if (is_cpuset_online(((des_cs) = css_cs((pos_css)))))
/*
- * There are two global locks guarding cpuset structures - cpuset_rwsem and
+ * There are two global locks guarding cpuset structures - cpuset_mutex and
* callback_lock. We also require taking task_lock() when dereferencing a
* task's cpuset pointer. See "The task_lock() exception", at the end of this
- * comment. The cpuset code uses only cpuset_rwsem write lock. Other
- * kernel subsystems can use cpuset_read_lock()/cpuset_read_unlock() to
- * prevent change to cpuset structures.
+ * comment. The cpuset code uses only cpuset_mutex. Other kernel subsystems
+ * can use cpuset_lock()/cpuset_unlock() to prevent change to cpuset
+ * structures. Note that cpuset_mutex needs to be a mutex as it is used in
+ * paths that rely on priority inheritance (e.g. scheduler - on RT) for
+ * correctness.
*
* A task must hold both locks to modify cpusets. If a task holds
- * cpuset_rwsem, it blocks others wanting that rwsem, ensuring that it
- * is the only task able to also acquire callback_lock and be able to
- * modify cpusets. It can perform various checks on the cpuset structure
- * first, knowing nothing will change. It can also allocate memory while
- * just holding cpuset_rwsem. While it is performing these checks, various
- * callback routines can briefly acquire callback_lock to query cpusets.
- * Once it is ready to make the changes, it takes callback_lock, blocking
- * everyone else.
+ * cpuset_mutex, it blocks others, ensuring that it is the only task able to
+ * also acquire callback_lock and be able to modify cpusets. It can perform
+ * various checks on the cpuset structure first, knowing nothing will change.
+ * It can also allocate memory while just holding cpuset_mutex. While it is
+ * performing these checks, various callback routines can briefly acquire
+ * callback_lock to query cpusets. Once it is ready to make the changes, it
+ * takes callback_lock, blocking everyone else.
*
* Calls to the kernel memory allocator can not be made while holding
* callback_lock, as that would risk double tripping on callback_lock
* guidelines for accessing subsystem state in kernel/cgroup.c
*/
-DEFINE_STATIC_PERCPU_RWSEM(cpuset_rwsem);
+static DEFINE_MUTEX(cpuset_mutex);
-void cpuset_read_lock(void)
+void cpuset_lock(void)
{
- percpu_down_read(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
}
-void cpuset_read_unlock(void)
+void cpuset_unlock(void)
{
- percpu_up_read(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
}
static DEFINE_SPINLOCK(callback_lock);
* One way or another, we guarantee to return some non-empty subset
* of cpu_online_mask.
*
- * Call with callback_lock or cpuset_rwsem held.
+ * Call with callback_lock or cpuset_mutex held.
*/
static void guarantee_online_cpus(struct task_struct *tsk,
struct cpumask *pmask)
* One way or another, we guarantee to return some non-empty subset
* of node_states[N_MEMORY].
*
- * Call with callback_lock or cpuset_rwsem held.
+ * Call with callback_lock or cpuset_mutex held.
*/
static void guarantee_online_mems(struct cpuset *cs, nodemask_t *pmask)
{
/*
* update task's spread flag if cpuset's page/slab spread flag is set
*
- * Call with callback_lock or cpuset_rwsem held. The check can be skipped
+ * Call with callback_lock or cpuset_mutex held. The check can be skipped
* if on default hierarchy.
*/
static void cpuset_update_task_spread_flags(struct cpuset *cs,
*
* One cpuset is a subset of another if all its allowed CPUs and
* Memory Nodes are a subset of the other, and its exclusive flags
- * are only set if the other's are set. Call holding cpuset_rwsem.
+ * are only set if the other's are set. Call holding cpuset_mutex.
*/
static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
* If we replaced the flag and mask values of the current cpuset
* (cur) with those values in the trial cpuset (trial), would
* our various subset and exclusive rules still be valid? Presumes
- * cpuset_rwsem held.
+ * cpuset_mutex held.
*
* 'cur' is the address of an actual, in-use cpuset. Operations
* such as list traversal that depend on the actual address of the
rcu_read_unlock();
}
-/* Must be called with cpuset_rwsem held. */
+/* Must be called with cpuset_mutex held. */
static inline int nr_cpusets(void)
{
/* jump label reference count + the top-level cpuset */
* domains when operating in the severe memory shortage situations
* that could cause allocation failures below.
*
- * Must be called with cpuset_rwsem held.
+ * Must be called with cpuset_mutex held.
*
* The three key local variables below are:
* cp - cpuset pointer, used (together with pos_css) to perform a
struct cpuset *cs = NULL;
struct cgroup_subsys_state *pos_css;
- percpu_rwsem_assert_held(&cpuset_rwsem);
+ lockdep_assert_held(&cpuset_mutex);
lockdep_assert_cpus_held();
lockdep_assert_held(&sched_domains_mutex);
* 'cpus' is removed, then call this routine to rebuild the
* scheduler's dynamic sched domains.
*
- * Call with cpuset_rwsem held. Takes cpus_read_lock().
+ * Call with cpuset_mutex held. Takes cpus_read_lock().
*/
static void rebuild_sched_domains_locked(void)
{
int ndoms;
lockdep_assert_cpus_held();
- percpu_rwsem_assert_held(&cpuset_rwsem);
+ lockdep_assert_held(&cpuset_mutex);
/*
* If we have raced with CPU hotplug, return early to avoid
void rebuild_sched_domains(void)
{
cpus_read_lock();
- percpu_down_write(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
rebuild_sched_domains_locked();
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
cpus_read_unlock();
}
* @new_cpus: the temp variable for the new effective_cpus mask
*
* Iterate through each task of @cs updating its cpus_allowed to the
- * effective cpuset's. As this function is called with cpuset_rwsem held,
+ * effective cpuset's. As this function is called with cpuset_mutex held,
* cpuset membership stays stable. For top_cpuset, task_cpu_possible_mask()
* is used instead of effective_cpus to make sure all offline CPUs are also
* included as hotplug code won't update cpumasks for tasks in top_cpuset.
int old_prs, new_prs;
int part_error = PERR_NONE; /* Partition error? */
- percpu_rwsem_assert_held(&cpuset_rwsem);
+ lockdep_assert_held(&cpuset_mutex);
/*
* The parent must be a partition root.
*
* On legacy hierarchy, effective_cpus will be the same with cpu_allowed.
*
- * Called with cpuset_rwsem held
+ * Called with cpuset_mutex held
*/
static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp,
bool force)
struct cpuset *sibling;
struct cgroup_subsys_state *pos_css;
- percpu_rwsem_assert_held(&cpuset_rwsem);
+ lockdep_assert_held(&cpuset_mutex);
/*
* Check all its siblings and call update_cpumasks_hier()
* @cs: the cpuset in which each task's mems_allowed mask needs to be changed
*
* Iterate through each task of @cs updating its mems_allowed to the
- * effective cpuset's. As this function is called with cpuset_rwsem held,
+ * effective cpuset's. As this function is called with cpuset_mutex held,
* cpuset membership stays stable.
*/
static void update_tasks_nodemask(struct cpuset *cs)
{
- static nodemask_t newmems; /* protected by cpuset_rwsem */
+ static nodemask_t newmems; /* protected by cpuset_mutex */
struct css_task_iter it;
struct task_struct *task;
* take while holding tasklist_lock. Forks can happen - the
* mpol_dup() cpuset_being_rebound check will catch such forks,
* and rebind their vma mempolicies too. Because we still hold
- * the global cpuset_rwsem, we know that no other rebind effort
+ * the global cpuset_mutex, we know that no other rebind effort
* will be contending for the global variable cpuset_being_rebound.
* It's ok if we rebind the same mm twice; mpol_rebind_mm()
* is idempotent. Also migrate pages in each mm to new nodes.
*
* On legacy hierarchy, effective_mems will be the same with mems_allowed.
*
- * Called with cpuset_rwsem held
+ * Called with cpuset_mutex held
*/
static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems)
{
* mempolicies and if the cpuset is marked 'memory_migrate',
* migrate the tasks pages to the new memory.
*
- * Call with cpuset_rwsem held. May take callback_lock during call.
+ * Call with cpuset_mutex held. May take callback_lock during call.
* Will take tasklist_lock, scan tasklist for tasks in cpuset cs,
* lock each such tasks mm->mmap_lock, scan its vma's and rebind
* their mempolicies to the cpusets new mems_allowed.
* @cs: the cpuset in which each task's spread flags needs to be changed
*
* Iterate through each task of @cs updating its spread flags. As this
- * function is called with cpuset_rwsem held, cpuset membership stays
+ * function is called with cpuset_mutex held, cpuset membership stays
* stable.
*/
static void update_tasks_flags(struct cpuset *cs)
* cs: the cpuset to update
* turning_on: whether the flag is being set or cleared
*
- * Call with cpuset_rwsem held.
+ * Call with cpuset_mutex held.
*/
static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
* @new_prs: new partition root state
* Return: 0 if successful, != 0 if error
*
- * Call with cpuset_rwsem held.
+ * Call with cpuset_mutex held.
*/
static int update_prstate(struct cpuset *cs, int new_prs)
{
return 0;
}
-/* Called by cgroups to determine if a cpuset is usable; cpuset_rwsem held */
+/* Called by cgroups to determine if a cpuset is usable; cpuset_mutex held */
static int cpuset_can_attach(struct cgroup_taskset *tset)
{
struct cgroup_subsys_state *css;
cpuset_attach_old_cs = task_cs(cgroup_taskset_first(tset, &css));
cs = css_cs(css);
- percpu_down_write(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
/* Check to see if task is allowed in the cpuset */
ret = cpuset_can_attach_check(cs);
*/
cs->attach_in_progress++;
out_unlock:
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
return ret;
}
cgroup_taskset_first(tset, &css);
cs = css_cs(css);
- percpu_down_write(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
cs->attach_in_progress--;
if (!cs->attach_in_progress)
wake_up(&cpuset_attach_wq);
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
}
/*
- * Protected by cpuset_rwsem. cpus_attach is used only by cpuset_attach_task()
+ * Protected by cpuset_mutex. cpus_attach is used only by cpuset_attach_task()
* but we can't allocate it dynamically there. Define it global and
* allocate from cpuset_init().
*/
static void cpuset_attach_task(struct cpuset *cs, struct task_struct *task)
{
- percpu_rwsem_assert_held(&cpuset_rwsem);
+ lockdep_assert_held(&cpuset_mutex);
if (cs != &top_cpuset)
guarantee_online_cpus(task, cpus_attach);
cs = css_cs(css);
lockdep_assert_cpus_held(); /* see cgroup_attach_lock() */
- percpu_down_write(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
cpus_updated = !cpumask_equal(cs->effective_cpus,
oldcs->effective_cpus);
mems_updated = !nodes_equal(cs->effective_mems, oldcs->effective_mems);
if (!cs->attach_in_progress)
wake_up(&cpuset_attach_wq);
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
}
/* The various types of files and directories in a cpuset file system */
int retval = 0;
cpus_read_lock();
- percpu_down_write(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
if (!is_cpuset_online(cs)) {
retval = -ENODEV;
goto out_unlock;
break;
}
out_unlock:
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
cpus_read_unlock();
return retval;
}
int retval = -ENODEV;
cpus_read_lock();
- percpu_down_write(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
if (!is_cpuset_online(cs))
goto out_unlock;
break;
}
out_unlock:
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
cpus_read_unlock();
return retval;
}
* operation like this one can lead to a deadlock through kernfs
* active_ref protection. Let's break the protection. Losing the
* protection is okay as we check whether @cs is online after
- * grabbing cpuset_rwsem anyway. This only happens on the legacy
+ * grabbing cpuset_mutex anyway. This only happens on the legacy
* hierarchies.
*/
css_get(&cs->css);
flush_work(&cpuset_hotplug_work);
cpus_read_lock();
- percpu_down_write(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
if (!is_cpuset_online(cs))
goto out_unlock;
free_cpuset(trialcs);
out_unlock:
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
cpus_read_unlock();
kernfs_unbreak_active_protection(of->kn);
css_put(&cs->css);
css_get(&cs->css);
cpus_read_lock();
- percpu_down_write(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
if (!is_cpuset_online(cs))
goto out_unlock;
retval = update_prstate(cs, val);
out_unlock:
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
cpus_read_unlock();
css_put(&cs->css);
return retval ?: nbytes;
return 0;
cpus_read_lock();
- percpu_down_write(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
set_bit(CS_ONLINE, &cs->flags);
if (is_spread_page(parent))
cpumask_copy(cs->effective_cpus, parent->cpus_allowed);
spin_unlock_irq(&callback_lock);
out_unlock:
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
cpus_read_unlock();
return 0;
}
struct cpuset *cs = css_cs(css);
cpus_read_lock();
- percpu_down_write(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
if (is_partition_valid(cs))
update_prstate(cs, 0);
cpuset_dec();
clear_bit(CS_ONLINE, &cs->flags);
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
cpus_read_unlock();
}
static void cpuset_bind(struct cgroup_subsys_state *root_css)
{
- percpu_down_write(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
spin_lock_irq(&callback_lock);
if (is_in_v2_mode()) {
}
spin_unlock_irq(&callback_lock);
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
}
/*
return 0;
lockdep_assert_held(&cgroup_mutex);
- percpu_down_write(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
/* Check to see if task is allowed in the cpuset */
ret = cpuset_can_attach_check(cs);
*/
cs->attach_in_progress++;
out_unlock:
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
return ret;
}
if (same_cs)
return;
- percpu_down_write(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
cs->attach_in_progress--;
if (!cs->attach_in_progress)
wake_up(&cpuset_attach_wq);
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
}
/*
}
/* CLONE_INTO_CGROUP */
- percpu_down_write(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
guarantee_online_mems(cs, &cpuset_attach_nodemask_to);
cpuset_attach_task(cs, task);
if (!cs->attach_in_progress)
wake_up(&cpuset_attach_wq);
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
}
struct cgroup_subsys cpuset_cgrp_subsys = {
is_empty = cpumask_empty(cs->cpus_allowed) ||
nodes_empty(cs->mems_allowed);
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
/*
* Move tasks to the nearest ancestor with execution resources,
if (is_empty)
remove_tasks_in_empty_cpuset(cs);
- percpu_down_write(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
}
static void
retry:
wait_event(cpuset_attach_wq, cs->attach_in_progress == 0);
- percpu_down_write(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
/*
* We have raced with task attaching. We wait until attaching
* is finished, so we won't attach a task to an empty cpuset.
*/
if (cs->attach_in_progress) {
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
goto retry;
}
cpus_updated, mems_updated);
unlock:
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
}
/**
if (on_dfl && !alloc_cpumasks(NULL, &tmp))
ptmp = &tmp;
- percpu_down_write(&cpuset_rwsem);
+ mutex_lock(&cpuset_mutex);
/* fetch the available cpus/mems and find out which changed how */
cpumask_copy(&new_cpus, cpu_active_mask);
update_tasks_nodemask(&top_cpuset);
}
- percpu_up_write(&cpuset_rwsem);
+ mutex_unlock(&cpuset_mutex);
/* if cpus or mems changed, we need to propagate to descendants */
if (cpus_updated || mems_updated) {
* - Used for /proc/<pid>/cpuset.
* - No need to task_lock(tsk) on this tsk->cpuset reference, as it
* doesn't really matter if tsk->cpuset changes after we read it,
- * and we take cpuset_rwsem, keeping cpuset_attach() from changing it
+ * and we take cpuset_mutex, keeping cpuset_attach() from changing it
* anyway.
*/
int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
projects / users / hch / xfs.git / commitdiff