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cpuset: use css_task_iter_start/next/end() instead of css_scan_tasks()
Now that css_task_iter_start/next_end() supports blocking while iterating, there's no reason to use css_scan_tasks() which is more cumbersome to use and scheduled to be removed. Convert all css_scan_tasks() usages in cpuset to css_task_iter_start/next/end(). This simplifies the code by removing heap allocation and callbacks. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
This commit is contained in:
Tejun Heo
parent
96d365e0b8
commit
d66393e54e
186
kernel/cpuset.c
186
kernel/cpuset.c
@ -828,56 +828,37 @@ static struct cpuset *effective_nodemask_cpuset(struct cpuset *cs)
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return cs;
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}
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/**
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* cpuset_change_cpumask - make a task's cpus_allowed the same as its cpuset's
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* @tsk: task to test
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* @data: cpuset to @tsk belongs to
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*
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* Called by css_scan_tasks() for each task in a cgroup whose cpus_allowed
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* mask needs to be changed.
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*
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* We don't need to re-check for the cgroup/cpuset membership, since we're
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* holding cpuset_mutex at this point.
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*/
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static void cpuset_change_cpumask(struct task_struct *tsk, void *data)
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{
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struct cpuset *cs = data;
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struct cpuset *cpus_cs = effective_cpumask_cpuset(cs);
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set_cpus_allowed_ptr(tsk, cpus_cs->cpus_allowed);
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}
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/**
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* update_tasks_cpumask - Update the cpumasks of tasks in the cpuset.
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* @cs: the cpuset in which each task's cpus_allowed mask needs to be changed
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* @heap: if NULL, defer allocating heap memory to css_scan_tasks()
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*
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* Called with cpuset_mutex held
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*
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* The css_scan_tasks() function will scan all the tasks in a cgroup,
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* calling callback functions for each.
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*
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* No return value. It's guaranteed that css_scan_tasks() always returns 0
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* if @heap != NULL.
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* Iterate through each task of @cs updating its cpus_allowed to the
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* effective cpuset's. As this function is called with cpuset_mutex held,
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* cpuset membership stays stable.
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*/
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static void update_tasks_cpumask(struct cpuset *cs, struct ptr_heap *heap)
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static void update_tasks_cpumask(struct cpuset *cs)
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{
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css_scan_tasks(&cs->css, NULL, cpuset_change_cpumask, cs, heap);
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struct cpuset *cpus_cs = effective_cpumask_cpuset(cs);
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struct css_task_iter it;
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struct task_struct *task;
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css_task_iter_start(&cs->css, &it);
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while ((task = css_task_iter_next(&it)))
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set_cpus_allowed_ptr(task, cpus_cs->cpus_allowed);
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css_task_iter_end(&it);
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}
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/*
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* update_tasks_cpumask_hier - Update the cpumasks of tasks in the hierarchy.
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* @root_cs: the root cpuset of the hierarchy
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* @update_root: update root cpuset or not?
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* @heap: the heap used by css_scan_tasks()
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*
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* This will update cpumasks of tasks in @root_cs and all other empty cpusets
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* which take on cpumask of @root_cs.
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*
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* Called with cpuset_mutex held
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*/
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static void update_tasks_cpumask_hier(struct cpuset *root_cs,
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bool update_root, struct ptr_heap *heap)
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static void update_tasks_cpumask_hier(struct cpuset *root_cs, bool update_root)
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{
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struct cpuset *cp;
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struct cgroup_subsys_state *pos_css;
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@ -898,7 +879,7 @@ static void update_tasks_cpumask_hier(struct cpuset *root_cs,
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continue;
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rcu_read_unlock();
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update_tasks_cpumask(cp, heap);
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update_tasks_cpumask(cp);
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rcu_read_lock();
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css_put(&cp->css);
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@ -914,7 +895,6 @@ static void update_tasks_cpumask_hier(struct cpuset *root_cs,
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static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
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const char *buf)
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{
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struct ptr_heap heap;
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int retval;
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int is_load_balanced;
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@ -947,19 +927,13 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
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if (retval < 0)
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return retval;
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retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
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if (retval)
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return retval;
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is_load_balanced = is_sched_load_balance(trialcs);
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mutex_lock(&callback_mutex);
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cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed);
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mutex_unlock(&callback_mutex);
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update_tasks_cpumask_hier(cs, true, &heap);
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heap_free(&heap);
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update_tasks_cpumask_hier(cs, true);
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if (is_load_balanced)
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rebuild_sched_domains_locked();
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@ -1052,53 +1026,22 @@ static void cpuset_change_task_nodemask(struct task_struct *tsk,
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task_unlock(tsk);
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}
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struct cpuset_change_nodemask_arg {
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struct cpuset *cs;
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nodemask_t *newmems;
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};
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/*
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* Update task's mems_allowed and rebind its mempolicy and vmas' mempolicy
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* of it to cpuset's new mems_allowed, and migrate pages to new nodes if
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* memory_migrate flag is set. Called with cpuset_mutex held.
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*/
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static void cpuset_change_nodemask(struct task_struct *p, void *data)
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{
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struct cpuset_change_nodemask_arg *arg = data;
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struct cpuset *cs = arg->cs;
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struct mm_struct *mm;
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int migrate;
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cpuset_change_task_nodemask(p, arg->newmems);
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mm = get_task_mm(p);
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if (!mm)
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return;
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migrate = is_memory_migrate(cs);
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mpol_rebind_mm(mm, &cs->mems_allowed);
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if (migrate)
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cpuset_migrate_mm(mm, &cs->old_mems_allowed, arg->newmems);
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mmput(mm);
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}
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static void *cpuset_being_rebound;
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/**
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* update_tasks_nodemask - Update the nodemasks of tasks in the cpuset.
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* @cs: the cpuset in which each task's mems_allowed mask needs to be changed
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* @heap: if NULL, defer allocating heap memory to css_scan_tasks()
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*
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* Called with cpuset_mutex held. No return value. It's guaranteed that
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* css_scan_tasks() always returns 0 if @heap != NULL.
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* Iterate through each task of @cs updating its mems_allowed to the
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* effective cpuset's. As this function is called with cpuset_mutex held,
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* cpuset membership stays stable.
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*/
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static void update_tasks_nodemask(struct cpuset *cs, struct ptr_heap *heap)
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static void update_tasks_nodemask(struct cpuset *cs)
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{
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static nodemask_t newmems; /* protected by cpuset_mutex */
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struct cpuset *mems_cs = effective_nodemask_cpuset(cs);
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struct cpuset_change_nodemask_arg arg = { .cs = cs,
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.newmems = &newmems };
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struct css_task_iter it;
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struct task_struct *task;
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cpuset_being_rebound = cs; /* causes mpol_dup() rebind */
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@ -1114,7 +1057,25 @@ static void update_tasks_nodemask(struct cpuset *cs, struct ptr_heap *heap)
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* It's ok if we rebind the same mm twice; mpol_rebind_mm()
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* is idempotent. Also migrate pages in each mm to new nodes.
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*/
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css_scan_tasks(&cs->css, NULL, cpuset_change_nodemask, &arg, heap);
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css_task_iter_start(&cs->css, &it);
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while ((task = css_task_iter_next(&it))) {
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struct mm_struct *mm;
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bool migrate;
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cpuset_change_task_nodemask(task, &newmems);
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mm = get_task_mm(task);
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if (!mm)
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continue;
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migrate = is_memory_migrate(cs);
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mpol_rebind_mm(mm, &cs->mems_allowed);
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if (migrate)
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cpuset_migrate_mm(mm, &cs->old_mems_allowed, &newmems);
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mmput(mm);
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}
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css_task_iter_end(&it);
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/*
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* All the tasks' nodemasks have been updated, update
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@ -1130,15 +1091,13 @@ static void update_tasks_nodemask(struct cpuset *cs, struct ptr_heap *heap)
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* update_tasks_nodemask_hier - Update the nodemasks of tasks in the hierarchy.
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* @cs: the root cpuset of the hierarchy
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* @update_root: update the root cpuset or not?
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* @heap: the heap used by css_scan_tasks()
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*
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* This will update nodemasks of tasks in @root_cs and all other empty cpusets
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* which take on nodemask of @root_cs.
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*
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* Called with cpuset_mutex held
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*/
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static void update_tasks_nodemask_hier(struct cpuset *root_cs,
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bool update_root, struct ptr_heap *heap)
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static void update_tasks_nodemask_hier(struct cpuset *root_cs, bool update_root)
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{
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struct cpuset *cp;
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struct cgroup_subsys_state *pos_css;
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@ -1159,7 +1118,7 @@ static void update_tasks_nodemask_hier(struct cpuset *root_cs,
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continue;
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rcu_read_unlock();
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update_tasks_nodemask(cp, heap);
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update_tasks_nodemask(cp);
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rcu_read_lock();
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css_put(&cp->css);
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@ -1184,7 +1143,6 @@ static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs,
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const char *buf)
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{
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int retval;
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struct ptr_heap heap;
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/*
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* top_cpuset.mems_allowed tracks node_stats[N_MEMORY];
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@ -1223,17 +1181,11 @@ static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs,
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if (retval < 0)
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goto done;
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retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
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if (retval < 0)
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goto done;
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mutex_lock(&callback_mutex);
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cs->mems_allowed = trialcs->mems_allowed;
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mutex_unlock(&callback_mutex);
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update_tasks_nodemask_hier(cs, true, &heap);
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heap_free(&heap);
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update_tasks_nodemask_hier(cs, true);
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done:
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return retval;
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}
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@ -1260,39 +1212,23 @@ static int update_relax_domain_level(struct cpuset *cs, s64 val)
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return 0;
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}
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/**
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* cpuset_change_flag - make a task's spread flags the same as its cpuset's
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* @tsk: task to be updated
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* @data: cpuset to @tsk belongs to
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*
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* Called by css_scan_tasks() for each task in a cgroup.
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*
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* We don't need to re-check for the cgroup/cpuset membership, since we're
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* holding cpuset_mutex at this point.
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*/
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static void cpuset_change_flag(struct task_struct *tsk, void *data)
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{
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struct cpuset *cs = data;
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cpuset_update_task_spread_flag(cs, tsk);
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}
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/**
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* update_tasks_flags - update the spread flags of tasks in the cpuset.
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* @cs: the cpuset in which each task's spread flags needs to be changed
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* @heap: if NULL, defer allocating heap memory to css_scan_tasks()
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*
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* Called with cpuset_mutex held
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*
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* The css_scan_tasks() function will scan all the tasks in a cgroup,
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* calling callback functions for each.
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*
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* No return value. It's guaranteed that css_scan_tasks() always returns 0
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* if @heap != NULL.
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* Iterate through each task of @cs updating its spread flags. As this
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* function is called with cpuset_mutex held, cpuset membership stays
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* stable.
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*/
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static void update_tasks_flags(struct cpuset *cs, struct ptr_heap *heap)
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static void update_tasks_flags(struct cpuset *cs)
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{
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css_scan_tasks(&cs->css, NULL, cpuset_change_flag, cs, heap);
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struct css_task_iter it;
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struct task_struct *task;
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css_task_iter_start(&cs->css, &it);
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while ((task = css_task_iter_next(&it)))
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cpuset_update_task_spread_flag(cs, task);
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css_task_iter_end(&it);
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}
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/*
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@ -1310,7 +1246,6 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
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struct cpuset *trialcs;
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int balance_flag_changed;
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int spread_flag_changed;
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struct ptr_heap heap;
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int err;
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trialcs = alloc_trial_cpuset(cs);
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@ -1326,10 +1261,6 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
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if (err < 0)
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goto out;
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err = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
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if (err < 0)
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goto out;
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balance_flag_changed = (is_sched_load_balance(cs) !=
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is_sched_load_balance(trialcs));
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@ -1344,8 +1275,7 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
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rebuild_sched_domains_locked();
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if (spread_flag_changed)
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update_tasks_flags(cs, &heap);
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heap_free(&heap);
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update_tasks_flags(cs);
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out:
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free_trial_cpuset(trialcs);
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return err;
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@ -2138,7 +2068,7 @@ retry:
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*/
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if ((sane && cpumask_empty(cs->cpus_allowed)) ||
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(!cpumask_empty(&off_cpus) && !cpumask_empty(cs->cpus_allowed)))
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update_tasks_cpumask(cs, NULL);
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update_tasks_cpumask(cs);
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mutex_lock(&callback_mutex);
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nodes_andnot(cs->mems_allowed, cs->mems_allowed, off_mems);
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@ -2152,7 +2082,7 @@ retry:
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*/
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if ((sane && nodes_empty(cs->mems_allowed)) ||
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(!nodes_empty(off_mems) && !nodes_empty(cs->mems_allowed)))
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update_tasks_nodemask(cs, NULL);
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update_tasks_nodemask(cs);
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is_empty = cpumask_empty(cs->cpus_allowed) ||
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nodes_empty(cs->mems_allowed);
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@ -2214,7 +2144,7 @@ static void cpuset_hotplug_workfn(struct work_struct *work)
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mutex_lock(&callback_mutex);
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top_cpuset.mems_allowed = new_mems;
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mutex_unlock(&callback_mutex);
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update_tasks_nodemask(&top_cpuset, NULL);
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update_tasks_nodemask(&top_cpuset);
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}
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mutex_unlock(&cpuset_mutex);
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