6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Waiman Long longman@redhat.com
[ Upstream commit c4c9cebe2fb9cdc73e55513de7af7a4f50260e88 ]
Currently the cpuset code uses group_subsys_on_dfl() to check if we are running with cgroup v2. If CONFIG_CPUSETS_V1 isn't set, there is really no need to do this check and we can optimize out some of the unneeded v1 specific code paths. Introduce a new cpuset_v2() and use it to replace the cgroup_subsys_on_dfl() check to further optimize the code.
Signed-off-by: Waiman Long longman@redhat.com Signed-off-by: Tejun Heo tj@kernel.org Stable-dep-of: a22b3d54de94 ("cgroup/cpuset: Fix race between newly created partition and dying one") Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/cgroup/cpuset.c | 39 +++++++++++++++++++-------------------- 1 file changed, 19 insertions(+), 20 deletions(-)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 7ac2a634128b3..07ea3a563150b 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -293,6 +293,12 @@ static inline void dec_attach_in_progress(struct cpuset *cs) mutex_unlock(&cpuset_mutex); }
+static inline bool cpuset_v2(void) +{ + return !IS_ENABLED(CONFIG_CPUSETS_V1) || + cgroup_subsys_on_dfl(cpuset_cgrp_subsys); +} + /* * Cgroup v2 behavior is used on the "cpus" and "mems" control files when * on default hierarchy or when the cpuset_v2_mode flag is set by mounting @@ -303,7 +309,7 @@ static inline void dec_attach_in_progress(struct cpuset *cs) */ static inline bool is_in_v2_mode(void) { - return cgroup_subsys_on_dfl(cpuset_cgrp_subsys) || + return cpuset_v2() || (cpuset_cgrp_subsys.root->flags & CGRP_ROOT_CPUSET_V2_MODE); }
@@ -738,7 +744,7 @@ static int generate_sched_domains(cpumask_var_t **domains, int nslot; /* next empty doms[] struct cpumask slot */ struct cgroup_subsys_state *pos_css; bool root_load_balance = is_sched_load_balance(&top_cpuset); - bool cgrpv2 = cgroup_subsys_on_dfl(cpuset_cgrp_subsys); + bool cgrpv2 = cpuset_v2(); int nslot_update;
doms = NULL; @@ -1206,7 +1212,7 @@ static void reset_partition_data(struct cpuset *cs) { struct cpuset *parent = parent_cs(cs);
- if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) + if (!cpuset_v2()) return;
lockdep_assert_held(&callback_lock); @@ -2035,7 +2041,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp, */ if (!cp->partition_root_state && !force && cpumask_equal(tmp->new_cpus, cp->effective_cpus) && - (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) || + (!cpuset_v2() || (is_sched_load_balance(parent) == is_sched_load_balance(cp)))) { pos_css = css_rightmost_descendant(pos_css); continue; @@ -2109,8 +2115,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp, * from parent if current cpuset isn't a valid partition root * and their load balance states differ. */ - if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && - !is_partition_valid(cp) && + if (cpuset_v2() && !is_partition_valid(cp) && (is_sched_load_balance(parent) != is_sched_load_balance(cp))) { if (is_sched_load_balance(parent)) set_bit(CS_SCHED_LOAD_BALANCE, &cp->flags); @@ -2126,8 +2131,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp, */ if (!cpumask_empty(cp->cpus_allowed) && is_sched_load_balance(cp) && - (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) || - is_partition_valid(cp))) + (!cpuset_v2() || is_partition_valid(cp))) need_rebuild_sched_domains = true;
rcu_read_lock(); @@ -2264,7 +2268,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
retval = validate_change(cs, trialcs);
- if ((retval == -EINVAL) && cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) { + if ((retval == -EINVAL) && cpuset_v2()) { struct cgroup_subsys_state *css; struct cpuset *cp;
@@ -2756,8 +2760,7 @@ int cpuset_update_flag(cpuset_flagbits_t bit, struct cpuset *cs, spin_unlock_irq(&callback_lock);
if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed) { - if (!IS_ENABLED(CONFIG_CPUSETS_V1) || - cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) + if (cpuset_v2()) cpuset_force_rebuild(); else rebuild_sched_domains_locked(); @@ -2943,8 +2946,7 @@ static int cpuset_can_attach(struct cgroup_taskset *tset) * migration permission derives from hierarchy ownership in * cgroup_procs_write_permission()). */ - if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) || - (cpus_updated || mems_updated)) { + if (!cpuset_v2() || (cpus_updated || mems_updated)) { ret = security_task_setscheduler(task); if (ret) goto out_unlock; @@ -3058,8 +3060,7 @@ static void cpuset_attach(struct cgroup_taskset *tset) * in effective cpus and mems. In that case, we can optimize out * by skipping the task iteration and update. */ - if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && - !cpus_updated && !mems_updated) { + if (cpuset_v2() && !cpus_updated && !mems_updated) { cpuset_attach_nodemask_to = cs->effective_mems; goto out; } @@ -3384,7 +3385,7 @@ cpuset_css_alloc(struct cgroup_subsys_state *parent_css) INIT_LIST_HEAD(&cs->remote_sibling);
/* Set CS_MEMORY_MIGRATE for default hierarchy */ - if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) + if (cpuset_v2()) __set_bit(CS_MEMORY_MIGRATE, &cs->flags);
return &cs->css; @@ -3411,8 +3412,7 @@ static int cpuset_css_online(struct cgroup_subsys_state *css) /* * For v2, clear CS_SCHED_LOAD_BALANCE if parent is isolated */ - if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && - !is_sched_load_balance(parent)) + if (cpuset_v2() && !is_sched_load_balance(parent)) clear_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
cpuset_inc(); @@ -3482,8 +3482,7 @@ static void cpuset_css_offline(struct cgroup_subsys_state *css) if (is_partition_valid(cs)) update_prstate(cs, 0);
- if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && - is_sched_load_balance(cs)) + if (!cpuset_v2() && is_sched_load_balance(cs)) cpuset_update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
cpuset_dec();