oom: make memory pressure duration configurable through oomd.conf

src/oom/oomd-manager.c

@@ -306,7 +306,7 @@ static int monitor_cgroup_contexts_handler(sd_event_source *s, uint64_t usec, vo
                         m->post_action_delay_start = 0;
         }
 
-        r = oomd_pressure_above(m->monitored_mem_pressure_cgroup_contexts, PRESSURE_DURATION_USEC, &targets);
+        r = oomd_pressure_above(m->monitored_mem_pressure_cgroup_contexts, m->default_mem_pressure_duration_usec, &targets);
         if (r == -ENOMEM)
                 return log_error_errno(r, "Failed to check if memory pressure exceeded limits");
         else if (r == 1) {
@@ -325,7 +325,7 @@ static int monitor_cgroup_contexts_handler(sd_event_source *s, uint64_t usec, vo
 
                         SET_FOREACH(t, targets) {
                                 log_notice("Memory pressure for %s is greater than %lu for more than %"PRIu64" seconds and there was reclaim activity",
-                                        t->path, LOAD_INT(t->mem_pressure_limit), PRESSURE_DURATION_USEC / USEC_PER_SEC);
+                                        t->path, LOAD_INT(t->mem_pressure_limit), m->default_mem_pressure_duration_usec / USEC_PER_SEC);
 
                                 r = oomd_kill_by_pgscan(candidates, t->path, m->dry_run);
                                 if (r == -ENOMEM)
@@ -471,7 +471,7 @@ static int manager_connect_bus(Manager *m) {
         return 0;
 }
 
-int manager_start(Manager *m, bool dry_run, int swap_used_limit, int mem_pressure_limit) {
+int manager_start(Manager *m, bool dry_run, int swap_used_limit, int mem_pressure_limit, usec_t mem_pressure_usec) {
         unsigned long l;
         int r;
 
@@ -487,6 +487,8 @@ int manager_start(Manager *m, bool dry_run, int swap_used_limit, int mem_pressur
         if (r < 0)
                 return r;
 
+        m->default_mem_pressure_duration_usec = mem_pressure_usec ?: DEFAULT_MEM_PRESSURE_DURATION_USEC;
+
         r = manager_connect_bus(m);
         if (r < 0)
                 return r;
@@ -505,6 +507,7 @@ int manager_start(Manager *m, bool dry_run, int swap_used_limit, int mem_pressur
 int manager_get_dump_string(Manager *m, char **ret) {
         _cleanup_free_ char *dump = NULL;
         _cleanup_fclose_ FILE *f = NULL;
+        char buf[FORMAT_TIMESPAN_MAX];
         OomdCGroupContext *c;
         size_t size;
         char *key;
@@ -521,10 +524,12 @@ int manager_get_dump_string(Manager *m, char **ret) {
                 "Dry Run: %s\n"
                 "Swap Used Limit: %u%%\n"
                 "Default Memory Pressure Limit: %lu%%\n"
+                "Default Memory Pressure Duration: %s\n"
                 "System Context:\n",
                 yes_no(m->dry_run),
                 m->swap_used_limit,
-                LOAD_INT(m->default_mem_pressure_limit));
+                LOAD_INT(m->default_mem_pressure_limit),
+                format_timespan(buf, sizeof(buf), m->default_mem_pressure_duration_usec, USEC_PER_SEC));
         oomd_dump_system_context(&m->system_context, f, "\t");
 
         fprintf(f, "Swap Monitored CGroups:\n");

src/oom/oomd-manager.h

@@ -16,7 +16,7 @@
  * percentage of time all tasks were delayed (i.e. unproductive).
  * Generally 60 or higher might be acceptable for something like system.slice with no memory.high set; processes in
  * system.slice are assumed to be less latency sensitive. */
-#define PRESSURE_DURATION_USEC (30 * USEC_PER_SEC)
+#define DEFAULT_MEM_PRESSURE_DURATION_USEC (30 * USEC_PER_SEC)
 #define DEFAULT_MEM_PRESSURE_LIMIT 60
 #define DEFAULT_SWAP_USED_LIMIT 90
 
@@ -33,6 +33,7 @@ struct Manager {
         bool dry_run;
         unsigned swap_used_limit;
         loadavg_t default_mem_pressure_limit;
+        usec_t default_mem_pressure_duration_usec;
 
         /* k: cgroup paths -> v: OomdCGroupContext
          * Used to detect when to take action. */
@@ -53,7 +54,7 @@ DEFINE_TRIVIAL_CLEANUP_FUNC(Manager*, manager_free);
 
 int manager_new(Manager **ret);
 
-int manager_start(Manager *m, bool dry_run, int swap_used_limit, int mem_pressure_limit);
+int manager_start(Manager *m, bool dry_run, int swap_used_limit, int mem_pressure_limit, usec_t mem_pressure_usec);
 
 int manager_get_dump_string(Manager *m, char **ret);
 

src/oom/oomd-util.h

@@ -31,6 +31,7 @@ struct OomdCGroupContext {
 
         /* These are only used by oomd_pressure_above for acting on high memory pressure. */
         loadavg_t mem_pressure_limit;
+        usec_t mem_pressure_duration_usec;
         usec_t last_hit_mem_pressure_limit;
 };
 

src/oom/oomd.c

@@ -19,11 +19,13 @@
 static bool arg_dry_run = false;
 static int arg_swap_used_limit = -1;
 static int arg_mem_pressure_limit = -1;
+static usec_t arg_mem_pressure_usec = 0;
 
 static int parse_config(void) {
         static const ConfigTableItem items[] = {
                 { "OOM", "SwapUsedLimitPercent",              config_parse_percent, 0, &arg_swap_used_limit    },
                 { "OOM", "DefaultMemoryPressureLimitPercent", config_parse_percent, 0, &arg_mem_pressure_limit },
+                { "OOM", "DefaultMemoryPressureDurationSec",  config_parse_sec,     0, &arg_mem_pressure_usec  },
                 {}
         };
 
@@ -160,7 +162,7 @@ static int run(int argc, char *argv[]) {
         if (r < 0)
                 return log_error_errno(r, "Failed to create manager: %m");
 
-        r = manager_start(m, arg_dry_run, arg_swap_used_limit, arg_mem_pressure_limit);
+        r = manager_start(m, arg_dry_run, arg_swap_used_limit, arg_mem_pressure_limit, arg_mem_pressure_usec);
         if (r < 0)
                 return log_error_errno(r, "Failed to start up daemon: %m");
 

src/oom/oomd.conf

@@ -14,3 +14,4 @@
 [OOM]
 #SwapUsedLimitPercent=90%
 #DefaultMemoryPressureLimitPercent=60%
+#DefaultMemoryPressureDurationSec=30s