg);
        case H2_SESSION_EV_FRAME_RCVD:
            h2_session_ev_frame_rcvd(session, arg, msg);
            break;
        case H2_SESSION_EV_NGH2_DONE:
            h2_session_ev_ngh2_done(session, arg, msg);
@@ -1957,6 +2026,9 @@ static void dispatch_event(h2_session *session, h2_session_event_t ev,
        case H2_SESSION_EV_PRE_CLOSE:
            h2_session_ev_pre_close(session, arg, msg);
            break;
        case H2_SESSION_EV_STREAM_CHANGE:
            h2_session_ev_stream_change(session, arg, msg);
            break;
        default:
            ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, session->c,
                          H2_SSSN_MSG(session, "unknown event %d"), ev);
@@ -1990,6 +2062,7 @@ apr_status_t h2_session_process(h2_session *session, int async)
    apr_status_t status = APR_SUCCESS;
    conn_rec *c = session->c;
    int rv, mpm_state, trace = APLOGctrace3(c);
    apr_time_t now;
    
    if (trace) {
        ap_log_cerror( APLOG_MARK, APLOG_TRACE3, status, c,
@@ -1997,6 +2070,7 @@ apr_status_t h2_session_process(h2_session *session, int async)
    }
                  
    while (session->state != H2_SESSION_ST_DONE) {
        now = apr_time_now();
        session->have_read = session->have_written = 0;

        if (session->local.accepting 
@@ -2034,40 +2108,43 @@ apr_status_t h2_session_process(h2_session *session, int async)
                break;
                
            case H2_SESSION_ST_IDLE:
                /* We trust our connection into the default timeout/keepalive
                 * handling of the core filters/mpm iff:
                 * - keep_sync_until is not set
                 * - we have an async mpm
                 * - we have no open streams to process
                 * - we are not sitting on a Upgrade: request
                 * - we already have seen at least one request
                 */
                if (!session->keep_sync_until && async && !session->open_streams
                    && !session->r && session->remote.emitted_count) {
                if (session->idle_until && (apr_time_now() + session->idle_delay) > session->idle_until) {
                    ap_log_cerror( APLOG_MARK, APLOG_TRACE1, status, c,
                                  H2_SSSN_MSG(session, "idle, timeout reached, closing"));
                    if (session->idle_delay) {
                        apr_table_setn(session->c->notes, "short-lingering-close", "1"); 
                    }
                    dispatch_event(session, H2_SESSION_EV_CONN_TIMEOUT, 0, "timeout");
                    goto out;
                }
                
                if (session->idle_delay) {
                    /* we are less interested in spending time on this connection */
                    ap_log_cerror( APLOG_MARK, APLOG_TRACE2, status, c,
                                  H2_SSSN_MSG(session, "session is idle (%ld ms), idle wait %ld sec left"), 
                                  (long)apr_time_as_msec(session->idle_delay),
                                  (long)apr_time_sec(session->idle_until - now));
                    apr_sleep(session->idle_delay);
                    session->idle_delay = 0;
                }

                h2_conn_io_flush(&session->io);
                if (async && !session->r && (now > session->idle_sync_until)) {
                    if (trace) {
                        ap_log_cerror(APLOG_MARK, APLOG_TRACE3, status, c,
                                      H2_SSSN_MSG(session, 
                                      "nonblock read, %d streams open"), 
                                      session->open_streams);
                    }
                    h2_conn_io_flush(&session->io);
                    status = h2_session_read(session, 0);
                    
                    if (status == APR_SUCCESS) {
                        session->have_read = 1;
                        dispatch_event(session, H2_SESSION_EV_DATA_READ, 0, NULL);
                    }
                    else if (APR_STATUS_IS_EAGAIN(status) 
                        || APR_STATUS_IS_TIMEUP(status)) {
                        if (apr_time_now() > session->idle_until) {
                            dispatch_event(session, 
                                           H2_SESSION_EV_CONN_TIMEOUT, 0, NULL);
                        }
                        else {
                    else if (APR_STATUS_IS_EAGAIN(status) || APR_STATUS_IS_TIMEUP(status)) {
                        status = APR_EAGAIN;
                        goto out;
                    }
                    }
                    else {
                        ap_log_cerror(APLOG_MARK, APLOG_DEBUG, status, c,
                                      H2_SSSN_LOG(APLOGNO(03403), session, 
@@ -2078,7 +2155,6 @@ apr_status_t h2_session_process(h2_session *session, int async)
                }
                else {
                    /* make certain, we send everything before we idle */
                    h2_conn_io_flush(&session->io);
                    if (trace) {
                        ap_log_cerror(APLOG_MARK, APLOG_TRACE3, status, c,
                                      H2_SSSN_MSG(session, 
@@ -2090,7 +2166,6 @@ apr_status_t h2_session_process(h2_session *session, int async)
                     */
                    status = h2_mplx_idle(session->mplx);
                    if (status == APR_EAGAIN) {
                        dispatch_event(session, H2_SESSION_EV_DATA_READ, 0, NULL);
                        break;
                    }
                    else if (status != APR_SUCCESS) {
@@ -2101,33 +2176,11 @@ apr_status_t h2_session_process(h2_session *session, int async)
                    status = h2_session_read(session, 1);
                    if (status == APR_SUCCESS) {
                        session->have_read = 1;
                        dispatch_event(session, H2_SESSION_EV_DATA_READ, 0, NULL);
                    }
                    else if (status == APR_EAGAIN) {
                        /* nothing to read */
                    }
                    else if (APR_STATUS_IS_TIMEUP(status)) {
                        apr_time_t now = apr_time_now();
                        if (now > session->keep_sync_until) {
                            /* if we are on an async mpm, now is the time that
                             * we may dare to pass control to it. */
                            session->keep_sync_until = 0;
                        }
                        if (now > session->idle_until) {
                            if (trace) {
                                ap_log_cerror(APLOG_MARK, APLOG_TRACE3, status, c,
                                              H2_SSSN_MSG(session, 
                                              "keepalive timeout"));
                            }
                            dispatch_event(session, 
                                           H2_SESSION_EV_CONN_TIMEOUT, 0, "timeout");
                        }
                        else if (trace) {                        
                            ap_log_cerror(APLOG_MARK, APLOG_TRACE3, status, c,
                                          H2_SSSN_MSG(session, 
                                          "keepalive, %f sec left"),
                                          (session->idle_until - now) / 1000000.0f);
                        }
                        /* continue reading handling */
                    }
                    else if (APR_STATUS_IS_ECONNABORTED(status)
@@ -2145,6 +2198,18 @@ apr_status_t h2_session_process(h2_session *session, int async)
                        dispatch_event(session, H2_SESSION_EV_CONN_ERROR, 0, "error");
                    }
                }
                if (nghttp2_session_want_write(session->ngh2)) {
                    ap_update_child_status(session->c->sbh, SERVER_BUSY_WRITE, NULL);
                    status = h2_session_send(session);
                    if (status == APR_SUCCESS) {
                        status = h2_conn_io_flush(&session->io);
                    }
                    if (status != APR_SUCCESS) {
                        dispatch_event(session, H2_SESSION_EV_CONN_ERROR, 
                                       H2_ERR_INTERNAL_ERROR, "writing");
                        break;
                    }
                }
                break;
                
            case H2_SESSION_ST_BUSY:
@@ -2154,7 +2219,6 @@ apr_status_t h2_session_process(h2_session *session, int async)
                    status = h2_session_read(session, 0);
                    if (status == APR_SUCCESS) {
                        session->have_read = 1;
                        dispatch_event(session, H2_SESSION_EV_DATA_READ, 0, NULL);
                    }
                    else if (status == APR_EAGAIN) {
                        /* nothing to read */
@@ -2218,7 +2282,7 @@ apr_status_t h2_session_process(h2_session *session, int async)
                                             session->iowait);
                if (status == APR_SUCCESS) {
                    session->wait_us = 0;
                    dispatch_event(session, H2_SESSION_EV_DATA_READ, 0, NULL);
                        dispatch_event(session, H2_SESSION_EV_STREAM_CHANGE, 0, NULL);
                }
                else if (APR_STATUS_IS_TIMEUP(status)) {
                    /* go back to checking all inputs again */
+5 −2
Original line number Diff line number Diff line
@@ -66,10 +66,11 @@ typedef enum {
    H2_SESSION_EV_PROTO_ERROR,      /* protocol error */
    H2_SESSION_EV_CONN_TIMEOUT,     /* connection timeout */
    H2_SESSION_EV_NO_IO,            /* nothing has been read or written */
    H2_SESSION_EV_DATA_READ,        /* connection data has been read */
    H2_SESSION_EV_FRAME_RCVD,       /* a frame has been received */
    H2_SESSION_EV_NGH2_DONE,        /* nghttp2 wants neither read nor write anything */
    H2_SESSION_EV_MPM_STOPPING,     /* the process is stopping */
    H2_SESSION_EV_PRE_CLOSE,        /* connection will close after this */
    H2_SESSION_EV_STREAM_CHANGE,    /* a stream (state/input/output) changed */
} h2_session_event_t;

typedef struct h2_session {
@@ -118,7 +119,9 @@ typedef struct h2_session {
    apr_size_t max_stream_mem;      /* max buffer memory for a single stream */
    
    apr_time_t idle_until;          /* Time we shut down due to sheer boredom */
    apr_time_t keep_sync_until;     /* Time we sync wait until passing to async mpm */
    apr_time_t idle_sync_until;     /* Time we sync wait until keepalive handling kicks in */
    apr_size_t idle_frames;         /* number of rcvd frames that kept session in idle state */
    apr_interval_time_t idle_delay; /* Time we delay processing rcvd frames in idle state */
    
    apr_bucket_brigade *bbtmp;      /* brigade for keeping temporary data */
    struct apr_thread_cond_t *iowait; /* our cond when trywaiting for data */
+2 −2
Original line number Diff line number Diff line
@@ -27,7 +27,7 @@
 * @macro
 * Version number of the http2 module as c string
 */
#define MOD_HTTP2_VERSION "1.10.20"
#define MOD_HTTP2_VERSION "1.11.0"

/**
 * @macro
@@ -35,7 +35,7 @@
 * release. This is a 24 bit number with 8 bits for major number, 8 bits
 * for minor and 8 bits for patch. Version 1.2.3 becomes 0x010203.
 */
#define MOD_HTTP2_VERSION_NUM 0x010a14
#define MOD_HTTP2_VERSION_NUM 0x010b00


#endif /* mod_h2_h2_version_h */