On Wed, Dec 1, 2021 at 5:19 PM Ruediger Pluem <rpl...@apache.org> wrote:
>
> On 12/1/21 3:59 PM, Eric Covener wrote:
> >
> > I wonder if the patch here could maybe key off of whether there is
> > slack space in ServerLimit or if
> > retained->total_daemons == active_daemons_limit to avoid creating more
> > slow to exit children when
> > the new condition is not the only way out?
>
> You mean something like:
>
> Index: server/mpm/event/event.c
> ===================================================================
> --- server/mpm/event/event.c (revision 1895463)
> +++ server/mpm/event/event.c (working copy)
> @@ -3201,7 +3201,8 @@
> * exits by itself (i.e. MaxRequestsPerChild reached), so the
> below
> * test makes sure that the situation unblocks when the load
> falls
> * significantly (regardless of MaxRequestsPerChild, e.g. 0) */
> - || idle_thread_count > max_workers/4 / num_buckets) {
> + || (active_daemons_limit == server_limit
> + && idle_thread_count > max_workers/4 / num_buckets)) {
> /* Kill off one child */
> ap_mpm_podx_signal(retained->buckets[child_bucket].pod,
> AP_MPM_PODX_GRACEFUL);
Or this:
--- server/mpm/event/event.c (revision 1895394)
+++ server/mpm/event/event.c (working copy)
@@ -3195,13 +3195,15 @@ static void perform_idle_server_maintenance(int ch
* XXX depending on server load, later be able to resurrect them
* or kill them
*/
- if ((retained->total_daemons <= active_daemons_limit
- && retained->total_daemons < server_limit)
+ if (retained->total_daemons < active_daemons_limit
/* The above test won't transition from true to false until a child
- * exits by itself (i.e. MaxRequestsPerChild reached), so the below
- * test makes sure that the situation unblocks when the load falls
- * significantly (regardless of MaxRequestsPerChild, e.g. 0) */
- || idle_thread_count > max_workers/4 / num_buckets) {
+ * exits by itself (i.e. old generation or MaxRequestsPerChild), so
+ * the below test makes sure that the situation unblocks when the
+ * load drops significantly and there are no child of an old gen
+ * occupying the scoreboard already (above active_daemons_limit) so
+ * to avoid another squatter potentially slow to exit too. */
+ || (retained->total_daemons == active_daemons_limit
+ && idle_thread_count > max_workers/4 / num_buckets)) {
/* Kill off one child */
ap_mpm_podx_signal(retained->buckets[child_bucket].pod,
AP_MPM_PODX_GRACEFUL);
?
It would unblock the situation only if/when there are no old gen
processes in the scoreboard, though it'd works only if ServerLimit >
active_daemons_limit (if they are equals, we can't/don't account for
quiescing processes).
Or maybe we could simply:
--- server/mpm/event/event.c (revision 1895394)
+++ server/mpm/event/event.c (working copy)
@@ -3186,8 +3186,8 @@ static void perform_idle_server_maintenance(int ch
* requests. If the server load changes many times, many such
* gracefully finishing processes may accumulate, filling up the
* scoreboard. To avoid running out of scoreboard entries, we
- * don't shut down more processes when the total number of processes
- * is high, until there are more than max_workers/4 idle threads.
+ * don't shut down more processes if there are quiescing ones
+ * already (i.e. retained->total_daemons > active_daemons).
*
* XXX It would be nice if we could
* XXX - kill processes without keepalive connections first
@@ -3195,13 +3195,7 @@ static void perform_idle_server_maintenance(int ch
* XXX depending on server load, later be able to resurrect them
* or kill them
*/
- if ((retained->total_daemons <= active_daemons_limit
- && retained->total_daemons < server_limit)
- /* The above test won't transition from true to false until a child
- * exits by itself (i.e. MaxRequestsPerChild reached), so the below
- * test makes sure that the situation unblocks when the load falls
- * significantly (regardless of MaxRequestsPerChild, e.g. 0) */
- || idle_thread_count > max_workers/4 / num_buckets) {
+ if (retained->total_daemons == active_daemons) {
/* Kill off one child */
ap_mpm_podx_signal(retained->buckets[child_bucket].pod,
AP_MPM_PODX_GRACEFUL);
?
And then kill processes only if there are no stopping ones already..
Cheers;
Yann.
