1 files changed, 287 insertions, 302 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index f76db9dcaa05..3cf2183b472d 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -97,12 +97,6 @@ struct cpuset {
 
         struct cpuset *parent;          /* my parent */
 
-        /*
-         * Copy of global cpuset_mems_generation as of the most
-         * recent time this cpuset changed its mems_allowed.
-         */
-        int mems_generation;
-
         struct fmeter fmeter;           /* memory_pressure filter */
 
         /* partition number for rebuild_sched_domains() */
@@ -128,10 +122,6 @@ static inline struct cpuset *task_cs(struct task_struct *task)
         return container_of(task_subsys_state(task, cpuset_subsys_id),
                             struct cpuset, css);
 }
-struct cpuset_hotplug_scanner {
-        struct cgroup_scanner scan;
-        struct cgroup *to;
-};
 
 /* bits in struct cpuset flags field */
 typedef enum {
@@ -180,27 +170,6 @@ static inline int is_spread_slab(const struct cpuset *cs)
         return test_bit(CS_SPREAD_SLAB, &cs->flags);
 }
 
-/*
- * Increment this integer everytime any cpuset changes its
- * mems_allowed value.  Users of cpusets can track this generation
- * number, and avoid having to lock and reload mems_allowed unless
- * the cpuset they're using changes generation.
- *
- * A single, global generation is needed because cpuset_attach_task() could
- * reattach a task to a different cpuset, which must not have its
- * generation numbers aliased with those of that tasks previous cpuset.
- *
- * Generations are needed for mems_allowed because one task cannot
- * modify another's memory placement.  So we must enable every task,
- * on every visit to __alloc_pages(), to efficiently check whether
- * its current->cpuset->mems_allowed has changed, requiring an update
- * of its current->mems_allowed.
- *
- * Since writes to cpuset_mems_generation are guarded by the cgroup lock
- * there is no need to mark it atomic.
- */
-static int cpuset_mems_generation;
-
 static struct cpuset top_cpuset = {
         .flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)),
 };
@@ -232,8 +201,9 @@ static struct cpuset top_cpuset = {
  * If a task is only holding callback_mutex, then it has read-only
  * access to cpusets.
  *
- * The task_struct fields mems_allowed and mems_generation may only
- * be accessed in the context of that task, so require no locks.
+ * Now, the task_struct fields mems_allowed and mempolicy may be changed
+ * by other task, we use alloc_lock in the task_struct fields to protect
+ * them.
  *
  * The cpuset_common_file_read() handlers only hold callback_mutex across
  * small pieces of code, such as when reading out possibly multi-word
@@ -335,75 +305,22 @@ static void guarantee_online_mems(const struct cpuset *cs, nodemask_t *pmask)
         BUG_ON(!nodes_intersects(*pmask, node_states[N_HIGH_MEMORY]));
 }
 
-/**
- * cpuset_update_task_memory_state - update task memory placement
- *
- * If the current tasks cpusets mems_allowed changed behind our
- * backs, update current->mems_allowed, mems_generation and task NUMA
- * mempolicy to the new value.
- *
- * Task mempolicy is updated by rebinding it relative to the
- * current->cpuset if a task has its memory placement changed.
- * Do not call this routine if in_interrupt().
- *
- * Call without callback_mutex or task_lock() held.  May be
- * called with or without cgroup_mutex held.  Thanks in part to
- * 'the_top_cpuset_hack', the task's cpuset pointer will never
- * be NULL.  This routine also might acquire callback_mutex during
- * call.
- *
- * Reading current->cpuset->mems_generation doesn't need task_lock
- * to guard the current->cpuset derefence, because it is guarded
- * from concurrent freeing of current->cpuset using RCU.
- *
- * The rcu_dereference() is technically probably not needed,
- * as I don't actually mind if I see a new cpuset pointer but
- * an old value of mems_generation.  However this really only
- * matters on alpha systems using cpusets heavily.  If I dropped
- * that rcu_dereference(), it would save them a memory barrier.
- * For all other arch's, rcu_dereference is a no-op anyway, and for
- * alpha systems not using cpusets, another planned optimization,
- * avoiding the rcu critical section for tasks in the root cpuset
- * which is statically allocated, so can't vanish, will make this
- * irrelevant.  Better to use RCU as intended, than to engage in
- * some cute trick to save a memory barrier that is impossible to
- * test, for alpha systems using cpusets heavily, which might not
- * even exist.
- *
- * This routine is needed to update the per-task mems_allowed data,
- * within the tasks context, when it is trying to allocate memory
- * (in various mm/mempolicy.c routines) and notices that some other
- * task has been modifying its cpuset.
+/*
+ * update task's spread flag if cpuset's page/slab spread flag is set
+ *
+ * Called with callback_mutex/cgroup_mutex held
  */
-
-void cpuset_update_task_memory_state(void)
+static void cpuset_update_task_spread_flag(struct cpuset *cs,
+                                        struct task_struct *tsk)
 {
-        int my_cpusets_mem_gen;
-        struct task_struct *tsk = current;
-        struct cpuset *cs;
-
-        rcu_read_lock();
-        my_cpusets_mem_gen = task_cs(tsk)->mems_generation;
-        rcu_read_unlock();
-
-        if (my_cpusets_mem_gen != tsk->cpuset_mems_generation) {
-                mutex_lock(&callback_mutex);
-                task_lock(tsk);
-                cs = task_cs(tsk); /* Maybe changed when task not locked */
-                guarantee_online_mems(cs, &tsk->mems_allowed);
-                tsk->cpuset_mems_generation = cs->mems_generation;
-                if (is_spread_page(cs))
-                        tsk->flags |= PF_SPREAD_PAGE;
-                else
-                        tsk->flags &= ~PF_SPREAD_PAGE;
-                if (is_spread_slab(cs))
-                        tsk->flags |= PF_SPREAD_SLAB;
-                else
-                        tsk->flags &= ~PF_SPREAD_SLAB;
-                task_unlock(tsk);
-                mutex_unlock(&callback_mutex);
-                mpol_rebind_task(tsk, &tsk->mems_allowed);
-        }
+        if (is_spread_page(cs))
+                tsk->flags |= PF_SPREAD_PAGE;
+        else
+                tsk->flags &= ~PF_SPREAD_PAGE;
+        if (is_spread_slab(cs))
+                tsk->flags |= PF_SPREAD_SLAB;
+        else
+                tsk->flags &= ~PF_SPREAD_SLAB;
 }
 
 /*
@@ -521,6 +438,7 @@ static int validate_change(const struct cpuset *cur, const struct cpuset *trial)
         return 0;
 }
 
+#ifdef CONFIG_SMP
 /*
  * Helper routine for generate_sched_domains().
  * Do cpusets a, b have overlapping cpus_allowed masks?
@@ -619,8 +537,7 @@ update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c)
  *      element of the partition (one sched domain) to be passed to
  *      partition_sched_domains().
  */
-/* FIXME: see the FIXME in partition_sched_domains() */
-static int generate_sched_domains(struct cpumask **domains,
+static int generate_sched_domains(cpumask_var_t **domains,
                         struct sched_domain_attr **attributes)
 {
         LIST_HEAD(q);           /* queue of cpusets to be scanned */
@@ -628,7 +545,7 @@ static int generate_sched_domains(struct cpumask **domains,
         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 */
-        struct cpumask *doms;   /* resulting partition; i.e. sched domains */
+        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 */
         int nslot;              /* next empty doms[] struct cpumask slot */
@@ -639,7 +556,8 @@ static int generate_sched_domains(struct cpumask **domains,
 
         /* Special case for the 99% of systems with one, full, sched domain */
         if (is_sched_load_balance(&top_cpuset)) {
-                doms = kmalloc(cpumask_size(), GFP_KERNEL);
+                ndoms = 1;
+                doms = alloc_sched_domains(ndoms);
                 if (!doms)
                         goto done;
 
@@ -648,9 +566,8 @@ static int generate_sched_domains(struct cpumask **domains,
                         *dattr = SD_ATTR_INIT;
                         update_domain_attr_tree(dattr, &top_cpuset);
                 }
-                cpumask_copy(doms, top_cpuset.cpus_allowed);
+                cpumask_copy(doms[0], top_cpuset.cpus_allowed);
 
-                ndoms = 1;
                 goto done;
         }
 
@@ -718,7 +635,7 @@ restart:
          * Now we know how many domains to create.
          * Convert <csn, csa> to <ndoms, doms> and populate cpu masks.
          */
-        doms = kmalloc(ndoms * cpumask_size(), GFP_KERNEL);
+        doms = alloc_sched_domains(ndoms);
         if (!doms)
                 goto done;
 
@@ -738,7 +655,7 @@ restart:
                         continue;
                 }
 
-                dp = doms + nslot;
+                dp = doms[nslot];
 
                 if (nslot == ndoms) {
                         static int warnings = 10;
@@ -800,7 +717,7 @@ done:
 static void do_rebuild_sched_domains(struct work_struct *unused)
 {
         struct sched_domain_attr *attr;
-        struct cpumask *doms;
+        cpumask_var_t *doms;
         int ndoms;
 
         get_online_cpus();
@@ -815,6 +732,18 @@ static void do_rebuild_sched_domains(struct work_struct *unused)
 
         put_online_cpus();
 }
+#else /* !CONFIG_SMP */
+static void do_rebuild_sched_domains(struct work_struct *unused)
+{
+}
+
+static int generate_sched_domains(struct cpumask **domains,
+                        struct sched_domain_attr **attributes)
+{
+        *domains = NULL;
+        return 1;
+}
+#endif /* CONFIG_SMP */
 
 static DECLARE_WORK(rebuild_sched_domains_work, do_rebuild_sched_domains);
 
@@ -998,14 +927,6 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
  *    other task, the task_struct mems_allowed that we are hacking
  *    is for our current task, which must allocate new pages for that
  *    migrating memory region.
- *
- *    We call cpuset_update_task_memory_state() before hacking
- *    our tasks mems_allowed, so that we are assured of being in
- *    sync with our tasks cpuset, and in particular, callbacks to
- *    cpuset_update_task_memory_state() from nested page allocations
- *    won't see any mismatch of our cpuset and task mems_generation
- *    values, so won't overwrite our hacked tasks mems_allowed
- *    nodemask.
  */
 
 static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
@@ -1013,17 +934,64 @@ static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
 {
         struct task_struct *tsk = current;
 
-        cpuset_update_task_memory_state();
-
-        mutex_lock(&callback_mutex);
         tsk->mems_allowed = *to;
-        mutex_unlock(&callback_mutex);
 
         do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL);
 
-        mutex_lock(&callback_mutex);
         guarantee_online_mems(task_cs(tsk),&tsk->mems_allowed);
-        mutex_unlock(&callback_mutex);
+}
+
+/*
+ * cpuset_change_task_nodemask - change task's mems_allowed and mempolicy
+ * @tsk: the task to change
+ * @newmems: new nodes that the task will be set
+ *
+ * In order to avoid seeing no nodes if the old and new nodes are disjoint,
+ * we structure updates as setting all new allowed nodes, then clearing newly
+ * disallowed ones.
+ *
+ * Called with task's alloc_lock held
+ */
+static void cpuset_change_task_nodemask(struct task_struct *tsk,
+                                        nodemask_t *newmems)
+{
+        nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
+        mpol_rebind_task(tsk, &tsk->mems_allowed);
+        mpol_rebind_task(tsk, newmems);
+        tsk->mems_allowed = *newmems;
+}
+
+/*
+ * Update task's mems_allowed and rebind its mempolicy and vmas' mempolicy
+ * of it to cpuset's new mems_allowed, and migrate pages to new nodes if
+ * memory_migrate flag is set. Called with cgroup_mutex held.
+ */
+static void cpuset_change_nodemask(struct task_struct *p,
+                                   struct cgroup_scanner *scan)
+{
+        struct mm_struct *mm;
+        struct cpuset *cs;
+        int migrate;
+        const nodemask_t *oldmem = scan->data;
+        nodemask_t newmems;
+
+        cs = cgroup_cs(scan->cg);
+        guarantee_online_mems(cs, &newmems);
+
+        task_lock(p);
+        cpuset_change_task_nodemask(p, &newmems);
+        task_unlock(p);
+
+        mm = get_task_mm(p);
+        if (!mm)
+                return;
+
+        migrate = is_memory_migrate(cs);
+
+        mpol_rebind_mm(mm, &cs->mems_allowed);
+        if (migrate)
+                cpuset_migrate_mm(mm, oldmem, &cs->mems_allowed);
+        mmput(mm);
 }
 
 static void *cpuset_being_rebound;
@@ -1032,104 +1000,48 @@ static void *cpuset_being_rebound;
  * 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
  * @oldmem: old mems_allowed of cpuset cs
+ * @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks()
  *
  * Called with cgroup_mutex held
- * Return 0 if successful, -errno if not.
+ * No return value. It's guaranteed that cgroup_scan_tasks() always returns 0
+ * if @heap != NULL.
  */
-static int update_tasks_nodemask(struct cpuset *cs, const nodemask_t *oldmem)
+static void update_tasks_nodemask(struct cpuset *cs, const nodemask_t *oldmem,
+                                 struct ptr_heap *heap)
 {
-        struct task_struct *p;
-        struct mm_struct **mmarray;
-        int i, n, ntasks;
-        int migrate;
-        int fudge;
-        struct cgroup_iter it;
-        int retval;
+        struct cgroup_scanner scan;
 
         cpuset_being_rebound = cs;              /* causes mpol_dup() rebind */
 
-        fudge = 10;                             /* spare mmarray[] slots */
-        fudge += cpumask_weight(cs->cpus_allowed);/* imagine 1 fork-bomb/cpu */
-        retval = -ENOMEM;
-
-        /*
-         * Allocate mmarray[] to hold mm reference for each task
-         * in cpuset cs.  Can't kmalloc GFP_KERNEL while holding
-         * tasklist_lock.  We could use GFP_ATOMIC, but with a
-         * few more lines of code, we can retry until we get a big
-         * enough mmarray[] w/o using GFP_ATOMIC.
-         */
-        while (1) {
-                ntasks = cgroup_task_count(cs->css.cgroup);  /* guess */
-                ntasks += fudge;
-                mmarray = kmalloc(ntasks * sizeof(*mmarray), GFP_KERNEL);
-                if (!mmarray)
-                        goto done;
-                read_lock(&tasklist_lock);              /* block fork */
-                if (cgroup_task_count(cs->css.cgroup) <= ntasks)
-                        break;                          /* got enough */
-                read_unlock(&tasklist_lock);            /* try again */
-                kfree(mmarray);
-        }
-
-        n = 0;
-
-        /* Load up mmarray[] with mm reference for each task in cpuset. */
-        cgroup_iter_start(cs->css.cgroup, &it);
-        while ((p = cgroup_iter_next(cs->css.cgroup, &it))) {
-                struct mm_struct *mm;
-
-                if (n >= ntasks) {
-                        printk(KERN_WARNING
-                                "Cpuset mempolicy rebind incomplete.\n");
-                        break;
-                }
-                mm = get_task_mm(p);
-                if (!mm)
-                        continue;
-                mmarray[n++] = mm;
-        }
-        cgroup_iter_end(cs->css.cgroup, &it);
-        read_unlock(&tasklist_lock);
+        scan.cg = cs->css.cgroup;
+        scan.test_task = NULL;
+        scan.process_task = cpuset_change_nodemask;
+        scan.heap = heap;
+        scan.data = (nodemask_t *)oldmem;
 
         /*
-         * Now that we've dropped the tasklist spinlock, we can
-         * rebind the vma mempolicies of each mm in mmarray[] to their
-         * new cpuset, and release that mm.  The mpol_rebind_mm()
-         * call takes mmap_sem, which we couldn't take while holding
-         * tasklist_lock.  Forks can happen again now - the mpol_dup()
-         * cpuset_being_rebound check will catch such forks, and rebind
-         * their vma mempolicies too.  Because we still hold the global
-         * cgroup_mutex, we know that no other rebind effort will
-         * be contending for the global variable cpuset_being_rebound.
+         * The mpol_rebind_mm() call takes mmap_sem, which we couldn't
+         * 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 cgroup_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.
          */
-        migrate = is_memory_migrate(cs);
-        for (i = 0; i < n; i++) {
-                struct mm_struct *mm = mmarray[i];
-
-                mpol_rebind_mm(mm, &cs->mems_allowed);
-                if (migrate)
-                        cpuset_migrate_mm(mm, oldmem, &cs->mems_allowed);
-                mmput(mm);
-        }
+        cgroup_scan_tasks(&scan);
 
         /* We're done rebinding vmas to this cpuset's new mems_allowed. */
-        kfree(mmarray);
         cpuset_being_rebound = NULL;
-        retval = 0;
-done:
-        return retval;
 }
 
 /*
  * Handle user request to change the 'mems' memory placement
  * of a cpuset.  Needs to validate the request, update the
- * cpusets mems_allowed and mems_generation, and for each
- * task in the cpuset, rebind any vma mempolicies and if
- * the cpuset is marked 'memory_migrate', migrate the tasks
- * pages to the new memory.
+ * cpusets mems_allowed, and for each task in the cpuset,
+ * update mems_allowed and rebind task's mempolicy and any vma
+ * mempolicies and if the cpuset is marked 'memory_migrate',
+ * migrate the tasks pages to the new memory.
  *
  * Call with cgroup_mutex held.  May take callback_mutex during call.
  * Will take tasklist_lock, scan tasklist for tasks in cpuset cs,
@@ -1141,6 +1053,7 @@ static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs,
 {
         nodemask_t oldmem;
         int retval;
+        struct ptr_heap heap;
 
         /*
          * top_cpuset.mems_allowed tracks node_stats[N_HIGH_MEMORY];
@@ -1175,12 +1088,17 @@ static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs,
         if (retval < 0)
                 goto done;
 
+        retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
+        if (retval < 0)
+                goto done;
+
         mutex_lock(&callback_mutex);
         cs->mems_allowed = trialcs->mems_allowed;
-        cs->mems_generation = cpuset_mems_generation++;
         mutex_unlock(&callback_mutex);
 
-        retval = update_tasks_nodemask(cs, &oldmem);
+        update_tasks_nodemask(cs, &oldmem, &heap);
+
+        heap_free(&heap);
 done:
         return retval;
 }
@@ -1192,8 +1110,10 @@ int current_cpuset_is_being_rebound(void)
 
 static int update_relax_domain_level(struct cpuset *cs, s64 val)
 {
+#ifdef CONFIG_SMP
         if (val < -1 || val >= SD_LV_MAX)
                 return -EINVAL;
+#endif
 
         if (val != cs->relax_domain_level) {
                 cs->relax_domain_level = val;
@@ -1206,6 +1126,46 @@ static int update_relax_domain_level(struct cpuset *cs, s64 val)
 }
 
 /*
+ * cpuset_change_flag - make a task's spread flags the same as its cpuset's
+ * @tsk: task to be updated
+ * @scan: struct cgroup_scanner containing the cgroup of the task
+ *
+ * Called by cgroup_scan_tasks() for each task in a cgroup.
+ *
+ * We don't need to re-check for the cgroup/cpuset membership, since we're
+ * holding cgroup_lock() at this point.
+ */
+static void cpuset_change_flag(struct task_struct *tsk,
+                                struct cgroup_scanner *scan)
+{
+        cpuset_update_task_spread_flag(cgroup_cs(scan->cg), tsk);
+}
+
+/*
+ * 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
+ * @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks()
+ *
+ * Called with cgroup_mutex held
+ *
+ * The cgroup_scan_tasks() function will scan all the tasks in a cgroup,
+ * calling callback functions for each.
+ *
+ * No return value. It's guaranteed that cgroup_scan_tasks() always returns 0
+ * if @heap != NULL.
+ */
+static void update_tasks_flags(struct cpuset *cs, struct ptr_heap *heap)
+{
+        struct cgroup_scanner scan;
+
+        scan.cg = cs->css.cgroup;
+        scan.test_task = NULL;
+        scan.process_task = cpuset_change_flag;
+        scan.heap = heap;
+        cgroup_scan_tasks(&scan);
+}
+
+/*
  * 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
@@ -1218,8 +1178,10 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
                        int turning_on)
 {
         struct cpuset *trialcs;
-        int err;
         int balance_flag_changed;
+        int spread_flag_changed;
+        struct ptr_heap heap;
+        int err;
 
         trialcs = alloc_trial_cpuset(cs);
         if (!trialcs)
@@ -1234,9 +1196,16 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
         if (err < 0)
                 goto out;
 
+        err = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
+        if (err < 0)
+                goto out;
+
         balance_flag_changed = (is_sched_load_balance(cs) !=
                                 is_sched_load_balance(trialcs));
 
+        spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs))
+                        || (is_spread_page(cs) != is_spread_page(trialcs)));
+
         mutex_lock(&callback_mutex);
         cs->flags = trialcs->flags;
         mutex_unlock(&callback_mutex);
@@ -1244,6 +1213,9 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
         if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
                 async_rebuild_sched_domains();
 
+        if (spread_flag_changed)
+                update_tasks_flags(cs, &heap);
+        heap_free(&heap);
 out:
         free_trial_cpuset(trialcs);
         return err;
@@ -1351,46 +1323,92 @@ static int fmeter_getrate(struct fmeter *fmp)
 static cpumask_var_t cpus_attach;
 
 /* Called by cgroups to determine if a cpuset is usable; cgroup_mutex held */
-static int cpuset_can_attach(struct cgroup_subsys *ss,
-                             struct cgroup *cont, struct task_struct *tsk)
+static int cpuset_can_attach(struct cgroup_subsys *ss, struct cgroup *cont,
+                             struct task_struct *tsk, bool threadgroup)
 {
+        int ret;
         struct cpuset *cs = cgroup_cs(cont);
-        int ret = 0;
 
         if (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
                 return -ENOSPC;
 
-        if (tsk->flags & PF_THREAD_BOUND) {
-                mutex_lock(&callback_mutex);
-                if (!cpumask_equal(&tsk->cpus_allowed, cs->cpus_allowed))
-                        ret = -EINVAL;
-                mutex_unlock(&callback_mutex);
+        /*
+         * Kthreads bound to specific cpus cannot be moved to a new cpuset; we
+         * cannot change their cpu affinity and isolating such threads by their
+         * set of allowed nodes is unnecessary.  Thus, cpusets are not
+         * applicable for such threads.  This prevents checking for success of
+         * set_cpus_allowed_ptr() on all attached tasks before cpus_allowed may
+         * be changed.
+         */
+        if (tsk->flags & PF_THREAD_BOUND)
+                return -EINVAL;
+
+        ret = security_task_setscheduler(tsk, 0, NULL);
+        if (ret)
+                return ret;
+        if (threadgroup) {
+                struct task_struct *c;
+
+                rcu_read_lock();
+                list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) {
+                        ret = security_task_setscheduler(c, 0, NULL);
+                        if (ret) {
+                                rcu_read_unlock();
+                                return ret;
+                        }
+                }
+                rcu_read_unlock();
         }
+        return 0;
+}
+
+static void cpuset_attach_task(struct task_struct *tsk, nodemask_t *to,
+                               struct cpuset *cs)
+{
+        int err;
+        /*
+         * can_attach beforehand should guarantee that this doesn't fail.
+         * TODO: have a better way to handle failure here
+         */
+        err = set_cpus_allowed_ptr(tsk, cpus_attach);
+        WARN_ON_ONCE(err);
+
+        task_lock(tsk);
+        cpuset_change_task_nodemask(tsk, to);
+        task_unlock(tsk);
+        cpuset_update_task_spread_flag(cs, tsk);
 
-        return ret < 0 ? ret : security_task_setscheduler(tsk, 0, NULL);
 }
 
-static void cpuset_attach(struct cgroup_subsys *ss,
-                          struct cgroup *cont, struct cgroup *oldcont,
-                          struct task_struct *tsk)
+static void cpuset_attach(struct cgroup_subsys *ss, struct cgroup *cont,
+                          struct cgroup *oldcont, struct task_struct *tsk,
+                          bool threadgroup)
 {
         nodemask_t from, to;
         struct mm_struct *mm;
         struct cpuset *cs = cgroup_cs(cont);
         struct cpuset *oldcs = cgroup_cs(oldcont);
-        int err;
 
         if (cs == &top_cpuset) {
                 cpumask_copy(cpus_attach, cpu_possible_mask);
+                to = node_possible_map;
         } else {
-                mutex_lock(&callback_mutex);
                 guarantee_online_cpus(cs, cpus_attach);
-                mutex_unlock(&callback_mutex);
+                guarantee_online_mems(cs, &to);
+        }
+
+        /* do per-task migration stuff possibly for each in the threadgroup */
+        cpuset_attach_task(tsk, &to, cs);
+        if (threadgroup) {
+                struct task_struct *c;
+                rcu_read_lock();
+                list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) {
+                        cpuset_attach_task(c, &to, cs);
+                }
+                rcu_read_unlock();
         }
-        err = set_cpus_allowed_ptr(tsk, cpus_attach);
-        if (err)
-                return;
 
+        /* change mm; only needs to be done once even if threadgroup */
         from = oldcs->mems_allowed;
         to = cs->mems_allowed;
         mm = get_task_mm(tsk);
@@ -1452,11 +1470,9 @@ static int cpuset_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val)
                 break;
         case FILE_SPREAD_PAGE:
                 retval = update_flag(CS_SPREAD_PAGE, cs, val);
-                cs->mems_generation = cpuset_mems_generation++;
                 break;
         case FILE_SPREAD_SLAB:
                 retval = update_flag(CS_SPREAD_SLAB, cs, val);
-                cs->mems_generation = cpuset_mems_generation++;
                 break;
         default:
                 retval = -EINVAL;
@@ -1706,6 +1722,7 @@ static struct cftype files[] = {
                 .read_u64 = cpuset_read_u64,
                 .write_u64 = cpuset_write_u64,
                 .private = FILE_MEMORY_PRESSURE,
+                .mode = S_IRUGO,
         },
 
         {
@@ -1795,8 +1812,6 @@ static struct cgroup_subsys_state *cpuset_create(
         struct cpuset *parent;
 
         if (!cont->parent) {
-                /* This is early initialization for the top cgroup */
-                top_cpuset.mems_generation = cpuset_mems_generation++;
                 return &top_cpuset.css;
         }
         parent = cgroup_cs(cont->parent);
@@ -1808,7 +1823,6 @@ static struct cgroup_subsys_state *cpuset_create(
                 return ERR_PTR(-ENOMEM);
         }
 
-        cpuset_update_task_memory_state();
         cs->flags = 0;
         if (is_spread_page(parent))
                 set_bit(CS_SPREAD_PAGE, &cs->flags);
@@ -1817,7 +1831,6 @@ static struct cgroup_subsys_state *cpuset_create(
         set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
         cpumask_clear(cs->cpus_allowed);
         nodes_clear(cs->mems_allowed);
-        cs->mems_generation = cpuset_mems_generation++;
         fmeter_init(&cs->fmeter);
         cs->relax_domain_level = -1;
 
@@ -1836,8 +1849,6 @@ static void cpuset_destroy(struct cgroup_subsys *ss, struct cgroup *cont)
 {
         struct cpuset *cs = cgroup_cs(cont);
 
-        cpuset_update_task_memory_state();
-
         if (is_sched_load_balance(cs))
                 update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
 
@@ -1858,21 +1869,6 @@ struct cgroup_subsys cpuset_subsys = {
         .early_init = 1,
 };
 
-/*
- * cpuset_init_early - just enough so that the calls to
- * cpuset_update_task_memory_state() in early init code
- * are harmless.
- */
-
-int __init cpuset_init_early(void)
-{
-        alloc_bootmem_cpumask_var(&top_cpuset.cpus_allowed);
-
-        top_cpuset.mems_generation = cpuset_mems_generation++;
-        return 0;
-}
-
-
 /**
  * cpuset_init - initialize cpusets at system boot
  *
@@ -1883,11 +1879,13 @@ int __init cpuset_init(void)
 {
         int err = 0;
 
+        if (!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL))
+                BUG();
+
         cpumask_setall(top_cpuset.cpus_allowed);
         nodes_setall(top_cpuset.mems_allowed);
 
         fmeter_init(&top_cpuset.fmeter);
-        top_cpuset.mems_generation = cpuset_mems_generation++;
         set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags);
         top_cpuset.relax_domain_level = -1;
 
@@ -1913,10 +1911,9 @@ int __init cpuset_init(void)
 static void cpuset_do_move_task(struct task_struct *tsk,
                                 struct cgroup_scanner *scan)
 {
-        struct cpuset_hotplug_scanner *chsp;
+        struct cgroup *new_cgroup = scan->data;
 
-        chsp = container_of(scan, struct cpuset_hotplug_scanner, scan);
-        cgroup_attach_task(chsp->to, tsk);
+        cgroup_attach_task(new_cgroup, tsk);
 }
 
 /**
@@ -1932,15 +1929,15 @@ static void cpuset_do_move_task(struct task_struct *tsk,
  */
 static void move_member_tasks_to_cpuset(struct cpuset *from, struct cpuset *to)
 {
-        struct cpuset_hotplug_scanner scan;
+        struct cgroup_scanner scan;
 
-        scan.scan.cg = from->css.cgroup;
-        scan.scan.test_task = NULL; /* select all tasks in cgroup */
-        scan.scan.process_task = cpuset_do_move_task;
-        scan.scan.heap = NULL;
-        scan.to = to->css.cgroup;
+        scan.cg = from->css.cgroup;
+        scan.test_task = NULL; /* select all tasks in cgroup */
+        scan.process_task = cpuset_do_move_task;
+        scan.heap = NULL;
+        scan.data = to->css.cgroup;
 
-        if (cgroup_scan_tasks(&scan.scan))
+        if (cgroup_scan_tasks(&scan))
                 printk(KERN_ERR "move_member_tasks_to_cpuset: "
                                 "cgroup_scan_tasks failed\n");
 }
@@ -2033,7 +2030,7 @@ static void scan_for_empty_cpusets(struct cpuset *root)
                         remove_tasks_in_empty_cpuset(cp);
                 else {
                         update_tasks_cpumask(cp, NULL);
-                        update_tasks_nodemask(cp, &oldmems);
+                        update_tasks_nodemask(cp, &oldmems, NULL);
                 }
         }
 }
@@ -2054,7 +2051,7 @@ static int cpuset_track_online_cpus(struct notifier_block *unused_nb,
                                 unsigned long phase, void *unused_cpu)
 {
         struct sched_domain_attr *attr;
-        struct cpumask *doms;
+        cpumask_var_t *doms;
         int ndoms;
 
         switch (phase) {
@@ -2069,7 +2066,9 @@ static int cpuset_track_online_cpus(struct notifier_block *unused_nb,
         }
 
         cgroup_lock();
+        mutex_lock(&callback_mutex);
         cpumask_copy(top_cpuset.cpus_allowed, cpu_online_mask);
+        mutex_unlock(&callback_mutex);
         scan_for_empty_cpusets(&top_cpuset);
         ndoms = generate_sched_domains(&doms, &attr);
         cgroup_unlock();
@@ -2092,11 +2091,12 @@ static int cpuset_track_online_nodes(struct notifier_block *self,
         cgroup_lock();
         switch (action) {
         case MEM_ONLINE:
-                top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
-                break;
         case MEM_OFFLINE:
+                mutex_lock(&callback_mutex);
                 top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
-                scan_for_empty_cpusets(&top_cpuset);
+                mutex_unlock(&callback_mutex);
+                if (action == MEM_OFFLINE)
+                        scan_for_empty_cpusets(&top_cpuset);
                 break;
         default:
                 break;
@@ -2206,26 +2206,24 @@ static const struct cpuset *nearest_hardwall_ancestor(const struct cpuset *cs)
 }
 
 /**
- * cpuset_zone_allowed_softwall - Can we allocate on zone z's memory node?
- * @z: is this zone on an allowed node?
+ * cpuset_node_allowed_softwall - Can we allocate on a memory node?
+ * @node: is this an allowed node?
  * @gfp_mask: memory allocation flags
  *
- * If we're in interrupt, yes, we can always allocate.  If
- * __GFP_THISNODE is set, yes, we can always allocate.  If zone
- * z's node is in our tasks mems_allowed, yes.  If it's not a
- * __GFP_HARDWALL request and this zone's nodes is in the nearest
- * hardwalled cpuset ancestor to this tasks cpuset, yes.
- * If the task has been OOM killed and has access to memory reserves
- * as specified by the TIF_MEMDIE flag, yes.
+ * If we're in interrupt, yes, we can always allocate.  If __GFP_THISNODE is
+ * set, yes, we can always allocate.  If node is in our task's mems_allowed,
+ * yes.  If it's not a __GFP_HARDWALL request and this node is in the nearest
+ * hardwalled cpuset ancestor to this task's cpuset, yes.  If the task has been
+ * OOM killed and has access to memory reserves as specified by the TIF_MEMDIE
+ * flag, yes.
  * Otherwise, no.
  *
- * If __GFP_HARDWALL is set, cpuset_zone_allowed_softwall()
- * reduces to cpuset_zone_allowed_hardwall().  Otherwise,
- * cpuset_zone_allowed_softwall() might sleep, and might allow a zone
- * from an enclosing cpuset.
+ * If __GFP_HARDWALL is set, cpuset_node_allowed_softwall() reduces to
+ * cpuset_node_allowed_hardwall().  Otherwise, cpuset_node_allowed_softwall()
+ * might sleep, and might allow a node from an enclosing cpuset.
  *
- * cpuset_zone_allowed_hardwall() only handles the simpler case of
- * hardwall cpusets, and never sleeps.
+ * cpuset_node_allowed_hardwall() only handles the simpler case of hardwall
+ * cpusets, and never sleeps.
  *
  * The __GFP_THISNODE placement logic is really handled elsewhere,
  * by forcibly using a zonelist starting at a specified node, and by
@@ -2264,20 +2262,17 @@ static const struct cpuset *nearest_hardwall_ancestor(const struct cpuset *cs)
  *      GFP_USER     - only nodes in current tasks mems allowed ok.
  *
  * Rule:
- *    Don't call cpuset_zone_allowed_softwall if you can't sleep, unless you
+ *    Don't call cpuset_node_allowed_softwall if you can't sleep, unless you
  *    pass in the __GFP_HARDWALL flag set in gfp_flag, which disables
  *    the code that might scan up ancestor cpusets and sleep.
  */
-
-int __cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask)
+int __cpuset_node_allowed_softwall(int node, gfp_t gfp_mask)
 {
-        int node;                       /* node that zone z is on */
         const struct cpuset *cs;        /* current cpuset ancestors */
         int allowed;                    /* is allocation in zone z allowed? */
 
         if (in_interrupt() || (gfp_mask & __GFP_THISNODE))
                 return 1;
-        node = zone_to_nid(z);
         might_sleep_if(!(gfp_mask & __GFP_HARDWALL));
         if (node_isset(node, current->mems_allowed))
                 return 1;
@@ -2306,15 +2301,15 @@ int __cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask)
 }
 
 /*
- * cpuset_zone_allowed_hardwall - Can we allocate on zone z's memory node?
- * @z: is this zone on an allowed node?
+ * cpuset_node_allowed_hardwall - Can we allocate on a memory node?
+ * @node: is this an allowed node?
  * @gfp_mask: memory allocation flags
  *
- * If we're in interrupt, yes, we can always allocate.
- * If __GFP_THISNODE is set, yes, we can always allocate.  If zone
- * z's node is in our tasks mems_allowed, yes.   If the task has been
- * OOM killed and has access to memory reserves as specified by the
- * TIF_MEMDIE flag, yes.  Otherwise, no.
+ * If we're in interrupt, yes, we can always allocate.  If __GFP_THISNODE is
+ * set, yes, we can always allocate.  If node is in our task's mems_allowed,
+ * yes.  If the task has been OOM killed and has access to memory reserves as
+ * specified by the TIF_MEMDIE flag, yes.
+ * Otherwise, no.
  *
  * The __GFP_THISNODE placement logic is really handled elsewhere,
  * by forcibly using a zonelist starting at a specified node, and by
@@ -2322,20 +2317,16 @@ int __cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask)
  * any node on the zonelist except the first.  By the time any such
  * calls get to this routine, we should just shut up and say 'yes'.
  *
- * Unlike the cpuset_zone_allowed_softwall() variant, above,
- * this variant requires that the zone be in the current tasks
+ * Unlike the cpuset_node_allowed_softwall() variant, above,
+ * this variant requires that the node be in the current task's
  * mems_allowed or that we're in interrupt.  It does not scan up the
  * cpuset hierarchy for the nearest enclosing mem_exclusive cpuset.
  * It never sleeps.
  */
-
-int __cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask)
+int __cpuset_node_allowed_hardwall(int node, gfp_t gfp_mask)
 {
-        int node;                       /* node that zone z is on */
-
         if (in_interrupt() || (gfp_mask & __GFP_THISNODE))
                 return 1;
-        node = zone_to_nid(z);
         if (node_isset(node, current->mems_allowed))
                 return 1;
         /*
@@ -2545,15 +2536,9 @@ const struct file_operations proc_cpuset_operations = {
 };
 #endif /* CONFIG_PROC_PID_CPUSET */
 
-/* Display task cpus_allowed, mems_allowed in /proc/<pid>/status file. */
+/* Display task mems_allowed in /proc/<pid>/status file. */
 void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task)
 {
-        seq_printf(m, "Cpus_allowed:\t");
-        seq_cpumask(m, &task->cpus_allowed);
-        seq_printf(m, "\n");
-        seq_printf(m, "Cpus_allowed_list:\t");
-        seq_cpumask_list(m, &task->cpus_allowed);
-        seq_printf(m, "\n");
         seq_printf(m, "Mems_allowed:\t");
         seq_nodemask(m, &task->mems_allowed);
         seq_printf(m, "\n");