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cgroup/cpuset: Globally track isolated_cpus update

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The current cpuset code passes a local isolcpus_updated flag around in a
number of functions to determine if external isolation related cpumasks
like wq_unbound_cpumask should be updated. It is a bit cumbersome and
makes the code more complex. Simplify the code by using a global boolean
flag "isolated_cpus_updating" to track this. This flag will be set in
isolated_cpus_update() and cleared in update_isolation_cpumasks().

No functional change is expected.

Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Chen Ridong <chenridong@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Waiman Long
2025-11-04 23:38:48 -05:00
committed by Tejun Heo
parent b1034a6901
commit be04e96ba9
1 changed files with 35 additions and 38 deletions
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73
kernel/cgroup/cpuset.c
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@@ -81,6 +81,13 @@ static cpumask_var_t subpartitions_cpus;
*/
static cpumask_var_t isolated_cpus;
/*
* isolated_cpus updating flag (protected by cpuset_mutex)
* Set if isolated_cpus is going to be updated in the current
* cpuset_mutex crtical section.
*/
static bool isolated_cpus_updating;
/*
* Housekeeping (HK_TYPE_DOMAIN) CPUs at boot
*/
@@ -1327,6 +1334,8 @@ static void isolated_cpus_update(int old_prs, int new_prs, struct cpumask *xcpus
cpumask_or(isolated_cpus, isolated_cpus, xcpus);
else
cpumask_andnot(isolated_cpus, isolated_cpus, xcpus);
isolated_cpus_updating = true;
}
/*
@@ -1334,15 +1343,12 @@ static void isolated_cpus_update(int old_prs, int new_prs, struct cpumask *xcpus
* @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,
static void 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)
@@ -1352,13 +1358,11 @@ static bool partition_xcpus_add(int new_prs, struct cpuset *parent,
if (parent == &top_cpuset)
cpumask_or(subpartitions_cpus, subpartitions_cpus, xcpus);
isolcpus_updated = (new_prs != parent->partition_root_state);
if (isolcpus_updated)
if (new_prs != parent->partition_root_state)
isolated_cpus_update(parent->partition_root_state, new_prs,
xcpus);
cpumask_andnot(parent->effective_cpus, parent->effective_cpus, xcpus);
return isolcpus_updated;
}
/*
@@ -1366,15 +1370,12 @@ static bool partition_xcpus_add(int new_prs, struct cpuset *parent,
* @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,
static void 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)
@@ -1383,14 +1384,12 @@ static bool partition_xcpus_del(int old_prs, struct cpuset *parent,
if (parent == &top_cpuset)
cpumask_andnot(subpartitions_cpus, subpartitions_cpus, xcpus);
isolcpus_updated = (old_prs != parent->partition_root_state);
if (isolcpus_updated)
if (old_prs != parent->partition_root_state)
isolated_cpus_update(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;
}
/*
@@ -1452,17 +1451,24 @@ static bool prstate_housekeeping_conflict(int prstate, struct cpumask *new_cpus)
return false;
}
static void update_isolation_cpumasks(bool isolcpus_updated)
/*
* update_isolation_cpumasks - Update external isolation related CPU masks
*
* The following external CPU masks will be updated if necessary:
* - workqueue unbound cpumask
*/
static void update_isolation_cpumasks(void)
{
int ret;
lockdep_assert_cpus_held();
if (!isolcpus_updated)
if (!isolated_cpus_updating)
return;
lockdep_assert_cpus_held();
ret = workqueue_unbound_exclude_cpumask(isolated_cpus);
WARN_ON_ONCE(ret < 0);
isolated_cpus_updating = false;
}
/**
@@ -1587,8 +1593,6 @@ static inline bool is_local_partition(struct cpuset *cs)
static int remote_partition_enable(struct cpuset *cs, int new_prs,
struct tmpmasks *tmp)
{
bool isolcpus_updated;
/*
* The user must have sysadmin privilege.
*/
@@ -1616,11 +1620,11 @@ static int remote_partition_enable(struct cpuset *cs, int new_prs,
return PERR_HKEEPING;
spin_lock_irq(&callback_lock);
isolcpus_updated = partition_xcpus_add(new_prs, NULL, tmp->new_cpus);
partition_xcpus_add(new_prs, NULL, tmp->new_cpus);
list_add(&cs->remote_sibling, &remote_children);
cpumask_copy(cs->effective_xcpus, tmp->new_cpus);
spin_unlock_irq(&callback_lock);
update_isolation_cpumasks(isolcpus_updated);
update_isolation_cpumasks();
cpuset_force_rebuild();
cs->prs_err = 0;
@@ -1643,15 +1647,12 @@ static int remote_partition_enable(struct cpuset *cs, int new_prs,
*/
static void remote_partition_disable(struct cpuset *cs, struct tmpmasks *tmp)
{
bool isolcpus_updated;
WARN_ON_ONCE(!is_remote_partition(cs));
WARN_ON_ONCE(!cpumask_subset(cs->effective_xcpus, subpartitions_cpus));
spin_lock_irq(&callback_lock);
list_del_init(&cs->remote_sibling);
isolcpus_updated = partition_xcpus_del(cs->partition_root_state,
NULL, cs->effective_xcpus);
partition_xcpus_del(cs->partition_root_state, NULL, cs->effective_xcpus);
if (cs->prs_err)
cs->partition_root_state = -cs->partition_root_state;
else
@@ -1661,7 +1662,7 @@ static void remote_partition_disable(struct cpuset *cs, struct tmpmasks *tmp)
compute_excpus(cs, cs->effective_xcpus);
reset_partition_data(cs);
spin_unlock_irq(&callback_lock);
update_isolation_cpumasks(isolcpus_updated);
update_isolation_cpumasks();
cpuset_force_rebuild();
/*
@@ -1686,7 +1687,6 @@ static void remote_cpus_update(struct cpuset *cs, struct cpumask *xcpus,
{
bool adding, deleting;
int prs = cs->partition_root_state;
int isolcpus_updated = 0;
if (WARN_ON_ONCE(!is_remote_partition(cs)))
return;
@@ -1722,9 +1722,9 @@ static void remote_cpus_update(struct cpuset *cs, struct cpumask *xcpus,
spin_lock_irq(&callback_lock);
if (adding)
isolcpus_updated += partition_xcpus_add(prs, NULL, tmp->addmask);
partition_xcpus_add(prs, NULL, tmp->addmask);
if (deleting)
isolcpus_updated += partition_xcpus_del(prs, NULL, tmp->delmask);
partition_xcpus_del(prs, NULL, tmp->delmask);
/*
* Need to update effective_xcpus and exclusive_cpus now as
* update_sibling_cpumasks() below may iterate back to the same cs.
@@ -1733,7 +1733,7 @@ static void remote_cpus_update(struct cpuset *cs, struct cpumask *xcpus,
if (xcpus)
cpumask_copy(cs->exclusive_cpus, xcpus);
spin_unlock_irq(&callback_lock);
update_isolation_cpumasks(isolcpus_updated);
update_isolation_cpumasks();
if (adding || deleting)
cpuset_force_rebuild();
@@ -1794,7 +1794,6 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd,
int deleting; /* Deleting cpus from parent's effective_cpus */
int old_prs, new_prs;
int part_error = PERR_NONE; /* Partition error? */
int isolcpus_updated = 0;
struct cpumask *xcpus = user_xcpus(cs);
int parent_prs = parent->partition_root_state;
bool nocpu;
@@ -2073,14 +2072,12 @@ write_error:
* and vice versa.
*/
if (adding)
isolcpus_updated += partition_xcpus_del(old_prs, parent,
tmp->addmask);
partition_xcpus_del(old_prs, parent, tmp->addmask);
if (deleting)
isolcpus_updated += partition_xcpus_add(new_prs, parent,
tmp->delmask);
partition_xcpus_add(new_prs, parent, tmp->delmask);
spin_unlock_irq(&callback_lock);
update_isolation_cpumasks(isolcpus_updated);
update_isolation_cpumasks();
if ((old_prs != new_prs) && (cmd == partcmd_update))
update_partition_exclusive_flag(cs, new_prs);
@@ -3103,7 +3100,7 @@ out:
else if (isolcpus_updated)
isolated_cpus_update(old_prs, new_prs, cs->effective_xcpus);
spin_unlock_irq(&callback_lock);
update_isolation_cpumasks(isolcpus_updated);
update_isolation_cpumasks();
/* Force update if switching back to member & update effective_xcpus */
update_cpumasks_hier(cs, &tmpmask, !new_prs);