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author | Li Zefan <lizefan@huawei.com> | 2014-07-09 16:47:50 +0800 |
---|---|---|
committer | Tejun Heo <tj@kernel.org> | 2014-07-09 15:56:16 -0400 |
commit | 8b5f1c52dcd1accd3a940cfcb148bef6de589524 (patch) | |
tree | 200c279a6b64f4e4ef8f34fdd9f3d4a7cc6b9736 /kernel | |
parent | 554b0d1c845e42ef01d7f6f5f24b3e4c6129ce8f (diff) | |
download | linux-8b5f1c52dcd1accd3a940cfcb148bef6de589524.tar.bz2 |
cpuset: use effective cpumask to build sched domains
We're going to have separate user-configured masks and effective ones.
Eventually configured masks can only be changed by writing cpuset.cpus
and cpuset.mems, and they won't be restricted by parent cpuset. While
effective masks reflect cpu/memory hotplug and hierachical restriction,
and these are the real masks that apply to the tasks in the cpuset.
We calculate effective mask this way:
- top cpuset's effective_mask == online_mask, otherwise
- cpuset's effective_mask == configured_mask & parent effective_mask,
if the result is empty, it inherits parent effective mask.
Those behavior changes are for default hierarchy only. For legacy
hierarchy, effective_mask and configured_mask are the same, so we won't
break old interfaces.
We should partition sched domains according to effective_cpus, which
is the real cpulist that takes effects on tasks in the cpuset.
This won't introduce behavior change.
v2:
- Add a comment for the call of rebuild_sched_domains(), suggested
by Tejun.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/cpuset.c | 28 |
1 files changed, 17 insertions, 11 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c index f8340026d01c..60577ccdbfc7 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -494,11 +494,11 @@ out: #ifdef CONFIG_SMP /* * Helper routine for generate_sched_domains(). - * Do cpusets a, b have overlapping cpus_allowed masks? + * Do cpusets a, b have overlapping effective cpus_allowed masks? */ static int cpusets_overlap(struct cpuset *a, struct cpuset *b) { - return cpumask_intersects(a->cpus_allowed, b->cpus_allowed); + return cpumask_intersects(a->effective_cpus, b->effective_cpus); } static void @@ -615,7 +615,7 @@ static int generate_sched_domains(cpumask_var_t **domains, *dattr = SD_ATTR_INIT; update_domain_attr_tree(dattr, &top_cpuset); } - cpumask_copy(doms[0], top_cpuset.cpus_allowed); + cpumask_copy(doms[0], top_cpuset.effective_cpus); goto done; } @@ -719,7 +719,7 @@ restart: struct cpuset *b = csa[j]; if (apn == b->pn) { - cpumask_or(dp, dp, b->cpus_allowed); + cpumask_or(dp, dp, b->effective_cpus); if (dattr) update_domain_attr_tree(dattr + nslot, b); @@ -771,7 +771,7 @@ static void rebuild_sched_domains_locked(void) * passing doms with offlined cpu to partition_sched_domains(). * Anyways, hotplug work item will rebuild sched domains. */ - if (!cpumask_equal(top_cpuset.cpus_allowed, cpu_active_mask)) + if (!cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask)) goto out; /* Generate domain masks and attrs */ @@ -870,6 +870,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct cpumask *new_cpus) { struct cpuset *cp; struct cgroup_subsys_state *pos_css; + bool need_rebuild_sched_domains = false; rcu_read_lock(); cpuset_for_each_descendant_pre(cp, pos_css, cs) { @@ -903,10 +904,21 @@ static void update_cpumasks_hier(struct cpuset *cs, struct cpumask *new_cpus) update_tasks_cpumask(cp); + /* + * If the effective cpumask of any non-empty cpuset is changed, + * we need to rebuild sched domains. + */ + if (!cpumask_empty(cp->cpus_allowed) && + is_sched_load_balance(cp)) + need_rebuild_sched_domains = true; + rcu_read_lock(); css_put(&cp->css); } rcu_read_unlock(); + + if (need_rebuild_sched_domains) + rebuild_sched_domains_locked(); } /** @@ -919,7 +931,6 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, const char *buf) { int retval; - int is_load_balanced; /* top_cpuset.cpus_allowed tracks cpu_online_mask; it's read-only */ if (cs == &top_cpuset) @@ -950,17 +961,12 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, if (retval < 0) return retval; - is_load_balanced = is_sched_load_balance(trialcs); - mutex_lock(&callback_mutex); cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed); mutex_unlock(&callback_mutex); /* use trialcs->cpus_allowed as a temp variable */ update_cpumasks_hier(cs, trialcs->cpus_allowed); - - if (is_load_balanced) - rebuild_sched_domains_locked(); return 0; } |