cgroup_get(cgrp);
cgroup_kn_unlock(of->kn);
+ /* Allow only one trigger per file descriptor */
+ if (ctx->psi.trigger) {
+ cgroup_put(cgrp);
+ return -EBUSY;
+ }
+
psi = cgroup_ino(cgrp) == 1 ? &psi_system : &cgrp->psi;
new = psi_trigger_create(psi, buf, nbytes, res);
if (IS_ERR(new)) {
return PTR_ERR(new);
}
- psi_trigger_replace(&ctx->psi.trigger, new);
-
+ smp_store_release(&ctx->psi.trigger, new);
cgroup_put(cgrp);
return nbytes;
{
struct cgroup_file_ctx *ctx = of->priv;
- psi_trigger_replace(&ctx->psi.trigger, NULL);
+ psi_trigger_destroy(ctx->psi.trigger);
}
bool cgroup_psi_enabled(void)
if (ret)
goto err;
+ /*
+ * Spawning a task directly into a cgroup works by passing a file
+ * descriptor to the target cgroup directory. This can even be an O_PATH
+ * file descriptor. But it can never be a cgroup.procs file descriptor.
+ * This was done on purpose so spawning into a cgroup could be
+ * conceptualized as an atomic
+ *
+ * fd = openat(dfd_cgroup, "cgroup.procs", ...);
+ * write(fd, <child-pid>, ...);
+ *
+ * sequence, i.e. it's a shorthand for the caller opening and writing
+ * cgroup.procs of the cgroup indicated by @dfd_cgroup. This allows us
+ * to always use the caller's credentials.
+ */
ret = cgroup_attach_permissions(cset->dfl_cgrp, dst_cgrp, sb,
!(kargs->flags & CLONE_THREAD),
current->nsproxy->cgroup_ns);
/**
* cgroup_can_fork - called on a new task before the process is exposed
* @child: the child process
+ * @kargs: the arguments passed to create the child process
*
* This prepares a new css_set for the child process which the child will
* be attached to in cgroup_post_fork().
/**
* cgroup_post_fork - finalize cgroup setup for the child process
* @child: the child process
+ * @kargs: the arguments passed to create the child process
*
* Attach the child process to its css_set calling the subsystem fork()
* callbacks.
/*
* There could be abnormal cpuset configurations for cpu or memory
- * node binding, add this key to provide a quick low-cost judgement
+ * node binding, add this key to provide a quick low-cost judgment
* of the situation.
*/
DEFINE_STATIC_KEY_FALSE(cpusets_insane_config_key);
kfree(cs);
}
+/*
+ * validate_change_legacy() - Validate conditions specific to legacy (v1)
+ * behavior.
+ */
+static int validate_change_legacy(struct cpuset *cur, struct cpuset *trial)
+{
+ struct cgroup_subsys_state *css;
+ struct cpuset *c, *par;
+ int ret;
+
+ WARN_ON_ONCE(!rcu_read_lock_held());
+
+ /* Each of our child cpusets must be a subset of us */
+ ret = -EBUSY;
+ cpuset_for_each_child(c, css, cur)
+ if (!is_cpuset_subset(c, trial))
+ goto out;
+
+ /* On legacy hierarchy, we must be a subset of our parent cpuset. */
+ ret = -EACCES;
+ par = parent_cs(cur);
+ if (par && !is_cpuset_subset(trial, par))
+ goto out;
+
+ ret = 0;
+out:
+ return ret;
+}
+
/*
* validate_change() - Used to validate that any proposed cpuset change
* follows the structural rules for cpusets.
{
struct cgroup_subsys_state *css;
struct cpuset *c, *par;
- int ret;
-
- /* The checks don't apply to root cpuset */
- if (cur == &top_cpuset)
- return 0;
+ int ret = 0;
rcu_read_lock();
- par = parent_cs(cur);
- /* On legacy hierarchy, we must be a subset of our parent cpuset. */
- ret = -EACCES;
- if (!is_in_v2_mode() && !is_cpuset_subset(trial, par))
+ if (!is_in_v2_mode())
+ ret = validate_change_legacy(cur, trial);
+ if (ret)
+ goto out;
+
+ /* Remaining checks don't apply to root cpuset */
+ if (cur == &top_cpuset)
goto out;
+ par = parent_cs(cur);
+
/*
* If either I or some sibling (!= me) is exclusive, we can't
* overlap
update_domain_attr_tree(dattr, &top_cpuset);
}
cpumask_and(doms[0], top_cpuset.effective_cpus,
- housekeeping_cpumask(HK_FLAG_DOMAIN));
+ housekeeping_cpumask(HK_TYPE_DOMAIN));
goto done;
}
if (!cpumask_empty(cp->cpus_allowed) &&
!(is_sched_load_balance(cp) &&
cpumask_intersects(cp->cpus_allowed,
- housekeeping_cpumask(HK_FLAG_DOMAIN))))
+ housekeeping_cpumask(HK_TYPE_DOMAIN))))
continue;
if (root_load_balance &&
if (apn == b->pn) {
cpumask_or(dp, dp, b->effective_cpus);
- cpumask_and(dp, dp, housekeeping_cpumask(HK_FLAG_DOMAIN));
+ cpumask_and(dp, dp, housekeeping_cpumask(HK_TYPE_DOMAIN));
if (dattr)
update_domain_attr_tree(dattr + nslot, b);
* effective_cpus. The function will return 0 if all the CPUs listed in
* cpus_allowed can be granted or an error code will be returned.
*
- * For partcmd_disable, the cpuset is being transofrmed from a partition
+ * For partcmd_disable, the cpuset is being transformed from a partition
* root back to a non-partition root. Any CPUs in cpus_allowed that are in
* parent's subparts_cpus will be taken away from that cpumask and put back
* into parent's effective_cpus. 0 should always be returned.
*
* Because of the implicit cpu exclusive nature of a partition root,
* cpumask changes that violates the cpu exclusivity rule will not be
- * permitted when checked by validate_change(). The validate_change()
- * function will also prevent any changes to the cpu list if it is not
- * a superset of children's cpu lists.
+ * permitted when checked by validate_change().
*/
static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd,
struct cpumask *newmask,
struct cpuset *sibling;
struct cgroup_subsys_state *pos_css;
+ percpu_rwsem_assert_held(&cpuset_rwsem);
+
/*
* Check all its siblings and call update_cpumasks_hier()
* if their use_parent_ecpus flag is set in order for them
* 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.
*/
rcu_read_lock();
cpuset_for_each_child(sibling, pos_css, parent) {
continue;
if (!sibling->use_parent_ecpus)
continue;
+ if (!css_tryget_online(&sibling->css))
+ continue;
+ rcu_read_unlock();
update_cpumasks_hier(sibling, tmp);
+ rcu_read_lock();
+ css_put(&sibling->css);
}
rcu_read_unlock();
}
* Make sure that subparts_cpus is a subset of cpus_allowed.
*/
if (cs->nr_subparts_cpus) {
- cpumask_andnot(cs->subparts_cpus, cs->subparts_cpus,
- cs->cpus_allowed);
+ cpumask_and(cs->subparts_cpus, cs->subparts_cpus, cs->cpus_allowed);
cs->nr_subparts_cpus = cpumask_weight(cs->subparts_cpus);
}
spin_unlock_irq(&callback_lock);
}
/*
- * update_prstate - update partititon_root_state
+ * update_prstate - update partition_root_state
* cs: the cpuset to update
* new_prs: new partition root state
*
cgroup_taskset_first(tset, &css);
cs = css_cs(css);
+ cpus_read_lock();
percpu_down_write(&cpuset_rwsem);
guarantee_online_mems(cs, &cpuset_attach_nodemask_to);
wake_up(&cpuset_attach_wq);
percpu_up_write(&cpuset_rwsem);
+ cpus_read_unlock();
}
/* The various types of files and directories in a cpuset file system */
/*
* Clone @parent's configuration if CGRP_CPUSET_CLONE_CHILDREN is
* set. This flag handling is implemented in cgroup core for
- * histrical reasons - the flag may be specified during mount.
+ * historical reasons - the flag may be specified during mount.
*
* Currently, if any sibling cpusets have exclusive cpus or mem, we
* refuse to clone the configuration - thereby refusing the task to
/*
* Don't call update_tasks_cpumask() if the cpuset becomes empty,
- * as the tasks will be migratecd to an ancestor.
+ * as the tasks will be migrated to an ancestor.
*/
if (cpus_updated && !cpumask_empty(cs->cpus_allowed))
update_tasks_cpumask(cs);
return cs;
}
-/**
- * cpuset_node_allowed - Can we allocate on a memory node?
+/*
+ * __cpuset_node_allowed - Can we allocate on a memory node?
* @node: is this an allowed node?
* @gfp_mask: memory allocation flags
*
int cpuset_memory_pressure_enabled __read_mostly;
-/**
- * cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims.
+/*
+ * __cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims.
*
* Keep a running average of the rate of synchronous (direct)
* page reclaim efforts initiated by tasks in each cpuset.
* "memory_pressure". Value displayed is an integer
* representing the recent rate of entry into the synchronous
* (direct) page reclaim by any task attached to the cpuset.
- **/
+ */
void __cpuset_memory_pressure_bump(void)
{
projects / J-linux.git / commitdiff