6.12-stable review patch. If anyone has any objections, please let me know.
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From: Waiman Long longman@redhat.com
[ Upstream commit bcd7012afd7bcd45fcd7a0e2f48e57b273702317 ]
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 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, 14 insertions(+), 25 deletions(-)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 70fac05123c6d..0012c34bb8601 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1940,12 +1940,6 @@ 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 @@ -1960,7 +1954,7 @@ 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; @@ -2025,10 +2019,10 @@ 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)))) { @@ -2130,8 +2124,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp, } 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(); }
@@ -2159,9 +2152,7 @@ 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) { @@ -2177,7 +2168,7 @@ 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); } @@ -2197,7 +2188,7 @@ 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 */ @@ -2258,8 +2249,7 @@ 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);
@@ -2327,7 +2317,7 @@ 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) @@ -2352,7 +2342,7 @@ 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) { @@ -2375,8 +2365,7 @@ 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) @@ -2429,8 +2418,8 @@ 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) @@ -2871,7 +2860,7 @@ static int update_prstate(struct cpuset *cs, int new_prs) 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);