Merge tag 'cgroup-for-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup updates from Tejun Heo:

 - cpuset isolation improvements

 - cpuset cgroup1 support is split into its own file behind the new
   config option CONFIG_CPUSET_V1. This makes it the second controller
   which makes cgroup1 support optional after memcg

 - Handling of unavailable v1 controller handling improved during
   cgroup1 mount operations

 - union_find applied to cpuset. It makes code simpler and more
   efficient

 - Reduce spurious events in pids.events

 - Cleanups and other misc changes

 - Contains a merge of cgroup/for-6.11-fixes to receive cpuset fixes
   that further changes build upon

* tag 'cgroup-for-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (34 commits)
  cgroup: Do not report unavailable v1 controllers in /proc/cgroups
  cgroup: Disallow mounting v1 hierarchies without controller implementation
  cgroup/cpuset: Expose cpuset filesystem with cpuset v1 only
  cgroup/cpuset: Move cpu.h include to cpuset-internal.h
  cgroup/cpuset: add sefltest for cpuset v1
  cgroup/cpuset: guard cpuset-v1 code under CONFIG_CPUSETS_V1
  cgroup/cpuset: rename functions shared between v1 and v2
  cgroup/cpuset: move v1 interfaces to cpuset-v1.c
  cgroup/cpuset: move validate_change_legacy to cpuset-v1.c
  cgroup/cpuset: move legacy hotplug update to cpuset-v1.c
  cgroup/cpuset: add callback_lock helper
  cgroup/cpuset: move memory_spread to cpuset-v1.c
  cgroup/cpuset: move relax_domain_level to cpuset-v1.c
  cgroup/cpuset: move memory_pressure to cpuset-v1.c
  cgroup/cpuset: move common code to cpuset-internal.h
  cgroup/cpuset: introduce cpuset-v1.c
  selftest/cgroup: Make test_cpuset_prs.sh deal with pre-isolated CPUs
  cgroup/cpuset: Account for boot time isolated CPUs
  cgroup/cpuset: remove use_parent_ecpus of cpuset
  cgroup/cpuset: remove fetch_xcpus
  ...

1 files changed, 144 insertions, 1011 deletions

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 4bd9e50bcc8e..a4dd285cdf39 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -22,11 +22,8 @@
  *  distribution for more details.
  */
 #include "cgroup-internal.h"
+#include "cpuset-internal.h"
 
-#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>
@@ -40,10 +37,8 @@
 #include <linux/sched/mm.h>
 #include <linux/sched/task.h>
 #include <linux/security.h>
-#include <linux/spinlock.h>
 #include <linux/oom.h>
 #include <linux/sched/isolation.h>
-#include <linux/cgroup.h>
 #include <linux/wait.h>
 #include <linux/workqueue.h>
 
@@ -57,30 +52,6 @@ DEFINE_STATIC_KEY_FALSE(cpusets_enabled_key);
  */
 DEFINE_STATIC_KEY_FALSE(cpusets_insane_config_key);
 
-/* See "Frequency meter" comments, below. */
-
-struct fmeter {
-	int cnt;		/* unprocessed events count */
-	int val;		/* most recent output value */
-	time64_t time;		/* clock (secs) when val computed */
-	spinlock_t lock;	/* guards read or write of above */
-};
-
-/*
- * Invalid partition error code
- */
-enum prs_errcode {
-	PERR_NONE = 0,
-	PERR_INVCPUS,
-	PERR_INVPARENT,
-	PERR_NOTPART,
-	PERR_NOTEXCL,
-	PERR_NOCPUS,
-	PERR_HOTPLUG,
-	PERR_CPUSEMPTY,
-	PERR_HKEEPING,
-};
-
 static const char * const perr_strings[] = {
 	[PERR_INVCPUS]   = "Invalid cpu list in cpuset.cpus.exclusive",
 	[PERR_INVPARENT] = "Parent is an invalid partition root",
@@ -90,133 +61,7 @@ static const char * const perr_strings[] = {
 	[PERR_HOTPLUG]   = "No cpu available due to hotplug",
 	[PERR_CPUSEMPTY] = "cpuset.cpus and cpuset.cpus.exclusive are empty",
 	[PERR_HKEEPING]  = "partition config conflicts with housekeeping setup",
-};
-
-struct cpuset {
-	struct cgroup_subsys_state css;
-
-	unsigned long flags;		/* "unsigned long" so bitops work */
-
-	/*
-	 * On default hierarchy:
-	 *
-	 * The user-configured masks can only be changed by writing to
-	 * cpuset.cpus and cpuset.mems, and won't be limited by the
-	 * parent masks.
-	 *
-	 * The effective masks is the real masks that apply to the tasks
-	 * in the cpuset. They may be changed if the configured masks are
-	 * changed or hotplug happens.
-	 *
-	 * effective_mask == configured_mask & parent's effective_mask,
-	 * and if it ends up empty, it will inherit the parent's mask.
-	 *
-	 *
-	 * On legacy hierarchy:
-	 *
-	 * The user-configured masks are always the same with effective masks.
-	 */
-
-	/* user-configured CPUs and Memory Nodes allow to tasks */
-	cpumask_var_t cpus_allowed;
-	nodemask_t mems_allowed;
-
-	/* effective CPUs and Memory Nodes allow to tasks */
-	cpumask_var_t effective_cpus;
-	nodemask_t effective_mems;
-
-	/*
-	 * Exclusive CPUs dedicated to current cgroup (default hierarchy only)
-	 *
-	 * The effective_cpus of a valid partition root comes solely from its
-	 * effective_xcpus and some of the effective_xcpus may be distributed
-	 * to sub-partitions below & hence excluded from its effective_cpus.
-	 * For a valid partition root, its effective_cpus have no relationship
-	 * with cpus_allowed unless its exclusive_cpus isn't set.
-	 *
-	 * This value will only be set if either exclusive_cpus is set or
-	 * when this cpuset becomes a local partition root.
-	 */
-	cpumask_var_t effective_xcpus;
-
-	/*
-	 * Exclusive CPUs as requested by the user (default hierarchy only)
-	 *
-	 * Its value is independent of cpus_allowed and designates the set of
-	 * CPUs that can be granted to the current cpuset or its children when
-	 * it becomes a valid partition root. The effective set of exclusive
-	 * CPUs granted (effective_xcpus) depends on whether those exclusive
-	 * CPUs are passed down by its ancestors and not yet taken up by
-	 * another sibling partition root along the way.
-	 *
-	 * If its value isn't set, it defaults to cpus_allowed.
-	 */
-	cpumask_var_t exclusive_cpus;
-
-	/*
-	 * This is old Memory Nodes tasks took on.
-	 *
-	 * - top_cpuset.old_mems_allowed is initialized to mems_allowed.
-	 * - A new cpuset's old_mems_allowed is initialized when some
-	 *   task is moved into it.
-	 * - old_mems_allowed is used in cpuset_migrate_mm() when we change
-	 *   cpuset.mems_allowed and have tasks' nodemask updated, and
-	 *   then old_mems_allowed is updated to mems_allowed.
-	 */
-	nodemask_t old_mems_allowed;
-
-	struct fmeter fmeter;		/* memory_pressure filter */
-
-	/*
-	 * Tasks are being attached to this cpuset.  Used to prevent
-	 * zeroing cpus/mems_allowed between ->can_attach() and ->attach().
-	 */
-	int attach_in_progress;
-
-	/* partition number for rebuild_sched_domains() */
-	int pn;
-
-	/* for custom sched domain */
-	int relax_domain_level;
-
-	/* number of valid local child partitions */
-	int nr_subparts;
-
-	/* partition root state */
-	int partition_root_state;
-
-	/*
-	 * Default hierarchy only:
-	 * use_parent_ecpus - set if using parent's effective_cpus
-	 * child_ecpus_count - # of children with use_parent_ecpus set
-	 */
-	int use_parent_ecpus;
-	int child_ecpus_count;
-
-	/*
-	 * number of SCHED_DEADLINE tasks attached to this cpuset, so that we
-	 * know when to rebuild associated root domain bandwidth information.
-	 */
-	int nr_deadline_tasks;
-	int nr_migrate_dl_tasks;
-	u64 sum_migrate_dl_bw;
-
-	/* Invalid partition error code, not lock protected */
-	enum prs_errcode prs_err;
-
-	/* Handle for cpuset.cpus.partition */
-	struct cgroup_file partition_file;
-
-	/* Remote partition silbling list anchored at remote_children */
-	struct list_head remote_sibling;
-};
-
-/*
- * Legacy hierarchy call to cgroup_transfer_tasks() is handled asynchrously
- */
-struct cpuset_remove_tasks_struct {
-	struct work_struct work;
-	struct cpuset *cs;
+	[PERR_ACCESS]    = "Enable partition not permitted",
 };
 
 /*
@@ -229,6 +74,12 @@ static cpumask_var_t	subpartitions_cpus;
  */
 static cpumask_var_t	isolated_cpus;
 
+/*
+ * Housekeeping (HK_TYPE_DOMAIN) CPUs at boot
+ */
+static cpumask_var_t	boot_hk_cpus;
+static bool		have_boot_isolcpus;
+
 /* List of remote partition root children */
 static struct list_head remote_children;
 
@@ -279,22 +130,6 @@ struct tmpmasks {
 	cpumask_var_t new_cpus;		/* For update_cpumasks_hier() */
 };
 
-static inline struct cpuset *css_cs(struct cgroup_subsys_state *css)
-{
-	return css ? container_of(css, struct cpuset, css) : NULL;
-}
-
-/* Retrieve the cpuset for a task */
-static inline struct cpuset *task_cs(struct task_struct *task)
-{
-	return css_cs(task_css(task, cpuset_cgrp_id));
-}
-
-static inline struct cpuset *parent_cs(struct cpuset *cs)
-{
-	return css_cs(cs->css.parent);
-}
-
 void inc_dl_tasks_cs(struct task_struct *p)
 {
 	struct cpuset *cs = task_cs(p);
@@ -309,59 +144,6 @@ void dec_dl_tasks_cs(struct task_struct *p)
 	cs->nr_deadline_tasks--;
 }
 
-/* bits in struct cpuset flags field */
-typedef enum {
-	CS_ONLINE,
-	CS_CPU_EXCLUSIVE,
-	CS_MEM_EXCLUSIVE,
-	CS_MEM_HARDWALL,
-	CS_MEMORY_MIGRATE,
-	CS_SCHED_LOAD_BALANCE,
-	CS_SPREAD_PAGE,
-	CS_SPREAD_SLAB,
-} cpuset_flagbits_t;
-
-/* convenient tests for these bits */
-static inline bool is_cpuset_online(struct cpuset *cs)
-{
-	return test_bit(CS_ONLINE, &cs->flags) && !css_is_dying(&cs->css);
-}
-
-static inline int is_cpu_exclusive(const struct cpuset *cs)
-{
-	return test_bit(CS_CPU_EXCLUSIVE, &cs->flags);
-}
-
-static inline int is_mem_exclusive(const struct cpuset *cs)
-{
-	return test_bit(CS_MEM_EXCLUSIVE, &cs->flags);
-}
-
-static inline int is_mem_hardwall(const struct cpuset *cs)
-{
-	return test_bit(CS_MEM_HARDWALL, &cs->flags);
-}
-
-static inline int is_sched_load_balance(const struct cpuset *cs)
-{
-	return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
-}
-
-static inline int is_memory_migrate(const struct cpuset *cs)
-{
-	return test_bit(CS_MEMORY_MIGRATE, &cs->flags);
-}
-
-static inline int is_spread_page(const struct cpuset *cs)
-{
-	return test_bit(CS_SPREAD_PAGE, &cs->flags);
-}
-
-static inline int is_spread_slab(const struct cpuset *cs)
-{
-	return test_bit(CS_SPREAD_SLAB, &cs->flags);
-}
-
 static inline int is_partition_valid(const struct cpuset *cs)
 {
 	return cs->partition_root_state > 0;
@@ -403,34 +185,6 @@ static struct cpuset top_cpuset = {
 	.remote_sibling = LIST_HEAD_INIT(top_cpuset.remote_sibling),
 };
 
-/**
- * cpuset_for_each_child - traverse online children of a cpuset
- * @child_cs: loop cursor pointing to the current child
- * @pos_css: used for iteration
- * @parent_cs: target cpuset to walk children of
- *
- * Walk @child_cs through the online children of @parent_cs.  Must be used
- * with RCU read locked.
- */
-#define cpuset_for_each_child(child_cs, pos_css, parent_cs)		\
-	css_for_each_child((pos_css), &(parent_cs)->css)		\
-		if (is_cpuset_online(((child_cs) = css_cs((pos_css)))))
-
-/**
- * cpuset_for_each_descendant_pre - pre-order walk of a cpuset's descendants
- * @des_cs: loop cursor pointing to the current descendant
- * @pos_css: used for iteration
- * @root_cs: target cpuset to walk ancestor of
- *
- * Walk @des_cs through the online descendants of @root_cs.  Must be used
- * with RCU read locked.  The caller may modify @pos_css by calling
- * css_rightmost_descendant() to skip subtree.  @root_cs is included in the
- * iteration and the first node to be visited.
- */
-#define cpuset_for_each_descendant_pre(des_cs, pos_css, root_cs)	\
-	css_for_each_descendant_pre((pos_css), &(root_cs)->css)		\
-		if (is_cpuset_online(((des_cs) = css_cs((pos_css)))))
-
 /*
  * There are two global locks guarding cpuset structures - cpuset_mutex and
  * callback_lock. We also require taking task_lock() when dereferencing a
@@ -484,6 +238,16 @@ void cpuset_unlock(void)
 
 static DEFINE_SPINLOCK(callback_lock);
 
+void cpuset_callback_lock_irq(void)
+{
+	spin_lock_irq(&callback_lock);
+}
+
+void cpuset_callback_unlock_irq(void)
+{
+	spin_unlock_irq(&callback_lock);
+}
+
 static struct workqueue_struct *cpuset_migrate_mm_wq;
 
 static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq);
@@ -500,6 +264,26 @@ static inline void check_insane_mems_config(nodemask_t *nodes)
 }
 
 /*
+ * decrease cs->attach_in_progress.
+ * wake_up cpuset_attach_wq if cs->attach_in_progress==0.
+ */
+static inline void dec_attach_in_progress_locked(struct cpuset *cs)
+{
+	lockdep_assert_held(&cpuset_mutex);
+
+	cs->attach_in_progress--;
+	if (!cs->attach_in_progress)
+		wake_up(&cpuset_attach_wq);
+}
+
+static inline void dec_attach_in_progress(struct cpuset *cs)
+{
+	mutex_lock(&cpuset_mutex);
+	dec_attach_in_progress_locked(cs);
+	mutex_unlock(&cpuset_mutex);
+}
+
+/*
  * Cgroup v2 behavior is used on the "cpus" and "mems" control files when
  * on default hierarchy or when the cpuset_v2_mode flag is set by mounting
  * the v1 cpuset cgroup filesystem with the "cpuset_v2_mode" mount option.
@@ -596,45 +380,6 @@ static void guarantee_online_mems(struct cpuset *cs, nodemask_t *pmask)
 	nodes_and(*pmask, cs->effective_mems, node_states[N_MEMORY]);
 }
 
-/*
- * update task's spread flag if cpuset's page/slab spread flag is set
- *
- * 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,
-					struct task_struct *tsk)
-{
-	if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys))
-		return;
-
-	if (is_spread_page(cs))
-		task_set_spread_page(tsk);
-	else
-		task_clear_spread_page(tsk);
-
-	if (is_spread_slab(cs))
-		task_set_spread_slab(tsk);
-	else
-		task_clear_spread_slab(tsk);
-}
-
-/*
- * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q?
- *
- * 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_mutex.
- */
-
-static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
-{
-	return	cpumask_subset(p->cpus_allowed, q->cpus_allowed) &&
-		nodes_subset(p->mems_allowed, q->mems_allowed) &&
-		is_cpu_exclusive(p) <= is_cpu_exclusive(q) &&
-		is_mem_exclusive(p) <= is_mem_exclusive(q);
-}
-
 /**
  * alloc_cpumasks - allocate three cpumasks for cpuset
  * @cs:  the cpuset that have cpumasks to be allocated.
@@ -750,13 +495,6 @@ static inline bool xcpus_empty(struct cpuset *cs)
 	       cpumask_empty(cs->exclusive_cpus);
 }
 
-static inline struct cpumask *fetch_xcpus(struct cpuset *cs)
-{
-	return !cpumask_empty(cs->exclusive_cpus) ? cs->exclusive_cpus :
-	       cpumask_empty(cs->effective_xcpus) ? cs->cpus_allowed
-						  : cs->effective_xcpus;
-}
-
 /*
  * cpusets_are_exclusive() - check if two cpusets are exclusive
  *
@@ -764,8 +502,8 @@ static inline struct cpumask *fetch_xcpus(struct cpuset *cs)
  */
 static inline bool cpusets_are_exclusive(struct cpuset *cs1, struct cpuset *cs2)
 {
-	struct cpumask *xcpus1 = fetch_xcpus(cs1);
-	struct cpumask *xcpus2 = fetch_xcpus(cs2);
+	struct cpumask *xcpus1 = user_xcpus(cs1);
+	struct cpumask *xcpus2 = user_xcpus(cs2);
 
 	if (cpumask_intersects(xcpus1, xcpus2))
 		return false;
@@ -773,35 +511,6 @@ static inline bool cpusets_are_exclusive(struct cpuset *cs1, struct cpuset *cs2)
 }
 
 /*
- * 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.
  *
@@ -830,7 +539,7 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial)
 	rcu_read_lock();
 
 	if (!is_in_v2_mode())
-		ret = validate_change_legacy(cur, trial);
+		ret = cpuset1_validate_change(cur, trial);
 	if (ret)
 		goto out;
 
@@ -996,18 +705,15 @@ static inline int nr_cpusets(void)
  *	   were changed (added or removed.)
  *
  * Finding the best partition (set of domains):
- *	The triple nested loops below over i, j, k scan over the
- *	load balanced cpusets (using the array of cpuset pointers in
- *	csa[]) looking for pairs of cpusets that have overlapping
- *	cpus_allowed, but which don't have the same 'pn' partition
- *	number and gives them in the same partition number.  It keeps
- *	looping on the 'restart' label until it can no longer find
- *	any such pairs.
+ *	The double nested loops below over i, j scan over the load
+ *	balanced cpusets (using the array of cpuset pointers in csa[])
+ *	looking for pairs of cpusets that have overlapping cpus_allowed
+ *	and merging them using a union-find algorithm.
+ *
+ *	The union of the cpus_allowed masks from the set of all cpusets
+ *	having the same root then form the one element of the partition
+ *	(one sched domain) to be passed to partition_sched_domains().
  *
- *	The union of the cpus_allowed masks from the set of
- *	all cpusets having the same 'pn' value then form the one
- *	element of the partition (one sched domain) to be passed to
- *	partition_sched_domains().
  */
 static int generate_sched_domains(cpumask_var_t **domains,
 			struct sched_domain_attr **attributes)
@@ -1015,7 +721,7 @@ static int generate_sched_domains(cpumask_var_t **domains,
 	struct cpuset *cp;	/* top-down scan of cpusets */
 	struct cpuset **csa;	/* array of all cpuset ptrs */
 	int csn;		/* how many cpuset ptrs in csa so far */
-	int i, j, k;		/* indices for partition finding loops */
+	int i, j;		/* indices for partition finding loops */
 	cpumask_var_t *doms;	/* resulting partition; i.e. sched domains */
 	struct sched_domain_attr *dattr;  /* attributes for custom domains */
 	int ndoms = 0;		/* number of sched domains in result */
@@ -1023,6 +729,7 @@ static int generate_sched_domains(cpumask_var_t **domains,
 	struct cgroup_subsys_state *pos_css;
 	bool root_load_balance = is_sched_load_balance(&top_cpuset);
 	bool cgrpv2 = cgroup_subsys_on_dfl(cpuset_cgrp_subsys);
+	int nslot_update;
 
 	doms = NULL;
 	dattr = NULL;
@@ -1111,32 +818,28 @@ v2:
 		goto single_root_domain;
 
 	for (i = 0; i < csn; i++)
-		csa[i]->pn = i;
-	ndoms = csn;
+		uf_node_init(&csa[i]->node);
 
-restart:
-	/* Find the best partition (set of sched domains) */
+	/* Merge overlapping cpusets */
 	for (i = 0; i < csn; i++) {
-		struct cpuset *a = csa[i];
-		int apn = a->pn;
-
-		for (j = 0; j < csn; j++) {
-			struct cpuset *b = csa[j];
-			int bpn = b->pn;
-
-			if (apn != bpn && cpusets_overlap(a, b)) {
-				for (k = 0; k < csn; k++) {
-					struct cpuset *c = csa[k];
-
-					if (c->pn == bpn)
-						c->pn = apn;
-				}
-				ndoms--;	/* one less element */
-				goto restart;
+		for (j = i + 1; j < csn; j++) {
+			if (cpusets_overlap(csa[i], csa[j])) {
+				/*
+				 * Cgroup v2 shouldn't pass down overlapping
+				 * partition root cpusets.
+				 */
+				WARN_ON_ONCE(cgrpv2);
+				uf_union(&csa[i]->node, &csa[j]->node);
 			}
 		}
 	}
 
+	/* Count the total number of domains */
+	for (i = 0; i < csn; i++) {
+		if (uf_find(&csa[i]->node) == &csa[i]->node)
+			ndoms++;
+	}
+
 	/*
 	 * Now we know how many domains to create.
 	 * Convert <csn, csa> to <ndoms, doms> and populate cpu masks.
@@ -1167,44 +870,25 @@ restart:
 	}
 
 	for (nslot = 0, i = 0; i < csn; i++) {
-		struct cpuset *a = csa[i];
-		struct cpumask *dp;
-		int apn = a->pn;
-
-		if (apn < 0) {
-			/* Skip completed partitions */
-			continue;
-		}
-
-		dp = doms[nslot];
-
-		if (nslot == ndoms) {
-			static int warnings = 10;
-			if (warnings) {
-				pr_warn("rebuild_sched_domains confused: nslot %d, ndoms %d, csn %d, i %d, apn %d\n",
-					nslot, ndoms, csn, i, apn);
-				warnings--;
-			}
-			continue;
-		}
-
-		cpumask_clear(dp);
-		if (dattr)
-			*(dattr + nslot) = SD_ATTR_INIT;
+		nslot_update = 0;
 		for (j = i; j < csn; j++) {
-			struct cpuset *b = csa[j];
-
-			if (apn == b->pn) {
-				cpumask_or(dp, dp, b->effective_cpus);
+			if (uf_find(&csa[j]->node) == &csa[i]->node) {
+				struct cpumask *dp = doms[nslot];
+
+				if (i == j) {
+					nslot_update = 1;
+					cpumask_clear(dp);
+					if (dattr)
+						*(dattr + nslot) = SD_ATTR_INIT;
+				}
+				cpumask_or(dp, dp, csa[j]->effective_cpus);
 				cpumask_and(dp, dp, housekeeping_cpumask(HK_TYPE_DOMAIN));
 				if (dattr)
-					update_domain_attr_tree(dattr + nslot, b);
-
-				/* Done with this partition */
-				b->pn = -1;
+					update_domain_attr_tree(dattr + nslot, csa[j]);
 			}
 		}
-		nslot++;
+		if (nslot_update)
+			nslot++;
 	}
 	BUG_ON(nslot != ndoms);
 
@@ -1296,7 +980,7 @@ partition_and_rebuild_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
  *
  * Call with cpuset_mutex held.  Takes cpus_read_lock().
  */
-static void rebuild_sched_domains_locked(void)
+void rebuild_sched_domains_locked(void)
 {
 	struct cgroup_subsys_state *pos_css;
 	struct sched_domain_attr *attr;
@@ -1348,7 +1032,7 @@ static void rebuild_sched_domains_locked(void)
 	partition_and_rebuild_sched_domains(ndoms, doms, attr);
 }
 #else /* !CONFIG_SMP */
-static void rebuild_sched_domains_locked(void)
+void rebuild_sched_domains_locked(void)
 {
 }
 #endif /* CONFIG_SMP */
@@ -1368,7 +1052,7 @@ void rebuild_sched_domains(void)
 }
 
 /**
- * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset.
+ * cpuset_update_tasks_cpumask - Update the cpumasks of tasks in the cpuset.
  * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed
  * @new_cpus: the temp variable for the new effective_cpus mask
  *
@@ -1378,7 +1062,7 @@ void rebuild_sched_domains(void)
  * 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.
  */
-static void update_tasks_cpumask(struct cpuset *cs, struct cpumask *new_cpus)
+void cpuset_update_tasks_cpumask(struct cpuset *cs, struct cpumask *new_cpus)
 {
 	struct css_task_iter it;
 	struct task_struct *task;
@@ -1428,8 +1112,6 @@ enum partition_cmd {
 	partcmd_invalidate,	/* Make partition invalid	  */
 };
 
-static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
-		       int turning_on);
 static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs,
 				    struct tmpmasks *tmp);
 
@@ -1443,11 +1125,11 @@ static int update_partition_exclusive(struct cpuset *cs, int new_prs)
 	bool exclusive = (new_prs > PRS_MEMBER);
 
 	if (exclusive && !is_cpu_exclusive(cs)) {
-		if (update_flag(CS_CPU_EXCLUSIVE, cs, 1))
+		if (cpuset_update_flag(CS_CPU_EXCLUSIVE, cs, 1))
 			return PERR_NOTEXCL;
 	} else if (!exclusive && is_cpu_exclusive(cs)) {
 		/* Turning off CS_CPU_EXCLUSIVE will not return error */
-		update_flag(CS_CPU_EXCLUSIVE, cs, 0);
+		cpuset_update_flag(CS_CPU_EXCLUSIVE, cs, 0);
 	}
 	return 0;
 }
@@ -1516,12 +1198,8 @@ static void reset_partition_data(struct cpuset *cs)
 		if (is_cpu_exclusive(cs))
 			clear_bit(CS_CPU_EXCLUSIVE, &cs->flags);
 	}
-	if (!cpumask_and(cs->effective_cpus,
-			 parent->effective_cpus, cs->cpus_allowed)) {
-		cs->use_parent_ecpus = true;
-		parent->child_ecpus_count++;
+	if (!cpumask_and(cs->effective_cpus, parent->effective_cpus, cs->cpus_allowed))
 		cpumask_copy(cs->effective_cpus, parent->effective_cpus);
-	}
 }
 
 /*
@@ -1662,7 +1340,7 @@ static inline bool is_local_partition(struct cpuset *cs)
  * @cs: the cpuset to update
  * @new_prs: new partition_root_state
  * @tmp: temparary masks
- * Return: 1 if successful, 0 if error
+ * Return: 0 if successful, errcode 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.
@@ -1676,7 +1354,7 @@ static int remote_partition_enable(struct cpuset *cs, int new_prs,
 	 * The user must have sysadmin privilege.
 	 */
 	if (!capable(CAP_SYS_ADMIN))
-		return 0;
+		return PERR_ACCESS;
 
 	/*
 	 * The requested exclusive_cpus must not be allocated to other
@@ -1690,26 +1368,20 @@ static int remote_partition_enable(struct cpuset *cs, int new_prs,
 	if (cpumask_empty(tmp->new_cpus) ||
 	    cpumask_intersects(tmp->new_cpus, subpartitions_cpus) ||
 	    cpumask_subset(top_cpuset.effective_cpus, tmp->new_cpus))
-		return 0;
+		return PERR_INVCPUS;
 
 	spin_lock_irq(&callback_lock);
 	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--;
-	}
 	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);
+	cpuset_update_tasks_cpumask(&top_cpuset, tmp->new_cpus);
 	update_sibling_cpumasks(&top_cpuset, NULL, tmp);
-	return 1;
+	return 0;
 }
 
 /*
@@ -1743,7 +1415,7 @@ static void remote_partition_disable(struct cpuset *cs, struct tmpmasks *tmp)
 	/*
 	 * Proprogate changes in top_cpuset's effective_cpus down the hierarchy.
 	 */
-	update_tasks_cpumask(&top_cpuset, tmp->new_cpus);
+	cpuset_update_tasks_cpumask(&top_cpuset, tmp->new_cpus);
 	update_sibling_cpumasks(&top_cpuset, NULL, tmp);
 }
 
@@ -1795,7 +1467,7 @@ static void remote_cpus_update(struct cpuset *cs, struct cpumask *newmask,
 	/*
 	 * Proprogate changes in top_cpuset's effective_cpus down the hierarchy.
 	 */
-	update_tasks_cpumask(&top_cpuset, tmp->new_cpus);
+	cpuset_update_tasks_cpumask(&top_cpuset, tmp->new_cpus);
 	update_sibling_cpumasks(&top_cpuset, NULL, tmp);
 	return;
 
@@ -1850,15 +1522,15 @@ static void remote_partition_check(struct cpuset *cs, struct cpumask *newmask,
  * @new_cpus: cpu mask
  * Return: true if there is conflict, false otherwise
  *
- * CPUs outside of housekeeping_cpumask(HK_TYPE_DOMAIN) can only be used in
- * an isolated partition.
+ * CPUs outside of boot_hk_cpus, if defined, can only be used in an
+ * isolated partition.
  */
 static bool prstate_housekeeping_conflict(int prstate, struct cpumask *new_cpus)
 {
-	const struct cpumask *hk_domain = housekeeping_cpumask(HK_TYPE_DOMAIN);
-	bool all_in_hk = cpumask_subset(new_cpus, hk_domain);
+	if (!have_boot_isolcpus)
+		return false;
 
-	if (!all_in_hk && (prstate != PRS_ISOLATED))
+	if ((prstate != PRS_ISOLATED) && !cpumask_subset(new_cpus, boot_hk_cpus))
 		return true;
 
 	return false;
@@ -2167,7 +1839,7 @@ write_error:
 		update_partition_exclusive(cs, new_prs);
 
 	if (adding || deleting) {
-		update_tasks_cpumask(parent, tmp->addmask);
+		cpuset_update_tasks_cpumask(parent, tmp->addmask);
 		update_sibling_cpumasks(parent, cs, tmp);
 	}
 
@@ -2325,17 +1997,8 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp,
 		 * it is a partition root that has explicitly distributed
 		 * out all its CPUs.
 		 */
-		if (is_in_v2_mode() && !remote && cpumask_empty(tmp->new_cpus)) {
+		if (is_in_v2_mode() && !remote && cpumask_empty(tmp->new_cpus))
 			cpumask_copy(tmp->new_cpus, parent->effective_cpus);
-			if (!cp->use_parent_ecpus) {
-				cp->use_parent_ecpus = true;
-				parent->child_ecpus_count++;
-			}
-		} else if (cp->use_parent_ecpus) {
-			cp->use_parent_ecpus = false;
-			WARN_ON_ONCE(!parent->child_ecpus_count);
-			parent->child_ecpus_count--;
-		}
 
 		if (remote)
 			goto get_css;
@@ -2359,7 +2022,7 @@ update_parent_effective:
 		/*
 		 * update_parent_effective_cpumask() should have been called
 		 * for cs already in update_cpumask(). We should also call
-		 * update_tasks_cpumask() again for tasks in the parent
+		 * cpuset_update_tasks_cpumask() again for tasks in the parent
 		 * cpuset if the parent's effective_cpus changes.
 		 */
 		if ((cp != cs) && old_prs) {
@@ -2416,7 +2079,7 @@ get_css:
 		WARN_ON(!is_in_v2_mode() &&
 			!cpumask_equal(cp->cpus_allowed, cp->effective_cpus));
 
-		update_tasks_cpumask(cp, cp->effective_cpus);
+		cpuset_update_tasks_cpumask(cp, cp->effective_cpus);
 
 		/*
 		 * On default hierarchy, inherit the CS_SCHED_LOAD_BALANCE
@@ -2472,8 +2135,7 @@ static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs,
 	 * Check all its siblings and call update_cpumasks_hier()
 	 * if their effective_cpus will need to be changed.
 	 *
-	 * With the addition of effective_xcpus which is a subset of
-	 * cpus_allowed. It is possible a change in parent's effective_cpus
+	 * It is possible a change in parent's effective_cpus
 	 * due to a change in a child partition's effective_xcpus will impact
 	 * its siblings even if they do not inherit parent's effective_cpus
 	 * directly.
@@ -2487,8 +2149,7 @@ static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs,
 	cpuset_for_each_child(sibling, pos_css, parent) {
 		if (sibling == cs)
 			continue;
-		if (!sibling->use_parent_ecpus &&
-		    !is_partition_valid(sibling)) {
+		if (!is_partition_valid(sibling)) {
 			compute_effective_cpumask(tmp->new_cpus, sibling,
 						  parent);
 			if (cpumask_equal(tmp->new_cpus, sibling->effective_cpus))
@@ -2598,7 +2259,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
 		invalidate = true;
 		rcu_read_lock();
 		cpuset_for_each_child(cp, css, parent) {
-			struct cpumask *xcpus = fetch_xcpus(trialcs);
+			struct cpumask *xcpus = user_xcpus(trialcs);
 
 			if (is_partition_valid(cp) &&
 			    cpumask_intersects(xcpus, cp->effective_xcpus)) {
@@ -2845,14 +2506,14 @@ static void cpuset_change_task_nodemask(struct task_struct *tsk,
 static void *cpuset_being_rebound;
 
 /**
- * update_tasks_nodemask - Update the nodemasks of tasks in the cpuset.
+ * cpuset_update_tasks_nodemask - Update the nodemasks of tasks in the cpuset.
  * @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_mutex held,
  * cpuset membership stays stable.
  */
-static void update_tasks_nodemask(struct cpuset *cs)
+void cpuset_update_tasks_nodemask(struct cpuset *cs)
 {
 	static nodemask_t newmems;	/* protected by cpuset_mutex */
 	struct css_task_iter it;
@@ -2950,7 +2611,7 @@ static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems)
 		WARN_ON(!is_in_v2_mode() &&
 			!nodes_equal(cp->mems_allowed, cp->effective_mems));
 
-		update_tasks_nodemask(cp);
+		cpuset_update_tasks_nodemask(cp);
 
 		rcu_read_lock();
 		css_put(&cp->css);
@@ -3036,44 +2697,8 @@ bool current_cpuset_is_being_rebound(void)
 	return ret;
 }
 
-static int update_relax_domain_level(struct cpuset *cs, s64 val)
-{
-#ifdef CONFIG_SMP
-	if (val < -1 || val > sched_domain_level_max + 1)
-		return -EINVAL;
-#endif
-
-	if (val != cs->relax_domain_level) {
-		cs->relax_domain_level = val;
-		if (!cpumask_empty(cs->cpus_allowed) &&
-		    is_sched_load_balance(cs))
-			rebuild_sched_domains_locked();
-	}
-
-	return 0;
-}
-
-/**
- * update_tasks_flags - update the spread flags of tasks in the cpuset.
- * @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_mutex held, cpuset membership stays
- * stable.
- */
-static void update_tasks_flags(struct cpuset *cs)
-{
-	struct css_task_iter it;
-	struct task_struct *task;
-
-	css_task_iter_start(&cs->css, 0, &it);
-	while ((task = css_task_iter_next(&it)))
-		cpuset_update_task_spread_flags(cs, task);
-	css_task_iter_end(&it);
-}
-
 /*
- * update_flag - read a 0 or a 1 in a file and update associated flag
+ * cpuset_update_flag - read a 0 or a 1 in a file and update associated flag
  * bit:		the bit to update (see cpuset_flagbits_t)
  * cs:		the cpuset to update
  * turning_on: 	whether the flag is being set or cleared
@@ -3081,7 +2706,7 @@ static void update_tasks_flags(struct cpuset *cs)
  * Call with cpuset_mutex held.
  */
 
-static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
+int cpuset_update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
 		       int turning_on)
 {
 	struct cpuset *trialcs;
@@ -3117,7 +2742,7 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
 		rebuild_sched_domains_locked();
 
 	if (spread_flag_changed)
-		update_tasks_flags(cs);
+		cpuset1_update_tasks_flags(cs);
 out:
 	free_cpuset(trialcs);
 	return err;
@@ -3166,9 +2791,6 @@ 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 and exclusive_cpus cannot be both empty.
 		 */
@@ -3177,13 +2799,18 @@ static int update_prstate(struct cpuset *cs, int new_prs)
 			goto out;
 		}
 
-		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 parent is valid partition, enable local partiion.
+		 * Otherwise, enable a remote partition.
 		 */
-		if (err && remote_partition_enable(cs, new_prs, &tmpmask))
-			err = 0;
+		if (is_partition_valid(parent)) {
+			enum partition_cmd cmd = (new_prs == PRS_ROOT)
+					       ? partcmd_enable : partcmd_enablei;
+
+			err = update_parent_effective_cpumask(cs, cmd, NULL, &tmpmask);
+		} else {
+			err = remote_partition_enable(cs, new_prs, &tmpmask);
+		}
 	} else if (old_prs && new_prs) {
 		/*
 		 * A change in load balance state only, no change in cpumasks.
@@ -3236,107 +2863,6 @@ out:
 	return 0;
 }
 
-/*
- * Frequency meter - How fast is some event occ