cgroup/cpuset: Revert "Allow suppression of sched domain rebuild in update_cpumasks_h...

Revert commit 3ae0b773211e ("cgroup/cpuset: Allow suppression of sched
domain rebuild in update_cpumasks_hier()") to allow for an alternative
way to suppress unnecessary rebuild_sched_domains_locked() calls in
update_cpumasks_hier() and elsewhere in a following commit.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index bb1ea78781261d2ef1f4e98da3a6affb35fcb7dc..1ddbdc8ea10ff89474b65bf4544bce97759b4331 100644 (file)
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -1922,12 +1922,6 @@ static void compute_partition_effective_cpumask(struct cpuset *cs,
        rcu_read_unlock();
 }
 
-/*
- * 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
@@ -1942,7 +1936,7 @@ static void compute_partition_effective_cpumask(struct cpuset *cs,
  * Called with cpuset_mutex held
  */
 static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp,
-                                int flags)
+                                bool force)
 {
        struct cpuset *cp;
        struct cgroup_subsys_state *pos_css;
@@ -2007,10 +2001,10 @@ 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) HIER_CHECKALL flag not set, and
+                * 3) force flag not set, and
                 * 4) for v2 load balance state same as its parent.
                 */
-               if (!cp->partition_root_state && !(flags & HIER_CHECKALL) &&
+               if (!cp->partition_root_state && !force &&
                    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)))) {
@@ -2112,8 +2106,7 @@ get_css:
        }
        rcu_read_unlock();
 
-       if (need_rebuild_sched_domains && !(flags & HIER_NO_SD_REBUILD) &&
-           !force_sd_rebuild)
+       if (need_rebuild_sched_domains && !force_sd_rebuild)
                rebuild_sched_domains_locked();
 }
 
@@ -2141,9 +2134,7 @@ static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs,
         * directly.
         *
         * The update_cpumasks_hier() function may sleep. So we have to
-        * 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.
+        * release the RCU read lock before calling it.
         */
        rcu_read_lock();
        cpuset_for_each_child(sibling, pos_css, parent) {
@@ -2159,7 +2150,7 @@ static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs,
                        continue;
 
                rcu_read_unlock();
-               update_cpumasks_hier(sibling, tmp, HIER_NO_SD_REBUILD);
+               update_cpumasks_hier(sibling, tmp, false);
                rcu_read_lock();
                css_put(&sibling->css);
        }
@@ -2179,7 +2170,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
        struct tmpmasks tmp;
        struct cpuset *parent = parent_cs(cs);
        bool invalidate = false;
-       int hier_flags = 0;
+       bool force = false;
        int old_prs = cs->partition_root_state;
 
        /* top_cpuset.cpus_allowed tracks cpu_online_mask; it's read-only */
@@ -2240,8 +2231,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
         * Check all the descendants in update_cpumasks_hier() if
         * effective_xcpus is to be changed.
         */
-       if (!cpumask_equal(cs->effective_xcpus, trialcs->effective_xcpus))
-               hier_flags = HIER_CHECKALL;
+       force = !cpumask_equal(cs->effective_xcpus, trialcs->effective_xcpus);
 
        retval = validate_change(cs, trialcs);
 
@@ -2309,7 +2299,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
        spin_unlock_irq(&callback_lock);
 
        /* effective_cpus/effective_xcpus will be updated here */
-       update_cpumasks_hier(cs, &tmp, hier_flags);
+       update_cpumasks_hier(cs, &tmp, force);
 
        /* Update CS_SCHED_LOAD_BALANCE and/or sched_domains, if necessary */
        if (cs->partition_root_state)
@@ -2334,7 +2324,7 @@ static int update_exclusive_cpumask(struct cpuset *cs, struct cpuset *trialcs,
        struct tmpmasks tmp;
        struct cpuset *parent = parent_cs(cs);
        bool invalidate = false;
-       int hier_flags = 0;
+       bool force = false;
        int old_prs = cs->partition_root_state;
 
        if (!*buf) {
@@ -2357,8 +2347,7 @@ static int update_exclusive_cpumask(struct cpuset *cs, struct cpuset *trialcs,
         * Check all the descendants in update_cpumasks_hier() if
         * effective_xcpus is to be changed.
         */
-       if (!cpumask_equal(cs->effective_xcpus, trialcs->effective_xcpus))
-               hier_flags = HIER_CHECKALL;
+       force = !cpumask_equal(cs->effective_xcpus, trialcs->effective_xcpus);
 
        retval = validate_change(cs, trialcs);
        if (retval)
@@ -2411,8 +2400,8 @@ static int update_exclusive_cpumask(struct cpuset *cs, struct cpuset *trialcs,
         * of the subtree when it is a valid partition root or effective_xcpus
         * is updated.
         */
-       if (is_partition_valid(cs) || hier_flags)
-               update_cpumasks_hier(cs, &tmp, hier_flags);
+       if (is_partition_valid(cs) || force)
+               update_cpumasks_hier(cs, &tmp, force);
 
        /* Update CS_SCHED_LOAD_BALANCE and/or sched_domains, if necessary */
        if (cs->partition_root_state)
@@ -2853,7 +2842,7 @@ out:
        update_unbound_workqueue_cpumask(new_xcpus_state);
 
        /* Force update if switching back to member */
-       update_cpumasks_hier(cs, &tmpmask, !new_prs ? HIER_CHECKALL : 0);
+       update_cpumasks_hier(cs, &tmpmask, !new_prs);
 
        /* Update sched domains and load balance flag */
        update_partition_sd_lb(cs, old_prs);