diff options
author | Waiman Long <longman@redhat.com> | 2023-06-27 17:35:03 +0300 |
---|---|---|
committer | Tejun Heo <tj@kernel.org> | 2023-07-11 00:01:23 +0300 |
commit | 3ae0b773211ed0231e7ee3e8d28ec4ab9bc5134b (patch) | |
tree | 8313e7db13ff71d6734d274e6a6737f9e616f0a8 /kernel/cgroup/cpuset.c | |
parent | 99fe36ba6fc16aa0962bc1f41ebcdec696203889 (diff) | |
download | linux-3ae0b773211ed0231e7ee3e8d28ec4ab9bc5134b.tar.xz |
cgroup/cpuset: Allow suppression of sched domain rebuild in update_cpumasks_hier()
A single partition setup and tear-down operation can lead to
multiple rebuild_sched_domains_locked() calls which is a waste of
effort. This can partly be mitigated by adding a flag to suppress the
rebuild_sched_domains_locked() call in update_cpumasks_hier(). Since
a Boolean flag has already been passed as the 3rd argument to
update_cpumasks_hier(), we can extend that to a full flag word.
The sched domain rebuild suppression is now enabled in
update_sibling_cpumasks() as all it callers will do the sched domain
rebuild after its return later on anyway.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/cgroup/cpuset.c')
-rw-r--r-- | kernel/cgroup/cpuset.c | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index c9bb44e50eb2..b278b60ed788 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1591,6 +1591,12 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd, } /* + * update_cpumasks_hier() flags + */ +#define HIER_CHECKALL 0x01 /* Check all cpusets with no skipping */ +#define HIER_NO_SD_REBUILD 0x02 /* Don't rebuild sched domains */ + +/* * update_cpumasks_hier - Update effective cpumasks and tasks in the subtree * @cs: the cpuset to consider * @tmp: temp variables for calculating effective_cpus & partition setup @@ -1604,7 +1610,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd, * Called with cpuset_mutex held */ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp, - bool force) + int flags) { struct cpuset *cp; struct cgroup_subsys_state *pos_css; @@ -1644,10 +1650,10 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp, * Skip the whole subtree if * 1) the cpumask remains the same, * 2) has no partition root state, - * 3) force flag not set, and + * 3) HIER_CHECKALL flag not set, and * 4) for v2 load balance state same as its parent. */ - if (!cp->partition_root_state && !force && + if (!cp->partition_root_state && !(flags & HIER_CHECKALL) && cpumask_equal(tmp->new_cpus, cp->effective_cpus) && (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) || (is_sched_load_balance(parent) == is_sched_load_balance(cp)))) { @@ -1764,7 +1770,7 @@ update_parent_subparts: } rcu_read_unlock(); - if (need_rebuild_sched_domains) + if (need_rebuild_sched_domains && !(flags & HIER_NO_SD_REBUILD)) rebuild_sched_domains_locked(); } @@ -1788,7 +1794,9 @@ static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs, * to use the right effective_cpus value. * * The update_cpumasks_hier() function may sleep. So we have to - * release the RCU read lock before calling it. + * release the RCU read lock before calling it. HIER_NO_SD_REBUILD + * flag is used to suppress rebuild of sched domains as the callers + * will take care of that. */ rcu_read_lock(); cpuset_for_each_child(sibling, pos_css, parent) { @@ -1800,7 +1808,7 @@ static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs, continue; rcu_read_unlock(); - update_cpumasks_hier(sibling, tmp, false); + update_cpumasks_hier(sibling, tmp, HIER_NO_SD_REBUILD); rcu_read_lock(); css_put(&sibling->css); } @@ -1913,7 +1921,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, spin_unlock_irq(&callback_lock); /* effective_cpus will be updated here */ - update_cpumasks_hier(cs, &tmp, false); + update_cpumasks_hier(cs, &tmp, 0); if (cs->partition_root_state) { struct cpuset *parent = parent_cs(cs); @@ -2382,7 +2390,7 @@ out: * Force update if switching back to member. */ if (!list_empty(&cs->css.children)) - update_cpumasks_hier(cs, &tmpmask, !new_prs); + update_cpumasks_hier(cs, &tmpmask, !new_prs ? HIER_CHECKALL : 0); /* Update sched domains and load balance flag */ update_partition_sd_lb(cs, old_prs); |