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-rw-r--r--kernel/cgroup/cpuset.c299
1 files changed, 225 insertions, 74 deletions
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index ffe0e00294..927bef3a59 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -25,6 +25,7 @@
#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/cpuset.h>
+#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
@@ -43,6 +44,7 @@
#include <linux/sched/isolation.h>
#include <linux/cgroup.h>
#include <linux/wait.h>
+#include <linux/workqueue.h>
DEFINE_STATIC_KEY_FALSE(cpusets_pre_enable_key);
DEFINE_STATIC_KEY_FALSE(cpusets_enabled_key);
@@ -204,6 +206,11 @@ struct cpuset {
*/
static cpumask_var_t subpartitions_cpus;
+/*
+ * Exclusive CPUs in isolated partitions
+ */
+static cpumask_var_t isolated_cpus;
+
/* List of remote partition root children */
static struct list_head remote_children;
@@ -1317,6 +1324,7 @@ static void compute_effective_cpumask(struct cpumask *new_cpus,
*/
enum partition_cmd {
partcmd_enable, /* Enable partition root */
+ partcmd_enablei, /* Enable isolated partition root */
partcmd_disable, /* Disable partition root */
partcmd_update, /* Update parent's effective_cpus */
partcmd_invalidate, /* Make partition invalid */
@@ -1419,6 +1427,109 @@ static void reset_partition_data(struct cpuset *cs)
}
/*
+ * partition_xcpus_newstate - Exclusive CPUs state change
+ * @old_prs: old partition_root_state
+ * @new_prs: new partition_root_state
+ * @xcpus: exclusive CPUs with state change
+ */
+static void partition_xcpus_newstate(int old_prs, int new_prs, struct cpumask *xcpus)
+{
+ WARN_ON_ONCE(old_prs == new_prs);
+ if (new_prs == PRS_ISOLATED)
+ cpumask_or(isolated_cpus, isolated_cpus, xcpus);
+ else
+ cpumask_andnot(isolated_cpus, isolated_cpus, xcpus);
+}
+
+/*
+ * partition_xcpus_add - Add new exclusive CPUs to partition
+ * @new_prs: new partition_root_state
+ * @parent: parent cpuset
+ * @xcpus: exclusive CPUs to be added
+ * Return: true if isolated_cpus modified, false otherwise
+ *
+ * Remote partition if parent == NULL
+ */
+static bool partition_xcpus_add(int new_prs, struct cpuset *parent,
+ struct cpumask *xcpus)
+{
+ bool isolcpus_updated;
+
+ WARN_ON_ONCE(new_prs < 0);
+ lockdep_assert_held(&callback_lock);
+ if (!parent)
+ parent = &top_cpuset;
+
+
+ if (parent == &top_cpuset)
+ cpumask_or(subpartitions_cpus, subpartitions_cpus, xcpus);
+
+ isolcpus_updated = (new_prs != parent->partition_root_state);
+ if (isolcpus_updated)
+ partition_xcpus_newstate(parent->partition_root_state, new_prs,
+ xcpus);
+
+ cpumask_andnot(parent->effective_cpus, parent->effective_cpus, xcpus);
+ return isolcpus_updated;
+}
+
+/*
+ * partition_xcpus_del - Remove exclusive CPUs from partition
+ * @old_prs: old partition_root_state
+ * @parent: parent cpuset
+ * @xcpus: exclusive CPUs to be removed
+ * Return: true if isolated_cpus modified, false otherwise
+ *
+ * Remote partition if parent == NULL
+ */
+static bool partition_xcpus_del(int old_prs, struct cpuset *parent,
+ struct cpumask *xcpus)
+{
+ bool isolcpus_updated;
+
+ WARN_ON_ONCE(old_prs < 0);
+ lockdep_assert_held(&callback_lock);
+ if (!parent)
+ parent = &top_cpuset;
+
+ if (parent == &top_cpuset)
+ cpumask_andnot(subpartitions_cpus, subpartitions_cpus, xcpus);
+
+ isolcpus_updated = (old_prs != parent->partition_root_state);
+ if (isolcpus_updated)
+ partition_xcpus_newstate(old_prs, parent->partition_root_state,
+ xcpus);
+
+ cpumask_and(xcpus, xcpus, cpu_active_mask);
+ cpumask_or(parent->effective_cpus, parent->effective_cpus, xcpus);
+ return isolcpus_updated;
+}
+
+static void update_unbound_workqueue_cpumask(bool isolcpus_updated)
+{
+ int ret;
+
+ lockdep_assert_cpus_held();
+
+ if (!isolcpus_updated)
+ return;
+
+ ret = workqueue_unbound_exclude_cpumask(isolated_cpus);
+ WARN_ON_ONCE(ret < 0);
+}
+
+/**
+ * cpuset_cpu_is_isolated - Check if the given CPU is isolated
+ * @cpu: the CPU number to be checked
+ * Return: true if CPU is used in an isolated partition, false otherwise
+ */
+bool cpuset_cpu_is_isolated(int cpu)
+{
+ return cpumask_test_cpu(cpu, isolated_cpus);
+}
+EXPORT_SYMBOL_GPL(cpuset_cpu_is_isolated);
+
+/*
* compute_effective_exclusive_cpumask - compute effective exclusive CPUs
* @cs: cpuset
* @xcpus: effective exclusive CPUs value to be set
@@ -1456,14 +1567,18 @@ static inline bool is_local_partition(struct cpuset *cs)
/*
* remote_partition_enable - Enable current cpuset as a remote partition root
* @cs: the cpuset to update
+ * @new_prs: new partition_root_state
* @tmp: temparary masks
* Return: 1 if successful, 0 if error
*
* Enable the current cpuset to become a remote partition root taking CPUs
* directly from the top cpuset. cpuset_mutex must be held by the caller.
*/
-static int remote_partition_enable(struct cpuset *cs, struct tmpmasks *tmp)
+static int remote_partition_enable(struct cpuset *cs, int new_prs,
+ struct tmpmasks *tmp)
{
+ bool isolcpus_updated;
+
/*
* The user must have sysadmin privilege.
*/
@@ -1485,26 +1600,22 @@ static int remote_partition_enable(struct cpuset *cs, struct tmpmasks *tmp)
return 0;
spin_lock_irq(&callback_lock);
- cpumask_andnot(top_cpuset.effective_cpus,
- top_cpuset.effective_cpus, tmp->new_cpus);
- cpumask_or(subpartitions_cpus,
- subpartitions_cpus, tmp->new_cpus);
-
+ isolcpus_updated = partition_xcpus_add(new_prs, NULL, tmp->new_cpus);
+ list_add(&cs->remote_sibling, &remote_children);
if (cs->use_parent_ecpus) {
struct cpuset *parent = parent_cs(cs);
cs->use_parent_ecpus = false;
parent->child_ecpus_count--;
}
- list_add(&cs->remote_sibling, &remote_children);
spin_unlock_irq(&callback_lock);
+ update_unbound_workqueue_cpumask(isolcpus_updated);
/*
* Proprogate changes in top_cpuset's effective_cpus down the hierarchy.
*/
update_tasks_cpumask(&top_cpuset, tmp->new_cpus);
update_sibling_cpumasks(&top_cpuset, NULL, tmp);
-
return 1;
}
@@ -1519,23 +1630,22 @@ static int remote_partition_enable(struct cpuset *cs, struct tmpmasks *tmp)
*/
static void remote_partition_disable(struct cpuset *cs, struct tmpmasks *tmp)
{
+ bool isolcpus_updated;
+
compute_effective_exclusive_cpumask(cs, tmp->new_cpus);
WARN_ON_ONCE(!is_remote_partition(cs));
WARN_ON_ONCE(!cpumask_subset(tmp->new_cpus, subpartitions_cpus));
spin_lock_irq(&callback_lock);
- cpumask_andnot(subpartitions_cpus,
- subpartitions_cpus, tmp->new_cpus);
- cpumask_and(tmp->new_cpus,
- tmp->new_cpus, cpu_active_mask);
- cpumask_or(top_cpuset.effective_cpus,
- top_cpuset.effective_cpus, tmp->new_cpus);
list_del_init(&cs->remote_sibling);
+ isolcpus_updated = partition_xcpus_del(cs->partition_root_state,
+ NULL, tmp->new_cpus);
cs->partition_root_state = -cs->partition_root_state;
if (!cs->prs_err)
cs->prs_err = PERR_INVCPUS;
reset_partition_data(cs);
spin_unlock_irq(&callback_lock);
+ update_unbound_workqueue_cpumask(isolcpus_updated);
/*
* Proprogate changes in top_cpuset's effective_cpus down the hierarchy.
@@ -1557,6 +1667,8 @@ static void remote_cpus_update(struct cpuset *cs, struct cpumask *newmask,
struct tmpmasks *tmp)
{
bool adding, deleting;
+ int prs = cs->partition_root_state;
+ int isolcpus_updated = 0;
if (WARN_ON_ONCE(!is_remote_partition(cs)))
return;
@@ -1580,21 +1692,12 @@ static void remote_cpus_update(struct cpuset *cs, struct cpumask *newmask,
goto invalidate;
spin_lock_irq(&callback_lock);
- if (adding) {
- cpumask_or(subpartitions_cpus,
- subpartitions_cpus, tmp->addmask);
- cpumask_andnot(top_cpuset.effective_cpus,
- top_cpuset.effective_cpus, tmp->addmask);
- }
- if (deleting) {
- cpumask_andnot(subpartitions_cpus,
- subpartitions_cpus, tmp->delmask);
- cpumask_and(tmp->delmask,
- tmp->delmask, cpu_active_mask);
- cpumask_or(top_cpuset.effective_cpus,
- top_cpuset.effective_cpus, tmp->delmask);
- }
+ if (adding)
+ isolcpus_updated += partition_xcpus_add(prs, NULL, tmp->addmask);
+ if (deleting)
+ isolcpus_updated += partition_xcpus_del(prs, NULL, tmp->delmask);
spin_unlock_irq(&callback_lock);
+ update_unbound_workqueue_cpumask(isolcpus_updated);
/*
* Proprogate changes in top_cpuset's effective_cpus down the hierarchy.
@@ -1676,11 +1779,11 @@ static bool prstate_housekeeping_conflict(int prstate, struct cpumask *new_cpus)
* @tmp: Temporary addmask and delmask
* Return: 0 or a partition root state error code
*
- * For partcmd_enable, the cpuset is being transformed from a non-partition
- * root to a partition root. The effective_xcpus (cpus_allowed if effective_xcpus
- * not set) mask of the given cpuset will be taken away from parent's
- * effective_cpus. The function will return 0 if all the CPUs listed in
- * effective_xcpus can be granted or an error code will be returned.
+ * For partcmd_enable*, the cpuset is being transformed from a non-partition
+ * root to a partition root. The effective_xcpus (cpus_allowed if
+ * effective_xcpus not set) mask of the given cpuset will be taken away from
+ * parent's effective_cpus. The function will return 0 if all the CPUs listed
+ * in effective_xcpus can be granted or an error code will be returned.
*
* For partcmd_disable, the cpuset is being transformed from a partition
* root back to a non-partition root. Any CPUs in effective_xcpus will be
@@ -1695,7 +1798,7 @@ static bool prstate_housekeeping_conflict(int prstate, struct cpumask *new_cpus)
*
* For partcmd_invalidate, the current partition will be made invalid.
*
- * The partcmd_enable and partcmd_disable commands are used by
+ * The partcmd_enable* and partcmd_disable commands are used by
* update_prstate(). An error code may be returned and the caller will check
* for error.
*
@@ -1716,6 +1819,7 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd,
int part_error = PERR_NONE; /* Partition error? */
int subparts_delta = 0;
struct cpumask *xcpus; /* cs effective_xcpus */
+ int isolcpus_updated = 0;
bool nocpu;
lockdep_assert_held(&cpuset_mutex);
@@ -1760,7 +1864,7 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd,
nocpu = tasks_nocpu_error(parent, cs, xcpus);
- if (cmd == partcmd_enable) {
+ if ((cmd == partcmd_enable) || (cmd == partcmd_enablei)) {
/*
* Enabling partition root is not allowed if its
* effective_xcpus is empty or doesn't overlap with
@@ -1783,6 +1887,7 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd,
cpumask_copy(tmp->delmask, xcpus);
deleting = true;
subparts_delta++;
+ new_prs = (cmd == partcmd_enable) ? PRS_ROOT : PRS_ISOLATED;
} else if (cmd == partcmd_disable) {
/*
* May need to add cpus to parent's effective_cpus for
@@ -1792,6 +1897,7 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd,
cpumask_and(tmp->addmask, xcpus, parent->effective_xcpus);
if (adding)
subparts_delta--;
+ new_prs = PRS_MEMBER;
} else if (newmask) {
/*
* Empty cpumask is not allowed
@@ -1940,38 +2046,28 @@ write_error:
* newly deleted ones will be added back to effective_cpus.
*/
spin_lock_irq(&callback_lock);
- if (adding) {
- if (parent == &top_cpuset)
- cpumask_andnot(subpartitions_cpus,
- subpartitions_cpus, tmp->addmask);
- /*
- * Some of the CPUs in effective_xcpus might have been offlined.
- */
- cpumask_or(parent->effective_cpus,
- parent->effective_cpus, tmp->addmask);
- cpumask_and(parent->effective_cpus,
- parent->effective_cpus, cpu_active_mask);
- }
- if (deleting) {
- if (parent == &top_cpuset)
- cpumask_or(subpartitions_cpus,
- subpartitions_cpus, tmp->delmask);
- cpumask_andnot(parent->effective_cpus,
- parent->effective_cpus, tmp->delmask);
- }
-
- if (is_partition_valid(parent)) {
- parent->nr_subparts += subparts_delta;
- WARN_ON_ONCE(parent->nr_subparts < 0);
- }
-
if (old_prs != new_prs) {
cs->partition_root_state = new_prs;
if (new_prs <= 0)
cs->nr_subparts = 0;
}
+ /*
+ * Adding to parent's effective_cpus means deletion CPUs from cs
+ * and vice versa.
+ */
+ if (adding)
+ isolcpus_updated += partition_xcpus_del(old_prs, parent,
+ tmp->addmask);
+ if (deleting)
+ isolcpus_updated += partition_xcpus_add(new_prs, parent,
+ tmp->delmask);
+ if (is_partition_valid(parent)) {
+ parent->nr_subparts += subparts_delta;
+ WARN_ON_ONCE(parent->nr_subparts < 0);
+ }
spin_unlock_irq(&callback_lock);
+ update_unbound_workqueue_cpumask(isolcpus_updated);
if ((old_prs != new_prs) && (cmd == partcmd_update))
update_partition_exclusive(cs, new_prs);
@@ -2948,6 +3044,7 @@ static int update_prstate(struct cpuset *cs, int new_prs)
int err = PERR_NONE, old_prs = cs->partition_root_state;
struct cpuset *parent = parent_cs(cs);
struct tmpmasks tmpmask;
+ bool new_xcpus_state = false;
if (old_prs == new_prs)
return 0;
@@ -2977,6 +3074,9 @@ static int update_prstate(struct cpuset *cs, int new_prs)
goto out;
if (!old_prs) {
+ enum partition_cmd cmd = (new_prs == PRS_ROOT)
+ ? partcmd_enable : partcmd_enablei;
+
/*
* cpus_allowed cannot be empty.
*/
@@ -2985,19 +3085,18 @@ static int update_prstate(struct cpuset *cs, int new_prs)
goto out;
}
- err = update_parent_effective_cpumask(cs, partcmd_enable,
- NULL, &tmpmask);
+ err = update_parent_effective_cpumask(cs, cmd, NULL, &tmpmask);
/*
* If an attempt to become local partition root fails,
* try to become a remote partition root instead.
*/
- if (err && remote_partition_enable(cs, &tmpmask))
+ if (err && remote_partition_enable(cs, new_prs, &tmpmask))
err = 0;
} else if (old_prs && new_prs) {
/*
* A change in load balance state only, no change in cpumasks.
*/
- ;
+ new_xcpus_state = true;
} else {
/*
* Switching back to member is always allowed even if it
@@ -3029,7 +3128,10 @@ out:
WRITE_ONCE(cs->prs_err, err);
if (!is_partition_valid(cs))
reset_partition_data(cs);
+ else if (new_xcpus_state)
+ partition_xcpus_newstate(old_prs, new_prs, cs->effective_xcpus);
spin_unlock_irq(&callback_lock);
+ update_unbound_workqueue_cpumask(new_xcpus_state);
/* Force update if switching back to member */
update_cpumasks_hier(cs, &tmpmask, !new_prs ? HIER_CHECKALL : 0);
@@ -3386,6 +3488,7 @@ typedef enum {
FILE_SUBPARTS_CPULIST,
FILE_EXCLUSIVE_CPULIST,
FILE_EFFECTIVE_XCPULIST,
+ FILE_ISOLATED_CPULIST,
FILE_CPU_EXCLUSIVE,
FILE_MEM_EXCLUSIVE,
FILE_MEM_HARDWALL,
@@ -3582,6 +3685,9 @@ static int cpuset_common_seq_show(struct seq_file *sf, void *v)
case FILE_SUBPARTS_CPULIST:
seq_printf(sf, "%*pbl\n", cpumask_pr_args(subpartitions_cpus));
break;
+ case FILE_ISOLATED_CPULIST:
+ seq_printf(sf, "%*pbl\n", cpumask_pr_args(isolated_cpus));
+ break;
default:
ret = -EINVAL;
}
@@ -3875,6 +3981,13 @@ static struct cftype dfl_files[] = {
.flags = CFTYPE_ONLY_ON_ROOT | CFTYPE_DEBUG,
},
+ {
+ .name = "cpus.isolated",
+ .seq_show = cpuset_common_seq_show,
+ .private = FILE_ISOLATED_CPULIST,
+ .flags = CFTYPE_ONLY_ON_ROOT,
+ },
+
{ } /* terminate */
};
@@ -4194,6 +4307,7 @@ int __init cpuset_init(void)
BUG_ON(!alloc_cpumask_var(&top_cpuset.effective_xcpus, GFP_KERNEL));
BUG_ON(!alloc_cpumask_var(&top_cpuset.exclusive_cpus, GFP_KERNEL));
BUG_ON(!zalloc_cpumask_var(&subpartitions_cpus, GFP_KERNEL));
+ BUG_ON(!zalloc_cpumask_var(&isolated_cpus, GFP_KERNEL));
cpumask_setall(top_cpuset.cpus_allowed);
nodes_setall(top_cpuset.mems_allowed);
@@ -4306,6 +4420,30 @@ void cpuset_force_rebuild(void)
force_rebuild = true;
}
+/*
+ * Attempt to acquire a cpus_read_lock while a hotplug operation may be in
+ * progress.
+ * Return: true if successful, false otherwise
+ *
+ * To avoid circular lock dependency between cpuset_mutex and cpus_read_lock,
+ * cpus_read_trylock() is used here to acquire the lock.
+ */
+static bool cpuset_hotplug_cpus_read_trylock(void)
+{
+ int retries = 0;
+
+ while (!cpus_read_trylock()) {
+ /*
+ * CPU hotplug still in progress. Retry 5 times
+ * with a 10ms wait before bailing out.
+ */
+ if (++retries > 5)
+ return false;
+ msleep(10);
+ }
+ return true;
+}
+
/**
* cpuset_hotplug_update_tasks - update tasks in a cpuset for hotunplug
* @cs: cpuset in interest
@@ -4322,6 +4460,7 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp)
bool cpus_updated;
bool mems_updated;
bool remote;
+ int partcmd = -1;
struct cpuset *parent;
retry:
wait_event(cpuset_attach_wq, cs->attach_in_progress == 0);
@@ -4353,11 +4492,13 @@ retry:
compute_partition_effective_cpumask(cs, &new_cpus);
if (remote && cpumask_empty(&new_cpus) &&
- partition_is_populated(cs, NULL)) {
+ partition_is_populated(cs, NULL) &&
+ cpuset_hotplug_cpus_read_trylock()) {
remote_partition_disable(cs, tmp);
compute_effective_cpumask(&new_cpus, cs, parent);
remote = false;
cpuset_force_rebuild();
+ cpus_read_unlock();
}
/*
@@ -4368,18 +4509,28 @@ retry:
* partitions.
*/
if (is_local_partition(cs) && (!is_partition_valid(parent) ||
- tasks_nocpu_error(parent, cs, &new_cpus))) {
- update_parent_effective_cpumask(cs, partcmd_invalidate, NULL, tmp);
- compute_effective_cpumask(&new_cpus, cs, parent);
- cpuset_force_rebuild();
- }
+ tasks_nocpu_error(parent, cs, &new_cpus)))
+ partcmd = partcmd_invalidate;
/*
* On the other hand, an invalid partition root may be transitioned
* back to a regular one.
*/
- else if (is_partition_valid(parent) && is_partition_invalid(cs)) {
- update_parent_effective_cpumask(cs, partcmd_update, NULL, tmp);
- if (is_partition_valid(cs)) {
+ else if (is_partition_valid(parent) && is_partition_invalid(cs))
+ partcmd = partcmd_update;
+
+ /*
+ * cpus_read_lock needs to be held before calling
+ * update_parent_effective_cpumask(). To avoid circular lock
+ * dependency between cpuset_mutex and cpus_read_lock,
+ * cpus_read_trylock() is used here to acquire the lock.
+ */
+ if (partcmd >= 0) {
+ if (!cpuset_hotplug_cpus_read_trylock())
+ goto update_tasks;
+
+ update_parent_effective_cpumask(cs, partcmd, NULL, tmp);
+ cpus_read_unlock();
+ if ((partcmd == partcmd_invalidate) || is_partition_valid(cs)) {
compute_partition_effective_cpumask(cs, &new_cpus);
cpuset_force_rebuild();
}
@@ -4941,7 +5092,7 @@ int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
retval = cgroup_path_ns(css->cgroup, buf, PATH_MAX,
current->nsproxy->cgroup_ns);
css_put(css);
- if (retval >= PATH_MAX)
+ if (retval == -E2BIG)
retval = -ENAMETOOLONG;
if (retval < 0)
goto out_free;