mpm_event,core: Handle async POLLIN/POLLOUT in CONN_STATE_PROCESS state.

* include/httpd.h:
  Rename CONN_STATE_CHECK_REQUEST_LINE_READABLE to CONN_STATE_KEEPALIVE
  and CONN_STATE_READ_REQUEST_LINE to CONN_STATE_PROCESS, keeping the
  old enums as aliases. Rework comments about each state.

* server/mpm/event/event.c:
  Use the new states names.
  Let the process_connection hooks return CONN_STATE_PROCESS for mpm_event
  to POLLIN or POLLOUT depending on c->cs->sense being CONN_SENSE_WANT_READ
  or CONN_SENSE_WANT_WRITE respectively.
  Remove (ab)use of CONN_STATE_WRITE_COMPLETION with CONN_SENSE_WANT_READ to
  mean poll() for read (and the need for the obscure c->clogging_input_filters
  to make it work as expected). This is what CONN_STATE_PROCESS is for now.
  Update the comment about the states that can be returned by process_connection
  hooks (and their usage).
  Use the same queue (process_q renamed from write_completion_q) for polling
  connections in both CONN_STATE_PROCESS and CONN_STATE_WRITE_COMPLETION
  states since they both use the same (server_rec's) Timeout. This implies
  that both states are accounted as "write-completion" in mod_status for now.

* server/mpm/motorz/motorz.c, server/mpm/simple/simple_io.c, modules/http/http_core.c:
  Use the new states names (only).

* include/scoreboard.h:
  Change comment about process_score->write_completion to note that the
  counter refers to CONN_STATE_PROCESS connections returned to the MPM
  too.

* modules/http2/h2_c1.c:
  Return the c1 connection with the CONN_STATE_PROCESS state rather than
  CONN_STATE_WRITE_COMPLETION when waiting for a window update (i.e. ask
  the MPM to poll for read directly). This avoids the transition to
  CONN_STATE_KEEPALIVE which could kill the connection under high load.


Github: closes #448



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1918022 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 8 insertions, 3 deletions

diff --git a/modules/http2/h2_c1.c b/modules/http2/h2_c1.c
index 739b1d14d5..0a3e8395ad 100644
--- a/modules/http2/h2_c1.c
+++ b/modules/http2/h2_c1.c
@@ -152,20 +152,25 @@ apr_status_t h2_c1_run(conn_rec *c)
             case H2_SESSION_ST_IDLE:
             case H2_SESSION_ST_BUSY:
             case H2_SESSION_ST_WAIT:
-                c->cs->state = CONN_STATE_WRITE_COMPLETION;
-                if (!keepalive) {
+                if (keepalive) {
+                    /* flush then keep-alive */
+                    c->cs->state = CONN_STATE_WRITE_COMPLETION;
+                }
+                else {
                     /* let the MPM know that we are not done and want
                      * the Timeout behaviour instead of a KeepAliveTimeout
                      * See PR 63534. 
                      */
+                    c->cs->state = CONN_STATE_PROCESS;
                     c->cs->sense = CONN_SENSE_WANT_READ;
                 }
                 break;
+
             case H2_SESSION_ST_CLEANUP:
             case H2_SESSION_ST_DONE:
             default:
                 c->cs->state = CONN_STATE_LINGER;
-            break;
+                break;
         }
     }