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Message-ID: <20241110025023.664487-4-longman@redhat.com>
Date: Sat, 9 Nov 2024 21:50:23 -0500
From: Waiman Long <longman@...hat.com>
To: Tejun Heo <tj@...nel.org>,
Johannes Weiner <hannes@...xchg.org>,
Michal Koutný <mkoutny@...e.com>
Cc: cgroups@...r.kernel.org,
linux-kernel@...r.kernel.org,
Juri Lelli <juri.lelli@...hat.com>,
Waiman Long <longman@...hat.com>
Subject: [PATCH 3/3] cgroup/cpuset: Further optimize code if CONFIG_CPUSETS_V1 not set
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@...hat.com>
---
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 0d56a226c522..655396e75b58 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;
@@ -1198,7 +1204,7 @@ 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);
@@ -2017,7 +2023,7 @@ 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;
@@ -2091,8 +2097,7 @@ 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);
@@ -2108,8 +2113,7 @@ 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();
@@ -2246,7 +2250,7 @@ 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;
@@ -2738,8 +2742,7 @@ 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();
@@ -2925,8 +2928,7 @@ 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;
@@ -3040,8 +3042,7 @@ 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;
}
@@ -3391,7 +3392,7 @@ 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;
@@ -3418,8 +3419,7 @@ 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();
@@ -3489,8 +3489,7 @@ 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();
--
2.47.0
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