core: add support for setting CPUAffinity= to special "numa" value

systemd will automatically derive CPU affinity mask from NUMA node
mask.

Fixes #13248

src/core/dbus-execute.c

@@ -56,6 +56,8 @@ static BUS_DEFINE_PROPERTY_GET2(property_get_ioprio_priority, "i", ExecContext,
 static BUS_DEFINE_PROPERTY_GET_GLOBAL(property_get_empty_string, "s", NULL);
 static BUS_DEFINE_PROPERTY_GET_REF(property_get_syslog_level, "i", int, LOG_PRI);
 static BUS_DEFINE_PROPERTY_GET_REF(property_get_syslog_facility, "i", int, LOG_FAC);
+static BUS_DEFINE_PROPERTY_GET(property_get_cpu_affinity_from_numa, "b", ExecContext, exec_context_get_cpu_affinity_from_numa);
+
 
 static int property_get_environment_files(
                 sd_bus *bus,
@@ -213,6 +215,7 @@ static int property_get_cpu_affinity(
                 sd_bus_error *error) {
 
         ExecContext *c = userdata;
+        _cleanup_(cpu_set_reset) CPUSet s = {};
         _cleanup_free_ uint8_t *array = NULL;
         size_t allocated;
 
@@ -220,7 +223,16 @@ static int property_get_cpu_affinity(
         assert(reply);
         assert(c);
 
-        (void) cpu_set_to_dbus(&c->cpu_set, &array, &allocated);
+        if (c->cpu_affinity_from_numa) {
+                int r;
+
+                r = numa_to_cpu_set(&c->numa_policy, &s);
+                if (r < 0)
+                        return r;
+        }
+
+        (void) cpu_set_to_dbus(c->cpu_affinity_from_numa ? &s : &c->cpu_set,  &array, &allocated);
+
         return sd_bus_message_append_array(reply, 'y', array, allocated);
 }
 
@@ -741,6 +753,7 @@ const sd_bus_vtable bus_exec_vtable[] = {
         SD_BUS_PROPERTY("CPUSchedulingPolicy", "i", property_get_cpu_sched_policy, 0, SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("CPUSchedulingPriority", "i", property_get_cpu_sched_priority, 0, SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("CPUAffinity", "ay", property_get_cpu_affinity, 0, SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("CPUAffinityFromNUMA", "b", property_get_cpu_affinity_from_numa, 0, SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("NUMAPolicy", "i", property_get_numa_policy, 0, SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("NUMAMask", "ay", property_get_numa_mask, 0, SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("TimerSlackNSec", "t", property_get_timer_slack_nsec, 0, SD_BUS_VTABLE_PROPERTY_CONST),
@@ -1770,6 +1783,20 @@ int bus_exec_context_set_transient_property(
 
                 return 1;
 
+        } else if (streq(name, "CPUAffinityFromNUMA")) {
+                int q;
+
+                r = sd_bus_message_read_basic(message, 'b', &q);
+                if (r < 0)
+                        return r;
+
+                if (!UNIT_WRITE_FLAGS_NOOP(flags)) {
+                        c->cpu_affinity_from_numa = q;
+                        unit_write_settingf(u, flags, name, "%s=%s", "CPUAffinity", "numa");
+                }
+
+                return 1;
+
         } else if (streq(name, "NUMAPolicy")) {
                 int32_t type;
 
@@ -1784,6 +1811,7 @@ int bus_exec_context_set_transient_property(
                         c->numa_policy.type = type;
 
                 return 1;
+
         } else if (streq(name, "Nice")) {
                 int32_t q;
 

src/core/execute.c

@@ -3021,6 +3021,33 @@ static int exec_parameters_get_cgroup_path(const ExecParameters *params, char **
         return using_subcgroup;
 }
 
+static int exec_context_cpu_affinity_from_numa(const ExecContext *c, CPUSet *ret) {
+        _cleanup_(cpu_set_reset) CPUSet s = {};
+        int r;
+
+        assert(c);
+        assert(ret);
+
+        if (!c->numa_policy.nodes.set) {
+                log_debug("Can't derive CPU affinity mask from NUMA mask because NUMA mask is not set, ignoring");
+                return 0;
+        }
+
+        r = numa_to_cpu_set(&c->numa_policy, &s);
+        if (r < 0)
+                return r;
+
+        cpu_set_reset(ret);
+
+        return cpu_set_add_all(ret, &s);
+}
+
+bool exec_context_get_cpu_affinity_from_numa(const ExecContext *c) {
+        assert(c);
+
+        return c->cpu_affinity_from_numa;
+}
+
 static int exec_child(
                 Unit *unit,
                 const ExecCommand *command,
@@ -3318,11 +3345,26 @@ static int exec_child(
                 }
         }
 
-        if (context->cpu_set.set)
-                if (sched_setaffinity(0, context->cpu_set.allocated, context->cpu_set.set) < 0) {
+        if (context->cpu_affinity_from_numa || context->cpu_set.set) {
+                _cleanup_(cpu_set_reset) CPUSet converted_cpu_set = {};
+                const CPUSet *cpu_set;
+
+                if (context->cpu_affinity_from_numa) {
+                        r = exec_context_cpu_affinity_from_numa(context, &converted_cpu_set);
+                        if (r < 0) {
+                                *exit_status = EXIT_CPUAFFINITY;
+                                return log_unit_error_errno(unit, r, "Failed to derive CPU affinity mask from NUMA mask: %m");
+                        }
+
+                        cpu_set = &converted_cpu_set;
+                } else
+                        cpu_set = &context->cpu_set;
+
+                if (sched_setaffinity(0, cpu_set->allocated, cpu_set->set) < 0) {
                         *exit_status = EXIT_CPUAFFINITY;
                         return log_unit_error_errno(unit, errno, "Failed to set up CPU affinity: %m");
                 }
+        }
 
         if (mpol_is_valid(numa_policy_get_type(&context->numa_policy))) {
                 r = apply_numa_policy(&context->numa_policy);

src/core/execute.h

@@ -182,6 +182,7 @@ struct ExecContext {
 
         CPUSet cpu_set;
         NUMAPolicy numa_policy;
+        bool cpu_affinity_from_numa;
 
         ExecInput std_input;
         ExecOutput std_output;
@@ -406,6 +407,8 @@ void exec_runtime_vacuum(Manager *m);
 
 void exec_params_clear(ExecParameters *p);
 
+bool exec_context_get_cpu_affinity_from_numa(const ExecContext *c);
+
 const char* exec_output_to_string(ExecOutput i) _const_;
 ExecOutput exec_output_from_string(const char *s) _pure_;
 

src/core/load-fragment.c

@@ -1330,13 +1330,25 @@ int config_parse_exec_cpu_affinity(const char *unit,
                                    void *userdata) {
 
         ExecContext *c = data;
+        int r;
 
         assert(filename);
         assert(lvalue);
         assert(rvalue);
         assert(data);
 
-        return parse_cpu_set_extend(rvalue, &c->cpu_set, true, unit, filename, line, lvalue);
+        if (streq(rvalue, "numa")) {
+                c->cpu_affinity_from_numa = true;
+                cpu_set_reset(&c->cpu_set);
+
+                return 0;
+        }
+
+        r = parse_cpu_set_extend(rvalue, &c->cpu_set, true, unit, filename, line, lvalue);
+        if (r >= 0)
+                c->cpu_affinity_from_numa = false;
+
+        return r;
 }
 
 int config_parse_capability_set(