pid1: bump DefaultTasksMax to 80% of the kernel pid.max value

This should be hopefully high enough even for the very big deployments. RHEL-only: feature Related: RHEL-40924
redhat-plumbers · Jun 27, 2024 · 96a9626 · 96a9626
1 parent 45768ef
commit 96a9626
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Showing 3 changed files with 4 additions and 4 deletions.
diff --git a/man/systemd-system.conf.xml b/man/systemd-system.conf.xml
@@ -520,10 +520,10 @@
         <listitem><para>Configure the default value for the per-unit <varname>TasksMax=</varname> setting. See
         <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>
         for details. This setting applies to all unit types that support resource control settings, with the exception
-        of slice units. Defaults to 15% of the minimum of <varname>kernel.pid_max=</varname>, <varname>kernel.threads-max=</varname>
+        of slice units. Defaults to 80% of the minimum of <varname>kernel.pid_max=</varname>, <varname>kernel.threads-max=</varname>
         and root cgroup <varname>pids.max</varname>.
         Kernel has a default value for <varname>kernel.pid_max=</varname> and an algorithm of counting in case of more than 32 cores.
-        For example, with the default <varname>kernel.pid_max=</varname>, <varname>DefaultTasksMax=</varname> defaults to 4915,
+        For example, with the default <varname>kernel.pid_max=</varname>, <varname>DefaultTasksMax=</varname> defaults to 26214,
         but might be greater in other systems or smaller in OS containers.</para>
 
         <xi:include href="version-info.xml" xpointer="v228"/></listitem>

diff --git a/src/core/manager.c b/src/core/manager.c
@@ -117,7 +117,7 @@
 /* How many units and jobs to process of the bus queue before returning to the event loop. */
 #define MANAGER_BUS_MESSAGE_BUDGET 100U
 
-#define DEFAULT_TASKS_MAX ((CGroupTasksMax) { 15U, 100U }) /* 15% */
+#define DEFAULT_TASKS_MAX ((CGroupTasksMax) { 80U, 100U }) /* 80% */
 
 static int manager_dispatch_notify_fd(sd_event_source *source, int fd, uint32_t revents, void *userdata);
 static int manager_dispatch_cgroups_agent_fd(sd_event_source *source, int fd, uint32_t revents, void *userdata);

diff --git a/src/core/system.conf.in b/src/core/system.conf.in
@@ -59,7 +59,7 @@
 #DefaultIPAccounting=no
 #DefaultMemoryAccounting={{ 'yes' if MEMORY_ACCOUNTING_DEFAULT else 'no' }}
 #DefaultTasksAccounting=yes
-#DefaultTasksMax=15%
+#DefaultTasksMax=80%
 #DefaultLimitCPU=
 #DefaultLimitFSIZE=
 #DefaultLimitDATA=